JPS59501122A - A device that selectively measures one of a plurality of physical variables - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed description of the invention] transducer calibration system Used in connection with software user systems, especially for correcting inaccuracies in the output signal. Transducer system chimney with special calibration means.

To date, high precision and accurate transducers have typically come at a relatively high cost. Manufactured with the utmost care. some transducer systems The system includes means for adjusting the output signal to give characteristics approximating the desired transfer characteristics. It is growing. However, this technique also requires a high degree of signal correction. In case.

It costs a lot of money.

The transducer system described above includes a large number of different pressure transducers. In many settings, such as hospitals, where thermometers and temperature transducers (i.e., thermometers) are used every It cannot be said that it is completely satisfactory in this environment. This provides high accuracy and Not only is there a strong demand for accuracy, but there is also a demand for minimizing costs. It is. Therefore, relatively inexpensive transducers can be used, yet with high accuracy and The need for a transducer system that can demonstrate It should be obvious. The present invention satisfies this need.

Summary of the invention The present invention is implemented as a transducer system for measuring defined physical variables. It will be done. This system is a system that monitors physical variables and generates signals representing them. A user means is provided so that the signal has the desired relationship with the physical variable. It differs in a predetermined form from .

The system according to the invention further provides a method for determining the signal and its desired relationship to the variable. and forming a corrected measure of the above physical variables with a calibration means characterizing the differences between modifying means for adjusting said signal in a prescribed form in response to said calibration means so as to It is equipped with

In particular, the transducer system of the present invention has the advantage that it has multiple individual transducers. calibration means, each of which is combined with an individual calibration means. be particularly valuable. A single modification means is provided for each transuser means. selectively connected to adjust and monitor its output signal based on the calibration means. form a modified measure of the physical variable. In this way, each transformer The user means, together with the correction means, can be formed relatively cheaply and provide a highly accurate and accurate output signal. can occur.

In a preferred embodiment, said calibration means is adapted to detect irregularities in said transducer means. Multiple indicators to characterize accuracy, e.g. multiple with selected resistance values. Equipped with a resistor. In particular, a plurality of resistors iu of first, second and sixth sets, a transformer Due to the difference between the juicer hand signal and its desired relationship to the above physical variables. Zero level error of command. The above correction means measures the resistance value of each resistor sequentially, and then adding a first correction factor to the signal of the transducer means to correct the spacing; multiplying the signal of the transducer means by a second correction factor to correct the adding a sixth positive coefficient to the transducer means signal to correct linearity; thereby conditioning the signal of the transducer means.

Other features and advantages of the invention may be obtained with reference to the accompanying drawings, which illustrate, by way of example, the principles of the invention. This will become clear from the following description of a preferred embodiment.

Brief description of the drawing FIG. 1 shows a modification of a selected one of a plurality of optical pressure transducers. Easily block pressure drainer systems to generate accurate pressure readings It is a diagram.

Figure 2 shows the monitoring and correction circuit of Figure 1 for selected pressure transducers. FIG.

Figure 6 shows the conversion characteristics for one typical pressure drainer of Figure 1. 2 is a graph showing a zero level error corrected by the monitoring and correction circuit of FIG. Ra.

FIG. 4 is a simplified diagram of the operational steps performed by the microprocessor of FIG. This is a flowchart.

Description of the preferred embodiment Now, in the accompanying drawings, particularly in Figure 1, it is shown that accurate pressure measurements are made for multiple individual locations. A pressure drain juicer system is shown. This system is %11a , -11n and any transducer. monitoring and modification for selectively monitoring and modifying the pressure signal formed by the sensor. The circuit 13 is also provided. Each transducer is designated b15a-15n. has its own electrical connector, and the monitoring and correction circuitry is connected to the transformer. Single connector 1 that can be selectively attached to one of the connectors of the juicer It has 7.

According to the invention, each of the transducer connectors 15a-15n has a Supports an indicator that characterizes the accuracy of the output signal of the corresponding transducer. the law of nature.

