NL8101534A - DEVICE FOR CALIBRATING METERS. - Google Patents

Description

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Title: Device for calibrating meters.

The invention in its preferred embodiment relates to calibration devices for testing the accuracy of fluid and in particular gas meters.

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In the prior art, U.S. Patent 5,185,319 is an early example of the use of a bell-jar calibrator comprising a bell-shaped container or bell-jar rectilinearly in and out of a container filled with a liquid, such as oil, or boiler is moved. Typically, a pulley mechanism is used, with a pulley located above the bell and a string hanging about the pulley with one end attached to the bell and the other end to a set of weights. A conduit is provided from the bell to the meter to be tested, when, when the bell is pulled upward, a fluid, for example gas, is drawn through the meter and into the bell. A valve is placed in the conduit for preventing, in its closed position, the flow of fluid from the meter into the space defined by the bell and its kettle, thus preventing the movement of the bell and the pulley suspended therefrom weights are prevented. When the valve is opened, the fluid flows into the bell, allowing the weights to exert their force on the bell to thereby lift it. When the weights are released, the cord and thus the bell jar is pulled upward to thereby generate a vacuum in the bell jar, the oil providing a seal to prevent air from otherwise leaking into the bell jar.

In order to determine the amount of fluid drawn by the meter, early practice sought to control the amount of movement of the bell, to correlate this movement with a certain amount of fluid that would be drawn by the meter, and the known , comparing the amount of fluid drawn by the meter and into the calibrator with the fluid as measured by the meter, usually indicated by the scale carrier positions of the meter. Conventional methods required physical measurements of the bell jar (bell band binding), which are inconvenient and susceptible to a number of possible BADpR) GINALp geoopen by averaging the irregular geometrical diameters and the wall thicknesses of the bell jar. eye interpo-. - 1 - 2 - '»! ƒ learn from the scale markers. The quoted accuracy of these common methods is about 0.3 $ at best. Thus, it is understood that such a bell-jar calibrator, which has the calibration standard for fluid meters, inherently lacked a high degree of accuracy, due to the errors introduced by (1) the initial and initial observations. end points of the bell jar movement, (2) the indications of the indications by the meter scale carrier of the first and the final volume and (3) the inherent inaccuracy of determining the bell jar volume. The major cause of errors in this technique was due to the difficulty of accurately measuring and determining the volume of the bell. The bell jar itself was formed with the greatest possible precision, however, changes in its diameter and therefore circumference inherently occurred. Taking many measurements of the circumference by the bell-band tapes was the best method devised at the time to obtain the average circumference of the bell-jar and from that the volume of the cylindrical part of the bell-jar.

The use of the bell jar calibrator has continued for many years, improvements being made mainly in the nature of determining the bell jar movement and determining the volume of fluid passing through the meter.

One of the earliest examples of an automatic calibrating system is found in U.S. Pat. No. 3,050,910, which discloses a bell, provided with optical pickups for sensing the movement of its bell as it moves upward through its motor 25 is being fed. A conduit extends from the bell to the meter, which conduit includes a first solenoid-operated valve for controlling fluid flow from the meter to the bell, as well as a second solenoid-actuated valve coupled to the conduit for allowing the fluid to drain from the bell when it returns to its bottom position.

During operation, the initially air-filled bell is lowered into its holder with a tendency to push air through the meter. A scale carrier pointer on the meter register and known as the "calibrator pointer" is sensed through a key-start optical pickup, opening the ΒΑΒ £ Θ ¥ Α6ΙΝΉρ while keeping the second valve closed to allow fluid flow from the bell jar by the meter possible - 3 -

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-% r '> Q — a. An automatic airtightness test has been "described in which both the first inlet and the second drain valve are closed, whereby, when pressure is built up, tests are made for leaks in the system and its valves are measured by measuring the pressure in the bell jar. -5 brought pressure.

Furthermore, U.S. Pat. No. 2,987,911 proposes a calibration system in which first and second temperature sensors are provided at the meter and calibrator outlets, respectively, calculating the temperature difference to develop a temperature equalization factor Tc, which is used to make a correction in the calculated volume.

. As suggested by U.S. Patent 3,933,027, attempts have been made to improve the bell-jar calibration system by automating its operation. This patent 15 proposes the placement of a series of viewing flags with respect to its bell, an optical encoder detecting the movement of these flags to provide indications of corresponding air volumes, as sucked by the meter coupled to the bell of the calibrator . Furthermore, a second optical encoder 20 is coupled to the meter's scale carrier to provide an output as a series of pulses indicative of the volume flowing through the meter. At the beginning of the meter test, a gate is brought into operation by the first optical encoder to initiate a count or time setting procedure, applying a clock signal to a bell clock counter and a meter clock counter.

The gate, which transmits the clock signals to the bell counter, is pressed shut upon reaching a certain count, corresponding to the known amount of fluid as sucked by the meter. When a similar amount of fluid has been measured by the meter, as indicated by the second optical encoder, a signal thereof is applied to a gate to terminate the clocking of the meter signals. At the end, first and second counts are accumulated in the bell clock and meter clock counters, the ratio of which can be easily calculated and displayed on an appropriate digital display. This ratio is considered to be the meter regis-BAD ÖWÖJéJAb, i.e. the ratio of the actual or calibrated fluid volume that has passed through the meter to that measured by the

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United States Patent 3,937,0U8 provides a similar teaching to United States Patent 3,933,027 and discloses an automatic bell-jar calibrator, further comprising means for sensing the series of pulses produced by the meter during a cycle of its operation. The volume actually passed through the meter is measured by an encoder, which produces a series of pulses, indicative of the rectilinear movement of the bell and thus the volume moved in or out of the bell during a test. The encoder provides a series of pulses, indicative of the volume moved by the bell, which encoder pulses are accumulated during a given number of cycles of the volume calibration operation with a known fluid volume displaced by the dome.

US patent 3,877,287 proposes a considerably different construction, in which instead of the bell-shaped holder, a cylinder is used to receive a piston, which is driven through the cylinder at a controlled speed by a motor, which is driven by a transport screw is rotatably coupled to the piston for driving it through the cylinder when the engine is running. As a result, the piston with a. constant speed driven through the tube or cylinder with a precision bore for expelling fluid from the cylinder and through the meter to be tested. This US patent proposes two ways of measuring the fluid flow rate, the first of which involves mounting a series of holes in a piston rod connecting the piston and the conveyor screw and sensing the movement of the holes along a photo detector. A second method uses an optical encoder coupled to the drive motor to provide a series of output pulses indicative of the piston displacement and thus the actual fluid volume displaced from the cylinder.

U.S. Pat. No. 3,631,709 also discloses a gauge calibrator which includes a piston and cylinder mechanism in which the piston is driven via a conveyor screw by a program-controlled motor. When in operation, the motor drives the piston through the cylinder via the screw conveyor, whereby a known volume of fluid (water) is passed through a series in series - 5 -

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placed meters are sucked. The engine control program causes the piston to move at different speeds, with corresponding fluid flow rates being established by the single-stroke gauges of the piston through the cylinder. A magnet is coupled to a shaft which connects the transport screw and the piston for mounting. Serve as a reed switch when the piston is pulled through the cylinder to start counting pulses obtained from a motor-coupled first or main pulse generator 5 The output of the main pulse generator is a series of pulses, and is applied to a register for providing an indication of the actual flow through the meters. Also, optical encoders are coupled to each of the meters to provide pulse signals to a second set of registers, where the measured fluid flow values measured by the meters can be accumulated and displayed. The standard or actual flow volume is determined as a predetermined number of counts from the first or main pulse generator to which the output of the individual meters is compared. The program control of the motor allows acceleration of the motor and its piston to a steady state before the start of measurement of the fluid flow through the meter to settle temporary phenomena in the fluid.

As indicated above, the prior art has automated the method of meter testing by automatically starting and ending counting pulses from a first encoder indicative of the standard fluid volume drawn by the meter, as well as counting pulses from a second encoder indicative of the fluid volume measured by the meter being tested.

However, the prior art has not addressed the problem of improving the ground accuracy of the calibrator. At this point in the development of the prior art, calibrators, especially those with a bell jar, are only able to achieve an accuracy of + 0.2 # under optimal conditions. It is thus clear that the fluid meters calibrated or tested with these calibrators cannot themselves achieve greater narrow-BAD QR16 .mid. One of the main reasons for the lack of ultimate precision in existing calibrators ι \ yjr. The lack of precision methods and devices for measuring with great accuracy the volume displaced in the bell or cylinder as disclosed by the patents discussed above.

It is the object of the present invention to provide a method and apparatus for measuring the volume of the test chamber of the calibrator with one part accuracy in 10 µm. If the volume can be obtained with such accuracy, it is necessary, as taught by this invention, to ensure that the structure containing the chamber is rigid and not deformable. In the past, the bell-shaped enclosures have not provided such a rigid construction, so that if they were accidentally nudged, the internal volume can be changed to an extent to affect the accuracy of the bell-calibrator readings. As will be described, the present invention selects a technique for measuring the displacement volume in the chamber of the calibrator by generating electromagnetic waves and determining the frequency, establishing resonance at first and second positions of a piston to be driven through the house. Choosing this method of measuring the volume of the container, as taught by this invention, requires the use of a housing having a substantially perfectly correct circular cylinder configuration so that the frequencies at which resonance is established, can be sharply determined to thereby determine the displacement volume in the rigid cylinder. Furthermore, in the development of the invention to be described, it became clear that when the volume of the calibrator was determined with great accuracy, it was necessary to use other parameters, such as the indication of the meter record or of the fluid volume, as drawn by the meter, which is tested, to be determined with a similar accuracy. In this connection, the invention aims at methods and devices for measuring the temperature and the pressure of the fluid in the meter and in the calibrator with a high degree of accuracy, so that a correction factor can be determined with a similar degree of accuracy in order to correct for fluctuations in these parameters, which are present in the meter, which BAtfcöRIQJMAI etches, and in the present calibrator. Such a technique is in contrast to the prior art, in which - 7 -

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A calibrator was placed in an environmentally conditioned room with limited fluctuations in the temperature and pressure of that room. However, as the precision with which the variables are to be measured approaches 10 ^ as achieved by the present invention for measuring the displacement volume of the calibrator, it becomes necessary to note that these parameters of the pressure and temperature are the calibrator and in the fluid flow meter during its testing nevertheless fluctuate, so that new methods and devices for measuring the pressure and temperature must be provided to ensure. of the desired precision. For example, if there is an error of 5/9 ° C in the fluid temperature measurement, the result may be an error of $ 0.2 in the displacement volume indicated by the calibrator. It is contemplated that the present calibrator system is capable of achieving an indication of the volume drawn by the meter being tested to an accuracy of 0.004%. With such accuracy, studies can then be conducted to determine the effects of other factors on fluid flow measurement. For example, the number of times that tests are performed on a particular meter will affect the meter reading measured. Furthermore, it is anticipated that the fluctuation in the velocity of the fluid flow, as well as the volume of the fluid flow through the meter, the indicated measured volume through the meter, as well as its meter registration, with respect to its standard volume, as measured by a calibrator will affect.

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In accordance with the invention, an apparatus and a method for calibrating a meter calibrator comprising a chamber, which in one embodiment is in the form of a substantially perfectly straight circular cylinder, further from a piston, which is rectilinear can move from a first position to a second position in the chamber, and from an encoder-shaped indicator coupled to the piston to provide a high resolution signal in the embodiment of a sequence impulses The chamber is coupled to a flow meter, which is tested 10. During calibration, the piston is moved to a first position and electromagnetic energy is generated in the volume, determined by the chamber and the piston, with the frequency of the electromagnetic energy field is changed to establish a state of a standing resonance wave in the determined voltime in the first piston position. The electromagnetic field is generated to be in a conventional state selected so that the electrical and magnetic component fields in its resonance state in the chamber are related to the dimensions of the chamber. Then, the piston is moved from its first to its second position accumulating or counting the output of the high resolution encoder. In the second piston position, the frequency of the electromagnetic energy is changed again to establish a resonance state of a standing wave in the housing, and the second frequency, at which this resonance wave state is established. Based on the determination of the first and second frequencies associated with establishing standing wave resonance states at the first and second piston positions, the volumes determined by the housing and by the first and second positions of the piston, determining the difference in volume or displacement volume. The displacement volume, which has been determined with great accuracy, is compared to the encoder output to determine the incremental fluid volume, as drawn by the piston for an incremental unit of the signal, for example a pulse of the sequence.

35 In particular, the diameters of the cross-sections of the first and second positions are first determined, and on the basis of these first and second diameters the volumes at these positions are calculated. Rt A Λ Λ Γ Τ # Τ '9 · Τ'

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^ «W * and the difference between them" is determined. Then, the displacement volume divided by the counted number of output pulses to provide a factor indicative of the incremental volume drawn by the piston per unit or pulse output of are 5 encoder.

According to a further feature, the electromagnetic energy applied to generate the standing wave state in the house is established in first and second states, chosen to reduce disturbances due to the nature, shape and nature of the wave. inner surface of the house. For example, the first and second states can be the states of generating electromagnetic energy.

According to the invention, a device and a method for measuring the volume of the calibration device, comprising a chamber, which for example has the shape of a substantially perfectly straight circular cylinder, and a piston, have also been described. , which can move rectilinearly in the cylinder between a first position and a second position. The volume measuring device includes an antenna mounted in the chamber and a coupled generator for applying electromagnetic energy to the antenna, thereby radiating electromagnetic waves into the chamber. A detector is coupled to the antenna for sensing electromagnetic energy, reflected from the chamber, and in turn coupled to a resonance detector in the form of a cathode ray tube, whereby a minimum of the electromagnetic energy level can be are determined. Furthermore, a frequency detector in the form of a counter is connected to the output of the generator for sensing the frequencies of the generator output at which the minimum level occurs, as observed on a display, corresponding to the creation of a 30 standing resonance wave in the chamber of the calibrator. The frequency or frequencies at which the standing resonance waves are produced in the chamber in turn determine the volume of the chamber of the calibrator. The electromagnetic field or electromagnetic fields are generated in the chamber with a state selected such that the electric and magnetic component sheet-BAD ^ RMSfWAlLet electromagnetic field in a resonant state in the chamber have a certain relation to the dimensions of the chamber with aj A jr · mf

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The invention is further elucidated with reference to the drawing, in which: Fig. 1 is a view of a calibration device for meters in accordance with the present teaching; Figures 2A and B are detailed views, partly in section of the calibration device more generally shown in Figure 1; FIG. 2C shows the construction of the housing of the calibrator shown in FIGS. 1 and 2A, and a control desk, wherein the operator can control and sense the data output of the calibrator. Figure 2D shows the spring return panel of the system control and status unit, as shown in Figure 2C; FIG. 3 is a functional block diagram of the arrangement of the computer system used to detect the various variables of the calibration device system and control the movement of the piston through the cylinder of the calibration device as shown in FIG. 1 and 2A, as well as providing an accurate indication of the meter record of the 20 meters tested; FIG. UA - E show the various signal conditioning and coupling circuits needed to provide signals in and out of the computer system as shown in FIG. 3; Figures 1 + F is a spatial view of the meter and the manner in which a proximity detector is arranged with respect to its encoding mechanism; Fig. - M show detailed diagrams of the signal conditioning and coupling circuits, generally shown in Fig. UA-E; Fig. 5 shows a high level diagram of the program as executed by the computer system of Fig. 3; Figures 6a and 6B show in a more detailed schematic the mode of operation brought about by the computer system of Figure 3; FIG. T shows in more detail the steps necessary for calibrating the inputs as applied to the signal conditioning and head BAD for the measurements of the temperature and pressure measurements on the computer system, as shown in FIG. 3,

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L ''> - 12 - fig. 8A - 8P show in detail the flow chart for reading out data stored in the computer system and entering the conditions under which the calibration device tests a certain meter (the letters I and 0 do not become clear for the sake of clarity 5 used); 9A-9Q show the steps accomplished by the computer system of FIG. 3 to perform the various tasks and provide manifestations thereof (for the sake of clarity, the letters I and 0 are not used); Fig. 10 is a schematic diagram of a circuit for applying a high-frequency signal to the microwave antenna in the cylinder of the calibrator, as shown in Figs. 1 and 2A for changing the signal frequency, as applied to the antenna wherein the volume of the cylinder can be determined with great accuracy to thereby accurately encode the output of the linear encoder of the calibrator; 11A-E show in various ways the input signals applied to and the output signal, as developed by the signal conditioning and logic circuits 170a and 170b, as shown generally in FIG. Uc and more in especially in fig. 1 + K; Figures 12A and B show respectively a spatial view of a cover to be placed on the piston as shown in Figures 1 and 2A, and a cross section of the spring-shaped closure disposed about the circumference of the piston cover; Fig. 13 is a graph illustrating the address of a chamber of a straight circular cylinder embodiment, which is energized with high-frequency electromagnetic fields with respect to the variable dimensions of the cavity and the frequencies of the excitation; and FIG. 1U is a vibrating cavity aces curve that represents the reflected energy Pr as a function of the excitation frequency.

Referring now to the drawing, and in particular to Figures 1 and 2A, the present calibrator system 10 is shown as coupled to a meter 38 to be tested.

The calibration device system 10 includes a cylinder 12 through which the BA BLÖktëHNAfen piston is driven rectilinearly by a programmable speed controllable motor 20, such as a servo motor.

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The cylinder 12 is carried in an upright position by a number of supports j6 (only two of which are shown) secured to a collar 77 which in turn is secured around the exterior of the cylinder 12. The "upper end of the cylinder 12 is closed by a head 86, from which a number of supports 88 (only one of which is shown) extend upwards. A carrier plate 94 is "attached to the" upper end of the supports 88 and the servomotor 20 is mounted "on top of plate 94. The top end of a transport screw 18 is rotatably mounted in the plate 94 by means of a leger 98, and is drivably connected to the drive shaft of the servo motor 20 by a coupling 100. A transport nut 22 is attached in a housing 23 is screwably mounted on the screw conveyor 18.

The screw conveyor 18 is telescopic in a sleeve 17, the top end of which is secured to the housing 23. The bottom end of the sleeve 15 extends through and is slidably received in a hub sleeve 96 in the head 86. The top end of a piston shaft 16 is secured to the lower end of the sleeve 17

An intermediate cylinder head 91 separates the upper part of the interior of the cylinder 12 from the lower part, which contains the piston 14. The piston shaft 16 protrudes outwardly and is slidably received in a hub sleeve 93 in the head 91, the lower end of the shaft 16 being connected to the piston 14.

Thus, when the servo motor 20 rotates, the transport screw 18 rotates in the nut 22, forcing the housing 23, the sleeve 17 and the shaft 16 to move vertically in one direction depending on the direction of rotation of the servo motor.

The bottom of the cylinder 12 is closed by a head 60, and the cylinder 12 therefore encloses and defines between the piston 14 and the head 60 a volume-controllable chamber 28. An opening 62 in the head 60 places the chamber 28 in communication with a conduit 30, a conduit 32, and a gauge 38. A first inlet valve, 34 is disposed between the cylinder 12 and the gauge 38 for controlling fluid flow, for example, a gas, therebetween. A second outlet valve 36 is connected to conduit 30 to allow fluid to drain from cylinder 12 when valve 36 is open.

BAD ORIGINAL Precise position of the piston drive shaft 16 and therefore the piston 14 is provided by an optical linear precision encoder 26, 4 4 C 7 1 t-U - coupled to the drive shaft 16 for sweeping. More specifically, the encoder 26 illustratively includes first and second sets of light sources and photodetectors arranged on either side of a linear scale 2b, with a plurality of scale markings 102. In one illustrative embodiment, the linear scale 2b is mounted on a fixed with respect to the movable encoder 26, and it contains U0,000 scale markers 102 (2,500 markers per 2.5 cm), of course only a limited number of such a large number of scale markers can be depicted in the drawing. Thus, when the encoder 26 is moved rectilinearly along the length of the linear scale 2b, first and second sets of impulse arrays A and A are developed 90 ° out of phase with each other when the light beams generated by the first and second light sources are the scale marks 102 are intercepted. The outputs 15 A and A of the optical encoder 26 precisely indicate the position of the piston 1U and also the fluid volume as drawn by the meter 3θ. As explained, the volume of the chamber 28 in the cylinder 12 is precisely measured, and each output pulse obtained from the encoder 26 provides an exact indication of an incremental .0 volume as sucked into the chamber 28 in the cylinder 12 when the piston 1b is removed, ie it is guided upwards by the servo motor 20. Before the piston 1U has started to move upwards in order to thus generate a vacuum in the chamber 28, the outlet valve 36 is closed and the meter valve 3 ^ + is opened for allowing fluid flow through meter 38 through line 32, open valve 3 ^ and a pair of lines 30 and 32 into housing 28. During a meter key, meter 38 provides an output sequence through its encoder ^ 0 pulses, indicative of fluid flow therethrough. The series of pulses obtained from the meter encoder Uo is compared with the series of 30 pulses obtained from the linear encoder 26 to provide an indication of the meter accuracy in meter recording, a ratio corresponding to the volume measured by the meter. meter encoder Uo, to the volume measured by the linear encoder 26.

35 Furthermore, the programmed movement of the piston 1U makes BA6rQfiiQH4fl * and a number of proximity sensors 50, 52 and 5 ^, as well as a pair of limit switches b $ and 53. As explained, the servo drives - - 15 -

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In the motor 20, the piston is rectilinear in the housing 28. As shown in Figs. 1 and 2A, the piston 1U is in its upper position, in which a stop 92 on the housing 23-26 contacts the upper limit switch 53 and it closes to thereby disable the servo motor 20 when the piston 1U is driven upward, thereby stopping the movement of the piston 11. When the servo motor 20 drives the piston in a downward direction, as shown in FIG.

1, the stop 92 can engage the lower limit switch U9 to stop the piston again. The top safety switch-10. boot 53 and the lower safety switch h9 are used to prevent physical damage to the calibrator 10 if the servo motor 20 continues to drive the piston 1U to either end by failure. Should the stop 92 engage any of the safety switches h9 or 53, the servo motor 20 would be de-energized and the piston brought to a sudden stop. In a self-volume testing operation, as explained, the proximity detectors 52 and 51 are also used to sense the movement of the piston 1U between prescribed locations. Generally, the servo motor 20 accelerates the piston 1U to 20 a certain speed, and the output of the linear encoder 26 is gated through the output of the proximity detector 52 to allow it to accumulate and count its pulses. The counting of the pulses obtained from the linear encoder 26 is disabled in gate self-test operation by the occurrence of an output from the proximity detector 5, indicating the travel of the stop 92 thereon. Thereafter, the servomotor 20 is decelerated to a stop. On the other hand, in the meter test operation, the piston 1U is driven upward by the servo motor 20, and as the stop 92 moves past the proximity detector 52, it generates an opening signal, with the occurrence of the following or leading edge of the next output pulse from the meter encoder 40, the counting of the output pulse and the linear encoder can then begin. In the meter test operation, counting of the linear encoder pulses 35 is terminated when the counting of the meter encoder pulses has reached a predetermined count corresponding to a fluid volume drawn by the meter.

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To facilitate an understanding of the invention, a brief summary of its operation is now given, providing a more detailed discussion of the operation of the calibrator 10 below. A first or actuation state determines whether the piston 1U is in its parking position, for example, by determining whether the proximity detector 50 detects the presence of the stopper 92, as set forth above, if not, the servo motor 20 is actuated to drive piston 11 to its parking position. If stop 92 is in a position to be sensed or before piston 14 is returned to its parking position, second or exhaust valve 36 is opened to allowing the outlet of fluid, driven out of the chamber 28, through the conduit 30, then the inlet valve 3 3 is closed to prevent fluid from passing through it and possibly damaging the meter 38. On a command of the operator to test a gauge 38, the first meter valve 3 ^ is opened and then the second valve 36 is closed to allow the flow dump flow through the meter 38, line 32, open valve 325 and line 30 into chamber 28 when piston 1U is driven upward by servo motor 20. Piston 1U is gradually accelerated to a predetermined constant rate and maintained at that selected rate during the fluid volume test measurement, the output pulses of encoders 26 and 40 being accumulated by a calculator containing registers for accumulating counts, respectively indicative of a precise volume, such as measured by the linear encoder 26, and for the volume, as measured by the meter 38. The meter key is actuated by the passage of the piston 1U along the proximity detector 52 of the start key, which detector occurs upon the occurrence of the meter. of the next output pulse or more precisely, the leading edge of the meter encoder allows the counting or accumulation of the meter encoder pulses, as well as the linear encoder pulses. Depending on the desired volume to be sucked by the meter 38 being tested, the meter key ends at counting a number of meter encoder pulses. In particular, BAO-SFBALSALI register for accumulating the meter encoders pulses 38 when counting the predetermined number in dependence. . ! - rr - volume volume, an output which is applied to the linear encoder system to terminate its counting of the input simpulses from the meter encoder UO. The stored counts indicative of volume volume as measured by the meter-5 encoder Uo and the linear encoder 26 are compared, i.e. a ratio is obtained therebetween to provide an indication of the meter record.

