DE2105836A1 - - Google Patents

Description

Dipi.-ing. Walter Meissner Dipung. Herbert Tischer

1 BERLIN 33, Herbertstrasse 22 MUNICH

Telephone: 8 87 72 37 - Wired word: Invention Berlin Postscheckkonto: W. M e I a a η er, Berlin West 12282 Bank account: W. Meissner, Berliner Bank A.-G., Depka 36,
Berlln-Halensee, KurfUretendamm 130, Account No. 96 716 ^ _BERUN 33 ( _GRUNEWALD) . _de £ 5 JAN.

HerbertetraBe 22 Docket 690066-A-WGY

MARATHON OIL QOMPAm :, Findley / Ohio - USA Computer set point station

The invention relates to connecting a computer with an analog control system to regulate operations. The controlling computer changes the digital ones Set point values in different control stations by addressing the individual station, on-mull points the set point value and introduce the new value.

The only prior art is the American patent application Serial No. ₀ 623, o15 from 14-. March 1967 became known.

The invention relates to methods for controlling physical and chemical processes, in particular by digital computers, which operate an analog device control, e.g. valves by actuation via the connecting device according to the invention.

The device commonly used to connect a digital computer to an analog device, such as a valve, is a motorized potentiometer such as is commercially available from many manufacturers. For example, special prospectus 98570-SI, 11-5B from Taylor Instrument Co., Rochester, New York, shows such a device. These potentiometers are subject to heavy wear because they contain moving parts,

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especially on the sliding contact. Furthermore, these potentiometers require considerable computer time as the Computer must address the potentiometer during the whole period during which the potentiometer is adjusted will.

The invention completely avoids the need for moving parts by, in preferred embodiments, Facilities used entirely in the solid state. The invention can be used as a connecting device between a Computer and a conventional analog control system can be used. In this procedure, the output of the Connection device according to the invention as a set point = input to an analog controller, preferably a recording controller. On the other hand, the devices according to the invention can also be used directly as "direct digital control" devices by delivering their output directly to the control valve or another device that can be operated analogously to be used.

The invention also has the following advantages:

1.) automatic bumpless transfer from hand-point setting to computer point setting;

2.) digital storage that can hold a value indefinitely;

3.) parallel input from the computer, the memory in the system can be accessed in less than a millisecond be brought up to date;

4.) the upper and the lower limit can be set in this way that the processing sequence cannot exceed safety limits;

5.) the maximum rate of change is in the

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position adjustable to a step function by knocking over to prevent the processing operation;

6.) Failure-free monitoring - if the system fails, the setting point automatically becomes the local setting point setting transferred back in the analog controller;

7.) the controller status indicator lamp only comes on after the computer has actually addressed the system and the mode of operation gives a positive test;

8.) the computer address of the system is switched to a card position, so that identical units with each other are interchangeable;

9.) the lowest computer outputs, e.g. 3. 21, and the Time (1 1.IiIIiSecond per unit) control up to 1o24 Units and more;

1o.) Galvanic isolation between the computer according to the invention and the processing flow controller with the associated device.

In summary: The invention relates to a method and apparatus for converting an output of a digital computer to operate an analog control system by sequentially changing the digital setting point values in two or more. -inalogregel stations by first addressing the individual analog control station, then zeroing the setpoint value of the individually addressed control station and introduction of the new digital setpoint value into the addressed Bowling station.

The drawings serve to explain the invention. In these is:

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Figure 1 is a schematic representation of the Hegel system according to the invention in connection with physical components of a processing plant;

Figure 2 is a block diagram of the individual parts of the control system ;

FIG. 3 is a circuit diagram of the setting point input valve control 19 and the memory 2o, as well as the digital-to-analog converter 21 according to Figure 2;

FIG. 4 shows a circuit diagram of the direct current-direct current converter 25, the setting device for the speed change 43, the oscillator 26 and the setting of the upper and lower limit 24, all of which belong to the control system according to FIG. 2;

Figure 5 sin. Circuit diagram of the output stage 14 for the changeable Addresses and the address logic 15 of the control system according to FIG. 2;