Monitoring and modification circuitry 13 adjusts the signals appropriately in response to these indicators. especially , these indicators indicate the actual pressure being measured by the transducer 11. The zero level, snokun and straight line of the signal for the desired relationship with the signal output to Indicates linearity errors. The zero level and span of a signal are modified while the analog form remains, while its linearity means that the signal corresponds to modified after being converted to digital form.

The above circuit produces a modified pressure measurement signal that accurately represents the pressure being measured. is output on line 18.

Since the transducer output signal must be modified, the transducer 11 need not be of extremely high precision and may be manufactured with substantially lower precision. I can do it. This naturally results in considerable cost savings.

Now, FIG. 2 shows that the monitoring/correction circuit 13 of FIG. 1 is connected to multiple pressure drain juicers. is a simple block diagram showing connections to a particular one of the JA-11Ns. . The transducer includes a movable diaphragm 19 and first and second optical fibers 2. 1 and 23, an LED light source 25, and a phototransistor 27. ing.

Light from the LED is sent through a first optical fiber and hits a diaphragm; This diaphragm reflects the light along a second optical fiber to the phototransistor. Apply to. The position of the movable diaphragm changes depending on the pressure to be measured; The amount of light that the diaphragm reflects along the second optical fiber is It changes depending on the location. Therefore, the voltage sent to line 29 by the phototransistor The flow changes depending on the pressure being measured.

An indicator supported by the transducer connector 5 appears in line 29. Eight resistors R1- characterize the accuracy of the uncorrected output signal of the transducer. It consists of R8. The transducer output signal is similar to the actual pressure being measured. The special features that must be performed in the monitoring and correction circuit 13 to ensure accurate instructions are provided. The specific resistance value of the resistor was changed during manufacture of transducer 11 to indicate a fixed modification. Especially selected.

In the graph of FIG. 6, the solid line 31 is determined during manufacture of the transducer. output by a typical pressure drain user 11 for a range of actual pressures. shows the amplitude of the signal. This actual conversion characteristic can be used to determine the desired transducer characteristics. Conversion Characteristics - This is shown by the dotted line 33 and is the output by a perfect transducer. It can be compared with -, which represents the input signal. Actual curve 31 and desired The difference between curve 33 and curve 33 represents transducer inaccuracy, or error. There is.

Resistors R1-R81d included in transducer connector 15) Identifying some characteristics of user inaccuracy and therefore monitoring and correcting circuit 1 The output signal of the 3-balance lance user can be adjusted appropriately. In particular, resistance The devices R1-R3 identify the deviation of the transducer output signal at zero pressure. , resistors R4-R5 separate the span of the transducer's actual output signal and the desired output Identify the difference between the span of the signal and resistors R7-R8 Identify the degree of nonlinearity in the output signal of the sensor.

The specific resistance values for each resistor R1-R8 are determined by the manufacturer of transducer 11. selected during. These resistance values represent the coefficients of the general curve matching method. , 5cie: Engineering, published in 1981 by I$cGraw dEngineering Programs Apple If Editi As stated in the paper titled “Nth Order Regression” by on. It is derived using an appropriate computer program. Zero level, S/( When correcting for linearity and linearity (i.e. zero, first and second order corrections), The curve matching method is as follows.

P = AO + AIX + A2X.

However, P - actual pressure To O-Zero level correction A1-Sufgun correction A2-Linearity correction x=) transducer output Naturally, in the case of a more complex curve, there are more Higher order corrections can be made using additional resistors.

The resistance value of each I'i1 of the resistors R1-R8 changes linearly, i.e. A set in which the difference between values is equal, or the resistance value of one order changes geometrically. ie, from a set in which the distance between successive values increases progressively. rear In the case of Can contain values. If the set of resistance values includes 16 values, each resistor It can represent binary data of bits. Therefore, the zero level of the transducer The magnitude and direction of the bell error and hispan error are characterized using 12-bit data. The magnitude and direction of the linearity error can be characterized using 8-bit data. can be used.

Returning to FIG. 2, the monitoring/correction circuit 13 first operates as follows.