In addition, measurements of the temperature and pressure are performed so that the measured volumes can be adjusted for these conditions. In particular, a temperature measuring device h2 and UU are provided at the inlet and outlet ports of the meter 38, respectively.

A differential pressure transducer U6 is provided to measure the difference between the pressure created in the conduit 32 by the fluid and the ambient pressure. In addition, a temperature measuring device 15 M em 57 is respectively provided at the conduit 30, coupled to the chamber 28, and to the piston 1H to provide indications of the temperature of the fluid in the chamber 28. In addition, a second differential pressure transducer 51 is provided in the piston 1U to provide an indication of the pressure difference between the ambient pressure and that established in the chamber 28. The temperature outputs TM3 and TM1, respectively, are obtained from the temperature measuring devices k2 and are averaged to provide a mean with there temperature AMT, wherein the outputs TP1 and TP2 of the temperature measuring means 57 and i + 8 are averaged respectively to provide an indication of the mean calibrator temperature APT. As detailed below, these input parameters are used to provide an adjustment of the measured volumes obtained from the encoders 26 and 0 depending on the measured conditions of pressure and temperature.

As shown in Fig. 2A, a microwave antenna 70 is mounted in the head 60 for generating microwaves in the chamber 28, whereby its volume can be accurately determined. This measurement is intended to be performed intermittently to detect even the smallest changes in the volume of the chamber 28. As explained *, the technique of establishing electromagnetic tracking in the microwave range makes a accuracy may -BAl ^ £) ^ 5JQ $ (at least one part in 10 ^ of the volume of the chamber 28. In order to Λ 4 A Λ PT ί mv ['*> V. 1' -iad accuracy of the temperature sensors b8 and 57 In addition, a temperature measuring device 68 is also provided in the conduit 30. As explained in detail below, the pressure and temperature measurements in the meter 38 and in the calibration device 10 are used to calculate a factor by which the volume as drawn into the calibration device 10 is adjusted for these variables In particular, the temperature transducers U8 and 57 measure the temperature at the bottom and top portions of the chamber 28 for obtaining a spatial average measurement 10. of the temperature over the Whole volume in the chamber 28 of the calibrator 10. Similarly, the temperature transducers b2 and kb provide indications of the temperatures of the gas at the inlet and the outlet of the meter 38, whereby a spatial average of the temperature of the gas flowing through the meter 38 can be obtained. The temperature transducers, as optionally included in the calibrator 10, are very stable platinum resistance thermometers with a low thermal mass, and provide accurate readings of these variables, whereby the volume as sucked into the calibrator 10 can be accurately determined.

As shown in Figs. 2A and B, the proximity members 50, 52 and 5b, as well as the limit switches 9 and 53, are carried by the upright part 90, which in turn is carried by one of the upright supports 88. One end of the linear shell 2U is carried by the portion 91 and extends downwardly substantially parallel to the direction of movement of the piston 14, its lower end being carried by an upper portion of the interior of the cylinder 12. Only a limited number of the approximately U0,000 marks 102 are shown in Figure 2A. In the lower portion of Fig. 2A, the inlet valve 31 and the outlet valve 36 are operated from the open to the closed positions by pneumatic actuators 66 and 6b, respectively.

Fig. 2A shows a sealing means, generally indicated at 78 for the piston 14 to prevent the fluid, as sucked through the meter 38 and into the chamber 28, from leaking along the edges of the piston 1¼. when it is straight in the cylinder 12

The details of this piston closure 78 are described in a copending U.S. patent application in the name of the applicant.

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Referring now to Figure 2C, the calibration device 10 is shown, as arranged in a controlled environment, formed by an enclosure .10U, which includes a space 106 for receiving the calibration device 10, and a control space 105, in which the control console is placed, which contains a display unit 111, which contains a printer, as well as a number of lights for indicating the different states of the calibrator, a CRT terminal 112, which contains a keyboard, whereby various commands by the operator can be imported, and a variety of heat generating equipment, 10. provided with energy sources, an engine control, amplifiers, etc. The control of the ambient conditions around the calibration device 10 is ensured by placing the calibration device 10 in the space 106 at a distance from the heat generating display unit 111 and the terminal 112. As shown in Fig. 2C, the signal to be 15 meter 38 keys are also placed in the calibration device space 106 and coupled to the calibration device 10 through line 32. The temperature in the calibration device space 106 Is measured by the four temperature sensitive members R0, R1, R2 and R3, which are arranged in space 106 and to a bracket 76 of the calibration device 10. A barometric pressure transducer 109 and a barometer are also mounted in the chamber 106 for measuring the ambient pressure. Electrical connections are made to the various temperature gauges, as shown in Fig. 2C, as well as the temperature and pressure gauges, as shown in Figs. 1 and 2A, 25 en and are conducted through a pair of troughs 110 to the control desk arranged in the control room 105. In this manner, the environmental conditions under which the meter 38 to be tested and the calibration device 10 operate can be accurately controlled to ensure the integrity of the measurements taken on the meter 38 and the calibration device 10. .

Referring now to FIG. 3, there is shown a functional block diagram of the computer apparatus of the computer system for performing the various operations, such as processing the temperature and pressure measurements of the linear encoder and meter encoder output signals, and Proper closing of the bath tali valves. In addition, outputs are provided to the CRT terminal 112 to indicate the measured parameters, as well as to the system 0 4 Λ 4 CT /

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Control and display unit 111 for displaying the different operating states of the calibrator system 10 ', wherein the operator can enter meter key operations selected by the keypad of the CRT terminal 112. The computer system contains a central.

5 certification unit (CPU) 1.20, from which 128 address signals are applied via an address collection line to a programmable dead memory (PROM) 12U 'and to a freely accessible memory (RAM) 126. A system clock 122 supplies system clock signals (for example 200 kHz) to the CPU 120. As shown in Fig. 3, the clock 122, the CPU 120, the PROM 12U and the RAM 126 are interconnected by a command data collector 1U0 (i / D), which may be illustratively in the form of a manifold with fourteen lines, which not only connects the aforementioned elements, but is also connected to each of the signal conditioning and coupling circuits 130, 132, 13U, 136 and 138.

The circuit 130 conditions and couples the signals indicative of the temperature signals TP1 and TP2 of the calibrator as obtained from the temperature measuring means 57 and U8, respectively. Furthermore, the meter temperature signals TM3 and TMU, as obtained from the members k2 and 1 + U, are also applied to the circuit 130. As shown in Fig. 2C, four additional room temperature sensors R0, R1, R2 and R3 are distributed in the space 106, in which the calibrator system 10, as shown in Figs. 1 and 2A, is arranged, in which connection it is clear that the environmental conditions around the calibrator system 10 are well controlled so as to adjust the ambient temperature of the calibrator system 10 so that stable as possible. It is common practice to store the meters 38 to be tested in this environment for some time so that they can achieve the same environmental conditions under which the calibrator system 10 is located. As shown in FIG. 3, the temperature signals are applied to a signal conditioning and logic circuit 150 and thence through a coupling circuit 151 to the 1 / D manifold 1U0.

Similarly, the pressure signals are applied to the conditioning and coupling circuit 132, which includes a signal conditioning and logic circuit 162 and a coupling circuit 16h. In particular the differential pressure measuring device 51, which outputs indicate the differential pressure PP1 of the calibration device 10, and of the pressure -21-

. . I

"- 4. -" J

Differential means 1 + 6, which outputs indicate the meter pressure MP2, and of the barometric pressure meter 109, the outputs of which indicate the data or atmospheric pressure PB of the space 106, are applied to the circuit 132.

The output of the meter encoder 1 + 0 and the linear optical encoder 26 are applied to the signal conditioning and coupling circuit 131 +. In particular, the output of the meter encoder Uo is applied to a signal conditioning and logic circuit 170a, the outputs of which are in turn applied to coupling circuits 171 and 173.

10. A clock circuit 175 applies a signal to the coupling circuit 173. In another embodiment, a proximity detector 27 is used to sense the rotation of the meter encoder 1 * 0 and the output of the proximity detector 27 is applied to the signal conditioning and logic circuit. 17'0a. This is shown in FIG. 3 by the input signals, referred to as rotary encoder pulses and meter key proximity detector, it being understood that only one of these inputs is fed to circuit 170a at a time. The output of the linear optical encoder 26 is applied to the i / D header 11 * 0 through the signal conditioning and logic circuit 170b and the coupling circuit 179.

20 In order to provide an indication of the measured parameters, such as the temperature, the pressure, as well as the fluid volumes, drawn in by the calibrator 10 and as measured by the meter 38, outputs of the I / D manifold 11 * 0 are supplied via the circuit 136 to display unit 111, which includes a hard print data printer.

In particular, circuit 136 includes a coupling circuit 192a for applying parameter output signals to the hard-print printer via a signal conditioning and logic circuit 190a. Furthermore, the circuit 136 includes a coupling circuit 192b, which provides the parameter output signals via a signal conditioning and logic circuit 190b to the CRT data terminal 112. In addition, command signals from the operator are input to the terminal keyboard via the terminal. logic circuit 190b and the coupling circuit 192b transferred to the I / D manifold 11 * 0. A clock circuit 193 controls the baud rate at which signals can be transferred between the CRT data terminal 112 and the computer system. The CRT 35 data terminal 112 may be in the form of a CRT display, which makes BA $ t $ ftfeï $ ^ £. And m ° of commands from the alphanumeric keys on its keyboard, as well as displaying the entered exercises

0 1 Π 1 5 'ζ A

ι '1. J - 22 - and the parametric data made accessible by the operator.

Finally, a signal conditioning and coupling circuit 138 is shown for interconnecting the I / D manifold 10U and the inlet valve 31 and the outlet valve 36, as well as for applying the control signals to the servo motor 20. Furthermore, the servo motor 20 is associated with a motor control, wherein feedback signals indicative of the speed of the servo motor 20 are applied through the logic circuit 19 to in turn influence the control of the servo motor 20. Furthermore, signals which indicating the state of the ser-10 motor 20, as well as an input signal from a switch for testing to indicate whether the rotary encoder Uo or the proximity detector 27 is to be used for measuring the meter flow, via the logic circuit 198 and the coupling circuit 200 inputted to the I / D manifold 1 ^ 0.

The signal conditioning and coupling circuit 130 is shown in more detail in FIG. Hk and includes two line inputs from each of the temperature transducers 57, 8, k2 and U4, indicative of the temperatures TP1 and TP2 of the calibrator and meter temperatures TM3 and TM, respectively. and is connected to a multiplexer 1U9. In addition, the four temperature transducers R0, R1, R2, and R3 are arranged distributed in space 106 of the calibrator, in which the calibrator system 10 is disposed, through the following four inputs to the multiplexer IU9.

The aforementioned temperature transducers are connected in amplifier 25 modules, which serve to develop voltage outputs proportional to the sensed temperature, and to apply these outputs to the corresponding inputs of the multiplexer 1 ^ 9.

In this manner, each temperature transducer is associated with its own amplifier module, so that its output to the multiplexer 1U9 30 can be adjusted to ensure a substantially regular output in terms of voltage amplitude and shift for each of the temperature transducers connected to the multiplexer 1U9 . The details of the amplifier modules for each of the transducers shown in Fig. Hk are explained below with reference to Fig. Hl 35 together with a detailed description of the signal conditioning BAftQBlgm circuit 150, as shown generally in Fig. Ua.

The multiplexer 1 ^ 9 is for time multiplexing the - 23 -

. I

-4 inputs to each of its eight inputs and scaling the temperature signal outputs so as to superimpose them one by one through an multiplexer 15U to an amplifier 152. The second multiplexer 15U is usually set for applying one of the eight temperature input signals through the processing amplifier 152 to the analog-digital (A / D) converter circuit 158. During calibration, the multiplexer 15¾ "is operated to apply a calibrating precision voltage to the A / D converter 158. As is well known in the art, the DC voltage of the analog signals is set at a level that can be easily accepted by the A / D orn converter 158, which in turn converts these analog signals to digital outputs, which are applied through its twelve output lines to a parallel input output (PI / 0) member 160. The Pl / O circuit 160 allows input commands to be transferred via the U / Γ bus 1U0 inputs 15 to the multiplexer 1U9 to control which of the inputs is to be sampled at a given time, as well as to the logic circuit 156 to allow the multiplexer 15¾ to output one of the multiplexer 1/9 or the voltage calibration input signal to the A / D converter chain T58. During operation, the CPU 120 places a call signal through the I / D bus 1U0 to the keten / 0 circuit 160, which responds thereto by enabling the reading of a call for information and converting it into digital data to be placed on the I / D manifold 1 ^ 0. In addition, an order is obtained from the PI / O-25 circuit 160 for timing the conversion of the analog signals to digital signals by the A / D converter circuit 158, and a signal indicative of the state of the A / D converter chain is applied through the Pl / 0 chain 160 to the I / D manifold 1U0. The voltage calibration signal allows to set the zero and magnitude of the interval of the computational amplifier 152, so that the full amplitude of each input signal can appear on the A / D-amz pus circuit 158.

The conditioning and coupling circuit 132 is shown more fully with respect to Figure UB, showing that the outputs of transducers 51 and b6, respectively, indicate the calibration

igri. ^ jt ^ gs or piston pressure PP1 and the meter pressure MF2, via calculation amplifiers 161a and 161b, are applied to a mulliplexer 163. Furthermore, Λ 4 Λ 4 C TA

- 2h - m * ♦ f | 1 X ^.

the output of the pressure transducer 109 for measuring the barometric or ambient pressure of the space 106 of the calibrator through a computing amplifier 161c applied to the multiplexer 163. Initially, the CPU 120 sends a command to the multiplexer 163 to choose which output of the pressure transducers 51, U6 or 109 is to be read via the I / D manifold 140 and the parallel input output (Ρΐ / θ3-circuit 168. In response to this, the P1 / 0-circuit 168 applies via the bus 169 with four lines of control signals at 0.

Multiplexer 163 for selecting one of the three pressure indication signals or a signal indicative of the voltage calibration input signal to be applied to an A / D converter 166 which converts the analog input signal to a corresponding digit. Language signal, which must be applied to the PI / 0 circuit 168 to be transmitted further through the 1 / D manifold 1 ^ 0. At the request of the CPCJ 15 120, the ΡΙ / 0 circuit 168 then carries, via the line 159, the A / D circuit 166 to convert the selected analog pressure output signal into a corresponding digital signal, which is passed through the I / D bus line 1U0. must be sent. The conversion of the analog input data into digital data requires a separate time period for the 20 A-to-D conversion to take place and, moreover, for the stabilization of the digital data appearing on the twelve data output lines of the A / D circuit 166 before they are read by the Pl / O chain 168.

When signal stabilization has occurred on the twelve data line output of the A / D circuit 166, a state signal on-25 is generated by the A / D circuit 166. In response to the state signal, the P1 / 0 circuit reads 168 the data appearing on the output lines of the A / D circuit 166, and apply these signals through the 1 / D bus 1 Uo to the RAM 126, as shown in FIG. 3. After this operation is complete, the system is able to select another pressure output, as obtained from another transducer, to convert this output to a digital signal to be sent to the RAM 126, as set forth above.

The coupling and conditioning circuit 13 ^ is discussed more fully with respect to Fig. Uc. The rotary meter encoder UO is coupled to the meter 38 to provide first and second BAftiO1s and A, which are mutually 90 degrees out of phase, to the signal conditioning and logic circuit 170a. In particular, the chain edits - 25 -

«V I

. ^ 4. <! 170a the input signals A to A to avoid possible difficulties due to "jitter" of the signals, as may be caused by mechanical vibration on the rotary measuring encoder 40.

The signal conditioning and logic circuit 170a generates a composite pulse signal corresponding to each set of input pulse and of the signals A and A and applies it to an interval clock 17 ^ containing a programmable counter 17ha into which a factor is loaded which depends on the selected fluid volume to be drawn through the meter 38 in a manner to be explained below. Specifically, that factor is placed in the counter 17¾¾ to be programmed, and when counting down to zero from that factor, an impulse is generated by the interval clock 17¾ and applied to a logic circuit 177, the output of which is applied to start a CPU interrupt 2 sub-program, which terminates the testing of the meter 38, as explained in detail below with reference to Fig. 9J. The logic circuit 170a addresses the input signal A from the rotary meter encoder Uo to apply a corresponding, conditioned pulse to an interval clock 176 which performs the operation of detecting the leading edge of the signal A before starting the signal. time setting or counting the counter 17 ^ a to be programmed, as well as the counter 176a and the linear encoder counter 182.

More specifically, the CPU 120 controls the calibrator 10, and detects that the piston 1¾ has accelerated from its parking position to its key start position, as indicated by the presence of an output signal from the proximity detector 52.

Upon sensing the output of the proximity detector 52, the program, as intermittently, for example, approximately every 1 + 0 ^ us, executed by the CPU 120, approaches the interval clock 176 to see if it has received an input signal from the signal conditioner. and logic circuit 170a, indicative of the leading edge of the input signal A of the rotary encoder transducer Uo. Upon sensing the first leading edge of the logic circuit 170a output, after the piston 1¾ has passed the proximity detector 52, a start signal is applied to the keten / 0 circuit 18U, which starts a signal for starting before counting apply counter 182 and also a start signal BAD 1 gldi ng 1 * 0 to the counter 17¾¾ to be programmed. In this manner, each of the counters 17 ^ a, 176a, and 182 becomes operative Λ Λ Π Λ Γ 7 /.

- 26 - t "1>" * is brought to start counting at the same time. In this exemplary embodiment, the tè programming counter 17Ua counts down in response to output signals from the rotary encoder transducer 1 * 0.

According to an important aspect of the invention, starting and ending the meter key, i.e. z. counting by the counter 17Ua to be programmed and the counter 182 executed responsively at the output of the rotary encoder Uo, dd; the accuracy of the meter 38 must be measured. More specifically, the rotary encoder 10 is coupled to the fluid or gas meter 38, as more fully described with reference to Fig. 1 * F, the rotary meter encoder 1 + 0, as coupled thereto, being rotated. rotatably mounted rod produces a series of pulses, corresponding to the rotation of this tangent arm and the cyclic movement of the meter membrane. As shown in Fig. 1 + F, the rotatable member is connected by coupling arms to the membrane of the meter, and its rotation is not rectilinear, so that the encoder 1 + 0 output is modulated in some way in frequency. Therefore, in order to obtain an accurate measurement of the rotary meter encoder 1 + 0, it is desirable to count the pulses as obtained from the encoder 1 + 0 so that the counting begins and ends at about the same point in the rotation of the rotary meter organ. This is accomplished by starting counting in response to the rotary meter encoder 1 + 0. In particular, a meter key 25 is performed by accelerating the piston 1k from its parking position to a constant speed, so that as it passes through the piston of the proximity detector 52, placed in the key start position, an output thereof is provided to enable, as explained below, the detection of the leading edge of the next output signal of the logic circuit 170a, corresponding to the leading edge of the next output signal A of the rotary meter encoder 1 + 0, De interval clock 176 is responsive to the leading edge to effect the simultaneous start of the counting of the counter 17'1 + a to be programmed and the counter 182. At 35, the counting down of the counter to be programmed is effected. BfFCflffifÖINAbaf its chosen factor, depending on the desired volume to be sucked by the meter 38, the interval clock 171+ provides its output

....... ”♦ I

«^ I

.4. 41 ii - 27 - to the logic circuit 177 to open the interrupt-2 of the CPU '120, which in turn ends counting of counters 17a and 182 and transfers the respective counts to corresponding locations in the RAM 126. It should be noted that the counting termination could be performed by a software, but would include an additional number of steps and thus would excessively complicate the programming of this system, as well as add to the time required. to perform the time setting described above. In addition, accomplishing start counting in response to the output of the rotary meter encoder Uo ensures more accurate testing and calibration of the meter 38 being tested.

As explained above, the sequence of output pulses, such as obtained from the rotary encoder U0, is applied to count down the count initially placed in the counter to be programmed. Importantly, the count, as placed in the counter 17a to be programmed, is variable depending on the volume to be drawn through meter 38 and into chamber 28. The count is based on the structural dimensions and properties of the meter 38, as well as the properties of the rotary meter encoder Uo in terms of the number of pulses it generates per revolution. In an illustrative embodiment, a count of U0000 is placed in the counter 17 to be programmed, corresponding to a volume of 0.028 m to be sucked by meter 40. Assuming that the properties of meter 38 and encoder 40 remain the same for variable volumes, illustrative counts of 20,000 and 10,000 can be stored in the counter 17 ^ -a to be programmed, if desired, 0.01U, respectively. and 0.007 m of fluid through the meter 38. By entering a count, based on the properties of the meter 38, into the counter 17 to be programmed, which is counted down by pulses 30 obtained from. the rotary meter encoder ^ 0, more accurate keying of the meter is ensured in that the beginning and end of the meter key are established at the same point in the meter's cycle of rotation and its rotary encoder Uo, as explained above .

As indicated in Fig. Uc, a clock signal A of 120 is obtained and the I / D header 1U0 is applied to the interval clock 176. A selected factor is set in the down

.- · I

- 28 - .....................

counter 176a positioned to provide an output of the interval clock 176 corresponding to a sampling pulse of one pulse per second. In an illustrative embodiment, the clock signal obtained from the clock 122 is of the order of 200 kHz, and the factor placed in the counter 5176a is such that the first one pulse per second is supplied to the logic circuit 178 and 1. hence to the engine control panel. As explained below, this sampling impulse is used for timing sampling of the pressure and temperature measurements.

The output of the linear encoder 26 is further a pair of signals A and A, 90 ° out of phase, which signals are applied to a logic and conditioning circuit 170b. The circuit 170b is similar to the circuit 170a in that it processes the input signals A and A to form and condition these input signals to cancel out "jitter", which could otherwise indicate a faulty output from the linear encoder 26. In addition, the circuit 170b is capable of sensing the direction in which the piston I moves from the input signals A and A, and if the output signals A and A do not indicate that the piston 1U 'moves in the given direction, no signals output from the logic and conditioning circuit 170b. The circuit 17'0b provides a series of conditioned pulses, corresponding to the output of the linear encoder, to the counter 1022, which after starting counts and accumulates the output of the linear encoder 26. The accumulated output of counter 182 is applied to the 25 P1 / 0 circuit 18i) and, after command, is transferred via the I / D manifold 1 ^ 0 to the remaining parts of the computer system.

In one embodiment, the rotary encoder transducer U0 is coupled to the meter 38, and in particular includes an optical encoder, which is rotatably coupled to the arm of the tangent-30 boussole of the household meter 38 to sense the rotation of the arm of the tangent broth as gas flows through the meter to provide a number of output signals A and A, as set forth above. In another embodiment, the proximity detector 27 can be used to sense the mechanical rotation of the tangent broth of the household meter 38 by a mechanism, BAlÊCffi & QIWAl, set forth to provide an output signal to a signal conditioning and logic circuit 170c, which in turn - 29 -

t ^ I

t I γ is connected to the interval clock 176 and to the interval clock 17 ^ · Due to the implementation of the mechanical mechanism coupled to the arm of the tangent broth of the meter 38, the proximity detector 27 produces a signal with less separation then produced by the optical encoder '2.6 when it senses the rotation of the arm of the tangent brim of the meter, the particular advantage of the proximity detector embodiment being that of the relative simplicity of its mechanical and electrical construction. The choice to use the proximity detector 27 or the rotary encoder transducer k10 is made by the operator by switching on a switch I9I as shown in FIG. UK. When the operator determines to use the proximity detector 27, the counter ITT a to be programmed is coded with the numbers 8, U and 2, corresponding to measured volume estimates of 0.028 m, 0.014 m and 0.007 m '. The operator 15 starts entering the appropriate factors for both the proximity detector 27 and the rotary encoder Uo by first switching the switch 191 to the correct position and entering the key volume via the keypad of the CET terminal 112.

In FIG. UF is shown a spatial view of a conventional meter 38 measuring fluid flow using two membranes, one of which is shown as 1202, the flow meter as shown in FIG. UF. is more fully set forth in U.S. Pat. No. 2,5 ^ U,665. As shown, a flag bar 1203 senses bending of the diaphragm 1202 to reciprocate the arm 20k. A second membrane (not shown) and an associated flag bar (not shown) cause the arm 1206 to reciprocate in an alternating cycle. As set forth in the aforementioned U.S. Patent, the assembly of the arms 1206 and 120U, and the arms 1208 and 1210 rotate the arm 1214 of the tangent 30 boussole in the manner described herein. A metal target 1212 at the intersection of the arms 1208 and 1210 is rotated along the proximity detector 27, outputting the logic circuit 170c for processing in the manner described above.