FIG. 6 shows a circuit diagram of the control logic 16 and the analog comparator 18 of Figure 2; and

Figure 7 ^e i ⁿ diagram of the failure of the supervisor control logic 16 of the system of FIG. 2

The control system according to Figure 1 is used to control a processing system, in which the components A and B flow into a reactor 1. The component A flows through the Nozzle plate 2. The differential pressure transmitter 3 measures the differential pressure (and thus the flow) at the nozzle plate. The flow controller 4 is an analog flow controller with a common remote setpoint input that is connected to the setpoint station 5 of the computer (CSPS). The controller 4 is located above a current-pressure converter 7 on flow control valve 6. A similar set point station 8 (CoPS) is due to a similar current-pressure converter 9 and to the pneumatically operated control valve 1o, both of which act on component B. The pressure transducer 11 and the flow transducer 3 are connected to the computer 12 switched back to the system after the

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Invention regulates the process. The temperature converter 13 is also on the computer to measure the temperature of the reactor 1 to report back.

The system of Figure 1 lets component A through Diisenplatte 2 flow, whereby the flow converter 3 a differential is created which is fed back to the computer 12. The component flows in a similar manner B to the pressure transducer 11, which transmits a signal back to the computer 12. The temperature converter 13 measures the temperature in reactor 1 and transmits the temperature signal to computer 12 back.

The computer analyzes these three quantities of flow, pressure and temperature and calculates the best setting of the flow control valve 6 according to a standard processing control program brought to zero and then the new, recalculated optimal setpoint is transferred to the memory of CSPS 5. CSPS 5 then gradually changes the digital setting point in the analog controller 4- until it agrees with the newly calculated optimal setting point that is in the memory of CSPS 5. This gradual change the Analοgregler-one Part point prevents "poking ¹ · or interruptions in controlling the process. The analogue controller 4 provides its electrical output signal accordingly, the pressure transducer current is converted to ^e in pneumatic signal 7 by the, so that the valve 6. At the same time, the analog controller 4 samples the flow from the flow converter 3 and moves the valve 6 further until the flow through the nozzle plate 2 is equal to the newly calculated optimal setting point.

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After the computer 12 has been addressed and zeroed and the new 3setpoint to the setpoint station 5, it interrupts the connection with GSPo 5 and addresses the computer setting point station 8. The previous setpoint value in CSPS 8 is zeroed and a new digital one Setpoint wrt (calculated approximately at the same time as the optimal setpoint value for CSPS 5 and briefly im Memory of computer 12 stored) is brought into CSPS 8. The computer set point station 8 transmits then a current signal which is converted into pressure in the converter 9 and is transmitted to valve 1o. CSPS 8 thus acts directly on valve 1o and changes its setting. The computer receives the new pressure signal from the transducer 11 and compares it with the newly calculated optimum Print, address it again, reset it to zero and set the digital setpoint in the station 8 again, if necessary, until the signal picked up by the pressure transducer 11 equals the newly calculated signal optimal pressure is. The set point that the computer transmits to the CSPS 8 pushes the valve position off and the computer itself determines whether this valve position is correct in order to achieve an optimal pressure obtain. This "direct digital control" is in contradiction to the "computer cascade analog control system", the is controlled by the computer set point station 5. CSPS 5 represents an independent analog in other ways Control loop back to achieve the optimum value at which it controls when the system is idle. The station 8 only adjusts the valve and the computer itself checks whether this position results in an optimal pressure, While the control system that is used on component A has the advantage that it can be used if the Computer itself is sufficient, the direct digital control for the pressure control on component B offers larger economic advantages by avoiding additional costs for the analog control loop.

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A single multi-conductor cable 29 connects the computer to the two computer set point stations. The usage of this single cable, in which the CSPo connections are connected in parallel, is characterized by the feature of addressing according to the invention.

The circuit of CSP3 5 or 8 (which are identical, except for the fixed "addresses" still to be described) is shown in the block diagram of FIG. 2. The circuits of the blocks in Figure 2 are shown in greater detail in Figure 3 and the following, which will be described.