Read each of the eight resistors R1-R8 sequentially, then read the unmodified transducer. The sensor output signal is read and adjusted based on the measured resistance value. Special In addition, the monitoring and correction circuit is a microprocessor that properly controls the operating sequence of the circuit. 35, a variable selector A37 that selects one of the eight resistors, and a resistor Select whether to measure the transducer signal or the transducer signal. Digital Plexer 839 and one selected measurement value adapted to the microprocessor Equipped with an analog-to-digital (A/D) converter 41 for converting into It is growing.

Eight resistors R1-R8 are electrically connected to multiplexer 837 via line 43. connected to the multi-lux control path 45 from the microprocessor 35. Appropriate digital control signals are sent to plexer eight. The selected resistor is the line 47 to a resistance-to-voltage converter 49, which converter comprises: A current is passed through the resistor to create a voltage proportional to its resistance.

This voltage is sent via line 51 to the first input terminal of multiplexer 839. . The microprocessor is connected to multiplexer B via multiplex control path 45. Select that input terminal by sending an appropriate digital control signal to the input terminal. multi It is converted into a selected digital signal by the plexer and sent to the micronorograph via the input path 55. Send it to Sessa. The microprocessor thus cycles through each of the eight resistors. Then measure and then go into monitoring pressure measurements.

As mentioned above, phototransistor 27 conducts a current representing the pressure being measured. Occur. However, before inputting this current measurement value to the microprocessor 35, In order to partially correct for inaccuracies in the transducer transfer characteristics, The value is adjusted accordingly. A circuit that performs this partial correction is a signal span a first multiplier-type denotal analog CD/A) converter 57 for adjusting the signal; a second multiplying D/A converter 59 and a summing amplifier for adjusting the zero offset of 61. phototransistor 29 to the preamplifier 63 where it is amplified and then passed through line 65 to the choke. The signal is sent to the upper demodulator 67. The functionality of this demodulator is described in detail below. . This chopper demodulator is connected via line 69 to a first multiplying D/A converter 57. Outputs the uncorrected pressure measurement signal to.

The first multiplying D/A converter 57 is controlled by the microprocessor 35. ・Based on the digital control word sent via zero control nogsufu 1, the uncorrected Adjust the amplitude of the pressure measurement signal. This allows the iR to respond to the entire pressure range. The above unmodified The amplitude of the positive signal is adjusted. The span corrected signal is summed via line 73. The signal is sent to the first input terminal of the amplifier 61. the second input of the amplifier via line 74; The voltage signal sent to the transducer corresponds to the zero offset of the transducer. Ru. The voltage signal is sent from the microprocessor via the span zero control bus. The reference voltage appearing at terminal 75 is controlled by a suitable digital word. It is formed by a second multiplier type D/A converter 59 that divides.

Therefore, the summing amplifier 61 increases the transducer's zero level forming a pressure measurement signal corrected for error. This partially fixed The measurement signal is sent via line 77 to the second input terminal of multiplexer B39. Ru.

Eight resistors R1'-R8 are measured and the appropriate control word is inserted into the first and second After being sent to the multiplication type D/A converters 57 and 59 respectively, the microprocessor 35 outputs the appropriate control word to multiplexer 839 and performs the above partial modification. Select that second input terminal holding the corrected pressure measurement signal. to this signal , then converted into a corresponding digital signal by the D/A converter 41 Sane 5. It is sent via input bus 55 to the microprocessor.

The monitoring/correction circuit 13 further stabilizes the intensity of the light generated by the LED 25. It is also equipped with a circuit to convert the This special circuit uses a transformer adjacent to the LED. A second phototransistor 79 disposed on the connector 15 of the It includes a combined preamplifier 81 and a differential amplifier 83. The second hototora The resistor generates a current that is generally proportional to the brightness of the light, and this current.

A corresponding voltage signal is generated via line 85 to the preamplifier.