The conditioning and coupling chain 136 is more fully shown BAD where ^ connection is made between the printer 111a, the display unit 111 for printing desired parameters, such as λ. μ n »rt / - 30 -

«V I

t »*« measured by the calibration device 10, which parameters measure the measured flow rate or velocities and the error rate or font percent ages for the tests performed. In particular, the printer 111a is coupled to the X / D header line 1U0 through a first logic circuit 190b and a parallel data controller (PDC) 192b, which provides two-way controlled access between the 1 / D connectors. collection pipe 1 ^ 0 and printer 111a. Thus, upon command by the PDC 192b, a signal is generated by the logic circuit 190b, the printer 111a. is checked and an adjusted acknowledgment signal 10. (ACKO) is transferred via logic circuit 190b and PDC 192b to indicate that printer 11 Ta is available for printing. If the printer 111a is occupied, an appropriate busy signal is returned to the I / D manifold 1 ^ 0. If a command has been issued to print data, the control portion of the signal is sent through PDC 192b and logic circuit 190b to control printer 111a to print those data appearing on the data channel from the logical chain 190b.

Furthermore, the operator can enter appropriate commands on the keyboard of the CRT terminal 112, which is connected to the computer system via the 1 / D manifold 1U0 via the logic circuit 190a and a serial data controller (SDC) 192a. The SDC 192a can record the serial data obtained from the CRT terminal 112 including commands entered by the operator on the terminal of the keyboard. The SDC 192a converts these series signals, input from the logic circuit 190a cm with an adjusted baud rate, set by the clock 193, and transmits a set of digital signals via the I / D bus 1U0 to the CPU 120. In turn data to be displayed on the CRT terminal 112 is sent through the I / D manifold 1U0 through the SDC 192a and through the logic circuit 190a to be displayed on the CRT of the terminal 30.

The signal conditioning and coupling circuit 138 couples, as shown in Fig. Ue, between the 1 / D manifold 1 ^ 0 and the first or inlet valve 3 ^ and the second or outlet valve 36, as well as providing signals to and from the engine control . Speed and direction motor control signals 35 are applied through the I / D controller 1U0 to be received and sent via the PI / 0 circuit 196 to a logic circuit 19 ^ a, these digital - 31 -

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1 * 1 »signals are applied to the motor controller to effect a corresponding operation of the servo motor 20. Similarly, at the appropriate time under the control of the program executed, signals are developed for closing or opening 5 of the valves 3 ^ and 36 by operating their associated solenoids 66 and 6kt, respectively, which valve control signals are applied through the P1 / 0 circuit 196 and logic circuit 19Ub to a pair of pneumatic valves arranged in the control space 105, as shown. see in Figure 2C, wherein a 3 ^ 5 kPa air source is optionally provided to each of the valve solenoids 66 and 6k, respectively, for opening and closing these valves on command. In this manner, the heat generated by the valve solenoids is removed from the temperature controlled chamber 106 for the calibrator. In addition, each of the solenoids 66 and 6b includes a proximity detector to determine whether the valve 15 is open or closed. The output signals developed by the proximity detectors 50, 52 and 51 * for determining approximately the position of the piston 1U 'are applied to the I / D collection line 10U via a logic circuit 19c and the PI / 0 196. A one-second sample clock signal is generated from the encoder panel (as explained above) and is applied to the P1 / 0 circuit 196 via the logic circuit 19 ^ d. Similarly, the operator may operate a switch to determine whether the meter fluid flow is obtained from the proximity detector 27 or from the encoder 26, as shown in Fig. b C, which command signal is applied through the ΡΙ / 0 circuit 196 to the I / D-25: manifold 1U0. In order to achieve proper control over the servo motor 20, the state of the motor in terms of its speed, direction and measured torque is applied to the I / D manifold 1Uo through logic circuit 198b and ΡΙ / 0 circuit 200.

The display unit 111 includes a front panel, as shown in Fig. 2D, and is designed to display a series of lights and backlit push buttons indicating the different states of the system. As shown in Fig. 2D, the display panel includes the printer 111a to provide pressure outputs of the flow rate and percent fluid through meter 38. In addition, a number of lights 111b to 111e are included. The light 111b becomes BAD to indicate that a self-test of the calibrator 10 is in progress as explained. The reserve lamp ** 32 η * τ 1 * * 111e. indicates that energy has been applied to the calibrator 10. and that a start ramp has begun - to place the calibrator 10 in its backup state. In this backup state, a number of keystrokes are required for the operator, and the calibrator 10 after completing the data entry via the keypad of the CRT terminal 112, automatically in the key initiation state, as indicated by the actuation of the light 11 Tc for the key initiation the meter 38 is actually tested in every condition. At the completion 10 of a meter key, the light 11 1d to indicate the completion of the key is energized. At this time, the final percent accuracy is calculated and printed in the printer 11 Ta. with hard prints. In addition, a backlit pushbutton 1T1g for stopping and a backlit pushbutton 15 11 Tf. included for reset. If, during one phase of the distance, the spring start push-button 11Tf is pressed, the calibrator 10 responds as if the energy were initially applied, as explained more fully with reference to Fig. 9E. The stop button 111g is only pressed 20 when an emergency occurs, which may cause damage to the calibration device 10. When the stop button 111g is pressed, the servo motor 20 quickly decelerates to a stop, and the calibration device 10 locked in its standstill state until primary energy has decreased and spring applied.

Upon application of energy, the calibrator 10 returns to the reserve state. During the execution of the program, appropriate signals are generated and applied through the I / D manifold 1 ^ 0, the ΡΤ / 0 circuit 200 and the logic and control circuit 198a to energize the appropriate indicator lights 111b - 111e.

The signal conditioning circuits, as shown in the functional block diagrams of Fig. Kk - are shown in more detail in the diagrams of Fig. Ug - M. The signal conditioning circuit 130, as shown generally in Fig. Hk, is more particularly shown in the diagrams of FIGS. UG, 4h and Ui.

In Fig. BG, the multiplexer 1 ^ -9 is shown as existing B ^ ö relays> equipped with kvik-wetted relay contacts, which reduce spring performance thereby provided, and are coupled to the channels connected. with the furthest modules before supplying its multiplexer relay IV9 with a voltage corresponding to the temperature, as measured by one of the temperature transducers 57 or U8 of the calibrator, the meter temperature transducer and UU or k2 or one of the room temperature transducers RO-R3 A selected channel is applied to the A / D by the energized relay of the multiplexer 1bg through the second multiplexer 15 ^, as shown in FIG. HG, and the amplifier 152. Converter 158, as shown in FIG. 1, H. In FIG. kE, the ΡΙ / 0 circuit 160 is shown as being coupled by the I / D manifold 1 ^ 0 to the CPU 120. In addition, an output of the Pl / O chain is obtained 160 to be applied to a HEX of a decoder 153, as shown in FIG. Ug, which in turn energizes one of a plurality of controllers 155 to close the associated relay of the multiplexer 1 ^ 9 Wherein the keten / 0 circuit output through the logic circuit 156, which includes an AND gate 156a, an inverter 156b and a logic translator 156c, is also applied to the multiplexer 15. When the output continues with reference to FIG. of a selected temperature measurement module is applied to the A / D converter 158, a conversion signal is applied to the A / D converter 158 from the keten / 0 circuit 160 through the extension circuit 153. In response to this conversion signal, the A / D converter 158 converts the input analog temperature signal into a corresponding digital signal to be sent through the P1 / 0 circuit 160 to the I / D bus 1U0, and sends a signal for the state of the end of converting via conductor 1U7 to the pi / o 160.

Referring now to Figure HI, there is shown a schematic of a amplifier module to which each of the temperature measuring members may be applied and amplified to provide a voltage output signal to be applied to the multiplexer 11 + 9 through an associated channel. The resistance temperature member (RTD) is coupled as one arm of a resistance bridge 201, which consists of the RTD and the resistors R1, R2 and R3. The energizing voltage, as applied to the a and b terminals of the bridge 201, as well as the output voltage, obtained from the terminals c and d thereof, are coupled to a conditioning circuit 203. In principle, the conditioning circuit contains BAD processing amplifier 205 »to which the output is laid from the n 4 n 4 eta - 3k - f * »r _ bridge 201 to be amplified before being placed on a Bessel sieve 207, whereby selected frequencies can be removed before being further amplified by a computational amplifier 209 to are applied to an associated channel of the multiplexer 1U9. An extremely stable voltage source serves to energize the circuit 203. As shown in Fig. Ui, the gain of the computational amplifier 205 is adjusted by the resistor placed between the terminals 10 'and 11 of the circuit 203, whereby the output shift is adjusted. set by adjusting the potentiometer coupled to terminal 29 of circuit 10 203. In addition, the voltage and current applied to energize bridge 201 are controlled by adjusting potentiometers R7 and Ré, respectively.

The signal conditioning circuit 16U, as shown generally in FIG. ^ B, is shown in more detail by the schematic 15 of FIG. KJ. The P1 / 0 circuit 168 is shown to be coupled to the I / D bus line 100 and to the CPU 120 for providing data transmission therebetween. A further input is made from the A / D converter 166 through an associated set of inverters 167 to the keten / 0 circuit 168. The pressure transducers 511 1 * 6 and PB are respectively connected via amplifiers 161a, b and c. with the multiplexer 163. As shown in Fig. Uj, the multiplexer 163 consists of a corresponding number of relays, which relays are energized for applying a selected output, as obtained from one of the pressure transducers, to the A / D- converter 166. The PI / 0-25 circuit 168 determines which relay of the multiplexer 163 is to be energized by applying control signals via the collector 169 to the logic circuit 165, consisting of a binary coded decimal to decimal converter and decoder 165a, that in fact selects the relay to be energized from the multiplexer 163 and a high-going signal through an associated output through a set of logic inputs. talers 1é5b apply to a corresponding set of power controllers 1ö5c, whereby a corresponding relay of the multiplexer 163 is energized to apply the corresponding temperature output to the A / D converter 166. Then, the PI / 0 168 applies a convert signal 35 through the conductor 159 to the A / D converter 166, which sends the input analog BAt ^ Rft9fcl / ®ze ^ a corresponding digital signal and a state signal to the PI / 0 circuit 168.

- 35 -

* * I

1 - 1 τ

Fig. UK shows a diagram of the conditioning circuit 13U, as is generally shown in the functional block diagram of Fig. Uc. The keten / 0 circuit 18U is shown as being coupled by the I '/ D header 1U0 to the CPU 120, and to the counter 518 consisting of a pair of counters 182a, 182b. In turn, the signal on this loner and logic circuit 170b is shown as consisting of a plurality of inverting OP gates 172, the output of which is applied to an input of the counter via an inverting EK gate 180 and an inverter. 182a. The output of the linear encoder 26 10 is via corresponding logic translators and. inverter and applied to said inverting OR gates 172 of the signal conditioning and logic circuit 170b. The rotary meter encoder Uo is applied to the signal conditioning and logic circuit 170a, which is similar to the signal conditioning and logic circuit 170b, to provide a composite signal to the interval clock 17U and a conditioned signal corresponding to the A- signal to the interval clock 176. It is clear that. the I / C circuits 17U and 176 of FIG. UK also include the programmable counters 17Ua and 176a, respectively.

The output of the interval clock 17U is applied via the logic circuit 177 »consisting of an inverting AND gate and a pair of inverting OR gates, as shown in FIG. Uk, to the interrupt 2 input of the CPU 120. The output of the interval clock 176 is applied to the control panel of the servo motor 20.

As shown in Fig. UK, the signal conditioning and logic circuit 170a includes first and second inputs, which receive the output signals A and A, respectively, as developed by the rotary meter encoder Uo. As shown in Figs. 11A and 11B, respectively, the A signal lags the A signal to provide, as explained, an indication of the direction of rotation in which the meter encoder Uo moves. Obviously, the meter encoder UO is designed for this particular clockwise rotation system, where, if "jitter" or mechanical vibration is given to the meter encoder Uo, the A signal may appear to be at least temporarily ahead of the A- signal, FIG. 11C showing the output signal A as it appears as if the A signal is ahead by 90 °, which BAD is undesirable and indicates an incorrect signal state. The signal conditioning and logic circuit 170a is designed to cancel I "r - = * v! 36 - of such states, as will now be explained. The A and A. signal are each passed through a level scaling and invert chain and applied to an inverting ÖF-port I8la, respectively. and 181b. The output of the inverting F gate 181a is coupled to an input of the inverting F gate 18bb, and the output of the inverting F gate 18bb is coupled through an inverter to an input of an inverting © F port l8lc. As shown in Fig. BK, an inverted signal, i.e. z «180 ° out of phase with an input to the inverting © F gate I8la, supplied to an inverting OR gate l8ld, the output of which is placed on the other input of the inverting © F gate 181c. The operative output of the signal conditioning and logic circuit 1T0a is obtained from the output of the inverting OR gate 181c, as shown in Fig. 11D, assuming that the meter encoder Uo is rotated clockwise or in the desired direction, and is applied to the interval clock 17 ^ to be counted, as set forth above. However, when for even a relatively short time the A signal appears to pre-empt the A signal, a direct current (or logic zero signal) output is obtained from the inverting OR gate 181c, indicating the presence of "jitter" 20 or any other erroneous signal. Similarly, the signal conditioning and logic circuit 170b receives the A and A signals as obtained from the linear encoder 26, which signals are also depicted by FIGS. 11A and 11B, respectively. Similarly, the A and A signals are applied to a similar set of inverting OR gates 169a, b, c and d. The output of the inverting OR gate 169c is applied to a latch consisting of a pair of inverting OR gates interconnected as shown in Fig. UK. Similarly, if the A signal, as obtained from the linear encoder 26 lags behind its A signal, the output, as shown in Fig. 11C, is applied through the latch 169e to the interval clock 176 to pass through its counter 176a. be counted. A further set of inverting OR gates is also included in the signal conditioning and logic circuit 170b to provide an output signal as applied to the input 22 of the interval clock 176 to indicate the occurrence that the A signal is ahead of the A signal, as obtained BA & hJftJfiJI ^ Akear encoder 26, indicating that the piston 1U is driven in an inverted state, ie by the servomotor 20 in a

* ·· I

«C 1

Kj Ί * 4 I '- 37 - is driven downwards to its parking position.

Fig. 4L shows a schematic of the signal conditioning and logic circuit 136 as shown in general in Fig. 4L.

1 * D. Data was transferred between the parallel data controller 5 (PDC) 192b and the CPU 120 through the I / D bus 1U0 and direct connections to the CPU 120. The output of the PDC circuit 192b is coupled to a logic circuit 190b and through a number of lines, as shown on the right side of the PDC 192b. The logic circuit 190b consists essentially of a logic translator associated with each of its outputs.

An inverting AND gate is included in logic circuit 190b to provide printer 111a with a reset signal. As shown in Fig. Ij-L, a search signal is applied to the printer 111a, which in turn applies an acknowledgment signal (ACK0) to the PDC circuit 192b, allowing data to be sent for printing by the printer 111a under the control of a set of signals thus marked. In addition, a busy signal can be developed by the printer 111a. for preventing transmission of data from the PDC circuit 192b to the printer 11 Ta. Furthermore, the SDC circuit 192a is coupled through the I / D manifold 1bo and direct connections to the CPU 120, with its output taken from the right side of the SDC circuit 192a through the logic circuit 190a to provide data in and out of the CRT terminal 112 under the control of preselected signals, as provided by the circuit, as shown on the left and indicated by control, the control signals, in short, providing fixed signals for determining the operating state of the CRT terminal 112. The logic circuit 190a coupled to the data output signal includes a logic translator and an inverter circuit in the form of a line driver, the data input line being processed to invert the signal for application. to the SDC chain 192a. The clock circuit 193 applies a signal via a logic circuit 195, consisting of logical translators, to the clock inputs of the SDC circuit 192a.

The signal conditioning circuit 138, as shown generally in FIG. UE, is more fully shown in the schematic of FIG.

Um. The keten / 0 circuit 200 is coupled to the CPU 120 by the I / D data transfer line 100 and the direct connections at the top and bottom, as indicated. The different ones of the P1 / 0 chain 200 taken ~ 38 - .-. i 1> * r outputs are coupled by logic circuit 19a to energize different lights, as shown in the system control and display unit 111. Logic circuit 198a "consists of a logic translator for each output of the PI 200 chain, and a plurality of controllers for "energizing" the associated lights.

In addition, signals from the switching mechanisms of the reset stem pushbuttons 1 TTf and 1 Hg are applied through logic circuit 198a, and in particular to a set of inverting AND gates, as shown in FIG., Whose outputs are inverted aan / 0 circuit 200. A second PI / 0 circuit 196 is coupled by the I / D data bus 1 ^ 0 and direct connections to the CPU 120. A set of its outputs is connected via a logic circuit 19 ^ a designed to control various functions, such as the direction and speed of the servo motor 20, which receives logic circuit 19 ^ a seven in— 15 inputs, which are fed through a set of inverting 0F gates and series-connected inverters and logic translators coupled to a corresponding number of controllers, the outputs of which control the direction and speed of the servo motor 20. Furthermore, two outputs of the PI / 0 circuit 196 are connected via a logic circuit 19 ^ b, 20 consisting of a series-connected inverter and a logic translator, applied to a controller before being applied to control the pneumatic solenoids 66 and 6h associated with valves 31 and 36. A set of five inputs is obtained from the logic circuit 19 ^ c, which processes inputs of the proximity detectors 50, 52 and 5 ^, which logic circuit 19 ^ c comprises a chain of resistors and diodes, as coupled via inverters with associated inputs of the PI / 0 circuit 196 The logic circuit 19d is coupled to the logic circuit 170a shown in Fig. Uc and comprises a series of inverting 0F gates, the input signal comprising a one second clock 30 signal for controlling the sampling of the various pressure and temperature control signals.

Referring now to Fig. 5, a high level flow chart of the various steps of the program, as stored in the PROM 12U and executed under the control of the CPU 120 35 using data input in the RAM 126, is shown. In the first BA & CffifS ^ In step 210, energy is applied to the computer system.

Thereafter, step 21U zeroes or clears the memory locations in RAM 126 before entering a starting subprogram 300, by starting the various portions of the computer system, as detailed below with respect to Figures 6a and 6B. It is noted that at various points during the duration of the program, a return is made through the entry point 232 to the step 21U for spring-starting the execution of the program. As shown in Fig. UB, a switch 139 is provided, which must be set to indicate whether it is viable to calibrate parts of the calibrator system 10 or perform a 10 meter test. If the switch 139 is placed in its calibration state, the decision step 216 proceeds to the step U00, in which a subprogram is performed to calibrate the various analog inputs obtained from the temperature and pressure measuring devices, as shown in FIG. 1. and 2A, and the associated 15 A / D converters, to which these signals are applied, as explained in more detail with reference to Fig. 7. When the system proceeds to step 500, the operator can read data from the various input measuring devices. such as the temperature measuring devices b2, Uk, U8 and 57, recall the pressure measuring devices 51 and U6 and the output of the linear encoder 26, 20. In addition, the operator can also initiate several of the meter's self-tests. This subprogram is described in more detail with reference to Figs. 8A-P. After collecting the correct data, the program proceeds to the step whether the subprogram 900, in which a key or a series of keys of the meter 38 is performed by the calibrator system 10, and the results thereof are transmitted or recorded on the CRT or the printer. Subprogram 900 is explained in more detail with reference to Figs. 9A-Q.

Referring now to FIGS. 6a and 6b, the start program 30 300 is given, with a command being sent in the step 302 through the I / D manifold 1U0 for passing through the logic circuit 198a as shown in FIG. UE. energize the light 111e for the backup state. In step 30U, a scaling factor, corresponding to a 0.028 m key, from RAM 126 is transferred to the counter 17 ^ a to be programmed in the interval clock 17U, so-BAD ^ gf ^ feg® ^ 11 in fig. * ^ C, for scaling the output of the meter encoder counter 179a to the correct position, by counting at 4q. -

- I

, I have a correct number of pulses, for example 40,000. the logic chain 1J7 outputs an impulse indicative of the meter 38 being sucked from 0.028 m. fluid. Then, in step 306, the interrupts in the operative state associated with the CPU 120 are braced to allow the interrupts to be executed at any time later in the program, for example, if the operator presses the reset push button 11Tf or stop pushbutton Hlg. Until this point in the starting subprogram 300, the interrupts associated with push buttons 11 Tf and 11 Tg would not be in the. 10. Operational condition may be placed, but interrupts are available to be operated after step 306 is performed.

Then, in step 308, the circuit shown in Figure 4c as associated with the rotary meter decoder 40 is started. Specifically, the logic circuit 170a is started, the interval clocks 15.k1 and 1j6 are reset, the PI / O circuit 184 is set to a selected state, the logic circuits 177 and 178 are reset and the ones to be programmed counters 174a and 176a programmed with the factors to be fed therein for down-counting.

In step 310., a command is sent through PI / 0 circuit 196 to logic circuit 194b to effect opening of second outlet valve 36. In particular, the proximity detector associated with valve 36 is checked, wherein, if the valve 36 is not open, the program waits until the valve 36 is open. Furthermore, in step 310, the control circuit associated with the servomotor 20 is started, in that the speed of the servomotor 20 is set to zero and a signal is applied to the servomotor 20 for keeping it in a freewheel state, wherein a logic circuit for sensing the torque of the servomotor 20 is reset, which logic circuit is coupled for sensing the control current going to the servomotor 20. In step 312, logic circuit 192b is started in its static I / O state with "handshake" outputs, and logic circuit 190b cleans the associated printer 111a and is ready to start printing. In step 314 SDC 192a is programmed to ensure that the data can be sent between CRT terminal 112 and CPU 120, and logic circuit 190a similarly instructs CRT terminal 112 * to clean itself. to prepare and prepare for receiving data as well as for cleaning the CRT display Then, in step 316, any data stored in A / D converter 166 as shown in Fig. UB is cleaned and the multiplexer 163 is set to its first channel, the output of the transducer 51 being applied by the multiplexer 163 to the A / D amps 166. The step 318 cleans the conditioning and coupling circuit 130, and cleans in the bi Without any data clean, stored in the A / D circuit 158, as shown in FIG. UA, and set the muting implants 1 ^ 9 and 15 ^ to their first channels, with the output voltage of the 10.. temperature transducer module of the calibrator through the multiplexers 1 ^ 9 and 15 ^ and the computing amplifier 152 is applied to the A / D circuit 158. In step 320, command signals are passed through the I / D bus 1U0 and the ΡΙ / 0- circuit 196, as shown in FIG. UE, is sent to operate the sole-15 by the logic circuit 19 ^ b. No. 66 for opening and then closing the first or meter valve 3 ^ · and for operating the solenoid 6k for closing the second or outlet valve 36. When it is desired to open one of the valves 3 ^ or 36 or to close, the associated proximity detector is interrogated, whereby if it is determined that it is in the desired position, no further action is taken, but if, however, the valve is not in the desired position, the logic circuit lUUb provides an output for actuating the associated pneumatic solenoid to open or close the valve as desired. In step 322, the program proceeds to an under-25 program, as explained with respect to Fig. 6B, in which the piston is returned to its parking position, ie, the lower position, corresponding to the position of the proximity detector 50, as shown. see in Figs. 1, 2A and 2B.

Fig. 6b shows the subprogram 322 for returning the piston to its lowest position. In the step 32U, a control signal is sent via the I / D bus line 10U, the keten / 0 circuit 196 for closing the first or meter valve 32 by the logic circuit 19 ^ b. Then, the step 326 determines the step of the piston, which may be somewhere between its lower and upper positions,

35 as can be seen in FIG. 1, wherein step 326, in particular, baths <stones> 196 interrogate logic circuit I9I + C to determine whether the output of proximity detector 50, as shown in 01-1 KU

τ. ^. I

k2 - Figs. 1 and 2, is high or one, and the subprogram, if so, goes to the end step 3U'6, where a command is sent to the P1 / O circuit 196 of Fig. UE for conditioning the logic circuits 19 ^ a and 198b so that the motor control for the servo motor 20 is set for a zero speed, and further for setting the interval clock 176 as shown in FIG. ^ C to to indicate that the encoder output is in its starting position, ie to set the counter 178a to zero to prepare it for starting to generate one second sampling pulses. If the piston 1V is not in its parking position, the subprogram proceeds to step 328, which determines whether the piston 1U is in an intermediate position, ie, the stop 92 is located between the proximity detectors 50 and 52, such as 1 and 2A and B, wherein the subprogram, when the piston 1¼ is in such a position, proceeds to step 330, wherein control signals are sent through the PI / 0 circuit 196 for setting the logic circuit 19W for driving the servo motor 20 counterclockwise, and further in step 332, the speed is controlled to accelerate to a selected speed, ie the ninth of sixteen speeds. However, if step 328 determines that the piston 1U is in its upper position, i.e., that its stop 92 is above the proximity detector 52, then step 33 ^ sets the logic circuit 19ba. of Fig. Ue to set the lowest speed, ie speed 1 of 16 and to rotate the servomotor 20 counterclockwise before going to step 338, in which the logic circuit 19a accelerates the servo motor 20 to its next highest speed up to a maximum of its twelfth speed. At that point in step 338, logic circuit 19 ^ c is approximated to determine whether the piston 1U is located at the proximity detector 52, the step 338, if not, accelerating the piston to its next higher speed until step 338 determines that the piston 1U is located at the proximity detector 52. At this point, the logic circuit 19 ^ a maintains the prevailing speed of the servo motor 20 until in the step 3 ^ 2 the parking proximity detector 50 detects the presence of the piston 1U, at which time the step 3 ^ the logic ke-BA ^ AtèlA adjusts to decelerate the piston 1U to a stop before entering step 3 ^ + 8, where the motor control is entered ^ 1 + 3 τ.

set at a zero speed.