The computer 12 in Figure 2 is connected to the terminal 14 for variable addresses containing "hard-wired" ä address a, which forms the digital address of the corresponding Einstellpunktstation. The variable address 14 is connected via the address logic 15 to the control logic 16, which returns a "ready" signal via a lock 17 to the computer and also the reset signal for "bumpless" transfer from the local (not computer-controlled) operating mode to the computer-controlled working method. The circuitry of elements 14, 15, 16, 17 and 18 is shown in detail in FIGS. 5-6 and 7.

The control logic 16 is at the setting point input gate 19, so that when addressing the relevant CSPS via the "

Elements 14 and 15 control logic 16 when displaying the Setpoint input gates 19 responds and the CSPS memory 2o resets. As a result, the signal arriving from line 22 can enter memory 2o via gate 19 enter. Since the signal from the computer is in digital form, a digital-to-analog converter 21 must be used provide. When transferring from the local computer set point the analog controller set point first becomes the comparator 18 for comparison with the set point given that was previously set on analog controller 4,

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while he was in the local mode In normal Operation is carried out by the output of the digital-to-analog converter 21 about the speed change setting 23 j the setting 24 for the upper and lower limit and the DC-DC converter 25 in the remote Set point in the analog controller 4. The oscillator 26 causes a rise to element 2o on the switch the local computer control, supplies the control logic 16 a clock pulse and chops the DC signal of the DC-DC converter 25 to the Isolate output from this element, the failsafe monitor 27 brings the analog regulator 4 into the local mode in the event of a failure in the computer control return. (This fail-safe feature does not work with direct digital control.) The computer indicator lamp 28a burns when the GSPS is controlled by the computer.

The circuit arrangement of the setpoint input value gate 19 »of the memory 2o and the digital-to-analog converter 21 shows Fig. 3. The digital memory circuits F-1 hhä to F-11 are bistable circuits (flip-flops), the two modes of operation allow. In the first, a "one" signal occurs through the zero line 31 and the line 32 becomes interrupted (i.e. its voltage drops for a short time, e.g. 15 milliseconds from a high to a • low value). This interruption opens the no-or-gates G1 to G1o and leaves the multi-conductor cable 22 (consisting of ten separate lines 22-A to 22-J) Signals into the corresponding flip-flops Ft1 to F-1o enter. The transistors T-O to T-1o then transmit the introduced binary values into an analog value, which is converted by the amplifier Δ-1 into the digital-analog (D / a) Output line 33 is transmitted, as can be seen in FIGS. 2, 4 and 6. A voltage divider with the resistors 34 and 35 and the Eelais b-6 and b-9 closes * - the loop and provides a feedback signal to the

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Monitor the computer. The common phrase "computer controlled Way "of the GSPS means the normal operation of the control system.

The second way of the memory section of the GSPS is to switch from local control to computer control and is called the "ascending type" of CSPS memory. The memory is over by a zero pulse a counting conductor 38 incoming pulse and via an incoming through the clock conductor 39 "UuIl-Eins-ÜTull" counting impulse in the ascending manner. The flip-flop F-1 to F-Io start the Talctgeberimpulse of conductor 39 to count and continue counting until the voltage output from D / A output 33 equals the Voltage of the controller setting point in line 4o becomes. This equality is achieved by applying these tensions to the comparator 18 detected. If the comparator 18 determines that these two voltages are equal are, it is high on line 48, which is normally at a low voltage, which is the clock pulse input disconnects from line 39. The signal on the counting line 38 is about 150 milliseconds switched off after its start. This second type allows for "bumpless" transmission from the local for computer control. The whole "ascending" type will I run it in less than 100 milliseconds.

The flip-flop F11 in Figure 3 is a logic overmeasuring device which, in the "ascending mode", allows the setpoint value to be overmeasured by more than 200 % of the setpoint value transmitted by the computer. It is intended to prevent a constant return, which could result from a small difference between the values on lines 33 and 4o.

Figure 4 shows the circuit of the speed change setting 43, the setting 24 of the top and the

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lower limit, of the DC-DC converter 25 and the oscillator 26.

