SU495647A1 - Multichannel blend preparation control system - Google Patents

Description

statok. The structure of the known system does not use information about the dynamic properties of the dosing units (pumps), which, as a rule, becomes known at the stage of research of control objects. When the task changes in the system, all the executive engines simultaneously start and compensate for the mismatched but equalized parameter in different control channels due to different rates of change of the controlled parameter n) occurs at different times. Moreover, the difference in time compensation can be very large. Since, in order to start working off the mismatch between the EDLs in different control channels, it is necessary to know the value of the DECD, which is determined by the magnitude of the EDL in the dm control channel with the minimum rate of change of control; parameter, then all the executing mechanisms stop and wait for the moment of compensation of the mismatch on the nth parameter. Only then are the values of mining for each control channel determined and the implementation mechanisms start up to compensate for these greatness. As a result, this transient time and disturbances in the ratio between the mixed components increase, which degrades the quality of the prepared product. In addition, in the known system, large overshoots are required for working out large discrepancies in the ratios between the EDMS in different control channels, which limits the range of operation of the device, because in areas close to the boundary position of the regulator, operation modes are possible. on an emphasis (nasp1, epi) that violates the optimality of the process of compensation of the value of mining.

The aim of the invention is to improve the quality of control.

Improving the quality of the mixture produced is achieved by the fact that the proposed system contains a block of delays made of serially connected coefficient setting devices, a multichannel multiplier and a multichannel converter, a time-interval interval, and in each channel, except for the nth, connected in series by a switching device and a coincident pulse suppression device, the outputs of which are connected to the counting inputs of a reversible counter, the first inputs of the switching device are connected to the digital zero-organ outputs, the second inputs through the interface block — with the outputs of the digital zero-organ of the n – channel, and the control inputs — with the output of the logic device, which triggers the input of the multicamp multiplier of the delay unit, and other inputs to the outputs of digital zero-bodies of all channels, and outputs. A multi-channel time-code converter is connected to the inputs of all logic devices, except for the lth channel, in which a digital null-organ is connected to the inputs of all logic devices.

The drawing shows a functional diagram of the system, which includes: dosing units I and 2 (respectively, for the 1st and 2nd nth channels of the control); drives of 3 and 4 speeds, regulators 5 and 6, actuators 7 and 8, sensors cKopocTi 9 and 10, coring units 11 and 12. Similar equipment is used for all channels (13 for the lth channel). The system also contains common blocks: a digital frequency setting unit 14, a ratio block 15 consisting of a block of coefficients 16 and a multiplier 17, as well as a mode selection unit 18 and an interface block 19, which contains a device of coefficients 20 and a multichannel multiplier 21. In addition , minimizing blocks 22, 23 and 24, containing digital zero-bodies 25 and 26, reversible counters 27 and 28, subtracting counters 29 and 30, doublers 31 and 32, logic devices 33 and 34 are included in each channel of the control.

In addition, the system includes a delay block 35 containing a coefficient setting device 36, a multichannel multiplier 37 and a code-time interval 38 multichannel converter, and switching devices 39 and devices are introduced into all minimizing units except the nth (24) 40 suppression of coincident pulses. The principle of the system is as follows.

When the common for the TASKS system is changed in the beginning, the actuator changes the number of revolutions of the aggregate (and the line capacity related to them) of the semiconductor control channel with the lowest rate of change of the controlled parameter with the highest possible speed. All other actuators of the system are launched with time delays, defined as the product of the magnitude of the task change by constant coefficients equal to the half-difference of the values inverse to the rate of change of the controlled parameters / 1-th and the corresponding control channels, according to

 one/

 B; Aff,

  2ltga "

tg "i

 ; - tefOn „,,

where bf is constant2tgat -tgctrt

tient for 1st channel; t; - time delay start-up t-ro actuator; tga - is the rate of change of the 1st control parameter; tga ,, - rate of change

-th controlled parameter; Afi - change of the task in the fth control channel.

At the moments of compensating for mismatches but controlled parameters, the actuators stop at the moment of compensating for the mismatch in the r.th control channel.