If the operator has the calibration / key switch set in its calibrating position, the program goes to subprogram 1 + 00, as shown more fully in fig. 7 · 1 »initially in step 5 1 + 02, a assignment sent to the logical chain. 190a of fig. 1 + D

for cleaning the CRT terminal 112. Step UoU displays an appropriate message on the CRT screen, indicating that the calibrator system 10 has entered a calibration state, which, as shown in FIG. 7, »indicates the various parameters which can be calibrated in this manner. Then, step 1 + Οβ returns the runner, as shown on the CRT, to its left margin pending the operator making an appropriate entry. Then, step 1 + 08, after the operator input via the keyboard of the CRT terminal 112, queries the keyboard to determine which of the possible keys has been pressed. For example, if it is determined that one of the sets of keys T and 0, T and 1, T and 2, T and 3, T and 1+, T and 5S T and 6 or T and 7 has been pressed, the subprogram moves to the step 1 + 10, in which a corresponding channel is selected by the multiplexer 11 + 9. Then, in step 1 + 12, a selection command signal is sent via the P1 / 0 circuit 160 to the multiplexer 11 + 9, wherein the selected channel is connected to the A / D converter 158 via the multiplexers 11 + 9 and 15 ^, the amplifier 152. Then step 1 + 11 + applies a conversion signal to the A / D circuit 158, wherein Step 1 + 16 displays the temperature as measured. At this point, the operator can calibrate the selected temperature transducer module to provide a correct reading by setting the zero and magnitude of the interval of the module's processing amplifier, which procedure is repeated until an accurate reading is displayed on the CRT. Although a detailed explanation is not given, it is clear that the similar keys P and 1, P and 2 and P and B can also be operated by the operator, the gains of the computational amplifiers 16a, 161b, 16lc of FIG. 1 + B can be similarly set to give accurate readings. Similarly, keys T and 0, T and 1, T and 2, 35 T and 3, T and l +, T and 5, T and 6, T and 7 can be pressed and their respective ^ v ^^ ji Cherry and chains are set to provide accurate readings. When pressing the V and P keys, such as. \ S \! , «: .- * * '4 i - uu. determined by the step Uo8, the program goes via the step ^ 50 to the step 1 * 52, before a command signal is sent via the P1 / Q-circuit 168 of FIG. UB for application by the multiplexer 163 the voltage calibration input signal 'V' to the A / D converter circuit 166, 5 which converts these inputs to digital values in the step. The voltage calibration input signal is set to set the zero and full scale values of the A / D converter 166, which values are appropriately displayed in step 4 56 at the CRT terminal 112. If the V and Tr key of the keyboard is pressed, the program 10 proceeds in a similar manner via the step UU2 to the step UUU, in which the voltage calibration input signal VT is applied to the A / D-cm setter 158 of FIG. 4A, and may be zero and full-scale values are similarly adjusted. "If another key is pressed on the keyboard, step ^ -08 branches through step U56 to step U58, rejecting that character to return to the starting point of the step ko8.

The data entry and retrieval subprogram, as generally shown in Fig. 5 as the step or program 500, is discussed more fully with respect to Fig. 8A -20 ÖP, showing an overview of the program 500 in Fig. 8A.

Initially, an instruction is given via the I / D bus 1 Uo to the logic and control circuit 198a of Fig. UE to energize the spare light 111e. Then, in step 50U, which is more fully shown in Fig. 8C, a determination is made as to whether a self-test is desirable, and if so, that subprogram is executed. Then, in step 506, it is determined whether it is desired to display the room temperatures, and if so, a display is made on the CRT of the terminal 112, as discussed more fully with respect to Fig. 8H. In step 508 30, an examination of the keyboard is performed to see if the operator wishes to recall data related to previous keys of meter accuracy, where data is displayed on the CRT, if required. representation, which subprogram 508 is discussed more fully with respect to Fig. 8J.

In step 510, appropriate flags are automatically set to allow B ^ S ^ PSGtNAll time during the meter key to monitor and display the pressure and temperature parameters, where the r k5 ~. ,! 1, the parent program for executing such a display is more fully "discussed with" with respect to FIG. 8K. In step 512 ', the subprogram is outlined for setting the desired key volume and the manner in which it is fed into the timer 17'Ua of the interval clock 1jU to be programmed, the subprogram being shown in Fig. 8L. Next, it is necessary for the "operator to enter a select key flow rate or rates via the CRT terminal keyboard, as is more fully" discussed with "regarding the subprogram of FIG. 8m. In step 516, the operator 10 sets to the number of times to repeat a "particular key, where the meter may be tested, for example, three times for a flow rate or for a selected volume and flow rate. The input of the repeat commands is discussed with respect to the subprogram of Fig. 8N. Thereafter, the step 518 sends cleaning commands 15. through the logic circuit 190a, cleaning any data stored in the buffers associated with the CRT terminal 112. At this point, step 520 makes a decision whether to determine the volume of the meter 38 with the output of the proximity detector 27 or with the output of the rotary encoder Uo. If the switch 20 is set to a logic "zero", a flag is set in step 522 to perform an encoder key, where, if the switch is set to a logic "one" position, a position 52U is set is set to perform the proximity detector key.

Continuing with program 500, as shown in Fig. 8b, the system obtains the meter temperature and pressure and displays it on the CRT, as well as the temperature and pressure of the calibrator, as measured during the meter key, which appears on the following way. Next, the step 528, if instructed, displays on the CRT data 30 indicative of the pressure and temperature in the meter 38 and the calibrator 10. When the key volume, i.e. 0.028 m, 3 o Q, 0lkmJ or 0.007 m, is set by operator input at CRT terminal 112, the entered value is decoded in step 530, and the selected value in step 532 is displayed by the CRT as : 35 BUTTON FULL. * x m. Thereafter, the desired flow rate or velocity keyboard is entered, decoded in step 53 ^, and the chosen rates in step 536 are displayed on the CRT as: "% 6 - ** ♦

m ^ I

«* '*'“ * FLOW SPEEDS are, jn QX, <3X ^ -QX. Similarly, in step 538 the number of repetitions for a "particular key or for" certain keys relative to the flow rates or volumes is decoded, and in step 539 the selected number of repetitions per flow rate or volume is displayed at the CRT as: BR. KEYS PER FLOW RATE = 1C. At this point, a carriage return line feed command is executed in step 5 ^ 0, removing a runner, such as placed by the CRT terminal on the CRT.

The subprogram 5CA is more fully illustrated in FIGS. 8C, 10 with a desirable self-test selected. Initially, in step 5 ^ 2, the data memory buffers associated with the CRT "or CRT terminal 112 are cleaned by commands generated by the logic circuit 190a. In step 5 ^ ^, the CRT, as shown in FIG. Fig. 8C shows an indication of the different self-keys that can be performed, for example volume V, leak L or NONE, the operator choosing one of these self-keys by pressing the appropriate key of the keyboard In step 5k6, the runners, as shown in Fig. 8C, are blinked to prompt the operator to respond before choosing the self-keys, whether it be the volume V, leak L or NONE In step 5 ^ 8, the subprogram moves to the desired self-test depending on the button selected in step 5 ^ For example, if the volume self-test V is selected, a volume self-test program is sent as output to the CRT in step 552., and the volume self-key is turned off at step 55 ^, as discussed more fully with respect to Fig. θΕ. If a leak key is selected, the subprogram goes through step 558 to provide a display on the CRT indicating the selected key and to start the leak eleven test, which is performed in step 560, such as is described more fully with respect to the subprogram of FIG. 8D. Then, the subprogram at step 556 determines whether there is another input to be taken into account, and the subprogram returns to step 5-6. If the operator presses the dodge key, as determined by step 5 ^ + 8, the subprogram exits via step 562 to the entry point 212 of the main scheme, as shown in Fig. 5, in which the program begins. If the operator presses Β / βθ (WttGIBWkeys, as observed by step 5 ^ 8, the subprogram exits through step 566 and returns to the program,

, I

- 1 * 7 - as shown in Fig. 8A to proceed to the next step 506. If any other key is pressed, the subprogram runs through the step 568 to reject that character in the step 570 and before returning to step 51 * 8 to identify another key.

The leak self-test subroutine 560 is more fully illustrated by "with reference to FIG. 8D. The leak self-test is a key for providing an indication of the integrity of the termination of the calibration device system. Initially" energizes logic circuit 198a in 1 * E in step 572 the self key and lights 11 Vb and 111c for key operation. Subsequently, the sub-program 322 for returning the piston to its parking position, as explained above with reference to Fig. 6b, is executed. Then, a command signal is output in step 57 ^ * through the P1 / 0-15 circuit 168 to set the multiplexer 163 to receive the signal through the second channel of the pressure transducer 51 (pressure PP1). Subsequently, the logic circuit 19hb is commanded to apply operating signals to the solenoids to effect the closing of the first inlet and second drain valves 31 * and 36. In step 578, a command is issued via the Pl / O-circuit 196 for operating the logic circuit 191 * a of FIG. 1 * E to control the servo motor 20 for clockwise driving the conveyor screw 18 at a relatively low speed, corresponding to "1". The servo motor 20 can. not energized as controlled by step 578 until the inhibition built in the program is evaded, such as by pressing a momentary switch (not shown) coupled to logic circuit 19bc to thereby enable operation of servo motor 20 when both valves 3l * and 36 are closed. Usually, the servo motor 20 cannot operate when the valves 3 * and 36 are closed, thus preventing possible damage to the piston seal. Next, an indication of the pressure in the A / D converter 166 is entered in step 580 and a check is made in step 582 to determine if the pressure has increased by a certain amount, as indicated by the pressure shown in the A / D chain 166 stored data, ie, the vacuum increase has exceeded h, 6j kPa. If the vacuum ®A ^ £ yi ^^^ increased to more than kPa, the subprogram decreases and repeats step 580. If the vacuum in chamber 28 has been added - 48 «** ♦

% \ I

ft * s '* *' to more than 4.67 kPa, the subprogram proceeds to step 504, at which command is given by the Pl / O circuit I96 to stop the servo motor 20. In step 586, a twenty second wait time is loaded into a register in RAM 126, and counted downwards to provide a time for leakage to occur in chamber 28. Then, in step 588, a conversion signal is applied to the A / Di converter 166 of Fig. 4b to determine the pressure, which is then sensed by the graft transducer 51. In step 590, the subprogram waits for the one second clock signal generated by logic circuit 178 of FIG. 4C and applied through logic circuit 194d of FIG. 4e to count down the twenty second count in step 592 placed in the register in RAM 126. Step 592 determines whether this register in RAM 126 has been counted down to zero, and if not, the subprogram returns to step 588, for each second of a twenty second interval, the piston pressure, as obtained from transducer 51 »is obtained and displayed on the CRT to thereby provide continuous monitoring of the calibrator pressure so that the operator can determine if there are leaks in chamber 28 for d e twenty seconds button. The ir count up counting continues until the register is zero, as determined by step 592, at which time a command is issued in step 594 for operating the logic circuit 194b to open the solenoid the second outlet valve 36. At this point, the position of the piston 14 is determined in step 596 by checking the state of the proximity detectors 50 and 52 by addressing the logic circuit 194c. At this time, the test has ended and an order is issued to the logic circuit 190a for energizing the test termination and self-test lights. Finally, in step 322, the piston 14 is returned to its parking position by the subprogram, as shown in Fig. 6B, before returning to step 556, as shown in Fig. 8C.

In Fig. 8E, the volume self-test subprogram 554 is shown in more detail. First, step 600 carries logic circuit 35 198a on lights 111b and 11 Tc for self-test and test to operate.

The volume self-test is entered to obtain an indication of the accuracy of the linear encoder - ^ 9- UO. Step 332 », as shown in Fig. ÖB, returns the piston 1¼ to its parking position before command signals are issued in step 602 through the logic 19¼¾ to operate the sole noids to open the first inlet valve 3 ^, and for operating the solenoid to close the second outlet valve 36. Next, an order is given in the step 60¼ to load the speed buffer, ie an addressed portion into the RAM 126, at its maximum speed of 16 '. Then, in step 606, the servo motor 20 is accelerated to the speed, as stored in this buffer in accordance with the parent program, as discussed with respect to Fig. 8F. Then, in step 608, counter 182 and counter 17 to be programmed as shown in FIG. KCt are blocked and reset to zero. Step 610 checks the state of the proximity detector 52 cm to determine whether the piston 1¼ is pulled to its key-15 start position, and if not, the check is repeated until the piston 1¼ reaches this position . When the piston 1¼ has reached its key start position, the program proceeds to step 612, in which the counter 17¼ a to be programmed is pressed and the linear counter 182 is opened to count the linear encoding pulses when the piston is 1¼ the proximity detector 52 is pulled to the proximity detector 5¼. In the step 61¼, the state of the squeezed proximity detector 5¼ is checked intermittently until the piston 1¼ is placed therewith, at which time the subprogram proceeds to the step 616 for pressing the line-25 counter 182. In the step 618, the eummulative number or the count of the linear encoder counter 182 sent through the ΡΙ / 0 circuit 18¼ to a named location in RAM 126. In step 620, an appropriate sequence of command signals is sent to logic circuit 19¼a, the servomotor 20 being decelerated to a standstill as described with respect to the subprogram shown in FIG. 8g. Flags are then set in step 622, indicating that the piston 1¼ is not located between the proximity detectors 50 and 52. In step 62¼, logic and control circuit 198a energizes lights 111b. and 111d for self-key and key-termination. At this point in step 626, the count of counter 182 becomes the count BADfflPÖHïAt. ^ from the piston 1¼ between the proximity detectors 52 and 5 ^ transferred from its place in the RAM 126 to be passed through the CRT of the Λ J η Λ 1 "T *

. «'. ·· *, * * 1 I

r * '50 T- 'end station 112' to be displayed, simultaneously cleaning the counter 182, Then the piston becomes 1U. returned to its parking position by step 332, as shown in Fig. 6b, and step 628 causes logic and control circuit 198a to energize light 111e for the standby state before returning to step 556, as shown in Fig. 8C.

The parent program for accelerating the engine indicated generally by reference numeral 606 in FIG. 8E is shown in more detail in FIG. 8f, in step 630 a command is made via the 1 / D manifold 1I + 0. sent to close the counters 182 and 17Ua of FIGS. i + C. Then, an opening command is sent to logic circuit 19 ^ a by commanding step 632 to command servo motor 20 to rotate clockwise to thereby raise piston 1U. At this point, the speed becomes 15 1, i.e., z. the lowest speed, loaded into the speed comparison buffer in the RAM 126 by the step 63 ^. In step 636, a command is given to logic circuit 19a to incrementally increase the speed of the servo motor 20 and the actual speed, as stored in the speed comparison buffer of the RAM 126, is compared with the finally named speed, stored in the speed buffer, and the parent program, if equal, ie the servo motor 20 has accelerated to the desired speed, goes to step 6U6. If not, step 6 ^ 0 performs a waiting time of about 0.25 seconds before sampling the state of proximity detector 52 via logic circuit 19 ^ + c, where if the piston is not in In this state, step 6UU counts the desired speed up by 1 before returning to step 636, placing the new speed in the speed comparison buffer of the RAM 126.

If the piston 1 is driven into its intermediate position, as observed by the step 6U0, the subprogram moves to the flag setting step 6U2, which indicates that the piston 1U has been prematurely moved and the subprogram is returned to step 60bt as shown in Fig. 8E. As can be seen in fig.

8e, the usual operation consists of accelerating the piston to the desired speed and then intermittently testing the BADföfttëtlNAk the proximity detector 52. When determining in the step 6U6 that the piston 1U has reached the key starting position, as indicated - 51 - m ^ | v '♦ * »<through the output of the proximity detector or 52, the subprogram branches to step 970» as is "discussed with" with respect to FIG. 9E to determine and determine the occurrence of the rising edge. of the next pulse A of the rotary meter encoder Uo, 5 - wherein, as explained further, the meter button is started by applying the pulse outputs obtained from the rotary meter encoder UO and the linear encoder 26 to their associated counters 17Ua and 182 .

The subprogram for decelerating the servo motor 20, as indicated in step 620 of Fig. 8E, is discussed more fully with respect to the subprogram shown in Fig. 8G. Initially, in step 6U8, the counter 17Ua and the counter 182, as seen in FIG. UC, for receiving the rotary and linear encoder outputs, respectively, are first pressed and then reset. In step 650, the rate comparison buffer is loaded into RAM 126 at rate 16, i.e., the highest rate available. Then, in step 652, the actual speed, as stored in the speed buffer of the RAM 126, is compared with the high speed 16, as loaded in the speed comparison buffer, and, if not equal, the speed loaded in the speed comparison buffer is down counted until the actual rate is equal to the rate loaded into the rate comparison buffer, at which time the subprogram moves to step 656 and the rate stored in the rate comparison buffer is counted down. In step 25 658, a command is issued to the logic circuit 19Ua to decelerate the servo motor 20 to this new speed, as placed in the speed buffer of the RAM 126. In the. step 660 compares the actual speed to zero, ie the servo motor 20 is stopped, and if not stopped, a 0.2 second wait time or delay is performed in step 662 before the motor speed down again. counting by steps 656 and 658. This operation continues until the servo motor 20 is stopped, ie the speed is zero, at which time step 660 returns the subprogram to step 622 of FIG. 8E.

Fig. 8H shows the subprogram 506 for the input of the selected temperatures in the space 106 of the calibrator, A i A J I · · * »by BAD 'V'i-3 · bet keyboard of the CRT terminal 112.

* v I

- 52 - which temperatures to display, and the steps for displaying them on the CRT of the terminal, it has been shown that knowledge of the temperature in space 106 of the calibrator is useful for examining the level of the control, which must be applied to the calibration device 10 in room 16.

The parent program, as shown in Fig. 8h, allows the operator to display each of the four room temperature outputs R0, R1, R2, and R3 of the temperature gauges shown in Figure 2C, as disposed in the room 106. These temperatures can be further addressed and displayed on the CRT of the terminal 112 until the operator terminates this operation by pressing the N and 0 keys on the keypad of the terminal. Initially, in step '66b, a command is sent to the logic circuit 190a, cleaning the buffers associated with the CRT terminal 112 via the control input. Thereafter, the step 666 causes the logic circuit 190a to display an indication, as shown in Fig. 8H, of the possible space temperature means that can be addressed, i.e., the space temperature means R0, R1, R2 or R3. If the operator does not want to address and display any of these temperatures, the N and 0-20 keys are pressed. At step 668, a carriage return line feed is performed, causing the runner to flicker, indicating that an operator response is required. In step 670, an interrogation is made of which key has been operated via logic circuit 190a, and if the keys R and 25, corresponding to the room temperature element R0, have been actuated, the subprogram goes to step 672a. step 67Ua, wherein a control signal is output through the I / D manifold 1U0 and the ΡΙ / 0 circuit 160 for selecting its fifth input by the multiplexer 1U9, wherein a voltage representation of the room temperature transducer R0 through the multiplexers IU9 and 15 ^ is applied to the A / D converter 158. In step 676a, a converter signal through the Pl / O circuit 160 is applied to the A / D converter circuit 158 for converting the analog input signal into binary digital data. Then, step 678a converts the binary digital data into decimal data, and step 680a converts this data into a floating decimal format by general B / f WOLL markings in this field. In step 682a, the digital floating -, - decimal data is converted into digital degrees Celsius according to the formula:

* 4 I.

A -., • «* 1 - 53 - [(RAW 'DIGITAL' NUMBER) (7,326007326 x10 ~ 3) (9) i = 0 (, 5 Τη step 68ka. Appropriate data is generated from the logic chain" 190a for displaying the room and emperatuor in degrees Celsius on the CTlT »display. Similarly, step 6j0 can sense the operation of each pair of keys by the operator corresponding to R0, R1, R2 and R3 This is for addressing these detectors, such as connected to the multiplexer 1 ^ 9 of Fig. UA, and processing and displaying the selected data on the CRT captured in Step 69 ^ or it is determined whether another input is desired, 10 and the operation returns to the beginning of step 670. If the operator presses the fallback key, the program goes through step 686 to return through the entry point 212 to the beginning of the program, such as shown in Fig. 5. If the N and 0 keys are pressed, the program proceeds to step 688 and returns 15. to the next parent program or step 5Q8, as shown in FIG.

8a. If an unrelated key is pressed, the subprogram disappears at step 690 and discards the character at step 692 before returning to the beginning of step 670.

The subprogram 508, as generally indicated in Fig. 8a for sampling data from pre-performed keys, is executed by the subprogram 508, more clearly shown in Fig. 8J. The subprogram can be entered after a meter key has been executed. First, in step 696, the CRT, in particular its buffers and displays, is cleaned from previously stored data. Next, by operating the logic circuit 180a to display the CRT, the step 698 displays the possible key parameters that can be addressed and displayed, namely K, the number of counts of the linear encoder 26, TP, the temperature of the calibrator, TM, the temperature of the 30 meter, PM, the pressure of the meter, PP, the pressure of the calibrator, and the percentage error of the previous test. If none of these values are to be displayed, the operator may press keys N and 0 corresponding to NONE at which time the program proceeds to the next step. In step 700, the runner becomes BAD ORK ^ NAÏ.n> indicating to the operator that he must select one of these parameters or NONE by pressing the appropriate A Λ A Λ r · -rr ► '.-- 4 * -5 ^ key. If in step 702 the linear encoder counts are selected by pressing key K, the parent program branches through step 70Ua to step 706a, addressing and reading the count of the linear encoder register in RAM 126 and created via the logical chain 190a to be displayed on the CRT. If the keys, corresponding to the temperature of the calibrator, are operated by the operator on the keyboard, operation similarly proceeds from step 702 through step 70Vb to step 706b, where the buffer contents for the 10 temperature of the calibrator, which buffer is an allocated place in RAM 126, is transferred from RAM 126 to be. displayed on the CRT. Similarly, the meter temperature, the calibrator temperature TP, the calibrator pressure PP or the gauge pressure P'M can be similarly addressed from a corresponding location in the RAM 126 and displayed on the CRT. Also, the percentage error of the difference between the standard volume, as drawn by the calibrator system 10, and the volume, actually measured by the meter 38, is calculated with respect to the standard volume and can also be displayed on the CRT. If a second or other key is pressed, step 716 returns the subprograarana to the beginning of step 700. If the dodge key is pressed, the subprogram exits through step 708 through the entry point 212 to the beginning of the program, as shown in Fig. 5 * If an unrelated key is pressed, the program proceeds through step 712 to reject the wrong character in step 71V before returning to the beginning of the step 702. After the operator has sensed one or all of the parameters he wishes to see on the CRT, he presses the N and 0 keys, returning the program to the next step or subprogram.

The program 510, as generally shown in Figure 8A, can address and display the parameters, as automatically measured and monitored during the duration of a test, and is shown in more detail in Figure 8K. First, in step 718, the buffers associated with the CRT are cleaned before steps 720, 722, J2k and 35 726 set flags in matching locations in the RAM 126 for the BAB33> Ett6èMAJ- of the calibrator and meter temperatures and the meter and calibration device pressures. So the flags are set - 55 -

.. - I.

* V 1 «to allow automatic display on the CRT of these parameters, after which the program 510 returns to the step 512, as shown in Fig. ÖA.

The step 512, as shown generally in Fig. 0A5, for setting the desired volume to be sucked by the meter 38 is discussed more fully with respect to the one shown in Fig. 8l. displayed subprogram. Initially, the CRT end stop 112 is cleaned in step Jk2 before the CRT shows possible volumes in step 7 ^ 6 on 3, for example 0.028 m, 3 3 10 0.011; m and 0.007 m, which volumes can be selected by the operator to suck through the meter 38 to be tested. In step 7 ^ 8, the runner is made to flicker to urge the operator to make his choice of volume. When the operator actuates the key associated with each of the volumes to be selected, the subprogram 15 512 goes to that volume. For example, if the correct key is pressed, indicating a desire to enter a value corresponding to 0.028 m, the subprogram moves through step 752a to step 75 ^ a, where the scaling factor corresponds to—

O

coming at 0.028 m, in a known position in the RAM 126 is set. The scaling factor is then transferred from this RAM location to the rotary encoder counter 17 ^ a.