This voltage signal is sent via line 87 to chopper demodulator 89 - for its function. (discussed below) and is sent via line 91 to the negative input terminal of the differential amplifier. It will be done. The base voltage appearing at terminal 75 is connected to the positive input terminal of the differential amplifier by the resistance component. It is sent through a splitter 93. The output of the differential amplifier is sent via line 95 to chopper demodulation. 97 - the function of which is described below - and via line 99 to L. ’lED. The feedback loop created by this is that the LED Stabilizes the brightness of the light output to a specified level.

The monitoring/correction circuit 13 further detects the direct current offset appearing in various circuit elements. It also has a chopper circuit that prevents it from affecting the pressure measurement being carried out. . This chopper circuit includes the chopper demodulators 67 and 89, and a chopper modulator. 97 and a 500H2 signal generator 101. generated by a signal generator The generated 500 Hz clock signal is passed through line 103 to each demodulator and Sent to modulator. The modulator essentially turns on LED 25 at a rate of 500Hz. an analog gate that switches on and off, thus The current signals generated by resistors 27 and 79 are also modulated accordingly. be done. The two chopper demodulators, which are essentially sample-and-hold circuits, Come on.

It operates to pass a corresponding voltage signal only during the time the LED is energized. mentioned above As mentioned above, in this chopper circuit, the DC offset that appears in various circuit elements is Conduct.

ensure that the accuracy of the pressure measurement is not affected.

FIG. 4 shows how the microprocessor 35 performs the successive measurements and corrections described above. 2 is a simple flowchart showing the steps performed accordingly. 1st step At 105, the variable N is set equal to 1, and in the next step 107 In this case, the microprocessor sends the appropriate digital word to the multiplex control multiplexer A37 selects input terminal N and multiplexer A37 selects input terminal N. This causes the bush B39 to select the input terminal 1. In step 109, A microprocessor reads and stores the digital gates appearing on input path 55. do. This word corresponds to the resistance value of resistor RN.

In the next step 111Vci of the program, the microprocessor 35 Determine whether variable N is equal to 6. If so, the microprocessor The sensor is adapted in step 113 based on the previous measurements of resistors R1-R3. The appropriate correction coefficient is output to the second multiplication type D/A converter 59. Next, ma The microprocessor increases the variable N by 1 in step 1.15, and to step 107 to select the input terminals of the two multiplexers 37° and 39. Return. On the other hand, if it is determined in step 111 that N is not equal to 3, then If so, the program proceeds to step 117 and determines whether N is equal to 6. It will be done. If so, the microprocessor, step 119, anti-5R4-R (first multiplication type D with an appropriate correction coefficient based on the measured value before i) / Output to A converter 57. The microprocessor then steps At 115, a step increases N by 1 and selects the input terminal of the multiplexer. The process returns to step 107.

If it is determined in step 117 that %N is not equal to 6, the program The program proceeds to step 121.

It is determined whether N is equal to eight. If not equal to 8, the micropro In step 115, the processor increases N by 1 and inputs the multiplexer. The process returns to step 107 for selecting the power terminal. In step 121, N is 8 If it is determined that the microprocessor 35 is equal to the eight resistors R1 - Having completed the measurement of R13, the program proceeds to step 123, where resistors R7 and Calculate the table for linearity correction based on previous measurements for R8. Next Then, in step 125, the microprocessor controls the multi-lux control path. 45 to select input terminal 2 of multiplexer B39.

The microprocessor then connects the input bus 55 at step 7''1.27. A digital word appears, which corresponds to a partially corrected pressure measurement. Read. Then, in step 129, the microprocessor Find the appropriate input for the linearity correction table formed in step 123.

Add this input to the input signal read in step 127 to obtain the fully corrected pressure. Form a force measurement. Step 13], the microprocessor The fully corrected pressure measurement is output on line 133.

The microprocessor 35 generates a digital word corresponding to the fully corrected pressure measurement. through line 133 to digital display device 135 and 'Q: D/A code. Destroyed to y-data 137. The D/A converter then converts the corresponding 71 7 Forming the flog signal on line 18 as an output by the system.