Resistor 42 and capacitor 43 limit the maximum increase in change at which the output from A / D line 33 is transferred to amplifier A-2 in DC-DC converter 25. A switch 44 changes the maximum increase at which the signal is given to the input of the amplifier A2 by the selection of different alternating capacitors 43-A to 43-C. In general, the input period increase will be in the range of one second to one thousand seconds, but it is not very critical and is preferably adapted to the rate of change which occurs in the controlled process. The transistor 45 compares the voltage on the wiper arm 46 of a variable potentiometer which has previously been set to the lower limit of the computer control. For example, the increase in the potentiometer can be set to a value equal to 50% of the control value and the computer will not regulate the process if the value of this parameter falls below 50% of the control value. If the computer tries to give the CSPS a control point that is lower than the lower limit set on the potentiometer slider arm 46, the control point corresponding to the lower limit is automatically given to the controller 4. Similarly, the transistor 47 compares the voltage at the input of the amplifier A-2 with the voltage at the wiper arm 48 of the potentiometer and thus gives a high limit in the area of the camcorder control. Usually, the high and low level values are selected according to the range of safety that the parameter can occupy in the process.

The control station 4 is from the CSPS through a transformer 49 (with the secondary windings 49b in Figure 7 and 49a in

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Figure 4) isolated to keep the control station output without grounding and the control station 4 from a short circuit to be able to isolate in the GSPS. For galvanic isolation, the DC signal from amplifier A-2 is fed through the Transistors 5 ° and 51 converted into V / echselstrom that can be operated by the oscillator 26 ″, which is shown in dashed lines in FIG. 4 and also in the block diagram of Figure 2 is shown. In the oscillator the resistor 52, the capacitor 53> the transistor 5 ^ and the basic resistors 55 and 56 a single-connection oscillating oscillator with an output of 2o Hz divided by two and squared by the flip-flop F-12. The exit of the flip-flop is through the buffer amplifiers 57 and 58 reinforced. The capacitor V / resistor pairs provide insulation. Through the line 63 becomes an unlimited Signal passed to control logic 16. The necessary rectification of the signal from the transformer 49 takes place by a rectifier 64. The rectified signal v. 'is given to the controller 4 via the lines 65-A and B. Relays B-4 and B-5 form the output monitor for the computer, similar to that provided by relays B-6 and B-9 (Figure 3). All computer monitoring relays will operated simultaneously and, if appropriate, can be combined electrically.

The I-shunt resistance of relay B-3 gives over the λ

Amplifier A-2 a fast entrance when the CSFS storage is located in the ascending manner described.

Figure 5 shows the circuitry of the variable address 14 and the address logic 15. The connection block 14 is wired to the only digital address of the CoFo, which is in Figure 5 is labeled "Ήΐ". JJie connections 1 to 128 are connected to the corresponding connections of the Computers "EGO" (electronic contact operate) connected,

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which contains a series of switches that are operated according to the programming of the computer.

The IBM computer model 18oo with the special control system described here is used, but it can also a digital memory equipped with a suitable ECO and a memory for regulating the physical one Plant can be used.

The address logic 15 in Figure 5 contains the logical gate, necessary to decode the address. The M) R gates 67A to 67D decode the address from the variable Address 14. If the address signal of the computer EGO is identical to the fixed address in variable address 14 the NOR gates introduce the address logic 15 Output to address select line 66 (Figure 2). This signal lasts as long as the computer is transmitting the address, which is generally around 10-15 Milliseconds is. This pulse closes the contact on the monitoring relays b-4, b-5, b-6 and b-9, whereby feedback to the computer takes place via these relays. The signal on line 66 also becomes the control logic 16, which thereby responds to the reset signal (if it exists) on the computer 28 (FIG. 6). * The signal at the computer 66 also causes the control logic 16 to respond to a setpoint value that occurs during the Excitation of the computer 65 can be transmitted. In operation, the control logic 16 responds to a reset pulse or a new set point, unless these two signals precede a signal that is the fixed one Address in the variable address 14 corresponds. Only if one corresponds to the address of the variable address 14 Signal received first, decoded by the address logic 15 and energized by the computer 66, the speaks Control logic 16 to the Hückstellsignale that on the Line 28 or new set points are transmitted, 'which come over the line 22. The resistors 68 and 69

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can have 1oo ohms or other corresponding values.

