SU930230A1 - Digital control - Google Patents

Description

(H) DIGITAL REGULATOR

I

The invention relates to a technique for the automatic control of objects with a delay, the adjustable value of which contains a random component, and can be used, for example, to automatically control the water level by means of electrically controlled gates of hydraulic structures on hydro-amelioration systems.

Discrete automatic water level regulators are known, which include an electric contact water level sensor, the setpoint value (task) is set by lowering or raising the sensor coupling relative to the water surface, and the dead zone of the regulator i.e. The zone within which the regulator does not react to a change in the regulated value is constant and is determined by the distance between the electrodes of the electrocontact sensor. .

In such regulators, in order to avoid false alarms due to irregular level changes, a delay switch is used, which turns on the regulator to test the error value only after a certain delay time 1.

However, such a device, being a good protection against false positives under the action of external time-concentrated (impulsive) interference, does not provide protection against interference such as noise caused by an accidental change in the water level caused, for example, by wind or an hour by passing water transport.

The closest in technical essence to the present invention is qi /}) level regulator containing a sensor, an actuator and a series-connected integrator, a parameter sensor, a block

mismatch, digit converter - pulse duration, software control unit, three outputs of which are connected to the second, third and fourth inputs of the converter digit - pulse duration, respectively, and output of the setter connected to the second input of the error block 23.

Since the controlled process has a transport lag caused by installing the sensor at a distance from the hydraulic structure, where the water level is steady, the integration constant must be shorter than the control cycle time by the amount of the delay time. In practice, the integration constant does not exceed 0.1 control cycle duration, limiting the capabilities of the integrator installed at the input of the digital sensor. Thus, the known controllers have limited possibilities for reducing the likelihood of false alarms caused by external disturbing forces, such as wind, which is their disadvantage. The low reliability of the work of well-known controllers requires the presence of staff on duty at the facility, which includes disabling the controller in the event of emergency situations, which reduces the technical and economic indicators of automation.

The purpose of the invention is to increase the reliability of the regulator when regulating objects with delay, the adjustable value of which contains a random component.

This goal is achieved by the fact that the digital controller contains a randomly connected sensor connected in series, an integrator meter, a block diagram of the comparison, the first And element and the second And element, the first input connected to the first input of the first And element, the second input with the second input of the first the element I and the input of the program control unit, the third input with the third input of the first element I and the third output of the program control unit, the fourth input with the second output of the error block, and the output with the first input Yelnia device, a second input coupled to an output of the first AND gate, whose fourth input is connected to the third

the output of the error block, the first output of which is connected to the second input of the comparison unit, the control input of the integrator meter is connected to the first output of the software control unit by the two inputs of the actuator.

FIG. 1 shows a block diagram of a digital controller; in fig. 2 and 3 characteristics of the input-output digital controller in the absence and presence of a dead zone control unit 1; in fig. - installation diagram of the level sensor relative to the hydraulic structure.

The digital controller contains a sensor of 1 parameter and a setpoint adjuster 2 of a variable value, the error block 3, a digit-duration converter of the control pulse A,

software control unit 5, actuator 6, adjustable body 7 of control object 8, integrator 9, first and second

four-input elements 10 and 11, a comparison unit 12, a sensor 13 of a random variable component, a meter-integrator 14.

A multi-digit code is removed from the outputs of block 1.2 and I. A multi-digit code is also removed from the first output of block 3, a negative error signal from the second output of block 3, and a positive error signal from the third output.

 The Yu – N blocks form a dead zone control unit based on the rms off of the random component of the controlled variable.

The regulator works as follows.

