JPH08226402A - Valve controller - Google Patents

Abstract

(57) [Abstract] [Purpose] To provide a valve controller which is integrally configured as a unit and is installed in a process site together with a measuring transmitter and a control valve. [Structure] Diaphragm valve 2 operated for controlled object 9
The valve controller 1 according to the present invention includes a control unit 10 and a positioner unit 20.
Further, the control unit 10 includes the interface 11 and the microprocessor 12 and the positioner unit 20.
Is a microprocessor 21, a D / A converter 22, an electropneumatic converter 23, a feedback lever 24, an angle detector 25, and an A / D converter.
And a converter 26. The electro-pneumatic converter 23 receives the supply air pressure and mainly includes the piezoelectric flapper 23A and the nozzle 23B.
And pilot valve 23C. Since the battery 30 is complicated, the supply destinations are not illustrated individually, but the interface 11, the microprocessor 12, and the microprocessor 2 are not shown.
1, power is supplied to the D / A converter 22 and the A / D converter 26.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention controls a fluid flow rate for operating a process control target based on a measurement signal of a state quantity such as temperature, pressure and flow rate related to the process control target and a corresponding set value signal. The present invention relates to a valve controller that determines the valve opening degree of the control valve, and particularly relates to a valve controller that is integrally configured as a unit and is installed at a process site together with a measuring transmitter and a control valve.

[0002]

2. Description of the Related Art A conventional example will be described with reference to the block diagram showing the configuration of FIG. In FIG. 2, the temperature, which is the state quantity of the process control target (hereinafter referred to as the control target) 9, is measured by the transmitter 51, and the measured value signal is input to the controller 52. The controller 52 outputs a control signal based on a predetermined control operation so that the deviation between the measured value signal and the set value signal corresponding to the controller 52 is output, and the operation amount is controlled via the diaphragm valve 54 as a control valve. Manipulate a certain fluid flow rate.
At that time, in order to accurately position the valve opening (valve position) of the diaphragm valve 54, a positioner 53 as a servo mechanism is used.
Intervene. The control signal is converted into operating air pressure via the positioner 53 under the feedback of the valve opening (valve movement) indicated by the alternate long and short dash line.

[0003]

In the conventional example, the controller 52 is generally installed in the control room, and the transmitter 51, the positioner 53, and the diaphragm valve 54 on the one hand are installed in the field. Not only does this increase the cost, but also the control is not good. In addition, the controller 52
It is also not preferable in operation that the positioner 53 is required individually.

The problem to be solved by the present invention is to solve the above problems of the prior art and to provide a valve controller which is integrally configured as a unit and is installed at a process site together with a measuring transmitter and a control valve. To provide.

[0005]

SUMMARY OF THE INVENTION The present invention is a valve of a control valve for controlling a fluid flow rate for operating a process control target based on a measurement signal of a state quantity related to the process control target and a corresponding set value signal. A valve controller that determines the opening degree, and a control unit that inputs the measurement signal of the state quantity and the corresponding setting value signal and outputs the setting value signal of the valve opening degree to the control valve; the setting value of the valve opening degree Based on the signal
The positioner unit that drives the control valve and positions the control valve based on the feedback of the valve opening is integrally provided.

Also, the present invention is preferably installed at a process site together with a control valve and an oscillator for outputting a measurement value signal.

[0007]

According to the present invention, the control unit inputs the state quantity measurement signal and the corresponding set value signal, outputs the valve opening set value signal to the control valve, and the positioner unit sets the valve opening set value. The control valve is driven based on the signal, and the control valve is positioned based on the feedback of the valve opening. Moreover, the control unit and the positioner unit are integrally configured.

Further, according to the present invention, since the control valve and the transmitter for outputting the measured value signal are installed at the process site, the signal lines between them can be short, and noise interference can be suppressed.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the valve controller according to the present invention will be described with reference to FIG. 1 which is a block diagram showing the structure thereof. In FIG. 1, the diaphragm valve 2 operated for the controlled object 9 and the oscillator 3 for measuring the temperature, which is the state quantity of the controlled object 9, are substantially the same although the reference numerals are different from the conventional example. Here, the valve controller 1 is newly installed in place of the controller 52 and the positioner 53 in the conventional example.

