JPS61286677A - Valve controller - Google Patents

Abstract

PURPOSE:To perform accurate position control, by detecting the actual opening displacement of a valve, feeding this back, and setting a displacement setting value in a pulse motor shaft, while comparing this value with the displacement of the pulse motor shaft for calculation. CONSTITUTION:A displacement value showing the actual opening of a valve is detected, while this value is converted into voltage through a displacement voltage converter 220 and fed to an operator 230. On the other had, a valve opening setting value is inputted into this operator as voltage and, after this voltage is compared with the voltage equivalent to the actual displacement and calculated, this result is fed to another operator 3 as a displacement setting signal of a pulse motor shaft via a controller 210. A voltage signal showing the displacement value of the pulse motor shaft is fed to this operator as a feedback signal, and compared with a signal out of the controller 210 and calculated.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a control device for various valves used in nuclear power plants, thermal power plants, and other fluid equipment.

(Prior Art) Conventionally, there are many types of drive devices for fluid-operated valves, many of which use pulse motors. FIG. 2 is a typical example, and shows a general valve control system using a pulse/air pressure converter using pulse smoke.

Briefly, a valve opening degree setting signal determined by other controls is output as a voltage signal, and is compared with a feedback signal, which will be described later, by a calculator 3. An amplifier or down contact signal of the pulse motor is output from the voltage/pulse converter 4 which generates a pulse according to the comparison deviation voltage of the calculation result. In response to this output signal, the pulse motor drive circuit 6 operates and drives the pulse motor 7.

When the pulse motor 7 is driven, the air pressure is converted into air pressure according to the set value of the valve opening setting signal 1 via the gear 9 mechanically connected to the shaft of the pulse motor 7 and the pulse/air pressure converter 10. , is transmitted to the valve 12 through the air piping and operates the valve 12.

On the other hand, the displacement of the pulse motor shaft is extracted by a resistor R by a potentiometer 13 mechanically connected to the pulse motor 7, converted to voltage by an R/V converter 14, and then inputted to the arithmetic unit 3 as a feedback signal. .

Here, the set value of the valve opening degree setting signal is determined by calculating and determining the amount of fluid controlled by the valve 12 as a result of the operation of the valve 12 through a controller (not shown).

Note that a signal obtained by counting the amplifier or down contact signal 5 indicating the displacement of the pulse motor may be used as the feedback signal.

By the way, according to the above conventional method, the valve opening setting value and the displacement of the pulse motor shaft are controlled proportionally.
The pulse motor is operated until the two match, but in reality, the set value of the valve opening and the actual value of the valve opening do not necessarily match, making it impossible to accurately control the flow rate through the valve. there were.

(Problems to be Solved by the Invention) As mentioned above, in the conventional valve control device, the valve opening setting value and the displacement signal of the pulse motor shaft are fed back and proportionally controlled. There was a problem that the actual value of the valve opening did not necessarily match, and accurate control could not be performed.

The present invention has been made to solve these problems, and aims to provide a valve control device that enables accurate position control of the valve opening.

(Means for solving the problem) Therefore, in the present invention, in a valve opening control device that detects the displacement of the pulse motor shaft and performs feedback control, the actual opening displacement of the valve is further detected and fed back. A displacement set value of the pulse motor shaft is set via a controller, and a comparison calculation is performed between this set value and the displacement of the pulse motor shaft. This is a means to solve the above problems.

(Operation) Detects the amount of displacement that indicates the actual opening of the valve, converts this amount into voltage through a displacement/voltage converter, and sends it to the computing unit. On the other hand, the valve opening set value is input as a voltage to this calculator, and after this and the voltage corresponding to the actual displacement of the valve are compared and calculated, this result is sent to the controller that performs a PT operation, for example. It is sent as a displacement setting signal for the pulse motor shaft to other computing units.