After selecting one of the desired key volumes, the subprogram returns to the next step 51 ^ as shown in Fig. 8A.

If the dodge key is selected, the subprogram goes through step 25756 to return to the main program through entry point 212.

If an incorrect key is accidentally pressed, the subprogram goes through step 758 to reject that entered character in step 760 before returning to the beginning of step 750.

Next in the program is the step or subprogram 51U, setting the desired flow rate at which the fluid is to be drawn through the meter 38, which selected flow rate, as set forth above, in turn determines the rate, to which the control turns the servo motor 20 and moves the piston 1U upward, as shown in Fig. 1. Referring now to Fig. 8m, step 762 initially cleans the buffers with the CRT terminal BAD (DRJCyèèA), and in step j6h, the possible flow rates of Q0 - QF are displayed on the CRT, where it is clear that QO corresponds to a minimum flow rate, for example, 0.56 mJ per minute, and QF corresponds to a maximum strcmings

O

speed, for example 11.2 mJ per minute. Step 766 causes the runner to flash on and off to prompt the operator to monitor his choice of flow rate. In step 768, an interrogation of the keyboard is performed to determine which key the operator pressed, for example, if the flow rate QO was pressed, the subprogram moves through step 770a to step 772a, with the flag for the particular speed QO is set 10 at a designated location in RAM 126. Then, step 77 ^ a displays the selected flow rate QO on the CRT, after which the system returns with the answer "STILL ONE" and flashes the cursor to indicate , that an answer is requested from the user. If another rate is also to be tested, step 75 ^ the program returns to the beginning of step 766, where a second and perhaps other flow rates within a single set of keys may be tested. If the operator presses the dodge key, the program advances through step 776 and the entry point 212 to the main program, as shown in fig. 5 · If an incorrect key 20 of the keypad of the CRT terminal 112 is pressed, the program continues step 780 for rejecting the incorrect character in step 782 before returning to the beginning of step 768.

If no other flow rates are to be selected for keying meter 38, the operator presses the N and 0 keys, returning the program through step 778 to next step 516, as shown in FIG. 8A .

The step or program 516 for setting the number of repetition keys to be set for each of the selected flow rates can be entered via the operator keyboard in a manner more specifically shown in Fig. 8N. Initially, in step 786, the buffers associated with the CRT terminal 112 and the CRT display screen are cleaned before the possible number of keys or repeat keys for the flow rate, i.e. 1, 2 or 3, are displayed on the CRT. Step 790 flickers runner 35 on the CRT to prompt the operator to make his choice of frame rate. Step 792 detects which of the end-mail keys has been pressed, where, for example, if a key is in-04 Λ 4 CV / é ü. , Λ * v · - 57 - pressed, indicating that only one key per flow rate must be performed, the subprogram proceeds through step T9ha to step 793a, displaying output "1" on the CRT before returning to the next step 518 of the main program-5 ma, as seen in Fig. ÖA. If two keys are to be executed, the subprogram exits from step 79bb to step 793b, commanding copying the flow rate flags for one repetition, and in step 796b for setting a flag for a second iteration in an allocated area 10 of the RAM 126. In step 796b, an indication of 2 is displayed on the CRT. If a selected key is to be repeated three times, the subprogram performs a similar series of steps 79 ^ c, 793c, and 796c. If an incorrect character is pressed on the keyboard, the program goes through step 795 to reject the incorrect character 15 in step 797 before returning to the beginning of step 792.

If the operator presses the dodge key, the program exits via step 798 to the entry point 212, making a return to the main program, as shown in Fig. 5.

The subprogram 528, as generally shown in Fig. 8A, displays temperature and pressure data during the execution of the meter key, as more fully represented by the subprogram divided in Fig. 8P. Initially, the CRT runner is moved to an output position, and the CPU 120 addresses the location in RAM 126 where the TM flag was automatically set during the previous subprogram 510. Since the TM flag is set, the content of the meter temperature buffer, ie an addressable place in the RAM 126, transferred through the logic circuit 190a to be displayed on the CRT, as indicated in step 802. After displaying, the subprogram moves to step 806, which examines the location of the RAM 126, 30 where the TP output flag, indicating that there was an indication for monitoring the calibrator temperature TP during a test, and the output of the calibration temperature buffer is transferred to be displayed on the CRT. After this display, the subprogram proceeds to step 810, which addresses the preset meter pressure flag and outputs the contents of the pressure buffer, i.e., a known location in RAM 126, to be displayed on the CRT. After displaying 'WW addresses; the preset PP output buffer flag, and the content becomes - 56 -. .! • · * '1 of the calibration pressure buffer transferred to be displayed on the CRT. After displaying this information, the subprogram returns to the next step 530, as indicated in FIG.

ÖB. The value output at this time corresponds to the values, which are then stored in the RAM buffers. If no key has yet been performed, zeros are initially stored in RAM 126 and output and displayed as TM - 0.0 ° C. This step formats the springing so that when a key starts the system replaces the zeros by appropriate numbers.

The execution of the keys of the meter 38 by the calibrator system 10, as well as the output of the results to the printer and the CRT is performed by the program, generally shown in FIG. 5 by reference numeral 900, as now is discussed in more detail with reference to FIGS. 9A-15 9P. Fig. 9A shows a high-level diagram of the various steps or subprograms necessary to perform the key of the meter 38, beginning with the step 322, as described above with respect to Fig. 6b for returning to its parking position. of the piston 1U, ie its lower conventional position 20 with respect to the cylinder 12, as shown in FIGS. 1 and 2A. Next, as discussed more fully with respect to FIG. 9B, the program 902 determines the type of key, ie whether the volume measured by the meter 38 is determined by the proximity detector 27 or by the rotatable optical encoder Uo, as shown in FIG. Uc, 25 and the determined volume to be drawn by the meter 38, in particular step 902 loading the appropriate volume factor into the counter 17 ^ -a to be programmed, and storing the appropriate divider in the buffer E0RP of the RAM 126. Next, the step 90U for the condition that one key per flow rate is to be executed determines the flow rate to be executed for that key, the system in particular addressing the location where the flow rate flags are stored in the RAM 126 to determine the appropriate flow rate to be used in the particular key. If the flow rate is located in this manner, program 35 proceeds to step or program 906a to determine which flow rate BAD ÜRJGlMAtien performed and obtain that flow rate and run the subprogram, as more specifically shown in ,. ..-y "! - 59 - FIGS. 9C and D. If it is decided in step 908 that two keys are to be executed for each flow rate, the program addresses the areas in RAM 126 for the respective flow rate flags, and performs the keys with the programmed flow rate in step 906b. If three keys per flow rate are required, it is first determined in step 912 whether the flow rate for the three corresponding speeds is entered, and if so, step 906c calls the flow rate flags from the allocated locations in RAM 126, and executes the keys of the meter 10 38 at these flow rate or rates. Thereafter, the command is sent to the logic and control circuit 198a to energize the backup state light before returning to step 216 as shown in FIG. 5.

The determination of the type of key and the volume to be measured is shown in general as the subprogram 902 in Fig. 9A, and is discussed more fully with respect to Fig. 9B, initially with the counter 1T ^ a to be programmed and the counter 182, as shown in FIG. UC, are pressed and reset in step 918. On this plinth, the state of the encoder / 20 proximity detector switch is determined in step 919 to decide whether the fluid volume generated by the meter 38 must be determined by the output of the proximity detector 27 or by the output of the rotary encoder 10. If the rotary encoder output is selected, the subprogram proceeds to step 920 to test the presence or state of the 0.028 m flag at the allocated location of the RAM 126, and if present, becomes the factor , which is equivalent to 0.028 m output pulses from the output of the optical rotary encoder 40 stored by the step 922 in the RAM E0RP, ie, an allocated location of the RAM 126, and the factor-30 number is loaded into the counter 17 to be programmed a. At this point, the subprogram returns to the next step 90U of the program shown in Fig. 9A. If the 0.028 m flag is not present, check

O O

step 92 U teaches the state of the 0.01 U m bit or 0.01 k no flag, and if present, as determined by step 92 U, becomes the counter 17 to be programmed, such as shown in Fig. Uc, by the step barPRIQinal.

920 loaded with an equivalent count and a corresponding factor is stored in the EORP buffer site of the RAM 126, before returning - 60 -. ! Return to step 904 of FIG. 9A. If the 0.028 m and 0.01 ^ no flags are not present, step 928 searches for the presence of the 0.007 m flag, as previously entered into the RAM 126 of the system by the operator, and step 930 loads the program counter 174a

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5 with a count corresponding to 0.007 m, and a corresponding factor is stored in the EORP buffer location of the RAM 126. If O O o no flag is present corresponding to 0.028 m, 0.014 nr or 0.007 m,

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step 932 automatically determines that a 0.028 m key is to be performed for meter 38 testing.

On the other hand, if step 919 determines that the output of the proximity detector 27 is to be used to measure the fluid flow through meter 38, the subprogram proceeds to step 934, where the state of the 0.028 m flag in the RAM 126 is checked, and if set, the counter to be programmed 15 174a of FIG. 4C is set by step 936 with a binary number equivalent to 0.028 m volume and a factor, usually 8, is set in the EORP buffer location of the RAM 126 before returning to the main program. If the 0.028 m flag is not. set, the subprogram proceeds to step 938, which includes checking the state

O

20 of the 0.014 m flag is output, and if present, becomes

O

a factor corresponding to 0.014 m, usually 4, is stored in the step 940 in the counter 174a to be programmed and also in the EORP buffer location of the RAM 126 before returning to the main program.

O

If the 0.014 m flag is not set, the subprogram proceeds to step 942, checking the state of the 0.007 m flag, 3 and, if present, becomes a factor equivalent to 0.007 m, usually 2, by step 944 is entered into the counter 174a to be programmed and the EORP buffer location of the RAM 126 before returning to the main program. If none of the 0.028, 0.014, or 0.007 m flags are set, the subprogram automatically sets step 946 to calibrate system 10 to perform a key for drawing 0.028 m of fluid through meter 38.

The following program 904 and subsequent programs, as shown in Fig. 9A, are a number of steps to determine which flow rate to execute and how many times each sample is tested. Referring now to Fig. 9C, step 948 operates logic and control circuit 198a to energize its

*> * 4 Y 'Y _ I

'*' I

- 61 - light 111c for hanging a key before lifting to step 950 to determine whether the flow rate or speeds to be output, as stored in RAM 126, is one of Q0 - QT »and moves if this being the case, the program proceeds to step 952a, where -5 determines whether the test is to be performed at the flow rate of Q0, and if so becomes a speed 0 in step 95 ^ -a · loaded into the speed buffer plates of the RAM 126, then in step 956a, the calibrator system 10 performs the test of the meter 38 at that selected flow rate, and outputs the results to the printer, as explained more fully with respect to FIG. 9.E and F. However, if the key is to be performed at the Q1 rate, a similar set of steps 95 ^ b and 956b is performed, with the rate 1 being loaded and performed in these respective steps. Similar sets of steps 952c-952h, 95 ^ c-95 ^ -h 15 and 956c-956h are performed, with corresponding flow rates being fed into the speed buffer and performed. If the decision in step 950 was no, the program proceeds directly to step 958, as shown in Fig. 9D, where a decision is made by examining the flags placed in the assigned areas of the RAM 126 to determine determine if a flow rate of Q8 - QF is selected, and if so, the parent program proceeds to step 960a and, if not, returns to the next step 908, as shown in Fig. 9A. Step 960a determines whether a meter is to be tested with the flow rate corresponding to the flow rate Q8, where, if this is the case, step 962a loads a speed 8 into the speed buffer of the RAM 126 and at that point by step 96Ua, testing the meter 38 through the calibrator system 10 is tested with that particular servo motor speed and flow rate. Similarly, steps 960b - 960h, 962b - 962h and 96Vb - 861th are performed, performing tests with the different flow rates and associated motor speeds before returning to the next step, which may be step 908 or 912 to determine the number of keys to be executed per flow rate.

BAD ORIGlSAL Fig. 9C and 10, after the flow rate with which a particular meter is to be tested was selected, the actual number of the lines 956 and 96U was selected. The actual meter key, - 62 - -.

k. ; J

performed by the calibrator system 10 is performed in the parent program shown in FIGS. 9E and F. First, the step 966 instructs the logic and control circuit 198a of FIG. UE to energize the key 111 operation light. Then, step 332, as shown in Fig. ΒΒ, returns the piston 1U to its park or bottom position, as shown in Fig. 1 and 2A. The step 968 instructs the logic circuit 19 ^ h to effect the opening of the inlet valve 3U and the closing of the outlet valve 36. As indicated above, a certain speed is stored in the speed buffer of 1t) the RAM 126 and the servo motor 20 driven under the control of the logic circuit 19 ^ a to that speed according to the subprogram 606, as shown in FIG. Importantly, the program 606 detects that the piston 1U has accelerated from its parking position to the key start position, as indicated by the output of the proximity detector 52, and that the piston speed has stabilized. Then, in step 970, the outputs obtained from the rotary encoder ho and the linear optical encoder 26 are prevented from passing through the signal conditioning and logic circuits 170a and 170b into their associated counters 17a and 182, respectively. , and the time dividers or factors, as originally selected on the basis of the key volume, are fed into the counter 17 to be programmed. After the piston has reached the key start position, as determined by the step 600, in the step 972, the output of the rotary encoder Uo is addressed intermittently, for example, every h0, to detect the occurrence of the rising edge of the next pulse thereof, as provided at the input to the interval clock 176. If it has not occurred, the subprogram at step 97 ^ checks the state of the proximity switch 5 ^, and if the piston 1h is in that position, there is, ie to its uppermost position in the cylinder 12, 30 an indication of an error, and the subprogram leaves via the starting point 975 in an interrupt subprogram, as explained with respect to Fig. 9G. On the other hand, when the leading edge of the output of the rotary encoder transducer ho occurs, the program proceeds to step 976, where the A output of the rotary 333ABÖf3IGJMAafductor Ho is applied to the interval clock 17 by the signal conditioning and logic circuit 170a. ^ and in particular to be at ------- 17'Ua. Furthermore, step 976 opens counter 182 to begin counting Tan the pulses obtained from the linear encoder 26 and the counter Ijka to be programmed. to count the pulses of the rotary encoder Uo. In addition, step 976 at this time opens the clock counting counter IJ6a, referred to in FIG. As clock A (e.g., 200 kHz) by dividing the clock by an appropriate factor for outputting via logic circuit 178. a one-second sampling signal, sampling the different values of temperature and pressure. In addition, an output is obtained via the interval clock 17 to open the logic circuit 177 which is further closed, thus allowing an interruption of the end of the key to be developed and, in particular, a logic one or a high signal are applied when counting down the input count by the programmable counter 1jka for applying a signal to the interrupt 2 input of the CPU 120 to start an interrupt subprogram, which is explained in detail below with reference to FIG. 9J. Then, in step 528, the data regarding the pressures and temperatures currently measured in the meter 38 and in the chamber 28 are output as discussed above with respect to FIG. 8P. Then, in step 980, the state of the counter 178a is tested in the interval clock 1j6, and the subprogram, if no pulses are accumulated, returns to the beginning of step 980 to wait for the first pulse output of the counter to occur. 178a. If a pulse or pulses are detected at the output 25 of the counter 16a, the subprogram goes to step 982, in which the counter 176a is reset to zero. Thus, the counter 176a is reset to zero upon the occurrence of the one-per-second pulse output of the logic circuit TJ8. Subsequently, in the step 98k, the meter pressure MP2, as obtained from the outputs of the pressure transducer U6, the calibration device space pressure, obtained from the pressure transducer PB, the calibration device pressure PP1, as obtained from the pressure transducer 515, the meter temperatures TM3 and TMk, as obtained from the temperature transducers h2 and and the calibrator temperatures TP1 and TP2, as obtained from the temperature transducers 57 and U8, placed in 35 BA0d @ BI € itWAl sites in the RAM 126 to be available for calculations to be performed thereon, as explained— ”----- 1 mrd in step 986, which is discussed more fully - 61 * -

I

With respect to Fig. 9L, the pressure and temperature data are converted to a floating, decimal form and in step 988, as more fully discussed, with respect to Fig. 9M, the data is accumulated and average. As explained in detail below, 5; the values of pressure and temperature in the meter 1 * 0 and in the chamber 28 accumulated intermittently, for example every second, from a time when the volume meter key started, until it ended, whereby any of the samples thus taken may be summed and divided by the number of samples for averaging the temperature and pressure parameters over time. Thus, the temperature and pressure parameters are considered to be continuously taken or monitored while testing a fluid flow meter. Even after the Ifha counter to be programmed. counted down, a final sample of these parameters is taken. Then, in step 990, it is determined whether the key 15- is ready by querying the INT2 register and, if the key is ready, the program proceeds to the next steps, as shown in Fig. 9F, and if this is not the case, the subprogram back to the beginning of step 528 to execute the then present values in the pressure and temperature buffers of the RAM 20 126 and to proceed with the meter key. The generation and storage of a flag for the end of the key allows the meter key to be terminated anywhere in the interval between the sampling pulses for taking the pressure and temperature measurements. As explained with respect to Fig. 9J, 25. thus, the flag for the end of the key is set when the countdown of the meter encoder register 17 ** a occurs in an allocated portion of the RAM 126, indicating that the key has ended.

However, the one-second sampling pulse obtained from the logic circuit 1J8 of Figure Uc has yet to take place in order to obtain the final pieces of the temperature and pressure data. The subprogram, as shown in Fig. 9A, and in particular step 990, thus allows to terminate the key and collect the last parts of the pressure and temperature data before the calibration system 10 is turned off. The use of the logic circuit 177 to zero the meter encoder counter 17 ^ a allows to quickly and effectively generate a signal or flag for the end of

If software were to be used, it would be

....... . I

It is necessary to repeatedly check the condition of the counter 17 ^ a to be programmed to determine if it had been counted down, thus significantly complicating the program to be stored in the FROM 12U and the accuracy of the time of the button termination would be reduced.

From the foregoing, it is clear that a meter key is started and terminated in response to the output of the rotary meter encoder 0. As explained above, the mechanism which couples the encoder Uo to the diaphragm of the meter 38 generates in some sense a frequency modulated signal, thus making it desirable to start and finish counting its output at about the same point in the rotation cycle of the rotary encoder i + 0. For this, the piston is accelerated from its parking position to a substantially constant velocity before passing the key start-5 position, as determined in step 6U6, at which point the key checks intermittently, for example every ^ 0 ^ us. the rising edge of the next A pulse of the rotary meter encoder hö. This next pulse A of the rotary meter encoder kQ starts counting down the counter 17 ^ a to be programmed, where> 0 is loaded into a count indicative of the key volume to be measured by the meter 38 being tested and at the same time to start counting the counter 182, which counts the output of the linear encoder 26 to provide an accurate indication of the key volume, is sucked into the calibration device 10. When counting down from the counter 17 ^ + a, a signal is applied to the logic circuit 177 to effect a CPU interrupt-2, which, as shown in FIG. 9J, squeezes the counters 17 ^ a and 182 and thus the counting each ends. Thus, the count, stored in the counter 182, indicative of the pulses obtained from the linear encoder 26, is operated to start and end its counts in response to the output of the rotary meter encoder Uo to ensure that the count, stored in counter 182, accurately corresponds to a count, as stored in the counter 17 ^ a to be programmed, which is indicative of the fluid measured by the fluid.

Referring now to FIG. 9P, the final value in step 992. —J ~ λ uw, wen na, the flag before the end of - 66 -

-: .λ,. I

the key is set, and converted to a floating, decimal form before accumulating and averaging. The final values of the pressure. and the temperature is output through logic circuit 190a of FIG.

UD to be displayed on the CRT terminal 112 in a manner, over-! 5; according to the subprogram, as described above with respect to Fig. 8P. Then, in step 99 ^, the count accumulated in counter 182 is converted to a floating, decimal form, and in step 620, the servo motor 20 is decelerated to a stop according to the parent program 620, discussed above with reference to Fig. 8G. After that, step 996 provides command signals through PI / 0 circuit 196 and logic circuit 19 ^ b to operate the solenoid associated with second outlet valve 36 to open it, and to operate the solenoid, associated with the first inlet valve 31 for closing it. Then, in step 998, the various parameters, as now finally collected, are used to calculate the volumes, as indicated by the output of the linear optical encoder 26 and the rotary optical meter encoder Uo in a manner that becomes more detailed. discussed with respect to Fig. 9ΙΓ. In the step 1000, a command is sent to the logic and control circuit 198a to energize the light 111d for key termination, and then in the step 1002, the output results, as calculated in the step 998, are transferred to the printer with hard prints, as discussed more fully with respect to Fig. 9P, and the piston 1U is returned to its lower, usual or parking position by step 322, as shown more fully in Fig. 6b. At this point, the program returns to the beginning of step 952a of Fig. 9C to determine whether to perform repeated or other flow rate keys.

In Fig. 9G, the subheading subprogram 975 is shown, which is mainly entered when the standstill pushbutton 111g is pressed by the operator or when a failure due to the assembly of an absence of rotatability has been determined in step 97 ^ of Fig. 9E. encoder counts and the presence of the cylinder in its upper position, corresponding to the placement of the 3§ADI0ftielWA <LsscIia ^ e ^aar 5 ^ · When the stop button 1l1g is pressed, the servomotor 20 is slowed to a stop, and the set "inclocks" to a standstill until primary energy is removed - 6τ - and then reapplied. When energy is reapplied, calibrator system 10 returns to its standby state.

In any case, the program starts at point 975 »as shown in Figure 9G, and in step 100 ^ causes logic and control circuit 5 198a to operate a light behind standstill pushbutton 111g. In step 1006, the prevailing motor speed, as obtained from the logic circuit 198b, is stored in the speed comparison buffer of the RAM 126. Then, the servo motor 20 is decelerated according to the deceleration subprogram 620, as shown in FIG. Then the. Step 1008 commands to logic circuit 19 * rt> to cause the associated solenoid to open the second outlet valve 36, and operate the associated solenoid to close the first inlet valve 3b. At this point, the subprogram enters wait step 1010 until power is out. removed and then reassembled.

As shown in Fig. 9H, an interrupt 1 program is entered when the operator presses the reset button 11lg of the system control and state module 111, interrupting the program being executed and disappearing to step 1012 wherein the logic and control circuit 198a is controlled to energize the light behind the reset button 111g. Then, in step 101U, the prevailing speed of the servo motor 20 is read out via the logic circuit 198b and stored in the speed comparison buffer, ie an addressable location of the RAM 126. At that point, the servo motor 20 becomes controlled under the logic circuit 19ba. . delayed to a standstill; 25 through the subprogram 620, as shown in Fig. 8G, and is returned to the program at point 212, and in particular to step 21U, as shown in Fig. 5.

A third interrupt subprogram, as mentioned above with respect to steps 976 and 990 of Fig. 9E, is shown in Fig. 9J as automatically executed at the end of the meter key when the interval key 17U outputs an impulse through its logic circuit 177 to the interrupt-2 input of the CPU 120, which pulse occurs after counting down the input of one of the factors, corresponding to 0.028, 0.01 ^ or 0.007 m of key volume, which is passed by the approx. librator system 10 must be aspirated through meter 38. In BAD ORIGINAL. .

first, the state of the system in step 1018 is stored in appropriate locations in the RAM 126, and in step 1020, the counters 17Ua and 182 Tan of FIG. 4c are pressed, and the stored count of the linear counter 182 stored in appropriate locations in the RAM 126 before each of the counters 17Ua and 182 is reset. In step 102U, one or a flag is placed in the register of key termination of RAM 126 upon the occurrence of counting down one of the aforementioned factors or parameters by counter 17a. Thus, the end of a test may take place midway between the one-second sampling pulses used to obtain pressure and temperature measurements. Thus, it is necessary to coat in order to obtain the final set of pressure and temperature measurements, which is done by setting the flag for the end of the key immediately upon the occurrence of counting down the aforementioned factors. . The calibrator system 10 remains operative to accumulate data, as indicated in FIG. 9E, until step 990 occurs, at which time the key termination of RAM 126 is checked to see if a key termination flag is set. whereupon, if so, the key is brought to an end. If the key is still running, in step 1028 the state of the system spring is called and operation of the calibrator system continues up to the interrupt point in the meter key program as shown in fig.

9E.