From the foregoing description, it can be seen that the present invention applies to any of a number of different transducers. Improved transformers that form accurate and highly accurate measurements of physical variables such as pressure. It will be clear that it provides a sugini sunstem. each transducer The sensor is equipped with special calibration means to indicate the inaccuracy of its output signal, and the The corrected circuit.

It can be selectively attached to any transducer and the above calibration means can be Read and adjust the transducer output signal appropriately to eliminate the indicated inaccuracy. Can be fixed.

Although the present invention has been described in detail with respect to embodiments currently considered to be preferred, It will be apparent to those skilled in the art that various modifications may be made without departing from the invention. Therefore, It is intended that the invention be defined solely by the scope of the claims.

Special publication 1984-501122 (7) international metrology report Kamasho 59-5011 visit 2 (8,)

Claims (1)

[Claims] 1. In a system that selectively measures one of a plurality of individual physical variables. A plurality of transformers, each of which monitors and generates a signal representing a separate physical variable. user means iJ, the signal is determined from the desired relationship between the physical variable and '. are different in fixed form, further associated with each of the above example transducer means, the above transducer means; between the signal generated by the reducer means and the desired relationship to the above physical variables; Multiple characterizations that characterize the differences between and further, the above exemplary transducer means and the above features associated therewith. The signature is selectively responsive to the means for transmitting the signal of said transuser means into a predetermined form. correction procedure such as adjusting the physical variable to form a corresponding corrected measurement of the physical variable A system characterized by having stages. 2 The above plurality of characterizations are based on each of the means 1l-1:1 and the combined transformer. characterizing the zero level, span and linearity of the signal generated by the reducer means; Said modification means include one selected transducer means to add its zero to the signal generated by the selected transducer means. A first correction coefficient is added to the signal to correct its level, and a second correction coefficient is added to the signal to correct its span. Multiply the above signal by a positive factor and add to it a sixth correction factor that corrects its linearity. 6, each of the plurality of characterization means has a plurality of indicators. and the first set of indicia is generated by the transnouser means associated therewith. zero level for the difference between a signal and its desired relationship to a physical variable and a second set of indicators characterizes the signal of said transducer means. and its desired relationship to the physical variable. and the sixth set of indicators communicates with the signal of the transuser means. , characterizing the linearity of the difference between its desired relationship to a physical variable and The system according to claim 1, wherein the system comprises: 4. Each of the plurality of display bodies of the plurality of characteristics means has a plurality of display bodies having a prescribed resistance value. of resistors, and the modifying means includes a selected characterization of each resistor of the means. 4. A system as claimed in claim 3, including means for measuring resistance. 5. The above system comprises one individual transducer means and corresponding features. further comprising a plurality of support means each supporting the means; and The modifying means includes means for selectively engaging each of the supporting means; The means for reading the signal generated by the transducer means described above is manually and means for adjusting on a stage basis. 6. Each characterization means is generated by its corresponding transducer means. Measures the difference between a signal and its desired relationship to a physical variable over the full range of signal values. A system according to claim 1, characterized in that: Z In a system that selectively specifies one of multiple physical variables - A number of transducers each monitor and generate a signal representing a separate physical variable. said signal is determined from a desired relationship with said physical variable. There are different forms. further associated with each of said transducer means on said sides and said transducer means; between the signal generated by the reducer means and the desired relationship to the above physical variables; A plurality of characterizations is provided for characterizing differences in values for a full range of signal values. Each of the plurality of characterized means comprises a plurality of resistors, the first set of resistors being the signals generated by the associated transnouser means and their relation to physical variables; which characterizes the zero level for the difference between the desired relationship of A set of resistors connects the signal of said transnouser means and its location to a physical variable. It characterizes the 9th aspect of the difference between the desired relationship and the 6th point. A set of resistors connects the signal of said transducer means and its location to a physical variable. It characterizes the linearity of the difference between the desired relationship and Furthermore, each individual transducer means and its corresponding characterization may support the means. It is equipped with multiple support means, Furthermore, it is provided with a correction means.4. This corrective measure is means for engaging a selected one of the plurality of support means; The above characterization supported on the selected support means measures the resistance of each resistor of the means. and transducer means supported on said selected support means. A first correction coefficient is added to the generated signal to correct its zero level, and the above signal is Multiply the above signal by a second correction coefficient that corrects for the snow, and then apply its linearity to the above signal. Adjust the above signal by adding a third correction factor that modifies and corresponds to and means for forming a corrected measurement of the physical variable. system. 