The duration of the regulation cycle TC is the sum of the pause duration Tfj and the duration of the control pulse t fi. Each adjustment cycle starts the pause processing by the program control unit 5, after which, from the output of the program control unit 5, a pulse is sent to

Claims (2)

total reset of the converter circuits digit - the duration of the control pulse and meter meter; oator I, the standard deviation of the random component of the controlled variable. Then, from the output of the program control unit 5, from its output, a pulse is received to enable the recording of the error value modulus module. the figure mismatch into converter is a control pulse 4. After that, from the output of block 5 prog, there is a lot of control simultaneously on the digit-duration of the control pulse l and on the third inputs of two four-input elements AND 10 and 11 nocTynaeV signal resolution of mismatch processing. If there is a mismatch at the output of the error block, the modulus of which exceeds the standard deviation of the random component of the controlled variable measured by integrator 1, then at the output of comparator unit 12, a signal is generated that is simultaneously present at the first inputs of elements AND 10 and 16. At the second inputs of elements AND there is a signal output from the converter, a control pulse duration k. On the fourth, third input, the signal is present only for that element AND, which corresponds to the mismatch sign, i.e. when the mismatch is positive, the signal is present at the fourth input of the element And 10, in the proTF1VNOM case - at the fourth input of the element 11. Thus, when there is a mismatch exceeding the measured standard deviation of the random component of the controlled variable, for example, the water level, one of the elements And, 10 or 11, a pulse arises, the duration of which is proportional to the magnitude of the mismatch magnitude. This impulse goes to one of the executive inputs. device 6 and operates in one of the two directions of movement of the regulating authority 7 - Lifting or Lowering. If the magnitude of the error value is less than the standard deviation of the servants of the controlled variable, then at the output of the comparator unit 12 the signal is zero and at the outputs of the elements And 10 and the signal is also zero. Consequently, the insensitivity of the controller is controlled by the magnitude of the standard deviation of the random component of the controlled magnitude, which prevents the controller from spurious actions due to external interference, for example, wind. This increases the reliability of the regulator and eliminates the presence of service personnel in the hydraulic structure to disable the regulator at the time of the wind. The value of the constant integration of the meter-integrator 1 of a random component of a controlled value, such as water level, is always greater than the value of the constant integration of integrator 9 of the parameter set at the input of the sensor 1. To confirm this, refer to Fig. 4, which shows the installation location of the sensor parameter 1 of the controller. The sensor of parameter 1 is set at a distance of 0 from the structure, where it is the water level considered steady. . Time of running in fi is the water level at the level sensor installation site; V is the average flow rate. The travel time and the value of the constant integration determine the duration of the pause in the control cycle. Since integration starts from the moment of the flush from the value level, then the pause duration is determined by the sum of the flush time t..jc of the integration time Tc, t Tn OB + MNT The integration time of the integrator meter Jk T is equal to the length of the pause T | "Tgn)" p T. Therefore, mit mgm is always performed. In practice, T tcnt 0.1 Tdob and Tv «4TM e I.TAOF. The total control cycle time is equal to. TCs - TL1H: AoE + - lup. In Fig. 3 it can be seen that the width of the dead zone, determined by the standard deviation of the random component of the level, expands with increasing noise. In the absence of interference, the controller has a characteristic of the input-output shown in FIG. 2. The claims. A digital controller containing an actuator and a sequentially connected integrator, a parameter sensor, a discrepancy unit, a digit-pulse width converter, a program control block, three outputs of which are connected to the second, third and fourth digit converter inputs, the pulse width of the second mismatch block, respectively. connected to the output of the setter, which is characterized by the fact that, in order to increase the reliability of the regulator when regulating objects with delay, the regulator contains Consequently, a random component sensor, a measuring integrator, a comparison unit, the first element I, the second element I, the first input of which is connected to the first input of the first element I, the second input to the second input of the first element I, and the input of the program control unit, the third input - with the third input of the first element And and Fig.1 0 is the third output of the software control unit, the fourth input is with the second output of the error block, and the output is with the first input of the actuator, the second input of which is connected to the output of the first And element, the fourth input of which is connected to the third output of the error block, the first output which is connected to the second input of the comparison unit, the control input of the meter-integrator is connected to the first output of the program control unit. Sources of information taken into account during the examination 1. P.M. Tyumenev. and others. The use of electric auto regulators in irrigation (review). Tashkent, Scientific Research Institute of Scientific Technical Information and Technical and Economic Studies of the State Planning Committee of the Uzbek SSR, 1975. p. 22-25. 2. Circle E.K. et al. Digital Controllers, M.-L., Energie, 1966, p. IjS-l S (prototype). You} (odvmd B} (one FIG. 2 Ftfg.3