This addressing characteristic of the circuit allows all CSPS to be connected to the computer through a single multi-conductor cable connect in parallel.

Figure 6 describes the circuit of the control logic 16 and (dashed) the comparator 18. The holding resistor and the NOR gates 71 and 72 allow the control logic 16 to respond to a reset signal at the computer 28 only when the address selection line 66 is energized. In operation, the line 66 is energized when a corresponding address by the variable i address 14 and the address logic is received 15th The NOR gate then has a zero output. The reset signal of line 28 and the zero signal of NOR gate 72 are received by the NOR gate which responds by energizing line 73 with a signal which is inverted by the buffer amplifier and onto a value gate line 32 which carries the signal to gate 19 of the setpoint input value (Figures 2 and 3).

The capacitor 73, the NOR gate 76, the buffer amplifier 77 and the resistor 78 together make up an impact multivibrator. In Srregung line 73 of multivibrator * is a short duration pulse (approximately o, 1 msec) to the zero line 31 (Figure 3) · This pulse represents the CSPS memory to zero. In the event of an output signal from the NOR gate 80, which in conjunction with the NOR gate 81 acts as a block for the constant energization of the line 82, whereby the computer indicator lamp 28 lights up and indicates that the corresponding CSPS has been addressed and is computer-controlled. During addressing by the computer, the signal on line 66 also goes to NOR gate 83 which energizes line 84 which in turn energizes relay windings B-4, -5, -6 and -9,

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the corresponding relays b-4-, -5, -6 and -9 closes and feed back the signal as described.

The line 85 is on one side of the NOR gate 81 and on one side of the NOR gate 86, which is through the resistor 87 and the delay capacitor 88 output to one side of the NOR gate 99, which itself gives an output to one side of the described NOR gate 79. With local regulator in local position line 85 is energized at a "one" level. Consequently NOR gate 79 prevents the compute indicator light from lighting up.

The NOR gate 9o is through the capacitor 91 and the resistor 92 on one side of the NOR gate 76 has an output. The elements 91> 92 and 76 thus result in an impact multivibrator which produces a signal of 0.1 millisecond generated in the zero line 31, the memory of the control logic in the point in time in which the Controller status line 85 by switching the controller is switched off by hand from local control to computer control.

The NOR gate 93, the capacitor 94- > the NOR gate 95 and the resistor 96 result in an impact multivibrator, which generates a pulse of 150 milliseconds in one side of the NOR gate 97 at the time the Line 85 is switched off by manual switching to the computer control.

This pulse goes to the NOR gate 97 and to the buffer amplifier 98 and brings the counting line 38 for 15 milliseconds to the logic zero level and thereby allows the control logic memory to work in an ascending manner. The same pulse of the buffer amplifier 98 also opens the NOR gate 99. The NOH gates 99 and 100 are parallel, see above that the pulse at the NOR gate 99 opens the NOR gate 1oo and

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thereby the 1o kHz signal get to the clock generator line leaves. The pulse of the NOR gate 97 also goes through the resistor 1o1 and excites the relay windings B-1, 3-2 and B-3 (Figure 7).

The circuit of the comparator 18 is shown in dashed lines in FIG shown. When the line 1o2 is energized with a one signal, the relay windings B-1, B-2 and operate B-3 (Figure 7) the transformer contacts b-1 and b-2 (Figure 6) and b-3 (Figure 4). The amplifier 1o3 then receives a voltage pulse from the capacitor 1o4 which is the setpoint value display, which is then located in the analog controller, and with the output of the digital-analog converter 21 is compared, which is given to the amplifier, which acts via the resistors 1o5 and 1o6. As long as that Voltage pulse of capacitor 1o4 (the regulator set point value) greater than the output of the difeital to analog converter is on the line 33, the amplifier 1o3 via the V / i of the stand 126 an output to one side of the NOR gate 1oo give the 1o kHz signal of the line 63 can get to the clock generator line 39. This increases the value in the CSPS memory 2o. A grounded zener diode 127 limits the voltage between the amplifier 1o3 and the NOR gate 1oo. When the control logic memory 2o is in the ascending manner, the (closing) relay b-3 causes the capacitor 43 | to rapidly charge via the resistor 1o9 (Figure 4). With the first transfer to the computer rule type, this will be the output of the CSPS on lines 65-a and 65-b quickly to the local Make the setting point on lines 4o-a and 4o-b the same and thus a "bumpless" transmission of the kind the local to the computer regulation.