They are launched in the direction of compensation of the remaining value of the difference between the EDM of the corresponding and the l-th control channel, modified with regard to the input scale scaling factor.

The actuators are reversed after compensating for half of the corresponding amount of mining and stop at the moments of compensating for mismatches on controlled parameters, if the uncompensated value of mining does not exceed the dead zone of the corresponding control channel.

The operation of the system is as follows.

In the delay block 35, the moments of formation of control signals that trigger the actuators in various control channels are determined based on the information about the increment value of the A / f -vA / n command obtained from the outputs of digital zero-organs 25 and 26, and constant information selectable from the device 36 task coefficients.

The trigger signal from the output of the mode selection unit 18 in the multichannel multiplier 37 multiplies the incoming signals at its input, and the second signal in the form of the code N-, fi; Aff is fed to the input of the multichannel converter 38, where it is converted into the time interval t, -. Delay signal at the end of the time interval T; enters the input of the logic device in the I-TOM control channel, which carries out a delayed start of the corresponding actuator.

Ratio blocks 15 and conjugation 19 extend the functionality of the system, allowing the use of drives with different speeds of rotation, which is most often necessary in practice. These blocks allow for the scaling of the master signal, the ratio required by the regulation between the components to be shifted, and the matching of the error signals in different control channels.

The ratio block 15 is built on the basis of a multichannel multiplier 17, the inputs of which receive a signal / s from the digital frequency master 14 in the frequency-pulse code, and constant mass spread factors / Ci-f / Cn from the coefficient block 16 in the parallel code. In the multichannel multiplier 17, the multiplication / C by the corresponding factor is performed and, from its outputs, is fed to the corresponding inputs of digital null-bodies 25 and 26 of all control channels in the frequency-pulse code as PI4 / p.

The interface block 19 is designed to match the error values in different control channels while integrating the difference between them. This is done by multiplying in the multichannel multiplier 21 the error signal in the lth channel

6

control A, coming from the output of digital null-organ 26 in the frequency-pulse code to coefficients inverse to the scaling coefficients ly / Ci-f, but from the device of coefficients 20 in the form of a parallel code. From the output of the multichannel multiplier 21, the signals in the form of a frequency-pulse code arrive at the inputs of switching devices 39 in all minimizing blocks, except for the nth one.

Switching devices are intended for switching, depending on the operation of input signals from digital zero-bodies of the corresponding and lth channels, matched in the interface block 19.

The operation of the switching devices 39 is carried out by signals from the respective logic devices 33. In the device 40 suppression of coincident pulses connected on the output of the switching devices 39, the suppression of the pulses arriving at the inputs of the reversing counter 27 simultaneously or separated by an interval less than the required 5 for normal switching trigger cell in the counter. These devices are necessary, since in the mode of changing the task to different inputs of the reversible counter of signals from different sources and with the simultaneous arrival of pulses to the counting inputs in it

0 failures may occur.

The system has three modes of operation.

1. At the established values of the controlled parameters, the task in the system is changed, i.e.

/ i4 / const, / 3 var.

2. At a constant setting under the influence of a common disturbance for the system (change in pressure, frequency, voltage, network), the controlled parameters change in one direction, i.e.

/ 3 const, /, - b / „var,

five

signA / i signA / 2. . . signA / ,,

3. With a constant setting of one or more controlled parameters under the influence of various disturbances change in independent directions, i.e.

0

f3 const, sing-af; signA // + i.

In the first task signal in the system / 3, coming from the digital frequency master 14 in the form of a frequency-pulse code is scaled in the ratio block 15 and in the form of the task f signals in the frequency pulse code goes to the inputs of digital zero-organs 25 and 26, where they are continuously compared with the current values of the controlled parameters / ir- / ,, arriving at the other inputs of digital zero-bodies 25 and 26, from the speed sensors 9 and 10 in the frequency-pulse code. Comparison of these signals is carried out continuously and the error signal is not at the output of digital zero-bodies 25 and 26

appears as the frequency of the compared signals, (.