The program 98, generally indicated in FIG. 9E for inputting the values of the pressure and temperature, is shown more fully in the subprogram shown in FIG. 9K, in which the first step 1032, an indication of the differential pressure, as obtained from the differential pressure gauge U6, is converted into binary data by the A / D converter 166, and is stored in a dedicated location in the RAM 126. Similarly, a differential pressure, such as measured by the piston pressure transducer 51 * converted into binary data by the A / D converter 166 and stored in a dedicated location of the RAM 126 by the step 103. Similarly, the barometric pressure, as measured by the transducer 109, is applied in the space 106, in which the calibrator system 10 is incorporated, 3 ^ A c R Ö Ö “lé lé NA NA / iP iP omgezet omgezet omgezet omgezet omgezet omgezet omgezet omgezet omgezet omgezet omgezet omgezet omgezet, converted into binary data by the step 1036 and stored in an allocated location in the RAM 126. τλ > · Λο «-ΐη Λβ ο + ·.« Τγη <»η 1038.10k0. 10h2. the temperature inputs TP1, TF2,> »^ A · * ί V j • 69 - ΤΜ3 and TMU of the temperature measuring devices 57, W, U2 and Uk converted into" binary data by the A / D converter 158, and stored in allocated placing the RAM 126 before returning to step 986 of FIG. 9E.

Step 986, as generally shown in Figure 9E, is more fully illustrated in the subprogram of Figure 9L, wherein in Step 10U6 each of the temperatures corresponding to the calibrator temperatures, TP1 and TP2, and the meter temperatures TM3 and TMU, from a binary voltage, are converted to degrees Celsius in a 10 floating format, and then stored in an allocated location in RAM 126. Then, in step 10U8, the binary voltages indicative of the press MP1, MP2, and the barometric pressure PB, taken from their assigned places in RAM 126 and converted to kPa in a floating, decimal format, and stored again in assigned places in RAM 126 before returning to the step 988, as shown in Fig. 9E.

The subprogram or step 988, as shown in Fig. 9E, for accumulating and averaging the test data, is shown more fully with respect to the subprogram, shown in Fig. 9E.

20 9M. In step 1050, the digital values of the first and second become

calibrator temperatures TP1 and TP2 are combined to provide an average calibrator temperature (ATP). This value, in turn, is added to the accumulated previous values of ATP, thus accumulating a series of N samples of the average calibrator temperature while performing a meter test. In step 1052, the meter temperatures TM3 and TMU are combined to obtain an average meter temperature (ATM) and this new value is combined with the pre-accumulated values of the average meter temperature 30 ATM to obtain a quantity indicative of N

successive samples of the ATM, taken during the duration of a meter test. In step 105U, a value of the ambient or barometric pressure PB is added to the sum of the barometric pressure PB plus the pressure difference MP2, measured between the ambient pressure and the pressure established in the meter 38 to obtain an average with pressure (APM).

BAD ORIQINAL

The average gauge pressure is added to the pre-accumulated values of the mean gauge pressure to obtain a quantity,

* · / *. ; I

- 70 - which is indicative of N successive samples of the AFM, measured during the meter test. In step 1056, a value of the ambient or barometric pressure PB is added to the differential pressure, as obtained from the differential pressure PP1 transducer or 51, to obtain an average calibration instrument pressure (APP). Device pressure (APP) is counted as the previously accumulated values of the average calibrator pressure to obtain a quantity indicative of IJ successive samples of the APP, measured during the meter test. In step 1058, the number of samples of 10 each of the values, previously taken in steps 1050, 1052, 105, and 105, added together to determine the total number of U samples, and in successive steps an average value of each of these parameters can be obtained by dividing by the factor N the accumulated quantity.

Now, step 998, as given in Fig. 9F, is discussed in more detail with respect to Fig. 9U. As indicated above, the accumulated values of the mean calibrator temperature (ATP), average meter temperature (ATM), average meter pressure (AMP) and mean calibrator pressure (APP) indicative of U samples taken during the meter test, and in step 1060 these mean values were obtained for each of the temperatures and pressures. Then, in step 1062, the error rate of the output of the meter encoder 40 of the fluid passing through the meter 38 with respect to the standard volume passed therethrough, as drawn by the calibrator system 10, is calculated according to the indicated equation. The values of meter pressure PM, calibrator pressure PP, calibrator temperature TP and meter temperature TM are the average values, as determined from step 1060, in addition to the calibrator volume count 30 K vas obtained as an indication of the accumulated counts produced by the linear encoder 26 and accumulated in counter 182, sheet counts are indicative of a selected standard volume 3 3 3 me, for example, 0.028 m, 0, θΑ a or 0.007 m. As shown in Fig. 9N, the ratios of PM-PP and TP-TM provide respective-βη. As explained above, there exist differences in fluid temperature and fluid pressure between the fluid in the meter calibrator 10 and the fluid gauge 38 which

* V. I

- 71 - is being tested. Said ratios, as determined by step 1062, provide appropriate correction factors, compensating for the differences in temperature to provide an accurate indication of the error rate of the meter reading of the fluid volume with respect to the calibrated indication or reading. by the meter calibrator 10. The factor K * is representative of the counts stored in the counter 174a to be programmed, indicative of the fluid flow as measured by the meter 38. As shown in step 1062, the factor K * 10 is multiplied by a constant C for converting the count,

..... O

for example 40,000 for 0.028 ar in a value of the volume to be drawn through the meter 38. In the exemplary embodiment, where the factor K *, as entered into the counter 174a to be programmed, is 40,000, the constant C is chosen as I ^ q '.' Qoo * Furthermore, the number of 15 counts obtained from the linear encoder 26 and counted by counter 182 multiplied by a calibration factor, which, as discussed in detail below, is obtained by accurately measuring the volume of the chamber 28 of the meter calibrator 12 and correlating the accurately measured volume with the 20 series of pulses output by the linear encoder 26. In an output example, for a chosen volume of 0.028 m from the chamber 28, it was determined that 30,790 output pulses were obtained from the linear encoder 26. Thus, the calibration factor is chosen as the inverse of this count or 26 '. 790 * * n <a ^ and a first volume 25 must be drawn through the meter 38 and the counter 174a to be programmed must be programmed with a count corresponding to a different flow, it is similarly necessary to use a different calibration factor corresponding to the volume, as determined in a chosen region of. the chamber 28. In practice, the count of 38,790 is obtained experimentally by moving the piston 14 o over a length of the chamber 28 corresponding to exactly 0.028 m, and calculating or otherwise determining the number of pulses, as performed by the linear encoder 26. Similar measurements and codings are performed experimentally to determine the counts

O

35 for a 0.014 and a 0.007 ar flow, corresponding to the output of the ORIGINAL linear encoder 26 when the piston 14 is moved over distances from the key position through the cylinder 12 and at 1 *. *. ♦ '- 72 - 3 3 example corresponding to 0.01 µm and 0.007 µl volumes in the cylinder. The actual counts and therefore the corresponding calibration factors for 0.01¼ and 0.007 m thus correspond exactly to the volumes, as determined by the cylinder wall of the chamber 28. In this way, a calculation can be made with great accuracy of the percentage of error between the reading of the meter 38 and the actual volume, as drawn into the chamber 28, by using calibration factors determined according to the precise volume of the respective areas of the cylindrical wall of the chamber 28. After step 1062 is executed, the program returns to the next step 1000, as shown in Fig. 9F.

The calculation of the average temperatures and pressures, as generally taught in the step or subprogram 1060 of Fig. 9N, is more fully represented by the subprogram, as shown in Fig. 9Q, as previously indicated in step 1050 wherein each measurement of the temperature is counted against the previous measurement to obtain the total indication of accumulated individual measurements of the calibrator temperature ATP during a single key. As indicated in step 106h, as shown in Fig. 9Q, this accumulated value of ATP is divided by the number of samples AVOIR = N + 2 and counted at 1 * 59.67 to provide the final mean temperature FTP of the calibrator in degrees Kelvin. Similarly, in step 1066, the values of the temperatures TM3 and TM1 * are successively added together 25 'during a meter key to provide the accumulated value of the average temperature ATM of the meter during the key, and the ATM is divided by the number of samples or counts of the one-second sample clock signal, which in turn is counted at U59.67 to provide a final mean temperature FTM expressed in degrees Kelvin. Similarly, in step 1068, the accumulated values of the mean pressure APM of the meter, as accumulated during the test, divided by the number of AVCTR samples taken during the test to provide a final FPM of the meter, are expressed in kPa. In step 1070, accumulated values of the mean calibrator pressure APP, as accumulated during a meter test, are divided by the number of AVCTR samples to provide an indication of the off%. t>. , <7 ~ • ·] - 73 - final pressure of the calibrator FPP, expressed in kPa before returning to the next step 1062 »as shown in Fig. 9N.

The accuracy of the meter calibrator 10 for measuring the volume drawn by the meter 38 depends on and is limited by the changes in the fluid pressure and temperature measurements during a meter volume test. The changes in fluid pressure and temperature, as occurring during a meter volume key, are greater than the changes that may occur during measurement 0 and calibrating the volume of the meter calibrator. Generally, therefore, the actual volume of fluid supplied by the meter 38 when the piston is moved 1¼ from a first to a second position can be approximated by the following expression:

/ po] + v2 [(ΛΤ / τ1) - (^ p / p1) J

15 in which and, respectively, the original volume, fluid pressure and temperature are present in the chamber 28 of the calibrator 10 at the start of a meter volume key, P and SIT are the corresponding changes in pressure and temperature, which changes occur during the tests and T and P are the mean deviations of P at the fluid meter 38. As explained above, the logic circuit 178 provides, as shown in FIG.

fcc, a one-second clock signal, which samples the output of the temperature transducers U2, U8 and 57, as well as the pressure transducers h6 and 51 to provide samples of these variables throughout the meter volume key. As discussed above, the periodic samples of meter temperature TM3 and TMU and calibrator temperature TP1 and TP2 as obtained in step 98U of FIG. 9E are summed in steps 1050, 1052, 105 ^ and 1056 of FIG. 9M for obtaining a spatial average meter temperature and calibrator temperature averaged in time by being sampled and summed during the test, as explained with reference to steps 106 +, 1066, 1068 and 1070 of FIG. 9Q. In this way, the continuous changes in both pressure and temperature at the fluid meter and calibrator 10 are monitored.

By averaging in this way in a spatial and temporal sense. "5.,; ! - 7 * »-

the changes in temperature and pressure that would otherwise cause an error in the calculation of the volume change can be avoided. Temperature changes in the fluid, as drawn into the meter calibrator and caused by adiabatic expansion 5 over a pressure drop of 373 Pa, may rise to 0.3 ° C, and cause an error in the calculation, which may rise to 0.1%. Thus, it is necessary to closely monitor the fluid pressure and temperature throughout the system, and make necessary corrections to obtain the "purge" volume sucked into the meter calibrator 10. For an accuracy of 0.05 # in the volume , the parameters $ T

and 6 P between the chamber 28 and the meter inlet are monitored to an accuracy of better than + 0.06 ° C and + 1.25 Pa, respectively. The temperature transducers described above with respect to Fig. 1. pressure transducers have such power to achieve the desired accuracy for temperature and pressure measurement, and provide the desired accuracy in volume measurement.

The step 1002, as shown in Fig. 9F for outputting the results of the keys executed on the meter 38, to the printer with hard prints, is more fully shown in Fig. 9P. In the first step 1072, the printer is checked by the logic circuit 190b to start its operation, after which the error rate, as previously calculated in step 1062, is printed by the printer. Then, in step 107 ^, a line feed command is created for the printer to advance its paper by one line before the flow rate at which the key was performed is displayed in step 1076 in step 1076. In step 1078, ten line feed command signals applied to the printer to then advance the lines before returning to step 322 in FIG. 9F

An important aspect of the invention lies in the method of accurately measuring the volume of the chamber 28 of the cylinder 12, and using that measurement to accurately calibrate the output of the linear encoder 26 to provide a manifestation of the volume per pulse output of the linear encoder 26. As indicated in Fig. 2A, the linear encoder 39AD contains pHHalAèld scale 2h with a plurality of markings 102 accurately and closely spaced, the optical encoder 26 being a. -JroTcf.hjs-Ft. corresponding to the movement of each of these markers along the op, <ιΤτ ifi, n hi'éé Vitn Τ "ΐ '·· ιΜΓι4ΐννιΐ · ^ ι.ί _ - T5 - · by accurately correlating the number such outputs with the accurately determined volume of the chamber 28, the linear encoder 26 can be encoded with a correspondingly high degree of accuracy to thereby improve the calibrated indication of the meter record or error of the meter 38 being tested.

In such a calibration procedure, it is first necessary to measure the volume of the chamber 28 with great accuracy. A method of volume measurement is employed which includes the creation of a high-frequency electromagnetic field in the cavity, the measurement method of which is now explained. The inner dimensions of the regularly formed chamber 28, completely surrounded by conductive walls, can be accurately determined by measuring the frequencies, with resonance states occurring for the electromagnetic field created in the chamber 28. For a given geometry, the electromagnetic fields in the chamber 28 take a variety of spatial forms At separate frequencies, the electromagnetic energy contained in the chamber 28 is stored over time intervals that are long compared to its wave period, where these resonance solutions are referred to as the Usual States of the Chamber 28. The ratio of the stored energy to the energy lost per cycle of the resonant frequency is determined as the quality factor or Q of the resonance The quality factor Q is a measure of the scattering losses due to the ohmic weather. positions of the walls for the electric straw one induced by the electromagnetic fields. For a particular conventional state, the resonant frequency per se is determined by the dimensions of the chamber 28 and the propagation speed of light in the medium filling the volume. Therefore, by simultaneously measuring the resonance frequencies of a number of common states, equal to the linear dimensions, that determine the volume (one for a sphere, two for a straight circular cylinder, etc.), the volume of the chamber can 28 are determined with an accuracy comparable to the accuracy of the frequency measurements.

35 BATH ORIGIty ^^ For a given chamber geometry there is an infinite set of common states, the resonant frequencies of which have a lower -------- i. The order of the linear dimensions of the chamber 28, but no upper limit. A volume change, caused by a mechanical displacement of one of its linear dimensions, in turn changes the resonance frequency of the low-order states by about the same fraction.

Briefly, as shown in FIG. 10, means in the form of the antenna T0 are provided to create or generate the electromagnetic field in the chamber 28, and to extract a relatively small portion of the stored electric-10 tromagnetic energy to be measured by the circuit of Figure 10.

As discussed in detail below, measurements are made to determine the frequencies f at which resonance occurs in the chamber 28. The choice of the shape of the chamber 28 is important, since if an arbitrarily shaped chamber is used, the mathematics The relationship between the resonant frequencies f and the dimensions of such a chamber cannot have a closed or analytical solution. Thus, the chamber 28 is chosen with a regular geometry to ensure that the scattered losses and coupling effects are negligible, and to provide known Mazwell-20 equations that determine the relationship between the chamber dimensions and the resonant frequencies depending of the boundary conditions, that the electric field E is radial, and the magnetic field H is tangent to the fully enclosed surfaces of the regularly formed chamber 28. Under these conditions, the field solutions for the chamber 28 take a relatively simple form and recognizable disturbances can be predicted.

Thus, in a preferred embodiment, the chamber 28 is selected as a straight circular cylinder formed by the inner surface of the cylinder 12, the head 60 and the free surface of the piston 14.

It is recognized that a chamber 28 of such shape makes it possible to drive the piston therethrough to displace a known volume of fluid, as set forth above. The usual states of the electromagnetic field established in chamber 28, designed as a straight circular cylinder, 3SADOftHHMflLin become two general classes, namely the transverse electrical states (TE), for which the electric field is zero according to the cylinder Tremor? 8. and the transverse magnetic states * / *** ·! - TT - (TM), for which the magnetic field is zero according to its cylindrical centerline. They are further determined by three integers 1, m and n, which for the TE states refer to the cylindrical coordinates r, Q and z are determined by: 5 1 = number of full-period change of E ^ with respect to Θ; m = number of half-period change of E ^ with respect to r; n = number of half-period change with respect to Θ; z.

A similar set of indices exists for the TM states, for which the integers 1, m, n are determined correspondingly for 10 with respect to the components of the magnetic field, and H 1.

The solutions for the resonant frequencies of the usual states are expressed in terms of the geometric dimensions and roots of Bessel functions by the general expression: f- (c / D) [(ÏS_) 2 + (§) 2 (£) 2] 1 / 2 (1) 15 where D is the diameter, L is the length, c is the speed of light in the medium filling the cavity © volume and χ1τη are given by: x. = me square root of J '. (x) = 0 for the TE states.

lm 1 x, = m square root of J_ (x) = 0 for the TM-t o e positions, lm i

Numerical values for these Bessel roots, corresponding to the different lower order TE and TM states are taken from the following table: cross-electric states cross-magnetic states _ (TE) _ _ (TM) _ TE X .. TM x, _ lm _ lm 11 1.84111 01 2.40483 25 21 3.05424 11 3.83171 01 3.83171 5.13562 31 4.21009 02 5.52008 41 5.31755 31 6.38016 12 5.33144 12 7.01559 .2 2 30 An expansion of the quantity (fD) against (D / L) of the output KWh) is a straight line intersecting (cx ^ / ΤΓψ and the slope (cn / 2) 2. state graph is shown in Fig. 13 for -? 8 - for the lower states of the straight cylindrical chamber 28 for values from n to 2. Fig. 13 graphically shows the "respective resonance frequency values as a function of the geometric parameter (D / L) and the change in resonant frequencies is changed from the linear dimension 5 L. Fig. 13 is also useful for predicting the number of resonances that may be expected in a given The frequency range for a fixed D / L ratio, as well as the values of L at which two different states have degenerated in frequency and therefore interfere with each other.

7.0 The state graph of Fig. 13 is used to determine the electromagnetic field excitation states, the expected resonant frequencies of the selected states and the size in terms of the diameter D and the length L of the chamber 28. In an exemplary embodiment of the chamber, as shown in Fig. 10, the diameter D is set at 30 cm, and the change in length L from 25 - 75 cm. As a result, the corresponding values of (D / L) have the range of values from 1.UU to 0.16. If the frequency sensing range is between 500 MHz and 1000 MHz, (fD) is variable between 2.32 20 2 · 2 x 10 and 9.29 x 10 (cycles / s) cm -1. The number of expected resonance states over the change in length L for this shape between the range of 500 and 1000 MHz is then exactly given by the number of lines contained in the rectangle shown in the state graph of Figure 13. As it can be seen that at L = 25 cm, there are only three states, which occur between 500 and 1000 MHz. These are n.1. the TM state, occurring at about 755 MHz, the TE state, occurring at 830 MHz, and the TM state, occurring at 960 MHz. For L -75 cm, on the other hand, there are eight states, namely TE ^^, TE ^ g, TMq1Q, TMq ^, TM ^ g, TEg ^, T®212 eEL ^ 113 'jfc * ie ^ slialve are not shown in Fig. 13. At an intermediate location, the number of states and their resonant frequencies f can be obtained from the intersection of the vertical line corresponding to the desired (D / L) value with the lines indicating the different states. Because the measurements of the resonant frequency of two different states, by themselves, determine both D and L, the other states may be & AD © fftGWWL as a redundancy check on the measurements or as a means of verifying the effects of disturbance caused by distortion.

• ^ Aa a «er oöTii nol t ίΤΟΤΤβ 1 Q1 STTI P

· · "7" V.. J

-79- order correction terms, which may be present.

In a qualitative sense, it is clear that the electric and magnetic field components of the electromagnetic field are perpendicular to each other and have a certain ratio at a resonant frequency to the dimensions D and L of the chamber 28 of regular geometry, and in especially the diameter and length of the chamber 28 ', as shown in Fig. 10. As explained, the relationship between the resonant frequency and the dimensions D and L for a given state can be given by a mathematical expression.

The chamber 28 with a straight circular cylindrical shape has two unknown dimensions, which determine its volume, ie its diameter D and its length L. It is therefore necessary to provide two mathematical expressions, which can be solved simultaneously for the unknown values D and L, so that it is necessary, as indicated above, to create electromagnetic fields in the chamber 28 with two different states, and to obtain the resonant frequencies of these two states, the values of D and L and thus the volume of the chamber 28 can be calculated. As discussed, the excitation states are chosen to determine resonance frequencies with associated high quality factors, whereby the effects of perturbations on errors in the measurement of D and L can be minimized.

The 7MQ10 state line has a slope of zero, as shown in Fig. 13, and is therefore independent of the size L of the chamber, and only a function of the diameter. This particular property can therefore be used to identify this condition in experimental measurements. The TM ^ q state of excitation can be used to obtain an independent measurement of the dimension D. Furthermore, it can be seen that the rate of change of the resonant frequency for one particular state, as a function of the dimension L, becomes determined by the last index n. As a result, the frequencies of the states, such as TE ^, shift to the same degree as L is changed, with the TE ^ g, TMq ^ and TE ^ g states shifting together at twice the rate.

BAlDi-ORieilfcArblge, the tuning properties of these states can be used to determine with a very high degree of accuracy the value of the absolute diameter of the -80-.

-. .., -. I

"·«. . ; cavity is determined.

The quality factor or Q of the chamber 28 resonance, as energized in a particular conventional state, is important in two respects. First, it determines the sharpness of the resonance frequency response and therefore limits the ultimate accuracy with which the resonance frequency can be measured experimentally. More importantly, the quality factor Q is a measure of the order of magnitude of the expected deviation from the resonant frequency of the idealized results, as given by the equation (1). In general, the theoretical expressions are more accurate in determining the geometrical dimensions of the cavity the higher the Q for a given state. Thus, the energization states of the chamber 28 are chosen to provide the highest quality effect ears Q, thus providing the more accurate determination of the size and thus the volume of the chamber 28.

For a volume consisting of perfectly conductive walls, the unloaded or intrinsic Qq of the chamber is infinite, and the frequency solutions for the usual resonant positions are exact.

For walls of finite resistance, the electric and magnetic fields in the chamber 28 penetrate the walls over a distance, determined as the skin depth 6 given by the expression: £ = [λρ / 120] 1 / 2 cm (2) in which ju is the permeability of the vandal material, Λ is the free space wavelength in cm and f * is the resistance (direct current) of the walls in 25 ohm-cm. Since finite skin depth makes the apparent dimensions of the room, as seen by the electromagnetic fields, slightly larger than the actual geometric dimensions, the loss effect caused by the ohmic losses on the walls disturbs and shifts the resonant frequency of the usual states to a lower 30 value. The measurement of this perturbation is the value of the ratio of the skin depth to the free space wavelength or (6 / Λ), which can be calculated through the equation (2) by applying known values of the DC resistance and the permeability of the wall - material. For a cavity made of copper (M 88 1, P - 1.72 x 9§ ^ * o ^ ib-cm), the skin depth is 3.8 x 10 “^ λ 1/2 cm. At 1000 MHz (A * 30 cm), the ratio (<8 / λ) is approximately equal to •> 1 * * * · __ *% * - 81 - 7 x 10 "6. This correction to the resonant frequency caused by finite conductivity, is clearly negligible for the present application For stainless steel series 300, (^ u = 1, p = 72 x 10 “^ ohm-cm), the ratio of (^ / Λ) at 1000 MHz is the same to t, 5 x 10 ^, 5, which does not become negligible compared to the desired, overall accuracy of 0.01% in absolute volume accuracy. In a preferred embodiment, the walls of chamber 28 are coated with -6 chromium (= 1, ƒ * = 13 x 10 ~ ohm-cm), and the corresponding value of (b / X) is equal to 2 x 10 ”^ at 1000 MHz. Consequently, based on theoretical calculations 10, the correction to the resonant frequency of the Usual conditions in chamber 28 of straight circular cylindrical shape are negligible, the expression given by equation (1) must be full are capable of giving a total volume determination to an accuracy of better than 0.01%.

In practice, however, the theoretical skin depth value for a particular material is never achieved due to a variety of reasons, such as wall imperfections, material contamination, and surface residual contamination. As a result, it is necessary to experimentally determine the effective skin depth by measuring the Q of the chamber 28 for selected preferred excitation states. and, if necessary, to make appropriate adjustments to the volume determination resulting from this effect.

The expression Q, q of the chamber 28 is obtained by verifying the ratio of the stored energy to the scattering losses occurring on the walls per cycle of the electromagnetic vibration, which can be written as: 2 ƒ H2dv Q = - 2- (3) S {/ axis where H is the magnetic field vector of the usual state and b is the skin depth. The Q factors in terms of the usual conditions and geometric shape for the chamber 28 with a straight cylindrical cavity are given by the following expressions: 2 2 2 2t 3/2 BAD ORIGINAL [Wil / xJ J [xlm + p RJ # ^ 2 ÏÏx2 + P2! * 3 + (1-R) (£ ^) 2] l lm X.

im - 82 -!

For TM states: s t * L * &?] 1/2% 'Q, - = -—- for n> 0 (5) 0 2 // (1 + R) x.

= - for n = 0 TT (2 + R) where R '* (D / L), P = n ff 12. and all other symbols, as defined above.

By verifying the right sides of the previous expressions for a given state and cavity geometry, and dividing them by the experimentally determined Q, an effective S / λ can be obtained. A direct comparison of the result obtained with the 10 calculated through equation (2) then provides a quantitative verification of the magnitude of the disturbance expected in the volume determination of the chamber 28.