Figure 7 shows the circuit of the lock 17 and a remaining one Part of the control logic circuit 16.

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A warning of a failure of a GSPS is provided by the line Ίο7ί cLi ^e ^ -i ^e relay winding B-8 energized, which gives a constant signal indicating the failure of the Hegler and automatically returns the controller to the local operating mode. Each time the computer is addressed, a pulse is returned to the computer via line 107. Various accessory circuits can provide a "ready" or additional "failure" signal to the computer which can be programmed to respond to the various emergency procedure programs.

When the line 1o7 is excited, the ITPN transistor 11 ο sends current to the line 11 and thus a “ready” signal back to the computer. The output to regulator 4 is monitored by the transformer's second secondary winding 4-9-b (the primary and the other secondary winding are shown in Figure 4). This output is rectified by the bridge rectifier 112 and fed to the amplifier 113 and compared with a reference voltage formed at the resistors 114 and 115. When the output voltage falls below a limit set by the resistors, the amplifier 113 will latch upwards as a result of the positive feedback through diode 116 and resistor 117, thereby applying a positive voltage to line 118 and energizing relay winding B-8, which Switch on failure monitoring lamp 119 to indicate the failure of the CSPS concerned.

In the arrangement according to the invention, commercially available switching elements can be used. For example, the Model SQ 10A amplifiers from Nexus of Canton, Massachusetts, described in their brochure · PB 1o3a-9/66 is described. The company supplies NOR gates and flip-flops Fairchild under the model 914 and 923, respectively, shown in their document BR-BR-0015-29-10OM. Rule-

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The Taylor company manufactures stations as model 94OR. In general, the usual techniques of computer control of setpoints and direct digital control are used used by computers in the arrangements of the invention, such as those described in "Computer Control of Industrial Process "by E.S. Sauhs," Computer Process Control "by Lee A. Gaines and" Mathematical Modeling in Chemical Engineering "by R.G.3. Franks are.

The arrangement according to the invention allows various modifications which are possible for the person skilled in the art. For example can all CSPS parallel to one a loop | continuous multi-conductor cable which runs over a large area caused by the processing system, which is just "before the connection to the Computer is returned to itself. Such a 'loop regulates every CSPS in the plant, even if they is interrupted at a single point in its length. Furthermore, the loop can only be made in that just breaking the loop and adding sections where it is desired without taking up the service of the CSPS. The CSPS is better at direct digital billing can be used as for operation via one of the analog stations described. Instead of the multi-conductor cable A single conductor cable can be used if a shift register is provided in each CSPS. One such Shift register receives the address signal as a series of pulses from the signal line and aligns each Impulse to another logical component of the register. After receiving all the impulses, they will then simultaneously transmitted to the CSPS, which works as a multi-conductor cable system. By using a carrier signal, the usual circuit for carrying the signals can be used to feed the pulses into the shift register. The CSPS can then be fed into a normal outlet

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the system can be plugged in, which makes it easy to transport results when this is desired.

An analogous construction with and gates instead of NOR gates are possible. A very wide variety of processing components, such as machines, can go through the arrangement according to the invention are regulated, the collectors and emitters of the individual transistors can be placed in the circuit.