When the task signal changes in mode selection block 18, the task increment sign signal is generated and through the signAfs channel is fed to logic devices 33 and 34 and to the multichannel multiplier 37. By this signal in the logic device 34 of the 5th control channel with the lowest rate of change of the controlled parameter a signal is generated that starts through the control unit 12 the actuator 8, which begins to move the regulator 6 at the maximum possible speed, as a result of which the speed starts to change and the drive, and with it the performance of the dosing equipment, in the direction of compensating for the arising mismatch of the controlled parameter A / ".

The actuators in the other control channels are triggered with delays T1-gtp-1 determined in delay block 35. The trigger signal from the digital output multiplier 37 multiplies the values of the increment of the setting Aff-bA / -i from the outputs of the digital null-bodies 25, on the corresponding constant coefficients specified by the coefficients assignments calculated and entered into the device 36. The L 1-t-Lp-1B codes of the multichannel converter 38 are converted into the corresponding Ti-rTH-i time intervals, after which the signals are generated that trigger the actuators through the logic devices 33 in the appropriate control channels to compensate for the error of the controlled parameters.

At the moment of compensating for mismatches on the controlled parameters in the corresponding digital zero-organs 25 and 26, signals are generated that, through the L / 1 - O-gA / p O channels, through logic devices 33, stop the corresponding actuators.

Theoretically, the transient process in the system should end at the moment of compensation for the mismatch in the controlled parameter D / 0 in the channel with the lowest rate of change. At this point, the reduced integral values of the dynamic errors of all control channels should be equal in magnitude. However, due to nonlinearities in the elements of the system, inertia and backlash in the actuators and regulatory bodies, as well as inaccuracies in the calculations, the PIDDs presented in different control channels may differ slightly from each other.

Determining the difference between the given EDS of the n-th and corresponding control channels by summing is done in reversible counters 27 of the difference between the mismatches in the control parameter of the corresponding channel and the "-th channel, converted to the corresponding channel using the interface block 19.

When operating in the 1st mode, for example, in the 1st control channel, the signal 1 // (| A / "from the interface unit 19 and A / 1 from a digital null organ 25 pa different inputs of the reversible counter depending on the signs of mismatches. The device 40 for suppressing coincident pulses suppresses simultaneously arriving pulses.

When working in the 2nd and 3rd modes by the control signal signAf; from the logic device 33, the switching device 39 connects only ± A /, signals to one or another input of the corresponding reversible counter, depending on the error sign. In this case, the reversible counter operates either in the summation mode or in the subtraction mode.

At the time of the theoretical termination of the non-continuous process, reversible counters 27 and 28 are interrogated from the digital zero-organ 26 to the logic devices 33 and 34, and the differences in the difference between the given ELDS of the n-th and corresponding channels, 27 as parallel code, rewritten into subtractive counters 29.

If this value exceeds the dead zone in any control channel, for example, 1, then the signal via channel sign (AAi) 3H, coming from the reversible counter to the logical device of the corresponding control drip, resolves the process of compensating the resulting difference between the given PIDs. With a control delay t / i, which polled the reversible counter 27, a frequency doubler 31 opens with some delay, the current error starting at the input of which is irrespective of the sign (.A / i).

In frequency doubler 31, frequency doubling is performed, and signal 2 (A / i) in the frequency-pulse code enters the counting input of the subtracting counter 29. Depending on the sign of NZ, the signals of sing.V27 from the sign trigger in the reversible counter 27 open in the subtracting counter 29 such input so that the input pulses 2 (Afi) write off the number in it. At the moment of writing down the number L29 written into it from the subtracting counter 29, doubled by the current mismatch, which is equivalent to writing off half of the difference between the given PIDs of the nth and the corresponding channel, the signal inv.V29 appears at its output, which through the logic device 33 reverses the effective mechanism 7. At the same time, the frequency doubler 31 closes with the same signal and the number in subtractive counter 29 is reset.

