SU826289A1 - Device for determining parameters of transient process - Google Patents

Description

The invention relates to automation and can be used to determine the parameters of the transition .i functions of the elements of control and regulation systems. A device for determining the parameters of a transient process in automatic control systems is known, which contains a control unit, a storage unit, time counters, and an extremum memory unit. However, the use of an extremum meter in the device introduces a significant error, as a result of which the device allows determining the parameters of the transient oscillating links second order with frequencies of damped oscillations from 0.1 to 10 Hz with accuracy not higher than 5%, which significantly limits the scope of application of alizator. The closest to the proposed technical entity is a device for determining a transient parameter in control and regulation systems, comprising a series-connected comparison unit, a first trigger, a first counter, a division block and a multiplication unit, as well as a serial telio connected second trigger and a second counter, the first input of the second trigger is connected to the output of the comparing unit, the output of the second trigger is connected to the second input of the first trigger, the output of the second counter is connected to volts The first input of the multiplication unit, and the first input of the comparison unit is connected to the input of the device 2. However, the known device determines the parameters of the transients that occur only when the signal is removed step-by-step when the element under test, i.e. when applying to the input of the so-called backward step. For some elements of control systems and

control, for example for pressure converters, it is possible to supply only exemplary straight steps, i.e. step increase of the signal. This is due to the fact that the existence of sample pulse pressure generators is intended to reproduce shock rising pressures. Thus, its field of application is significantly limited. Moreover, this device has a lack of accuracy because it does not take into account the zero level offset at the output the element under study. This is due to the fact that the parameters of the transition process in this device are determined from the data on the achievement of the transition process zero level. However, for elements with zero offset, the output signal in the steady state is different from zero and is equal to A, where Ld is the zero offset. Regarding the value of & Q, the transient parameters should be determined. The calculation shows that ignoring the zero offset by 1% can lead to errors in determining the parameters of the transition process up to 10%.

The purpose of the invention is to enhance the functionality and increase accuracy.

The goal is achieved by sequentially connecting a program block, a key and a memory block to the device, the second output of the program block is connected to the device output, the third output is connected to the second input of the second trigger, the second key input is connected to the device input, and the output of the memory block is connected to the second input of the comparison block.

A wide class of control and regulation system elements has a transient view function.

n (

xltV - W

 t

 sin ((ottq) 4u,

, (th

Transitional function (1) is obtained when a step signal is applied to

INPUT of the element under study, and the transition function (2) corresponds to a stepwise removal of the signal

To unambiguously describe the dynamics of an element, it is sufficient to determine the values of parameters 1 and w in equations (l) and (2). The latter are determined by the formulas:

&

WITH

(.four)

a-cos

where t

Accordingly the first

and the second moments of time when the transient reaches the value КХ о + Д Q when determining the parameters in (1) and UQ in determining the parameters in (2). Thus, by determining the moments of time t and t and calculating the parameters E and CO, we can uniquely determine the transition function of the element.

The proposed device makes it possible to determine the parameters of transients I.60, obtained by stepwise removal and by stepwise feeding a signal at the input of the element under study, as well as to increase the accuracy of determining these parameters.

The drawing shows a block diagram of the device.

The device contains software block 1, the element under study 2, comparing the block 3, key 4, memory block 5, the first and second triggers 6 and 7, time counters 8 and 9, block 10 multiplication, block 11 division.

The device when the step signal at the input of the investigated element works as follows.

. In the initial state, key 4 is opened, triggers 6 and 7 are in the state of scientific research institute O.

From software block 1 to the element 2 under study, a constant XQ level signal is applied. After attenuation of the transient process, the signal at the output of the object under investigation takes a steady value equal to

Q, which is stored in memory block 5. After this, program block 1 closes key 4 and reduces the signal at the input of test element 2 to a zero level. After a time sufficient for the transients to decay in the element 2 to be examined, a step signal is sent to it from the program block 1. At the same time, software block 1 sends a Start command to trigger 6. Trigger 6 is set to state 1 and starts a time counter 9, which determines the time tI — the first time the transient reaches the steady state KX + UQ value. On transition, the output signal has a steady-state value of KX + & at time t, a comparison block 3 is triggered, the inputs of which receive a transition process y (t) + Ao and a constant level КХр + .. from the memory block 5. The pulse from the output of the comparison block 3 sets the trigger 6 to the state O , in the time counter 9, an interval (to t) is recorded. At time t, a pulse from the output of trigger 6 sets three ger 7 to state 1, this starts the time counter 8, which determines the half period (,). When the transition process passes through the set value KX Q + Do®, the time ment t is triggered the comparing unit 3, and the pulse from its output sets the trigger 7 to 0, the time count 8 is turned off and the interval (t tyj) is fixed in it. The functional dependency is solved by the Idelenes block and the functional dependency is

- -K; OS

unit 10 multiply.

Thus, at the output of blocks 9 and 10, DC voltages are obtained, proportional to the parameters and (O, independent of D,

The device with step-by-step signal removal at the input of the element under study works as follows.

In the initial state, the key 4 is open, the triggers 6 and 7 are in the state O, Program block 1 supports the zero level of the signal at the input of the element under study.

In this position, the input of the memory unit 5 through the key 4 receives the signal Sig Dr,

ABOUT

4 is closed in epoblock 1

key

A device for determining transient parameters comprising successively interconnected

4S a comparison unit, a first trigger, a first counter, a division unit and a multiplication unit, as well as a second trigger and a second counter connected in series, the first input of the second

The trigger 50 is connected to the output of the comparing unit, the output is connected to the second input of the first trigger, the output of the second counter is connected to the second input of the multiplication unit, the first input of the block

Claims (2)

Comparison JJ is connected to the input of the device, characterized in that, in order to increase the accuracy and expand the functional capabilities of the device, enter the language of the module 5 and save the value of the UQ signal, which later enters the input of the comparison block 3, to the unit under test element 2 signal of a constant level XQ. After attenuation of transient npoi eccoB control unit 1 produces a stepwise removal of the signal at the input of the element 2, further work is similar to the operation of the device when Th stepwise signa, with the only difference that the moments t tn and time correspond to the passage of the transition process until steady state values. The values of certain parameters and (o also do not depend on the displacement dd. The proposed device, in comparison with the known, allows to expand the functionality of the device, since it is possible to determine the parameters of transient processes occurring not only at stepwise removal of the signal at the input of the element under study, but also and when the signal is staggered, this greatly expands the class of elements under study .In addition, the accuracy of determining the parameters of transient processes is improved, since the effect of bias is eliminated the zero level of the element under study. The calculation shows that the dp of the studied elements of the control and regulation systems with a zero offset of 1% increases the accuracy of determining the parameters of the transient functions by 10%. serially connected program block, key and storage block, the second output of the program block is connected to the device output, the third output is connected to the second input of the second trigger, the second key input is connected to the device input, and the output of the storage block is connected to the second input comparing .blok. Sources of information taken into account in the examination 1, USSR Author's Certificate No. 392464, cl. G. 05 V 23/02, 1973. 2. USSR author's certificate No. 607191, cl. G 05 B 23/02, 1978 (prototype).