As before, a voltage signal indicating the amount of displacement of the pulse motor shaft is sent to this calculator as a feedback signal.
A comparison operation is performed with the signal from the controller. in this way,
The control device according to the present invention adds a new circuit to the conventional control device, which feeds back the actual value of the valve opening and constantly compares and controls the valve opening with the set value, so that the actual value always matches the set value. It becomes possible to do so.

(Example) Embodiments of the present invention will be described below with reference to FIG.

In the figure, each part with reference numerals 1 to 12 indicates the same part as the conventional one shown in FIG. 2, and will not be explained again here.

In this embodiment, an arithmetic unit 230 and a controller 210 are newly arranged in series between the valve opening degree setting signal 1 and the arithmetic unit 3 in FIG. 2, and the actual displacement of the valve 12 is detected. is passed through the displacement/voltage converter 220 as a voltage signal 200, and the arithmetic unit 230 compares and calculates the valve opening setting signal 1 with the valve opening setting signal 1.

The controller 210 includes, for example, a proportional/integral controller (PI).
controller) is preferred.

Next, to explain its operation, the computing unit 230 calculates the deviation between the valve opening setting signal 1 and the voltage signal 200 indicating the actual valve opening converted by the displacement/voltage converter 220. Based on this result, the controller 210 sets the displacement setting value of the pulse motor shaft, and the signal is sent to the arithmetic unit 3, where the R/V converter 14 corresponds to the actual displacement of the pulse motor shaft.
It is compared with the signal from.

This calculation result is converted into a pulse by a voltage/pulse converter 4, and a contact signal indicating up/down, which is the displacement of the pulse motor, is output. Upon receiving this signal, the pulse motor drive circuit operates to operate the balsmoke 7. The actual displacement of the pulse motor 7 is detected by the potentiometer 13, and the R/V
It is converted into a voltage signal via a converter and input to the arithmetic unit 3.

On the other hand, the displacement of the seven shafts of the pulse motor is transmitted to the gear, and is converted by the pulse/air pressure converter 10 into air pressure corresponding to the set value of the valve opening setting signal 1. This converted air pressure is transmitted to the valve 12 through the pipe 11, and the valve 12 is operated until the internal pressure of the valve 12 becomes equal to the air pressure of the air. The displacement of this valve 12, that is, the actual valve opening is measured by a displacement/voltage converter 220.
The voltage signal 200 is converted into a voltage signal 200 and output to a calculator 230 for comparison with the valve opening setting signal 1.

Thereafter, similar actions are repeated to maintain control of the valve.

In addition to the control device, it detects the actual opening of the valve, feeds it back, compares it with the valve opening set value, and outputs the result as the displacement set value of the pulse motor shaft via the controller. Therefore, if the difference between the set value of the valve opening degree and the actual opening degree is large, the output of the controller increases and the pulse motor is displaced to the + side, resulting in an increase in the actual valve opening degree. This also works in the opposite case, so that the actual value always operates to the point where it matches the set value.

Therefore, according to the device of the present invention, the setting accuracy of the flow rate flowing through the valve is compensated, and the flow rate can be controlled reliably.

[Brief explanation of drawings]

FIG. 1 is a block diagram of valve opening degree control showing an embodiment of the present invention, and FIG. 2 is a conventional control block diagram of the same. Explanation of main parts of the diagram 1 - Valve opening setting signal 3 - Computing unit 7 - Pulse motor 12 - Valve 210 - Controller 220 - Displacement/voltage converter 230 - Computing unit patent applicant Mitsubishi Heavy Industries Co., Ltd. Figure 1

Claims (1)

[Claims] In a valve opening control device that detects the displacement of the pulse motor shaft and performs feedback control, it also detects the actual valve opening displacement, feeds it back, compares it with the valve opening set value, and then controls the valve opening via the controller. A valve control device characterized in that a displacement set value of the pulse motor shaft is set, and a comparison calculation is performed between the set value and the displacement of the pulse motor shaft.