8. Disposal that measures defined biological parameters and generates corresponding signals In the type transducer device, A transformer that measures a defined biological parameter and generates a corresponding signal. transducer means, a signal generated by said transducer means, and said biological transducer means; means for characterizing the differences between the desired relationships for the parameters; The above transnouser means and features are a conjoint support that supports both the means. and a means for measuring the biological parameters defined above. the support means is inserted at least partially into the body so as to means for transmitting a signal generated by said transducer means and characterized in that comprising a connector means for supporting a and accordingly adjust the signal generated by the transnouser means. Disposable transformer characterized in that it is adapted to be selectively attached to a device for adjusting Nousa device. 9. The above characterized means is configured to control the zero level of the signal of the transducer means; The disposable transformer according to claim 8, which is characterized by sharpness and linearity. Sjuuser device. 10 The above characterized means comprises at least one resistor, the resistance value of which is equal to the above the signal of the transnouser means and the desired relationship to the defined biological noclameter. The disposable transformer user according to claim 8, characterized by the difference between the Device. 11. A plurality of systems each measuring a separate physical variable and each generating a corresponding signal. of the individual transducer means and any force 1 of the individual transducer means. and a device for selectively monitoring signals generated by a hand, each associated with said transnouser means on said side and said transducer means; the correlation between the signal generated by one means and the desired relationship to the physical variables mentioned above. A plurality of individual characterization means and the transoser means on each side of the above and associated features comprising a plurality of individual support means each supporting the means. each support means is capable of generating power from the transoser means it supports. connector means for transmitting the generated signal and for supporting the means; and the connector means reads the characterization means and responds accordingly. selectively attached to a device for adjusting the signal of said transoser means; A system characterized by: 12. The above characterized means has a zero level of the signal of the transuser means, The improvement according to claim 11, characterized by sharpness and surface linearity. 1) The above characterized means includes at least one resistor, the resistance value of which is greater than or equal to between the signal of the transnouser means and the desired relationship to a defined physical variable. The improvement according to claim 11, characterized by the difference in: 14. A method of measuring one of a plurality of individual physical variables, comprising: selecting a particular one of the plurality of transducer means; Each transducer means monitors a separate physical variable and outputs a corresponding signal. and each transuser means has a signal generated thereby and an object. The individual characterizations characterizing the differences between the desired relationships for the physical variables are It is combined. Further, measuring the output signal generated by the selected transducer means established, Furthermore, the above features in combination with the selected transducer control are: reading means to determine the signal of said transducer means and its location relative to the physical variable; determine the difference between desired relationships; and further, the transducer hand based on the differences determined in the monitoring step. characterized in that the signals of the stages are adjusted to form a modified measure of the physical variable. Law. 15. Said characterization in combination with said selected transducer means means Characterize the zero, span and linearity of the signal of the above transducer means. In the adjustment step, a first correction coefficient is added to the signal to correct its zero level. , multiplying said signal by a second correction factor that modifies its span, and multiplying said signal by a second correction factor that modifies its span; Claim 14 including the step of adding a third correction factor to correct the linearity of The method described in. 16. Said characterization in combination with said selected transducer means means is the relationship between the signal of said transducer means and the desired relationship to the physical variable. a plurality of resistors having prescribed resistance values characterizing the differences between the resistors; The reading step includes a step of measuring the resistance value of each resistor. The method according to paragraph 14. 1Z The uniformity adjustment step in combination with the above selected transducer means: adjusting the zero level of the transuser means based on a first set of indicators; adjusting the span of the signal of the transuser means based on a second set of indicators; and adjusting the linearity of the signal of said transducer means based on a third set of indicators; 15. The method of claim 14, comprising the steps of: