SU432457A1 - PNEUMATIC DISCRETE REGULATORY OPTIMAL MODE - Google Patents

Description

one

The present invention relates to the field of process control in the chemical, petrochemical, oil refining and other sectors of the industry and is intended for optimal automatic process control using objectively existing internal connections of the process.

Known pneumatic optimal regulators provide a search for an extremum either with a non-profit on the right or on the left. Their main disadvantages are expressed in the presence of continuous fluctuations at the extremum, the zone of which for a number of processes exceeds the permissible value.

The proposed pneumatic discrete optimal mode controller containing an integration unit connected to the output channel, the limiting unit and the generator-pulse generator, unlike the known ones, contain a ratio control device with a throttle attachment, a repeater, an adder and an operational amplifier, repeaters with positive and negative bias, two antiphasely included comparison elements, one of the control chambers of which is connected via repeaters with positive and negative bias are not available with the output of the operational amplifier of the ratio control device.

other control chambers — with output, anti-phase output of an operational amplifier, adder of a ratio control device, a pneumorele, connected according to the “OR” scheme and connected to outputs of anti-phase included comparison elements, one of which is connected to the output of the limiting unit, and a continuous memory cell controlled The chamber of which is connected to the output of the pneumorelle, and the memory chamber and the output are connected respectively to the output of the generator-pulser unit and the input of the integrator. In addition, the cameras for setting the signal level of the output of the adder and the operational amplifier of the ratio control device are connected via a repeater to the camera for remotely setting the throttle set-top box ratio. Thanks to this design, reliability is increased and the dynamic characteristics of the device are improved.

A schematic diagram of the regulator is shown in the drawing. Designations of signals arriving at the inputs and outputs of the controller: Pyi, Pyz - ratio parameters (input); Yak - the task of the ratio; RKZ, RKT - given and current value of the ratio; Rvh - the command signal to disable the controller; РХ - control signal (controller output); ROV, ONE - the parameter of the lower limit and its task; ov, -Povz - parameter of the upper limit and its task; Jaz is the third limiting signal. Pneumatic discrete optimal mode regulator is designed to automatically maintain the specified optimal process mode. The optimal mode is determined by the ratio of the two target conflicting parameters of the process Pyi and, the value of which is determined by the local or external optimality criterion. The regulator is implemented on the USEPPA pneumatic elements and consists of the block I of the ratio and control of the output of the regulator, the block of restraint II, the block of the generator-pulsator III and the block of integration IV. Block I provides a continuous error signal between the current and a given ratio and the formation of two discrete output control signals for the PX controller and consists of proportional and discrete parts. A proportional part of it is made on two chokes adders 1, 2, setter 3, adjustable choke 4, repeater with offset 5, constant chokes and two elements of comparison 6, 7 with choke adder 8. The elements are connected according to the ratio regulator circuit, in which there is no integral part, power amplifier and disconnecting, its relay, and the input of the throttle prefixing element 1 and the camera to set the signal level of the output of the elements of comparison 6 and 7 through the repeater 8 is given a reduced ratio signal by P Pk. This allows the monitoring of the specified () and current (Pk) values of the ratio and calibration of the meter scale. Elements 1, 2, 3, and 4 of the circuit perform the functions of a throttle set-top box ratio, element 7 - an adder, 7 and 8 - an operational amplifier. The value of the ratio К Р К - - - - is set by changing the conductivity of adjustable resistances: 2 times for adjusting Kz manually when calibrating the meter / St and Kz with additional adjusting 4, and 1 for adjusting Ki - remotely changing the RK. The ratio can be adjusted from 0.1 to 10. Compliance with the required ratio of target parameters (shown / R) (/ C - given by (/ C) pressure Run I of the RK is checked by equality (Pyi Py2) of the output pressures from elements 1 and 2 or equality () of the output pressure from the repeater 5 and the comparison element 6, since in the comparison element 6 Pyi and Py2 balance each other, and the SCR level is proportional to different, but constant for fixed positions, adjustable resistance value K. compared and 6) PI and the op-amp are anti-phase, change when the current ratio (/ St) changes around the level of the RKZ signal proportional to / C3, and is used to generate control signals by incrementing the output of the P regulator. so that minor deviations of / St from Kz cause mismatch between PI and PZ, exceeding the insensitivity threshold of the regulator elements. This makes it possible to increase the precision of the regulation of the ratio, and the stability of the adjustment process is preserved, since the greatly amplified error signal is worked out with scraper additives, the optimum value and frequency of which are determined for each object. The tuning of the SAR is greatly simplified, since for this purpose it is necessary to determine only the dead zone and the transition time on the control channel. The discrete part of block 1 is made on two repeaters 9, 10 with a positive and negative shift, two elements of comparison I, 12, pneumorele 13 and a cell of continuous memory 14; the control chambers of the comparison elements I, 12 are connected via the repeaters 9, 10 to the output of the operational amplifier (7, 8), and the other control cameras to the output of the adder (the comparison element) 6; the outputs of the comparison elements 11, 12 through the relay 13, connected according to the OR circuit, are connected to the control camera of the continuous memory cell 14, the memory camera of which is connected to the output of block III, and the output to the control cameras of the continuous memory cell 15, 16 integration block IV. In addition, the input of the comparison element 11 is connected to the block M. Restriction P. Block I at the output has two discrete signals: Pa - provides the choice of the direction of the spider addition to the output of the PX controller (-} - or -); RB - executes its implementation or detects it, if the change in the regulated value (the ratio) does not exceed the specified stabilization zone (2). Stabilization zone 2, within which the controller output does not change, is adjusted by repeaters with a shift of 9 -v. in 0 + T from the conditional zero level of the signal specified by the RCC. The width of the setting of the stabilization zone depends primarily on the total insensitivity of the elements of the meter and controller, as well as on the requirements of the process. The limitation unit 11 provides for the reverse of the signal Pa, if other parameters, when the regulated variable is followed to the specified process conditions, reach values higher or lower than the allowable ones. It consists of the elements of comparison 17, 18, pneumorel 19, 20 and setting devices 21, 22 with constant throttles: the element of comparison 18 together with the pievmorel 19, 20 works for the upper and third constraints, and the element of comparison 17 for the lower one. The magnitude of the restriction is determined by the respective setting units 22, 21.

The generator-emulsifier III generates uniformly alternating pressure pulses (0.1; O-atmospheric, 1-pressure supply, equal to 1.4 atm) and consists of comparison elements 23, 24 tanks, adjustable chokes and shut-off pneumorele 25, which is controlled by pressure RVH. coming from the secondary device when installing it in an intermediate position (Manual-Automatic). The duration of the pulse is Pb 0 and is adjusted accordingly by the chokes of this block.

The integration unit IV, by commands of the correlation and control unit, generates and outputs to the actuator the output signal of the controller P and consists of repeaters with a shift included with + DXx - 26 and - LXx - 27, memory cells 15, 16, repeater 28, providing Pa connection of the repeater output (27 or 26) to the input of memory cell 16, constant throttles, switching off the relay 29 and power amplifier 30 with the tracking device 31. Both memory cells 15, 16 are controlled by the signal RB cell 16 provides a delay per clock, and cell 15 generates a signal output regulator PxiAPx- Reliable ieredach provide output on a line elements 31, 30, and disabling the regulator - an element 29 Pnx command.

The specified steady-state process conditions may be disrupted by changes in the input variables. These changes through internal communications are permanently unavailable at the output, causing a deviation of two output conflicting process parameters. The measured opposite deviations are used by the regulator to form a control signal, which is forcibly changed by the magnitude of the value ± DFx and causes a change in the input main parameter (s), having a greater degree of influence on the process than the input unregulated variables. In this case, the deviations of the process mode are compensated, which reduces the imbalance between the current and the given ratio of conflicting parameters Pyi and Py2. Pneumatic signals proportional to Pyi and Py2 from the measuring instruments are fed to the input of the throttle attachment of the ratio, at the output of which pressure is formed: Pyi (Pyi

-0.2) - / Ci, Py2 (Py2-0.2) - / C2, where / Ci and / yadana the conductivity of variable resistances in 1 and 2. Both pressures affect the membrane blocks of the adder 6 and the operational amplifier 7, the output pressure koto

ryh are equal: Р1 Ркз: ± (Рu1 - Ру2); ± (Py1-Py2) - / Co, where / (o - is adjustable by adjustable resistance at 8. The pressures PI, Ro-7 and f 2 +7 continuously flow, respectively, into the control chambers of the comparison elements I and 12, which form the initial discrete (0 , 1) the signals of the direction of the output of the controller and the issuance of the step additive.

An equilibrium in the proportional part of block I occurs when the process output parameters are maintained at a given pressure P ,; ratio, as with this Yau1 Ruo. Therefore, when Kt Kz

PVI -0.2 AGG

there is a Pi Pi P2

I, 2-0,2 ATi

  - I; T.

The balance is broken at. If a

.ch, then, and vice versa, and, if. In the first case, when, but + Y, the pressure of the output element And, and the element 12 -

Ra 1, as they are included in antiphase. In the second case, when but is Y; from element I Pa 1, and from element 12 Pa 0. Pressure Pa enters restriction unit II and, together with Pa, is the input to pneumorele 13, the output pressure P of which controls the output of memory cell 14 and repeats evenly alternating pulses of the generator-pulsator i.e. Рb Рп 0 or 1. When PI-Ro or Pr-PI decreases unbalance when Pi P2-fY О, the output of element 12 will change 1 to O or, but the output of element 11 will change 1 to 0. As in the first, and in the second case, the exit pnevmorele

13 will replace 1 with O, since in this case 0. Since P 0 is the command pressure RB of the memory cell 14 constantly repeats O or 1 stored in the memory chamber by the pressure of a large backpressure (0.8 at), i.e. RB 0

or .

If the current value of the Ron lower limit parameter is higher than its RONZ setting, and the current value of the upper ROP limit parameter is lower than its DOWN setting and the parameter

the third restriction is absent, then the signal Pa passes to the control chamber of the pneumorel 28. The violation of the restrictions leads to the reversal of the signal Pa: s in case of violation of the lower limit and s

in case of violation of the upper limit or the presence of a third restriction.

If Pa 0 then, under the action of a small backpressure (0.4 at), the pneumorele 28 connects the output

repeater 27, equal to PX-ARX. with memory camera 16. The pulse impulse detector is connected and RB 0, then the PX-ARx signal will pass to memory camera 16 and repeat of memory cell 16, repeat

 exit and pass into the memory chamber

cells of memory 15, but will not pass into the repetition chamber, since the entrance to it is blocked by a large backwater. The output of memory cell 15 at this time repeats the pressure P remembered for the previous step, which through an amplifier with a tracking device and a switching off relay enters the regulator output and simultaneously to the inputs of the repeaters 26, 27. At the output of the last, the corresponding values are added to it -DFx and. The output of the controller changes when the signal changes from RB 0 to. The pressure PX-D / x is memorized in memory cell 16 at the same time and enters the repetition chamber of memory cell 15, the output of which decreases on the cells. Since the output of the memory cell 15 is connected to the inputs of the repeaters 26, 27, the outputs of which vary by -DMX and H-D / x, respectively, the pressure PX-DLx + Dx comes into the memory cell of the memory cell 16. The process is repeated when changing to RB 0. Forced reduction of the regulating parameter is carried out until Pi-Pz -y at., I.e., so far, Ja 1, a. When but the signal Pa 1 will become Pa 0. This leads to a change in P and the signal Pb becomes equal to O or 1 and remains, like the controller output, constant — the process is in the stabilization zone.

The regulator works in a similar way if, but its output increases pa each step by + DXx as long as P2-PI Y. When P2-Pi 7, but also the signal Pa 1 becomes Pa -0. This will lead to a change of sign to P 0 - the process will also enter the stabilization zone.

Thus, the controller, forcibly changing the increment value of the input main parameter (s), ensures that the process returns to the stabilization zone, i.e., to the specified optimal conditions for the process.

Subject invention

Claims (2)

1. A pneumatic discrete optimal mode controller comprising an integration unit connected to an output channel, a limiting unit and a generator-impulse unit, characterized in that In order to increase the reliability and dynamic characteristics of the device, it contains a ratio control device with a throttle prefix, a repeater, an adder and an operational amplifier, repeaters with a positive and negative shift, two antiphase comparison elements, one of the control chambers of which through repeaters with positive and negative shift connected to the output of the operational amplifier of the ratio control device, and other control cameras with the output, antiphase output of the operational amplifier, the adder of the ratio control device, pneumorele, connected according to the OR circuit and connected to the outputs of the antiphase comparison elements, one of which is connected to the output of the limiting unit and a continuous memory cell whose control chamber is connected to the outlet of the pneumorelle, and the memory chamber and the outlet are connected respectively to the output of the heater block- the pulser and the input of the integration unit. 2. The optimal mode regulator according to claim 1, characterized in that the cameras setting the signal level of the output of the adder and the operational amplifier of the ratio control device are connected via a repeater to the camera of the remote setting of the throttle set-top box ratio. 25 G © pFgg - - -.--. l4J | h -r in J.. z. ff.