19 claims
7 sheets of drawings with 7 figures

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Claims (1)

Docket 69OO66-A-WGY. MARATHON OIL COMPANY, Findlay / Ohio - USA Claims Method for transforming the output of a digital computer to operate a control system with successive changing of the digital control point values in the individual storage tanks in several control stations, identified by Addressing the control station with an addressing signal that allows this station to respond to a command signal, μ Transmitting a command signal to zero the setpoint value of the relevant addressed control station to bring, and then transmitting a command signal to the new digital control point value in the memory of to bring addressed control station. 2o Device for connecting a digital computer to a Analog control system, characterized by the following combination: a) a digital computer, which is responsible for regulating the system according to the received | inputs are programmed, which indicate the states in the individual points in the system, whereby the Computer means providing the digital address and the command signals at the output; b) a direct digital control station or an analog control station with a device for regulating at least one variable of the system on the incoming signals, which indicates the desired control point value for that variable; c) an upstream address that differs from similar previously switched by at least one other -2o- 209815/0879 station distinguishes; d) a comparator for the comparison of the address appearing at the output by the computer with the one before switched address; e) a memory for the 7ths of the digital control signals the computer; f) a device that transmits the values of the digital control signals brings out the computer to zero; g) an address logic for transferring the digital command signals from the computer to the memory, if and only if the command signals precede or be accompanied by an address signal, that of the one before switched address of the relevant control station. 3. Apparatus according to claim 2, characterized in that a memory transfers the digital control values to the control station until the digital control value is received by a Zero command of the computer is brought to Hull, the zero command signal from a correct ^ address signal accompanies or precedes it. 4. Apparatus according to claim 4, characterized in that a device for limiting the rate of change the transmission of the signals from the memory to the control station regulates so that the signal of the digital control value at the input of the control station is at a speed changes that do not exceed a given maximum rate of change, creating the new digital Control value is gradually applied to the system. 5. Apparatus according to claim 4-, characterized in that the device for limiting the speed of reduction has a capacity with a given time constant that corresponds to the desired maximum rate of change is equivalent to. -21-209815 / 0879 6. Apparatus according to claim 2, characterized in that the signal at the output of the computer by means of a multi-conductor cable is transmitted to the comparator which is connected to several address comparators. 7 · Device according to claim 6, characterized in that the address signal is in binary form and each is binary Bit transmitted via a special line. 8. Apparatus according to claim 7j, characterized in that every binary bit is carried on both a bit line and a watch-bit line and the redundancy is checked in order to check whether the bit signal corresponds to the Ulcht bit signal, 9 · Device according to claim 2, characterized in that the control station is a direct digital control station that controls the variable of the system and thereby the value the variable is measured by a scanner, which puts the value on the computer and not on a local one Control station transmits. 10. Apparatus according to claim 2, characterized in that the control station is an analogue control station and that's off The signal received in the memory sets a set point on an analog control loop and the value of the Variables is determined by a scanner that transmits the value back to the analog control station. 11. Apparatus according to claim 6, characterized in that the multi-conductor cable forms a loop leading to itself returns so that two alternate paths transmit the computer signal to the control station. 12. Apparatus according to claim 1, characterized in that the memory transfers the new digital control values to the -22- 209815/0879 gelstation transmits until the digital control value is applied to a zero command signal given by the computer Zero comes accompanied by or preceded by a correct addressing signal. 13. Apparatus according to claim 12, characterized in that the transmission of the signal from the memory to the control station is limited by the rate of change limiter is, so that the signal at the input of the control station with a digital control value is at a speed changes that does not exceed a given maximum rate of change, whereby the new digital control value is gradually applied to the system. 14, device according to claim 1, characterized in that the computer transmits signals to the comparator by sending each number of the signal over a special wire of a multi-conductor cable and these signals are transmitted to several comparators, of which each is connected to the lines of the multi-conductor cable. 15. The method with a device according to claim 14, characterized characterized in that the addressing signal is of binary form and each binary bit is carried on a special line. 16. The method according to claim 15> characterized in that that every binary bit is carried both on a bit line and on a non-bit line and redundancy is checked to see if the bit signal corresponds to a non-bit signal. 209815/0879 17 * Method according to claim 1, characterized in that that the Hegel station is a direct digital control station and controls a variable, the fourth of which by a Scanner is measured, which the, / ert to the computer and does not transmit to the local Hegel station. 19. Method according to Claim 1, characterized in that the control station is an analog control station and the signal received from the memory sets the set point on an analog loop, and the who * of the variable determined by a scanner ^ lrd, d «? the Jert back to the analog rule station. 209815/0879 iNSPECTED Lee r ^ eit