JPS6346524A - Valve controller - Google Patents

Abstract

PURPOSE:To improve reliability of the feedback signal and to ensure the control of the valve opening amount with high accuracy, by defining the estimated displacement value of a pulse motor shaft set by the pulse count value and the pulse number obtained by the numeric integration of the pulse rate as a feedback signal. CONSTITUTION:A pulse counter 100 and a coefficient device 101 are provided in the form of a feedback system with no use of a potentiometer, etc. In such a constitution, the output pulses of a pulse generator 6 are integrated by a pulse counter 100. The result of said integration is supplied to the device 101 and the displacement value of a pulse motor shaft is estimated by the device 101. The deviation is calculated by a computing element 4 between the estimated displacement value of the pulse motor shaft and the set displacement value of the motor shaft of a regulator 3. Then a negative pulse rate is delivered from a function generator 5 if an estimating signal 18 for displacement value of the pulse motor shaft is larger than said set value. Thus the displacement value of the motor shaft is decreased. While a positive pulse rate is delivered to increase the displacement value of the motor shaft respectively.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a valve control device that controls the opening degree of a valve used in a nuclear power plant or the like.

[Conventional technology]

FIG. 3 shows a conventional example of a valve control device that drives a valve stem using a pulse motor. Using the deviation value by the calculator 2, the deviation value is obtained by subtracting the valve opening detection signal 14, which is a shift feedback signal, from the valve opening setting value signal l output from the plant equipment (not shown). The controller 3 calculates the pulse motor shaft displacement set value. The calculator 4 calculates the deviation between the pulse motor shaft displacement set value, which is the output of the regulator 3, and the pulse motor shaft displacement signal 15.

Using this deviation as input, the function generator 5 generates a pulse rate that defines the speed of the pulse motor shaft, and generates a pulse? 5
In 6, the pulse motor shaft (stem) is adjusted according to the pulse rate.
Outputs up/down pulses (contact signals) indicating the rise/fall of .

The pulse motor drive circuit 7 inputs pulses and operates the pulse motor 8 by IKtmf. Axis (stem) of pulse motor 8
The air pressure corresponding to the value of the valve actual opening detection signal 1 is transmitted to the pulse/air pressure converter O via the gear 16 mechanically connected to the pulse/air pressure converter O.
It is generated by the air pressure converter 9.

Air is conveyed through the air pipe 17 to operate the valve 1o. The opening degree of the valve 10 is detected by a detector 11.

Feedback in the form of electrical signals.

A potentiometer 12 mechanically connected to the pulse motor 8 extracts the displacement of the pulse motor shaft as a resistance value (not shown), and after converting the resistance / into a voltage signal with a pressure converter 13,
The signal is input to the arithmetic unit 4 as a feedback signal. In this case, the amount of fluid flowing through the valve IO is taken out as a signal by the operation of the valve 10.

Valve actual opening detection signal 1 (D value is calculated through another regulator).

[Problem that the invention seeks to solve]

As described above, in the conventional device, a potentiometer is used when extracting the shaft displacement of the pulse motor as a feedback signal. The displacement of the pulse motor shaft is the same as the change in the pulse motor shaft angle).

The displacement of the pulse motor shaft is detected as a change in resistance value based on a change in the potentiometer axis coaxial with the pulse motor shaft.

Since the potentiometer has a sliding part, when the pulse motor shaft slides, the potentiometer wears out, making it unreliable for use in a control system.

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide a valve control device that achieves a highly reliable feedback signal and highly accurate valve opening control by using means that does not have a sliding part as a feedback control system. .

[Means for solving problems]

The present invention is characterized by taking the following measures in order to solve the above problems and achieve the objectives. In other words, one aspect of the present invention is an adjusting means that compares the valve opening & setting signal and the valve actual opening detection signal and operates to eliminate the deviation;
A function generator that generates a pulse rate equivalent to the speed of a pulse motor for driving the valve stem based on the output of the adjustment means, and a pulse generator that generates driving pulses for the pulse motor based on the pulse rate from this function generator. In the valve control device having the above, an estimated value of the displacement of the pulse motor shaft is calculated based on the count value of the # marked pulses or the number of pulses obtained by numerical integration of the pulse rate.

The present invention is characterized in that it includes a feedback system that negatively feeds back the calculated value to the input side of the function generator.

[Effect]

As described above, the pulses are counted, and the estimated value of the pulse motor shaft displacement amount is calculated from the counted value and used as a feedback signal.

Here, estimated value of pulse motor shaft displacement = (integrated value of pulses) × (pulse motor shaft displacement f per unit pulse)
I'll go.