In the 2nd mode of operation of the system, when with a constant setting of / c const from the common cause, the current values of the controlled parameter n var begin to change, and in one direction, i.e.: with the same mismatch signs

signA / i signA / 2.,. signAf „,

Mode determination is performed in mode selection unit 18 based on the signal signA / i-r signA / n, coming from the digital null-organs of all control channels. If the mismatch signs of all channels are the same, then in block 18 of mode selection, a 2-mode operation signal is generated that arrives at the logical blocks of all channels. With this signal all channels are prepared for operation. After reaching the value of the EDM in each channel of the corresponding dead zone (AL J-) en, the disturbances with respect to the mixture ratio will be small. Signals

sign () 3H -f sign (AyVn) eq, through the corresponding logic devices 33 and 34, actuators 7 and 8 are started to compensate for the accumulated PSD, and then stop at the moments of error compensation. Errors between the given EDLs will be estimated by the difference of the areas of the triangles formed between the straight lines of the current parameters and the axes f and t. These areas do not differ much from each other, and the differences between them, and, consequently, between the above EDLs, will be less than dead zones in the control channels.

The 3rd mode of operation of the system occurs when disturbances in different control channels originate from independent causes with a constant setting. This mode is determined in mode selection block 18 by the signA / iT-signAf signals from digital zero-bodies 25 and 26, which prepare minimizing blocks 22, 23 and 24 for operation. By g / 2 signals from logic devices 33 and 34 39, depending on the sign on one or another input of the reversible counters 27 and 28, pulses the current mismatches Afi-rAf, where they are summed. After exceeding in any, for example, in the 1st channel of the dead zone, the actuator 7 is started via logic device 33 to compensate for the resulting error via a logic device 33. At the time of compensation of the mismatch from the digital nullorgan 25, the logic device 33 receives the A / 1 O signal, which the accumulating code N27 from the reversing counter 27 sequentially rewrites, then the frequency doubler 31 opens, and the counting input of the subtracting counter 29 starts to receive pulses of the doubled frequency of the current mismatch, writing off the number entered in it. After the half of the accumulated HMD has been written off, the inv-N20 signal through the logic device 33 reverses the executive-mechanic-meas- ure.

reversing counter 27, the inv N27 signal appears corresponding to the theoretical end of the transient. Due to non-linearities, this moment may not be ... co-operation with the moment of compensation of the current mismatch on the controlled parameter, therefore at times A / 1 O each time the value of the uncompensated PIDD in the reversible counter 27 is estimated and if this value

exceeds the dead zone, the process of writing it off repeats. The actuator stops if no signal sign (AjVi) S appears above the dead band between the two A / i O signals. The transition process ends there.

Invention Formula

A multichannel system for the preparation of mixtures, containing n load-coupled dosing units, each of which is connected to a corresponding constant speed drive through a regulator connected through an actuator and control unit to the output of a minimizing unit made from reversing and subtracting counters, the outputs of which are connected to the logic device connected to the output

unit, from a digital zero-organ and frequency doubler, whose inputs are connected to a digital zero-organ, a subtractive counter output and a logic device, and the output is connected to a subtractive counter, the first input of the digital zero-organ is connected to the speed sensor of the drive, the first output to logical device, and in the lth channel with the minimum rate of change of the controlled

the parameter of the digital zero-organ outputs are connected to the counting inputs of the reversible counter, the interface block, the digital frequency adjuster, through the relation block connected to the digital zero-organs, and the block

mode selection, the inputs of which are connected to the output of the digital speed controller and the output of the digital zero-organ, and the outputs to the inputs of logic devices, characterized in that, in order to improve the quality of control, the system contains a delay unit made of series-connected factors setting devices , a multichannel multiplier and a multichannel converter, a code-time interval, and

in each channel, except for the n-th, a switching device connected in series and a device for suppressing coincident impulses, a cov whose outputs are connected to the counting inputs of a reversible counter, the first inputs

the switching device is connected to the outputs of the digital null organ, the second inputs through the interface block are connected to the outputs of the digital null organ of the n-channel, and the control inputs are connected to the output of the logic device &

The multiplier of the delay unit is connected to the output of the mode selection unit, other inputs are connected to the outputs of digital zero-bodies of all channels, and the outputs of the multichannel transducer are a code-time interval connected by the inputs of all logic devices, except for the p-th channel, the digital zero-body in which associated with the inputs of all logic devices.