The chamber 28 is coupled to an external measuring circuit, as shown in Fig. 10, where microwave energy is fed into the chamber 28 to create an electromagnetic field therein, and extract reflected energy therefrom. The chamber 28 is a reflecting cavity, which requires only a coupling member in the form of the antenna TO. As discussed in detail below, the resonance property, and in particular the resonant frequency, of a particular conventional state, determined by measuring the energy, is reflected from the antenna 70 as a function of the incident microwave frequency. The use of a reflecting chamber 28 allows for minimal disturbance of an idealized cavity response, and an embodiment using a directional coupling member 110β, 25 that allows sampling of the reflected energy without interference from the incident energy. As shown in Fig. 10, the energy output of a time base generator 1100 is applied to energize the antenna 70, the reflected energy of which can be transferred by the coupling member 1106 to a crystal detector 1110.

"_____ The presence of the coupling member in the form of the antenna 70 introduces an additional loss in terms of the scattering of the electromagnetic resonance energy stored in the chamber • -.1-1—>, a +, measure . This is

Tiihr-'MTa ^ '- "- r-hirrnrBlniTi-Mnrii ·' · '' y - ^ - ί '> - -', -... .. ...

· - * "*" I

Usually determined as an equivalent coupling Q or Qc to distinguish the "unloaded" Q of the cavity or Qq. In addition, the interaction of the cavity and the rest of the circuits of FIG. 10 through the antenna T0 must be taken into account in order to derive an accurate description of the "cavity coupling system" for verifying the appropriate expressions in the application.

It can be shown that for a reflecting chamber 28, ie a chamber for which energy is input and extracted by a single antenna T0, the ratio of the reflected energy to the incident energy is given near a resonance by the expression: ·, / * $ ' (P./PJ = -Γ — Γ1-5-5 “(6) 1A (i * V + (»> 0 -y> o where V is the frequency, i / the resonant frequency, Qö is the unloaded Q of the cavity resonance and Q is the coupling Q, which is 0 proportional to the energy loss by the coupling member.

5 At the resonant frequency V, the ratio of the reflected energy to the incident energy is determined as the reflection coefficient for the determined usual state, ie: 'Vó' 'yo ~ Pm K - V2 / (V%> 2 t7 )

For β = φ, the cavity 100 # is considered coupled and Qq = Qc · This state corresponds to the low frequency equivalent chain case, where the load impedance is matched with the generator impedance.

Combining equations (6) and (j) and eliminating Q,

V

the unloaded from the usual state with regard to the measurable parameters is given by: <l = v r (pji) - & h. (p / p)] 1/2 / (y - y) d + β 1/2> <β) o o L r o r r o o

Therefore, by measuring β and the frequency width at any energy level (P / P) on the cavity resonance response curve, the quantity Q can be determined. If a "half energy" point 30 such that: P1 / 2 * 0 + f) / 2 »(9) * ----- 1 ,, - t corresponding to the two half energy points, - 8k -

. .-F .... / I

known as the "half width" of the resonance response, which is given by: where ν 'is the frequency corresponding to the half energy-5 points. For this case, the equation (8) can be further reduced to: <a = (2 ** J Δ *) / <1 + P 1/2) * (10) o o 1

The value of Qq is therefore variable between (ν '/ Δ V) and (2 1 / / 4 ν') depending on the degree of coupling.

'10 A graphical representation of the room response curve, along with the determined parameters, is shown in Fig. 1U. The center frequency of the response, V, corresponding to a minimum of reflected energy, is the resonant frequency of the usual state.

It is clear that the frequency measuring circuit, as shown in Fig. 10, causes a change in the resonant frequency, ie the pulling of the frequency caused by the interaction between the chamber 28 and the elements of the circuit of Fig. 10.

In the circuit, as shown in Fig. 10, in which the frequency of the time base generator 1100 is changed by a factor of about 2, the directional coupler 1106 receives the output energy from the time base generator 1100 and applies a relatively small portion thereof to the antenna 70 Specifically, the energy applied to the auxiliary or output gate of the directional coupler 1106 is approximately Q0% of the output of the time base generator 1100. The chamber 28 is connected to the main input gate, and the crystal detector 1110 is connected. with the third gate of the directional coupler 1106 for measuring the microwave energy reflected from the chamber 28. The use of the directional coupler 1106 results in a factor of 100 attenuation or "padding" between the time base generator 1100 and the load, as imposed by the antenna 70. As a result, the time base generator 1100, respectively, is separated from the antenna 70, dw .z. the coupling system, to ensure that no mutual action takes place disturbing the room response. As a result of the separation imposed by the coupling member 106 between the antenna, "degree of frequency measurement" determined 1. * ~ '- 85 -

I

by the quality factor Q of the chamber 28, the coupling coefficient y3 and the VSW. between the crystal detector 1110 and the cavity coupling set. Assuming that the time base generator 1100 is completely disconnected from the cavity 28, it provides a cavity 28 with a quality factor Q of 5000, a coupling coefficient β of 0.5 and a residual VSWR of 2, a frequency measurements on the order of 1.3 x 10 or 0.0013 $. This deviation is of an order of magnitude hotter than required to achieve a desired overall chamber volume measurement to an accuracy of better than 0.01 $.

Furthermore, an analysis of the cavity 28 and its associated vibration frequency measurement system, as shown in Fig. 10, have shown that perturbations due to deformations in the geometry of the chamber 28, regardless of whether they are due to the non-roundness of the cylindrical shape of the cavity 28 or minor local surface irregularities and deformations indicate that these disturbances can be compensated for by taking the following precautions. If the machine tolerance of the chamber 28 is such that the diameter D of its cylindrical shape is kept within the limits of 0.305 millimeters unround, the diameter D and thus the volume of the chamber 28 can be determined with an accuracy of the order of 1 <T5 or less, and thus such distortion can be neglected for the present method of measuring volume. Similarly, the shift in. the chamber resonance frequencies for a conventional condition, caused by a minor inward or outward dent in the interior wall of the chamber 28, are considered negligible if the hole size is well below the cutoff wavelength of the electromagnetic field established in the chamber 28, and the hole does not couple an electromagnetic field to another structure, under which conditions the frequency counting 30 is approximately proportional to the ratio of the third power of the hole diameter to the volume of the chamber 28. Thus, in practice the frequency measurement for inward or outward dents in the walls of the chamber 28 is negligible, for example a hole with a diameter of 2.5 cm, such as placed in the chamber 28, with a diameter of about 30 cm and a length of 50 cm, providing a change in the resonant frequency from just seven parts in 10 µ.

* if the inlet 62, as well as the - 86 - receptacles for receiving the transducers 51 and 57 through the piston 1U, which openings or holes may be filled with metal plugs, during the volume measurement and the calibration to virtually eliminate the these sources of error affect the determination of the resonant frequency.

In order to meet the accuracy requirement of + 0.01 / 5 in the measurement of the displacement volume of the chamber 28, the resonance frequency measuring circuit, as shown in Fig. 10, must be able to measure the resonant frequencies of the usual states, such as X established in chamber 28, to 1 part in 10 ^.

The circuit, as shown in Fig. 10, is designed to reduce the systematic error, which can affect the measurement of the resonant frequencies f, perturbations due to mismatched impedances between the time base generator 1100 and the an-I5 tenne 70 , changes and fluctuations in the microwave energy, strange noise and sensitivity to component drifts. As shown in Fig. 10, the microwave energy source is in the form of the time base generator 1100. The time base generator 1100 can, as shown, be operated at a fixed frequency (CW) or automatically for time basis through a range between 50 kHz and 300 MHz with a frequency set between 0.05 Hz and 30 kHz. In addition, the output of the time base generator 1100 can be controlled by its vernier knob 1100a for going through said range at a frequency change controlled by the operator. The output of the time base generator 1100 is passed through a co-axial cable to a directional coupler 1102, which acts as a transformer, transferring a portion of the energy applied across the coupler 1102 to a frequency counter 1108. As below Counter 1108 shows the frequency at which a standing wave is established in chamber 28. In turn, the output of coupler 1102 is passed through a similar coaxial cable to a second coupler 110¼ in turn. to be applied to a microwave antenna JQ through the directional coupler 1106. As shown in Fig. 10 and more detailed in Fig. 2A, the microwave antenna 70 is a simple, BAD ORIGINAL. ^ 35 metal gravy 70a, and isolated by an insulator 70b from the head 60 of the chamber 28.

"Ncppm is known, the antenna - 8T - * * 1", f. . 70 energy reflected from the chamber 26 upon the occurrence of a standing wave decreases significantly compared to the energy reflected at other frequencies. This is known as the resonant state, and its frequency as the resonant frequency. Thus, when the frequency of the output of the time base generator 1100 is changed, a resonant frequency is selected at which a standing wave occurs in the chamber 28, depending on the shape and dimensions of the chamber 28. The frequency at which the standing wave is generated , as discussed, determines the chamber dimensions in terms of the diameter D and the length L, and therefore the volume of the chamber 28. To sense the energy fall at the resonant frequency, the coupling member 1106 is connected to the crystal detector 1110, which converts the microwave energy reflected from the antenna 70 into a direct current signal. In turn, the crystal detector 1110 applies its DC current output to the Y input of a cathode ray oscillograph 1112.

The X input to the cathode ray oscillograph 1112 is provided by the time base generator 1100 so that when the generator 1100 is set in the time base state, the reflected energy response from the chamber 28 is a function of the input signal frequency and is displayed on the cathode ray oscillograph 1112. As can be seen in the extended spring 1112a, the energy reflected by the antenna 70 dips to a minimum 1113 at the resonant frequency in a manner shown in FIG. 1U. The frequency at which the minimum 1113 occurs is displayed on the counter 1108. The second coupler 110U> 5 applies microwave energy to a crystal detector 111U, which provides a corresponding DC signal to be amplified by a computing amplifier 1115 and applied to the time base generator 1100. providing level control over the output of the vibration base generator 3100, wherein substantially a regular energy drain 30 is placed on the time base generator 1100 as it passes through the frequency at which a standing wave occurs.

The circuit of FIG. 10 is operated in the following manner to obtain a measurement of the resonant frequency. First, the timebase generator 1112 is set for a wide range in order for the 35% effective, in principle, to display all common state resonances simultaneously on the cathode ray oscillograph screen —— + · ί. separate a certain state - wj 7ü tit 'i <i in mι mr «mn - - 88 - 1j *' v! this can be represented by an appropriate choice of the range width and center frequency thereof. Unambiguous identification of the states can be accomplished by measuring their resonant requirements for a given piston position setting in the 7 chamber 28, and using the equation (1) or alternatively the piston position and compare the change speed of their resonant frequencies as a function of the piston position with that shown in Fig. 13.

The resonant frequency of a given state is measured by first displaying the response curve on the screen of the cathode ray oscillograph, then switching the time base generator 1100 to its CW state and manually fine tuning frequency button 1100a until the voltage displayed on the cathode ray oscillograph 1112 is a minimum. The display on the frequency counter 15 1108, when this minimum is reached, is then the resonant frequency of the usual cavity state. For convenience, the second beam of the cathode ray oscillograph 1112 can be used to better determine the position of this minimum by adjusting the system to the time base state and manually changing the vertical position 20 of the second beam so that it is just the bottom of the resonance response curve. When the generator 1100 is switched to operate in its CW state, the resonant frequency f of the chamber 28 is then the frequency setting of the generator 1100, corresponding to the state that the two beams coincide. In a preferred embodiment, the effect due to frequency drifts of the generator 1100 by simultaneously reading the frequency output when the two beams exactly coincide is canceled, so that the measurement can be performed with a much greater degree of accuracy than the inherent stability of the time base generator 1100. Moreover, since the measurement depends only on determining the minimum in the room response curve, the measurement is independent of non-rectilinear response of the generator 1100, as well as fluctuations in the incident microwave energy with time. Repeated measurements at a given state indicate that the resonant frequencies of the 3fAD®9 '^ W> are determined to an accuracy of better than +3 kHz or about five parts in 10 ^.

... · * .. ΛΛ ^, · "" βν (ΎΓιη vaa preferred for the

.,. ,,. -V. . I

- 89 - Accurately measuring the volume of a section of the chamber 28 discussed in detail. Generally, the present method includes measuring the resonant frequency of the chamber 28 for two different energizing states. As an example, the straight cylindrical chamber 28 is considered and the measurement of the resonance frequencies in the TMq ^ q and TE ^^^ states. Both states are not degenerative, and their resonant frequencies can be determined to an accuracy of 1 part in 10 or better using standard techniques. The TMq.jq state (parallel plate state) depends only on the mean diameter (D) of the chamber 28 and independently of the cavity height (L), the state being dependent on both (D) and (L). The volume of the chamber 28 can therefore be determined from the measurement of two frequencies. For the case of TM01q state: -X = resonance wavelength - —— or D * ^ 11 ^ X01 15 where D = diameter, X-. »First Bessel root or J (X) = 0.

Ul O

For the case of TE. State: \ 2 Λ p = resonance wavelength = -—- (12) / r axi 11a; ~

Vtrr | T

where D = diameter, L = length or height of cavity, X ^ ^ = first root of J ^ (X) »0.

Combining the two results gives ^ ol 1 / o y r ~ C y I ^ ^ * λ ,, ι-1 / a '->. in (, 3) "ΙΛ A" (X01,

As for the resonant frequencies, the results can be expressed as: r “j

Xmc. f. X .. 2 -1/2 d = -91- L = —- 1 - -L. JU. (1J +) 7Tfi 2f2 [f2 X01 where = 1.84ί2, X ^ = 2, ^ 048 and c * light speed in the medium filling the cavity (air for the present application).

BAD ORIGIN ^? 1 * what ^ t the total volume of the room:

>? -,. I

"I

-90- Γ 1 -1/2 Φ *> i ‘*, _A 22 fn 2

Volume * Γ L = "y \ A" 4 1 xoij, ο Γ f 2 X 21 "1/2, CV, .11.-11- (, 5, ζϊϊφ2 [f / 1X01 J.

3

As can be seen, the first order volume is proportional to or 3 1 / f. Therefore: 5 3 * λ_ or 3 [&] (16) 7

Thus, the frequencies can be accurately measured to 1 part in 10, such as by the counter 1108, and so the theoretical accuracy 7 for v is on the order of 3 parts in 10.

The method can be used to continuously measure the volume change of the straight circular cylinder 12 caused by a positive displacement of its piston 11. Both the volume of the chamber 28 before and after the piston movement, as well as the speed of the volume change can be measured in a simple way. For the device shown in Fig. 10, when the piston 11 moves from position X to position Y, the resonance frequency of the IIq-jq state remains the same (or changes little due to irregularity in the diameter of the cylinder) and shifts the resonant frequency of the TE, ^ state by an amount proportional to the displacement In L. In position X, the resonant frequencies f1 and f2 are measured and added in the equation (2) for providing an indication of a first volume V1. Thereafter, the piston 1U is moved to a second position Y and a second set of resonant frequencies f'-j »f'2 for the states and TE.sub.1, respectively, is taken and a second volume V2 calculated according to the equation ( 15) · Finally, a displacement volume Δ V is calculated by subtracting from the value V2 of the second volume, as determined at position Y, from the first determined volume, as determined at position X. In addition, by continuously monitoring the The change in the diameter of the chamber 28 (due to machining imperfections) between and t. are honored as a function of L. In a similar way, *. (t

"I

The rate of volume change is measured by continuously monitoring the resonance frequency of the TE state.

Disturbances for the foregoing relations included dielectric properties of air, the presence of coupling lines 30 and 32 and the other gas inlet 62, surface irregularities, finite electrical conductivity of the mating material of the chamber 28, and degeneration due to condition crossing. As long as the first order irregularities are small compared to Λ (which is of the order of 30 cm or greater), the perturbations are proportional to the change in volume. Thus, the method averages over distortions and gives a measurement proportional to the pure volume of the chamber 28.

The coupling lines 30 and 32 and the gas inlet 62 are of dimensions well below the cut-off wavelength of the microwaves, and will disturb the resonant frequency by at most 1 part 5 in 10 µ, and can be corrected in the first order .

Likewise, the disturbance due to the finite electrical conductivity of the wall material of the chamber 28 should be of the same magnitude if the walls are made of or coated with a highly conductive metal such as copper, silver, gold -3 or aluminum, and acceptable care has been taken in polishing. As an example, the theoretical skin depth for copper at 300 MHz is 3 * 8 x 10 ”^ cm. The perturbation of volume is on the order of the ratio of the skin depth to the linear size of the resonant vibration cavity, which is about 7.6 x 10 voor for a straight circular cylinder with a radius of 50 cm. The actual skin depth can be estimated from the scattering losses in the cavity, which are directly related to the quality factor or Q of the chamber, which can generally be measured experimentally to an accuracy of about 1%. As a result, a first order correction can be performed, v 30, which reduces the uncertainty to better than a few parts m 10.

The resonance frequency change between vacuum and air in the cavity is given by: ^ vacuum / air ^ ^ ^ ^ dielectric constant for air at microwave frequencies, which for dry air at STP is the value of -6 orrro ~ - · ς ^ 6.5 x 10 ". Therefore, the frequency change from vacuum - 92 -

1: Τ ·. ... J

to air on the order of 2J x 10. Since £ is known accurately at microwave frequencies as a function of pressure and temperature for dry air, this shift can be corrected to een an accuracy of at least 1 part in 10. The expression: 5 [(£ (£ -1) 20Cj 98kFJ = (P / 760) / (1 +0.0031.2 (t-20)] can be used to correct pressure and temperature dependence from £ to better than an accuracy of 0.1 $. Since the frequency perturbation is initially only 2.7 x 10, an overall accuracy in the resonance frequency determination can be -7.

TQ expects on the order of 10 if the barometric pressure is monitored to better than 0.1 # (or about 1 * / 30 kPa).

The contribution of the water vapor (relative humidity) to the dielectric constant of air can be expressed as: [Ψ ^ \ 2 p '18> ΐ5 where T is the temperature, as measured by a precision temperature organ in degrees Kelvin, and P the partial pressure is of water vapor in millibars. For T = 20 ° C (293 ° K), the saturation vapor pressure (100 # relative humidity) is 23 millibars. For this extreme case, therefore, is: 20 (-1 ^ water vapor x 10 * "^ ® 100, which is about 1/3 that for dry air. This effect can again be corrected to the first order by measuring the relative humidity , and an accuracy of the order of 10 * can be achieved in determining the vacuum resonance frequency of the cavity.

Both the TE and the IMq-jq are not degenerative in frequency with other resonance TEM states. Unintentional degeneration due to unintentional intersection can be avoided by properly selecting volume dimensions. The conditions for state intersection between D / L> 0 to D / L * 3 are:

30 D / L * 0, U5; D / L = 1 and D / L * 2.1U

(at D / L »0.1 * 5, the ^ q-jq state is degenerative with the TE. ^^ at D / L = 1, the TMq ^ q state is degenerative with the TE. ^ state and BAD \ föl £ i / & AÏ. 2nd toe'fcaa'3 · degenerative with the ΤΜ. ^ Ϊ063Ϊ811 <1) ·

Therefore, by choosing the D / L ratios other than these values, mutual interactions with unwanted states are avoided, and

* V

- 93 - is. the resonance behavior of the cavity is well determined, and the formulas for calculating the resonant frequencies from the dimensions of the chamber 28 are strictly valid.

As an exemplary embodiment, it is chosen to operate in the r region of 1 <D / L <2.1 k, it being necessary that the net movement 5 3 'of the piston 1¼ displaces a volume of 2.2652 x 1 (r cm Then the following shape can be used: D = 101 +, 88 cm * 52.1 * 1 * cm = piston end position YQ Lg = 70.66 cm = first piston position X.

Therefore, the net displaced volume is: - (26.22) * 2.2652 x 105 cm3.

As can be seen, the D / L ratio is also variable from 1.33 for the first position to 2 for the final position, which is clearly within the desired T5 operating range. In this case: = resonance frequency of TMq.jq state = 219.0 MHz f2 (i) = output value of the TE. ^ State = 253.9 MHz (D / L = 1.33) fg (f) = final value of the YE-yyy state = 331.5 MHz (D / L = 2)

Similarly, for a total volume of 0.056 m 3, the frequencies are: f1 * 31 * 7.6 MHz fg (i) = 1 * 03.0 MHz f2 (f) - 526.2 MHz.

The frequency dependence for an upward change in L can be expressed as: fmm * A £ - _-___ k (19)

f [(1.3739) (L2 / D2) + 1 J L K

which gives for D / L = 1.33: (Δ f / f) * 1.1 (Δ L / L) (20) 30 and for D / L »2: (& f / f) * 1.5 ( Δ L / L)

As can be seen, the uncertainty when measuring L is almost the same as for the frequency measurement. As a result, a very firm attitudes can be achieved for determining the volume displaced in this dimension shape.

“'* * *' ''” ”^ Wnat, to estimate the quality factor Q of the -9 ^ - '· Τ ,,,, 1 resonance states, because the accuracy is highly dependent on the measurement of the resonant frequencies of the sharpness of the resonances For the condition: * 0.22 for D / L * 1.33 5 - 0.19 for D / L = 2. ii / a where S is the skin depth given by S ~ | ^ (Ap) / 120 T / u J, f * is the resistance of the vand material of the chamber 28, A is the wavelength and / U is the permeability of the vand material.

—6

If the chamber 28 is made of copper, then | ° = 1, T x 10, IQ, u »1 and δ ss H, U3 x 10 ^ cm at 219 MHz. Therefore "k Q = 6.8 x 10 for D / L = 1.33 and Q * 5.9 x 10 ^ for D / L = 2.

Depending on the coupling coefficient, the width of the resonance curve at the half energy points is variable between 15 (2fQ / Q) and (fQ / Q), where fQ is the resonant frequency. Therefore, the width of the * resonance curve for the values of Q has been calculated: at fQ = 219 MHz: 3.2 </) f £ 6, U kHz for Q = 6.8 x 10 ^ and 3.7 <Δ f < kHz for Q * 5.9 x 1θ \

Because f can usually be determined to an accuracy of -2 ° ... -7. .

20 of 10 of f or better, an accuracy m of the order of 10 is to be expected in determining f. This, in turn, means accuracy of this order when measuring the diameter D of the chamber 28.

Similarly, for the TE. State: 25 Qj = 0.28 for D / L = 1.33, Q j * 0.27 for D / L = 2, giving: Q * 7.5 x 10 " ^ at 253.9 MHz, and 30 * 5.5 × 10 ^ at 331.5 MHz.

As before, the widths of the resonance curves are: 3, fc <f <6.8 kHz at 253.9 MHz and 6.0 <f <12.0 kHz at 331.5 MHz.

BAD ORIGINASet the criterion assuming that f can be accurately determined ~ P A ^ to 10 from Δf, holds for the worst case of (12.0 kHz) -3? A ~ 7 - <v i, “m” 1. TTit the previously derived expression for D / L = 2, '., J - 95 - Δ S Λ Γ Λ r 1

-a - 1.5 I.

f L J

Ο —7

Therefore, (4 L / L) can be "determined to (U x 10) / 1.5 = 2.7 x 10-T .g ;;;

It is also possible to disturb the resonance frequency of a cavity condition due to the presence of a gas inlet and outlet 62 on. a head 60 of the cylinder 12. From the theorem of the adhatic immutability and a knowledge of the field shape within the cavity, the frequency contraction caused by the hole can be estimated in a non-complicated way.

If the hole size is clearly below the cutoff wavelength (which is always the case here), the frequency counting is proportional to the ratio of the third power of the hole diameter to the volume of the chamber 28.

To illustrate, the expression for the change in the>. resonance frequency of the state caused by the opening 62 located in the center of the plate 60, given by: (Af / fQ) * (d3) / 8D2L (Χ01) ^ 2 (Χ01) (21) where d is the diameter is then the hole, J ^ (Xq ^) is the value of the Bessel function at and Δf is the frequency shift.

* 0 When numerically verifying using D = 10 ^, 88 cm, L = 52, W om, X01 = 2,1.01.83 and J, 2 (χ ^,. 0> aé95j „or4t.

(Δf / fQ) = 3.35 x l (TTd3

As can be seen for d on the order of 2 cm or less, the frequency shift is only on the order of 2 x 10 ~ ^. The shift is therefore very small, and this consequence can be virtually eliminated with a suitable first calibration procedure, such as covering the opening 62 with an adapted metal stopper, as a systematic error in the accuracy of the method.

Coupling the microwave energy to the chamber 28 for the two states ^ and TE ^ ^ ^ is best accomplished by placing the coaxial power line, terminating in the antenna bXd'oWigTi611 ^ a * s about halfway out of the center of the end plate 60 of the cylinder 12, the loop being oriented in a radius. The magnetic field at this location is approximately 90% of the maximum field. As a result, both .....—----------- ._ ___ 1 ** ♦ i v - 96 - states are energized to the same degree of coupling with great effectiveness. Moreover, the coupling by placing it on the head 60 is not affected by the movement of the displacement piston 1U.

