SU1228072A1 - Pulse-relay regulator - Google Patents

Abstract

The invention relates to the field of control systems. The aim of the invention is to improve the accuracy and speed of the controller. The goal is achieved by the fact that in the regulation. a torus containing four single-oscillators, an RS-trigger, the first and second non-symmetric relay elements, an amplifier, an integrator, two knobs, an OR element, a D-trigger, a second, a grethy, fourth and fifth key elements, three AND elements are introduced and the element and NOT. 2 Il.

Description

The invention relates to automatic pulse controllers in which the output signal is a continuous function of the deviation of the input signal from a predetermined value, and can be used in systems of automatic control of various processes in heat and power engineering and chemistry when used as actuators of mechanisms with constant speed. movements for objects with low inertia, for example, in installations for temperature control by changing the concentration of the components of the mixture of two components ntov different temperatures.

The aim of the invention is to improve the accuracy and speed of the controller.

Figure 1 shows the functional diagram of the controller; Fig. 2 shows timing diagrams of the main signals of the regulator during the development of a disturbing or control action.

The regulator (Fig. 1) contains amplifier 1, integrator 2, asymmetrical relay elements 3 and 4, deadband adjusters 5 and 6, key elements 7-11, element SHIII 12, 13-16 single-oscillators, AND-NOT element 17, elements 18-20, RS-flip-flop 21, D-flip-flop 22. In the control process, the controller controls the actuator at a constant speed.

The operation of the regulator is carried out as follows.

The controller Ugjj i signal is equal to the difference between the set and actual values of the controlled parameter, and amplified by amplifier 1 is fed to the input of the integrator 2. From the integrator 2 output, the signal goes to the inputs of unbalanced relay elements 3 and 4. Depending on polarity the error signal when the signal at the output of the integrator 2 reaches the level set by the deadband generator 5 or 6, the corresponding unbalanced relay element, for example, element 3, is triggered. oznikaet signal and (moment of time t in Figure 2) and is applied to one input of the OR gate 12, causing the appearance at the output of the last

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signal Uj, which launches the one-shot 13. At the same time, the signal and the output of the asymmetrical relay element 3 is fed to one of the inputs of the RS flip-flop 21, causing, if necessary, switching it. When switching the trigger 21 inverted signals Ua and Uo at its output

dah, arriving at the inputs of elements And 19 and 20 and preparing the inclusion of the winding of the actuator corresponding to the polarity of the error signal Ug.

The triggering of one-shot 13-16 is performed on the leading edge of the input signal. When triggered by the signal V of the one-shot 13 at its outputs for the pulse time t, the signals are inverted. The signal Uj, of a single value, is fed to the control input of the key element 7, and the signal from the inverse output of the single-vibrator I3, arriving at the input of the one-vibrator 14, takes a zero value. When the key element 7 is triggered, the integrator 2 is zeroed out and, accordingly, the signals U and Uj are reduced to zero. Since in the initial state, i.e. until the launch of the one-shot 13, the signals and, Ug, and, U have single values, then when the one-shot 13 is started, the signal at the output of the element 18 becomes equal to 0, which causes the switching off of the key elements 9 and 10 and preparation for switching on the actuator 23 The pulse duration tg is assumed to be as short as possible, but long enough to trigger subsequent devices. If thyristor-type devices are used as key elements 8-11, the disconnection of which occurs not at the moment when the control signal O is equal, but when the simultaneous condition of equality of current through the thyristor is fulfilled, the pulse duration tg is chosen not less than T / 2, where T - the voltage period of the power supply to the actuator motor. This ensures the normal operation of the circuit and the exclusion of the possibility of a short circuit when switching

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key elements.

At the time of the end of a pulse with the duration tj, the reverse occurs.

inverting the signals U and Ots at the outputs of the one-shot 13. In this case, the start of the one-shot 14 occurs, the output impulses of which t determines the duration. control pulse arriving at the windings of the actuating device (time t,., FIG. 2). The signal Uj at the direct output of the one-shot 14 recognizes a single value, and the signal Vg at its inverse output is zero. Equality O of the signal U provides the possibility of switching on key elements 9 and 10 during a control pulse and, simultaneously, causes the appearance of a single level of signal voltage Od at the output of the AND – NE element 17. At the output of element 20, a signal appears control input of the key element 11. When the key element 11 is turned on, one of the windings of the actuator motor is connected to the supply voltage and the actuator moves during the time t to the side, ensuring ivayuschuyu decrease error signal. At the moment of termination of the control pulse of duration t

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reverse inverting the signals at the outputs of the one-shot 14. At the same time, it becomes equal to the O signal Ug at the output of the AND-NE element 17, which causes, respectively, the disconnection of the key element 11.