The valve controller 1 is mainly composed of a control unit 10
And a positioner section 20 and a battery 30 as a power source for the electric and electronic units. Further, the control unit 10 includes an interface 11 and a microprocessor 12, and the positioner unit 20 includes a microprocessor 21 and a D / A converter.
22, electro-pneumatic converter 23, return lever 24, angle detector 25
And an A / D converter 26. The electro-pneumatic converter 23
Receives the supply air pressure and is mainly composed of a piezoelectric flapper 23A, a nozzle 23B and a pilot valve 23C.
The battery 30 supplies power to the interface 11, the microprocessor 12, the microprocessor 21, the D / A converter 22, and the A / D converter 26, though the supply destinations thereof are not shown individually because of the complexity. .

By the way, the valve controller 1 has its control section.
The set value signal is input from the host computer 8 and the measured value signal is input from the transmitter 3 to the interface 11 of 10. When the setting and measurement signals are transmitted in the form of light through the optical fiber, they are converted into digital electric signals at the interface 11. The microprocessor 12 performs control calculation based on the deviation between the set value and the measured value, and the control signal of the calculation result is output to the microprocessor 21 of the positioner unit 20 as the second set value signal related to the valve opening degree. . In the microprocessor 21, an operation signal which is a valve opening command is calculated on the basis of a feedback of a valve opening value which will be described later, and the diaphragm valve is operated as an operation air pressure through the D / A converter 22 and the electropneumatic converter 23. 2 is output. at the same time,
The valve opening, that is, the movement of the valve rod is first mechanically fed back to the return lever 24 of the positioner 20, and its displacement is converted into an electric quantity through the angle detector 25 and the A / D converter 26, and finally it is converted. It is fed back to the microprocessor 21.

In short, the valve controller 1 is a control unit that outputs a set value signal of the valve opening degree for the diaphragm valve 2.
10 and the positioner part that determines the valve opening of the diaphragm valve 2.
20 and 20 are integrally configured in a compact size, and are installed in the field together with the diaphragm valve 2 and the transmitter 3. Therefore, the shortening of the signal lines between them and the interference of noise can be suppressed, which leads to cost reduction and improvement of control accuracy. Further, by using the valve controller 1, a conventional controller is not required apart from the host computer 8 for the set value signal, so that the whole plant can be simplified and rationalized.

[0013]

According to the present invention, the following excellent effects can be expected. (1) In the valve controller of the invention, a control unit that outputs a set value signal of the valve opening degree for the control valve and a positioner section that determines the valve opening degree of the control valve are integrally configured as a unit,
Especially when it is installed in the field together with the control valve and the transmitter, the signal lines between them can be shortened and noise interference can be suppressed. As a result, costs can be reduced and control accuracy can be improved. (2) A plant can be simplified and rationalized by using the valve controller of the present invention as a component.

[Brief description of drawings]

FIG. 1 is a block diagram showing the configuration of an embodiment according to the present invention.

FIG. 2 is a block diagram showing a configuration of a conventional example.

[Explanation of symbols]

 1 Valve Controller 2 Diaphragm Valve 3 Transmitter 8 Host Computer 9 Controlled Object 10 Control Section 11 Interface 12 Microprocessor 20 Positioner Section 21 Microprocessor 22 D / A Converter 23 Electro-Pneumatic Converter 23A Piezoelectric Flapper 23B Nozzle 23C Pilot Valve 24 Feedback Lever 25 Angle detector 26 A / D converter 30 Battery

Claims (2)

[Claims] 1. A valve controller for determining a valve opening of a control valve for controlling a fluid flow rate for operating a process control target based on a measured signal of a state quantity related to the process control target and a corresponding set value signal. And a control unit that inputs the measurement signal of the state quantity and the corresponding set value signal and outputs the set value signal of the valve opening to the control valve; and drives the control valve based on the set value signal of the valve opening. And a positioner section for positioning the control valve based on the feedback of the valve opening. 2. The valve controller according to claim 1, wherein the valve controller is installed at a process site together with a control valve and a transmitter that outputs a measurement value signal.