Next, a description is given of a second preferred method for measuring a displacement volume in chamber 28 and for calibrating the series of pulses using this precisely determined volume, as provided by the optical linear encoder 26. In a similar manner to that described above, the piston 1U is moved from a first position, as indicated in Fig. 10 by the designation L1, to a second position, indicated by the designation Lg, the piston being moved by a displacement of Δ L. The cylinder 12 is inherently rigid, so that the calibration, as described, can only be performed occasionally cox to ensure that no long-term systematic changes, such as dimensional distortion of the cylinder 12, the misalignment and faulty operation of the optical linear encoder 26 or distortion of the piston 1k has occurred. In order to bring the absolute measurement accuracy of the microwave volume calibration up to a maximum of 20, it is necessary that the mechanical shape of the cylinder 12 be as close as possible to that of a completely, totally enclosed, straight circular cylinder, and thus all possible sources of eliminates or reduces systematic disturbances that could potentially affect microwave measurements.

Referring now to Figure 12A, certain mechanical changes have been made. First, the physical gap present between the piston 1U and the walls of the chamber 28 must be effectively blocked to prevent microwave energy from escaping through this gap. As explained in a copending U.S. patent application 30, the gap due to the nature of the seal between the piston 14 and the wall of the chamber 28 is significant. A cover 11 is made of a suitable metallic material, such as stainless steel, and further has a series of spring-shaped fingers 15, as detailed in FIG. 12B, disposed between the piston 11 and the interior of the chamber 28, which fingers when be in place over the piston 14 of the cover 11, reach into the gap between the piston ~ n Your transformer close contact *.> <.. '---. , -Γ * V '- 97 - are with the piston 1U' and the wall. The fingers 15 act as a short circuit that reflects the electromagnetic field that would otherwise be conducted through the said gap. In an exemplary embodiment, the spring-shaped finders 15 are made of a beryllium copper. Furthermore, the pressure and temperature sensors 51, 5T, 58 and 68 have been removed and replaced with appropriate bare metal plugs sized to provide a substantially flush surface with the interior walls of the chamber 28. Furthermore, the fluid inlet port is 62 in the head 60 covered by a metal plate to provide a substantially TO in one flat surface over the top of the head 60. In addition, the inner peripheral walls of the chamber 28 have been cleaned with an appropriate solvent to remove residual traces of the oil, which may have seeped from the piston seal. Noting that the required calibration is determined by a displacement volume ΔV and 15 not by the absolute volume of the chamber 28, the mechanical changes described above do not affect the accuracy of the calibration. When the measurements, as described, have been made for the modified chamber 28, the same set of measurements can be made immediately afterwards with the chamber 28 returned to its usual operating state, and a set of appropriate calibration factors can be generated to interrelate the two make measurements.

The results of the second measurements can then be used as a data lock, from which subsequent absolute calibration checks can be compared without having to go through the entire procedure of modifying and reassembling the chamber 28.

Briefly, the volume measuring and calibration method includes the step of moving the piston 1U to a first position, indicated by the designation in Fig. 10, by rotating the rotatable portion 19 of the servo motor 20 manually. In the first position, the antenna 70 is energized with electromagnetic energy of a first state TE, and a second state TE, selected to minimize the disturbances described above. The frequencies fj and fg, establishing resonance for each state, are observed by considering the counter 1108. Then, the 35BABL3 © fi3GlftiMi) e'w'0Sen is moved a distance ΔL to a second position, as indicated by the designation Lg, where the antenna 70 is energized again - the energy of the first and second states, and - 98 - =>, Τ. · »· λ m ui ii 11» "».! " • T. · ....) associated frequencies at which resonance is established for each of the states are noted. The output of the optical linear encoder 26 is applied to a counter which counts the pulses of the linear encoder when the piston 1U is moved 5 the distance Δ L. The diameters D ^ and Dg of the chamber 28 at each of the first and second positions corresponding to the designations and Lg are calculated. At this point, a calculation of the Δ L is performed using the pre-calculated values of D ^ and Dg. The calculated value of Δ L is divided by the number of pulses obtained from the linear encoder 26, as counted during the movement of the piston 1¾ over the distance Δ L to provide a length calibration factor using the measurements of D ^ and Dg. The volume AV, corresponding to the volume, as determined by planes passing through the points and Lg and the inner circumference of the chamber 28, is expressed by a mathematical expression regarding the diameters D ^ and Dg and Δ L. the output of the optical-mine encoder 26 to be calibrated for a given volume, for example for 0.028 m, this value is placed in this equation, which is solved for the calculated values D 1 and D g to provide the value of Δ L, corresponding to the movement of

O

the piston 1U for sucking 0.028 m of fluid through the meter 38.

The calculated value of Δ L is multiplied by the pre-calculated length calibration factor to provide the number of pulses output by the optical linear encoder 26 when the piston is moved a length Δ L for sucking 0.028 o -m in the chamber 28. As explained above, the count obtained from the linear encoder 26 is used to calculate the calibration factor included in the calculation performed in step 1062 as shown in Fig. 9N. In particular, the calibration factor is the inverse of the counts obtained for 0.028 of fluid drawn into chamber 28, and provides a correction for the calculation of the error rate in the meter reading based on an accurate measurement of the volume of the chamber 28, as set forth above.

3 $ AD ORIGIN In most cases, it is necessary to measure the frequencies at which the standing wave states are established at the positions and Lg. The be-a-n on D_ requires, as discussed, a * »· <<. ' ---

* ♦ I

- 99 - value of the speed of light, which changes for changing ambient conditions of temperature, pressure and relative humidity. Corrections for changes in the speed of light are expected to be small, and the calculation of the speed of light is usually performed once or twice during calibration of the optical linear encoder 26.

The speed of light in vacuum, Co, is 2.997925 x 10 ^ cm / s. The "corresponding value c for air is obtained by dividing Co by the" refractive index of air "at the respective wavelength. For the microwave region (f <30 GHz), the refractive index n is related to the atmospheric parameters via the equation: (n-1) x 10ëIlii (P + i§i2 *) (22) where P is the total pressure in millibars, T is the temperature in degrees kelvin and e is the partial vapor pressure of water in millibars. then given by: c * Co / n = c ^ [l + Or (P +) x 10 "6J (23)

The temperature and barometric pressure can be obtained directly from the readings of a thermometer and a barometer, located near the meter calibrator 10. The partial vapor pressure of water 20 can be derived from the relative humidity data obtained with a pendulum psychometer using the psychometer formula, or more simply by using a standard table, such as the “Smithsonian Physical Table”, no. 6H0.

To calculate a value of ΔL it is necessary to determine the average value of the diameter of the chamber 28, and more particularly to determine the values of the diameters D ^ and Dg at the positions and Lg, respectively . The calculation of D1 and Dg is performed with great care, because the resulting volume uncertainty is approximately twice the uncertainty of this measurement. As explained above, the piston is moved to the first position, corresponding to the designation, where the frequencies f ^ and fg for the standing resonance wave state are established for the two different states. The preferred method consists of BAf3e®F ^ € ilB (J u £ timely measuring the resonant frequencies f ^ and fg of two different states with the same electrical properties as a we-Kct.and L. and solving for the mean diameter

* I

t

• '9>. I

* .....

- 100 -

D Using the correct theoretical expression.

In a preferred embodiment, where the chamber 28 is in the form of a straight circular cylinder, the preferred pair of states, the TE, and TE, are for this purpose. As discussed, it has been shown that the quality factor Q, obtained by energization in these states, is great in thus reducing the effects of perturbations on the measurements of the resonance frequency. The mean diameter of the cylinder at any given position of L is given by the expression:, 0 D (L) = -1 ^ 15028 = - (2θ ^ ltf22 (L) -fia (t) j 1/2 where f the resonant frequency is of the TE state and f the resonant frequency is of the 12112 state, and c is the speed of light in air, as calculated by equation (23) Using two different states of electromagnetic wave energy. The various perturbations, such as the skin depth difference, the reactive frequency metering caused by the antenna TO, the degree of deviation, of the inner circumference of the chamber 28 from a perfectly straight circular cylinder, are equalized, and the absolute value of D obtained with great accuracy. Careful operation of measurements of the frequencies at counter 1108, as shown in FIG. 10, allows absolute accuracies of the values D as a function. T are obtained on the order of 1 part in 10 µm or 2.5 µm at a diameter of 30 cm. This degree of accuracy is in the same order as the changes in volume of the chamber 28 due to thermal expansion and shrinkage, as set up in a temperature stabilized environment, in which the temperature is kept within a range of + _ 0.56 ° C.

In order to confirm these measurements, as well as to provide a quantitative means of verifying the order of magnitude of the disturbances to be expected in the measuring system, the diameter can be determined independently by measuring the resonant wave frequencies ÖBiPfftiAl propagation of electromagnetic waves of the ^ Mq-jq state in the chamber 28. With such an energizing state, the resonance is. -irsn the length L and may therefore be used for a

* V

+ · 4 *> J ___ - 101 - do not change regular cylinder when piston position 1U is changed .. Excitation in the TMq ^ q state is sensitive to various other disturbances, which must be considered to the same extent of accuracy as for the two states discussed above. For the ^ Mq-jq state, the mean diameter is given by the expression: D (L) = 0.765U799c / f (25) where f is a resonant frequency of the state.

When the mean diameter D of the chamber 28 as a function of L is determined in the desired degree of accuracy, the value of ΔL is obtained and correlated to the observed number of im-. pulses from the optical linear encoder 26 to obtain the length calibration factor in terms of length per pulse interval or number of pulses per centimeter. The piston position is set to 3 and the resonant frequencies at f ^ and fg for the selected states ΤΕ. ^ And TE ^ ^ are measured. The piston 1U is then moved by rotating the rotating part 19 to a new position Lg, and the resonant frequencies of the same states are again measured, counting the number of optical encoder pulses during the piston 1U protection from his first to his second position. The number of pulses is divided by Δ L = L-j-Lg to provide the desired length calibration factor. The distance Δ L = (L ^ -Lg) must be sufficiently large that the calibration accuracy is not limited by the impulse count accuracy (hp 1 in this case), 25 and the calibration must be performed over a number of DL intervals to ensure that no non-linearity effects are present in these measurements.

For the TE ^ state, the change in the distance Δ L is given by the expression: Λ L - (LL) Γ f 2 f 0 «5860671C 2 ^ - f 2- · 0, ^ 8.60Ψ · 1 · - ~ AL 30 AL- (Lg-L1) g f2 - | ^ d (l2) JL * L1> (gg-j! Where fg and D (Lg) are the resonance frequency of the TE ^ -j state and the predetermined mean diameter at the piston position Lg, and and BAX} QjftlQftlAgtref f and the values are at the position.

For the TE ^ g state, the change in distance becomes A L ---- A ^ ny. expression : -------- ' * *· * . i) Γ - 302 '-ί / 2 AL * (L2-L) * CI: zf ~ ° * 5860671c] 1 _ f2e r 0 ^ 0671¾2] 1 /] - D (Lg) J) [I Dd ^)] J (27) wherein the different quantities are determined in a similar manner as above.

Similar expressions can be written for any energizing state, where more than one state can be used to check the internal uniformity and absolute accuracy of these measurements.

The absolute calibration of the displacement volume AV between the piston positions and Lg is provided by the following expression: 1Q Av = v2-v1 (/ 7 * A £ d22 (Al) + (d22-d12) l1 (28) where Dg and D ^ the mean diameters are of the cylindrical cross sections at the piston positions L1 and Lg and Λ L * (1 ^ - Lg) From a consideration of the equation (28) it is clear that if a certain value is assumed for the calibration absolute displacement volume Δ V, for example 0.028 m, and knowing the values of

Dg and D., the corresponding value of A L, i.e. the distance by which the piston A must be moved to suck 0.028 ur fluid into the chamber 28 of the meter calibrator 12, can be calculated. The purpose of the calibration is to obtain the number of pulses, such as 20 obtained from the optical linear encoder 26, which pulses are output for a desired displacement volume ΔV, and is obtained by multiplying the obtained value of AL for a given volume with the length calibration factor to provide the equivalent number of pulses output by the optical linear encoder 26.

The selection of the TE-j-j and TE-g states for energizing the cavity 28 was based on repeated determinations using a number of resonances of the usual state to determine the quality factor Q for each of the states. These determinations of the Q of a conventional state require the measurements of the ratio of the reflected energy (Pr) to the incident (Po) at the resonance frequency, and the frequency width of the response curve, BAD Q $! £ 4 $ half energy level, determined by P = (Po. + Pr) 1/2 '/ 2. It is desirable that the DC voltage response of the

• -'I

*> 4t, '- __ - 103 - crystal detector 1110. is linear with input microwave energy. This condition can be met by "operating the crystal detector 1110 in the so-called" linear detection "corresponding to an DC current level, which is usually less than 20 mV. If necessary, the rectilinearity of the response can be verified using the step damping means located on the time base generator 1100. Once established, the coupling efficiency (Pr / Po) can be measured directly on the screen of the cathode ray oscillator. count 1112. regarding the corresponding voltage ratio. The half energy level can then be calculated as an equivalent voltage.

The half width of the response curve, as shown in Figure 1U, is just the difference between the two frequency settings, as set on the time base generator 1100, corresponding to the half energy levels on either side of the resonant frequency, as observed at 5, the cathode ray oscillograph 1112. The Q of the resonance is calculated using the expression given by the equation (10).

From these determinations of Q, it has been shown that the TE-1-1 state has a quality factor Q of about 6000-7000 over the piston 1U run, the TE-j-2 state having a quality factor Q of> 0 8000 - 10,000. As indicated above, the quality factor is a measure of the order of magnitude of the expected deviation of the resonant frequency from the idealized results, as provided by the equation (1). Thus, by applying these states, the resonant frequency can be measured with greater accuracy, and the perturbations caused by imperfections in surface imperfections, as well as the consequences of frequent measuring in the skin depth, can be minimum.

Thus, the use of the states and TE ^ ^ is believed to provide determinations with greater accuracy of the resonant frequency, and thus of the mean diameter D, and of the volume displacement between the two piston positions.

Thus, a meter calibrator has been described, which can measure a fluid and, in particular, a gas flow through a meter with a high degree of accuracy. In one aspect, the volume of the 35 ΒΑΒΐΘΒΑΒΐΘ & 311 ^ 1 Afearin fluid is aspirated, measured with utmost precision, and compared to the encoder output, which detects motion - ii-inder, indicating it

> ... I

- 10U - volume drawn into the cylinder with a correspondingly high degree of accuracy is provided. This standard or calibrated volume is compared to the meter output being tested to provide an indication of the meter record, as well as the error rate of the meter fluid reading relative to the actual or calibrated volume, indicated by the optical encoder of the meter calibration system. Furthermore, the meter calibrator system is controlled by a computer system, in which a number of keys are performed in which parameters of the meter -10 and calibrator temperature and pressure are taken into consideration to adjust the indication of the measured volume of fluid flow, as well as repeated tests under different circumstances are performed. In particular, different volumes of fluid may be drawn through the meter calibrator through the meter 15 by entering corresponding count factor and into a counter of the computer, and counting down the selected count to zero to determine the meter key. According to a further aspect, a new and special method is used for determining with great accuracy the volume of the cylinder into which the fluid is sucked, for a specific displacement of the piston. This accurate measurement is determined by the frequencies creating existing waves for first and second piston positions to provide an accurate indication of the fluid volume and output of the optical encoder coupled to sense the movement of the piston.

Many changes can be made to the above-described apparatus and method, and various embodiments of the invention can be carried out without departing from its scope, so that all subjects contained in the foregoing description and the drawing should be interpreted as illustrative and not in a limiting sense.

BAD ORIGINAL

Claims (23)

A method of calibrating a meter calibration device, characterized in that the meter calibration device comprises a chamber "having the geometry of a straight circular cylinder, which has a diameter D and a length L, furthermore a piston which is straight— 5 can move in the chamber for conducting fluid between the fluid meter being tested and the chamber, and measuring means responsive to the movement of the piston to provide a signal indicative of the degree of piston movement, each incremental unit of the signal corresponding to an incremental movement of the piston and thus the volume of fluid passed through the fluid meter being tested, the method comprising the steps of moving the piston to a first position in the chamber, further generating first and second electromagnetic fields in the chamber, each electromagnetic field having a separate conventional device. and is chosen such that the electric and magnetic component fields of the first and second fields in the resonance state in the chamber relate to the diameter and length of the chamber, measuring first and second frequencies, the first and second electromagnetic fields in the chamber establish a resonant state, moving the piston to a second position, displaced from the first position, accumulating the signal obtained from the measuring means, generating third and fourth electromagnetic fields in the chamber, each electromagnetic field of which has a separate usual state, chosen such that the electric and magnetic component fields of the third and fourth fields in the resonance state in the chamber have a certain relationship with the diameter and the length of the chamber, measuring the third and fourth resonant frequencies, showing the third and fourth electromagnetic fields establishing resonance states in the chamber, determining the diameter and the length of, and thus a first volume, determined by the chamber and the piston in its first position, on the basis of the first and second resonant frequencies, and on the basis of the third and fourth frequencies the diameter and length of and thus a second volume, determined BAD ORIGINAL by the chamber and the piston in the second position, and determining the piston displacement volume as the difference between the second and the first - 106 - 1>. Volumes, and correlating the accumulated signal from the measuring means with the displacement volume to provide a manifestation of the incremental value of the fluid, represented by an incremental unit of the measuring means signal. A method according to claim 1, characterized in that the measuring means provide an output in the form of a series of pulses, each pulse representing an incremental "movement of the piston, the output pulses being counted during the movement of the piston from its first position to its second position. A method according to claim 2, characterized in that the correcting comprises the step of determining a length calibration factor as the infrared length, over which the piston has been moved to produce a single pulse through the measuring means. 1 *. Method according to claim 3, characterized in that the correction comprises determining first and second diameters of the chamber at the first and second piston positions, respectively, on the basis of the measurements of the first, second, third and fourth frequencies, further determining, for a given volume and the given first and second diameters, the piston displacement necessary to direct the determined fluid volume between the fluid meter being tested and the chamber, and based on the length calibration factor and the piston displacement determining the number of pulses to be generated by the measuring means for moving the determined volume between the meter being tested and the chamber. A method according to claim 1, characterized in that the states for generating electromagnetic energy in the chamber are chosen to reduce the disturbances as they would otherwise be generated by the nature, shape and surface of the chamber . Method according to claim 5, characterized in that the first and second states are the Mq-jq and TE ^ ^ ^ states of electromagnetic energy generation, respectively. 7. A method according to claim 5, characterized in that the first and second states are respectively the TE and the generation of the electromagnetic energy. BAD OWGIN Method according to claim 1, characterized in that the steps are repeated, the first position in each successive set of steps. - 107 - is changed so that the piston is moved through another part of the room. 9. Device for calibrating a meter calibration device, characterized in that the meter calibration device comprises a chamber, provided with a rigid, non-deformable shape, the inner circumference of which is designed as a straight circular cylinder with a determinable length and diameter. further, a piston which can move rectilinearly in the fluid guiding chamber. between a fluid flow meter being tested and the chamber, motor means for driving the piston at a substantially constant speed during the test of the fluid flow meter, and precision measuring means responsive to the movement of the piston in the chamber for providing a series of pulses, each pulse representing an incremental movement of the piston and thus the volume of fluid passed through the fluid meter being tested, the device onryating means for moving the piston from a first position to a second position, further means for generating an electromagnetic field of variable frequency for producing first and second electromagnetic fields, each of which has a separate usual state, at each of the first and second positions, so selected that the electric and magnetic component fields of the first and second fields at the resonance state in the chamber are related to the diameter and length of the chamber, means for determining first and second frequencies, upon which the standing wave resonance states are established in the cylinder at each of the first and second piston positions, and means for counting the number of pulses outputted from the measuring means when the piston is moved from its first to its second position, whereby a manifestation indicative of the incremental volume of the chamber, represented by a pulse, can be obtained on based on the displacement volume between the first and second piston positions, as determined from the measured resonant frequencies, and the counted number of pulses. Device according to claim 9, characterized in that the first and second states selected to reduce the disturbances would be generated by the nature, shape and surface of the chamber. Γ- - ♦ J - 108 - 11. A method of calibrating a meter calibrator, characterized in that the calibrator includes a chamber with a regular geometry, and a piston which can be sweep rectilinearly into the chamber for passing fluid between a fluid meter being tested , and the chamber, the method comprising the steps of generating electromagnetic energy in the chamber having a first and a second, separate conventional state, each of which states is selected such that the electrical and magnetic component fields of that electromagnetic field its resonance state is associated with 10 'the dimensions of the regular geometry chamber, obtaining reflected energy from the regular geometry chamber, sensing a first frequency of the electromagnetic energy, which creates a resonance state of the first usual state in the room, sensing a second frequency of the electromagnetic energy, which creates a resonance state of the second usual state in the chamber, determining the dimensions and thus the volume of the chamber on the basis of the observed resonance frequency, guiding the piston through the chamber and of a manifestation indicative of the degree of the piston movement, and calibrating the manifestation of the piston movement based on an accurate determination of the chamber volume. The method of claim 11 characterized by selecting the first and second conventional states for reducing the disturbances. which would otherwise be generated by the nature, shape and surface of the room. Method according to claim 12, characterized in that the states are selected as the TIS-j-j-j and TE states. 1U. Method according to claim 12, characterized in that the states are selected as the TE ^ g and the TMq ^ q states. 30 15 ". Method according to claim 12, characterized in that the states are selected as the ^ Mq-jq and TE ^ ^ states. 16. Device for measuring the volume of the chamber of the meter calibrator, characterized in that the calibrator further comprises a piston which can move rectilinearly in the chamber for guiding a fluid between the meter being tested, and the chamber, BADOTWÖWiAÊe measuring device, is provided with means for generating and changing the frequency of outputted electromagnetic micro->> - -; Ί k. * ..> J - 109 - wave energy, further from antenna means, coupled to the means for radiating waves of electromagnetic energy into the chamber, from means for sensing the electromagnetic energy leaving the chamber, from means for sensing a resonance condition, many means being coupled to the energy sensing means, to provide an indication of the occurrences of the minimum levels of energy leaving the chamber, corresponding to the creation of a resonance standing wave in the chamber state, and means for determining the frequencies for standing wave resonance states are established in the chamber, thereby accurately determining the volume of the chamber. Device according to claim 16, characterized in that the boosting means comprise means for changing the frequency of the electromagnetic microwave energy until a standing wave condition has been established in the chamber. 18. Device as claimed in claim 17, characterized in that the enhancement means automatically change the frequency of the microwave electromagnetic energy output. Device according to claim 17, characterized in that the boosting means-2Q parts comprise manually operable means for changing the frequency of the output electromagnetic wave energy. 20. Device according to claim 16, characterized in that the energy sensing means and the boosting means are each coupled to the antenna means and to the resonance state sensing means, thereby providing a manifestation of the level of energy leaving the chamber as a function of the frequency of the electromagnetic energy generated by the electromagnetic boosting means. 21. Device according to claim 16, characterized in that the frequency sensing means are coupled to the output of the electromagnetic energy generating means, and comprise means for displaying the frequency of the electromagnetic energy. 22. Device as claimed in claim 21, characterized in that the navigation means comprise a counter. 23. Apparatus as claimed in claim 16, characterized in that means 35 are coupled to the output of the electromagnetic energy-boosting BADD419 signal for detecting the level of the energy and for providing a feedback signal indicative of the ni - ---- A? I *. »/ J - 110 - level of energy to the electromagnetic energy generating means, thereby stabilizing the energy level required by the electromagnetic energy generating means. 2k. A method of accurately measuring the volume of a calibration device, characterized in that the calibration device comprises a chamber of regular geometry, the method comprising the steps of generating an electromagnetic energy field in the chamber of a conventional state chosen so that the electric and magnetic component fields of the energy field at a resonance state in the chamber are related to the dimensions of the regular geometry chamber, further obtaining reflected energy from the regular geometry chamber, observing the frequency of the electromagnetic energy, which frequency establishes a resonant state for the usual state in the chamber, and determining the dimensions and thus the volume of the chamber on the basis of the observed resonant frequency. Method according to claim 2h, characterized in that the geometry of the chamber is a straight circular cylinder, the dimensions to be measured being the diameter and axial length of the chamber, and the step 20 of determining the length and diameter and therefore determines the volume of the straight circular cylindrical chamber. 26. A method according to claim 25, characterized in that the usual electromagnetic energy field generating state is selected to minimize disturbances due to the nature, shape and surface of the chamber. 27. A method according to claim 26, characterized in that the selected state is the TE state. 28. A method according to claim 26, characterized in that the selected state is the TE state. A method according to claim 26, characterized in that the selected state is the TMq ^ q state. bad original Λ 4 f \ Λ F ^ <