Simultaneously, the launch of the new vibrators 15 and 16 (the moment of time t, j in figure 2). The pulse capacity at the output of the one-shot 15 is equal to t, which makes it impossible to turn on the key elements 9 and 10 before the guaranteed switching off of the key elements 8 and 1 1. The pulse duration at the output of the one-shot 16 tp determines the allowable length of the pause between successive control pulses. After the time tg (time t in Fig. 2), the opposite occurs, the signal is inverted at the output of the one-shot 15, the output of the element 18 is formed by a single value of the signal U and the inclusion of key elements and 10. At the same time, the windings are shorted actuator 23 and improving the quality characteristics of the regulatory system -tO

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vani using the controller. At time t, you complete the switching of the elements of the regulator circuit, which are reset. If the input of the regulator continues to operate, the error signal U of the same polarity and the time interval between the leading edges of the pulses at the output of the unbalanced relay element 3 is not less than (, + t), the operation of the regulator elements is repeated in the described sequence and at the output the controller generates a sequence of control pulses whose frequency linearly depends on the magnitude of the error signal Ug.

The presence of the one-shot 16 ensures that the controller is switched to the relay mode when the error signal transmits a certain value, at which the one-shot 14 turns on when there is a pulse at the output of the one-shot 16. The state of the D-trigger 22 is checked by the Ut signal on its leading edge. If the pulse duration at the output of the one-shot 16 is such that it is inverted at the time of the end of the pulse (time t. Figure 2) before the start of the one-shot 14, switching of the D-flip-flop does not take place and the operation of the next control pulse generation occurs as described ( moments

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time t.

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t. "). If a

(, and 9 the operation of the one-shot 14 occurs at the time when the signal and, at the output of the one-shot 16, has a zero value, i.e. when the single-vibrator 16 is started (time t in FIG. 2), the D-flip-flop switches at the output of the NAND 17 element, a single value of the signal U is formed and the controller enters the relay mode of operation until the error signal decreases to the 16-value set by the one-oscillator.

In order to ensure the stable operation of the controller in the relay mode at any values of the error signal, as a one-shot 16, it is advisable to use one-shot with a restart, for example, type КМ155АГЗ

performed regardless of the state in which the mono-oscillator is located. When using conventional one-shot vibrators, which are restarted only after the previous pulse, for example K155AG1, the relay mode may fail at a certain value of the error signal, since the front of the U signal from the output of the single-vibrator 14 may turn out to be formed at when the one-shot 16 is not triggered despite the magnitude of the error signal exceeding the limit value.

Thus, at small values of the error signal Uj, the controller performs integral frequency-pulse modulation of the control signal, and at large values, it does. relay control, which provides an increased speed of control systems when applying the proposed controller design. The presence of key elements 9 and 10 and short-circuiting the windings of the actuator 23 when the control pulse is removed leads to an increase in the accuracy of testing in the steady state.

Claims (1)

Invention Formula A pulse relay controller containing four single-oscillators, an RS trigger, a first unbalanced relay element connected by a control input to the output of the first master, a series-connected amplifier, an integrator, a second unbalanced relay element connected by a control input to the output of the second master, and an OR element connected by an output to the input of the first single-oscillator, the direct output of which is connected to the control input of the first key element connected in parallel with the integrator capacitor, the output and A first non-symmetrical relay element is connected to the second input of the OR element, characterized in that, in order to increase accuracy and speed, the controller contains a D-flip-flop, second, third, fourth and fifth key elements, three And elements and an element NID, the inverse output of the first single-selector is connected to the input of the second single-selector and to the first input of the first element I, the outputs of the first and second asymmetric relay elements are connected respectively to the first and second inputs of the RS flip-flop, the direct output of which connected to the first input of the second element And, and inverse - with the first input of the third element. And, the direct output of the second one-shot is connected to the clock input of the D-flip-flop, and the inverse - to the second input of the first AND element, to the inputs of the third and fourth single-oscillators and to the first input of the NAND element, the output of which is connected to the second inputs of the second and The third elements And whose outputs are connected respectively to the control inputs of the second and third key elements connected in series with the corresponding windings of the actuator, the inverse outputs of the third and fourth one-oscillators are connected to Correspondingly, with the third input of the first element I and with the information input of the D-flip-flop, the output of which is connected to the fourth input of the first element I and to the second input of the element NAND, the output of the first element I connected to the control inputs of the fourth and fifth key elements connected in parallel actuator windings. Fi9.1 Editor K. Voloshchuk Compiled by V.Kuzin Tehred I.Popovich Order 2286/48 Circulation 836 Subscription VNIIPI USSR State Committee for inventions and discoveries 113035, Moscow, Zh-35, Raushsk nab., 4/5 Production and printing company, Uzhgorod, Projecto st., 4 Proofreader A.Zimokosov