In other words, the estimated value of the pulse motor shaft displacement calculated from the pulse count every moment is fed back, and the estimated value of the displacement is set by calculating the deviation from the set value of the pulse motor shaft displacement calculated from the valve lift signal deviation. If the value is larger than the set value, a down pulse is output to reduce the Tanabata shaft displacement, and if it is smaller than the set value, an up pulse is output to increase the motor shaft displacement.

Further, the pulse rate, which is the input to the pulse generator, is numerically integrated to calculate the number of pulses, and from this value, an estimated value of the pulse motor shaft displacement amount is calculated and used as a feed signal. Assuming that the pulse rate is 27 seconds per pulse and the pulse motor shaft displacement amount per pulse is dα, the estimated value Lcm of the pulse motor shaft displacement amount is calculated by the following formula, where t, .about.t, is the integration time interval.

In other words, the pulse rate is integrated, and the estimated value of the pulse motor shaft displacement is calculated from this value and fed back. If it is larger than the set value, a down pulse is generated to reduce the motor shaft displacement, and if it is smaller than the set value, an up pulse is generated to increase the motor shaft displacement.

〔Example〕

Embodiments of the present invention will be described below with reference to FIGS. 1 and 2, in which the same parts as in FIG. 3 are given the same reference numerals.

FIG. 1 is a block diagram of a first embodiment of the present invention. That is, the potentiometer 12 and the resistance/voltage converter 1
3, a pulse counter 100 and a coefficient multiplier 101 are provided as a feedback system.

According to this configuration, the output pulse of the pulse generator 6 is generated by the pulse motor 1θ0, and the coefficient unit 1 inputs the output pulse.
01 to estimate the pulse motor @displacement A:.

The deviation between this estimated displacement amount and the motor shaft displacement amount set value of the regulator 3 is calculated by the operator 4, and if the pulse motor shaft displacement estimated value signal 18 is larger than the same setting &L↓, the function generator A negative pulse rate is output from 5 to reduce the amount of motor shaft displacement. In the opposite case, a positive pulse rate is output to increase the amount of motor shaft displacement.

FIG. 2 is a block diagram of a second embodiment of the invention. That is, in place of the conventional potentiometer 12 and resistance/voltage converter 13, an integrator 102 and a coefficient unit 103 are provided as a feedback system.

According to this configuration, the pulse rate output from the function generator 5 is integrated by the integrator 100, and the result is integrated by the coefficient unit 101.
The amount of displacement of the pulse motor QIl is estimated through

The deviation between this estimated displacement amount and the motor shaft displacement setting value of the regulator 3 is calculated by the calculator 4, and if the estimated value 9 of the 6-barsmo-evening axis displacement amount is larger than the same setting value, A negative pulse rate is outputted from the function generator 5 to reduce the motor/evening axis displacement t, and in the opposite case, a positive pulse rate is outputted to increase the motor shaft displacement amount.

According to the embodiment described above, negative feedback control is achieved by obtaining a stationary feedback signal without using a potentiometer, so there is no reduction in signal reliability due to wear etc. as in the conventional case. This allows high-sensitivity control to be achieved with just one valve.

〔Effect of the invention〕

As described above, in the present invention, the pulse motor shaft displacement estimated value based on the pulse count value or the number of pulses obtained by numerical integration of the pulse rate is used as the return R signal without using the NI return signal from the detector having the sliding wJ part. In particular, it is possible to improve the reliability of the feedback signal, thereby providing a valve control device capable of controlling the valve opening degree to a high degree of N.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing the structure of a first embodiment of a valve control device according to the present invention, FIG. 2 is a block diagram showing the structure of a second embodiment of the present invention, and FIG. 3 is a block diagram showing the structure of a conventional valve control device. FIG. 2 is a block diagram showing the configuration. 1... Valve actual opening detection signal % 2, 4... Arithmetic unit, 3
...Adjuster, 5.Function generator, 6.Pulse generator, 7.Drive circuit, 8.Pulse motor, 9.
...Pneumatic pressure conversion section. IQ... Valve s 11... Detector, 100, 102.
...Nokuruskau/ri% 101,103...Coefficient unit.

Claims (1)

[Claims] A control means operates to eliminate the deviation by comparing a valve opening setting signal and an actual valve opening detection signal, and a pulse rate corresponding to the speed of a pulse motor for driving the valve stem is determined based on the output of this control means. In a valve control device having a function generator that generates pulses and a pulse generator that generates driving pulses for a pulse motor based on the pulse rate from the function generator, the pulses are generated by a count value of the pulses or numerical integration of the pulse rate. 1. A valve control device comprising: a feedback system that calculates an estimated value of a pulse motor shaft displacement amount based on the number and feeds back the calculated value negatively to the input side of the function generator.