JPH0447248A - Automatic apparatus for testing control valve - Google Patents

Abstract

PURPOSE:To enable automatic, quick and exact execution of a test of a control valve by a system wherein the opening of the control valve and a control signal thereof according to a control instruction are controlled by a programmable computation device on the basis of signals from a position signal generator and a pressure signal generator. CONSTITUTION:A position signal from a position signal generator 10 and a pressure signal from a pressure signal generator 11 detecting an air pressure signal impressed on a control valve 1 are inputted to a programmable computation device 12. Meanwhile, a control signal generating device 13 outputs an electric signal for control of the control valve to a solenoid operated valve 7 and an electropneumatic converter 14 under the control of the device 12. Based on a control valve opening signal from the generator 10 and the pressure signal from the generator 11, the device 12 records the opening of the control valve every time when a control signal turns to be at each set level. Besides, an air pressure impressed actually on the control valve 1 is fed back to the device 12, and when the control signal becomes a correct value through repetition of feedback, it records a signal of the opening of the control valve 1. Therefore, correct performance data can be collected automatically.

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Field of Industrial Application) 'The present invention relates to an apparatus for automatically testing control valves used, for example, in process control.

(Prior Art) Control valves used for process control and the like are periodically subjected to performance tests because if their performance deteriorates, it may have a significant impact on the entire system.

Traditionally, performance testing methods for such control valves include:
A method as illustrated in FIG. 2 has been implemented.

In the same figure, the control valve 1 is equipped with an actuator 2 for driving and a positioner 3 for stabilizing the operation of the control valve 1. The test is carried out by reading the opening degree of the control valve 1 using the scale 6. That is, by sequentially repeating this operation for each control signal (air pressure) and recording the opening degree of the control valve 1 for each control signal, the linearity, hysteresis, repeatability, and other performances of the control valve 1 are calculated.

In addition, regarding the response time and dead time, the solenoid valve 7 inserted in the air signal system can be turned on and off using the switch 8.
At this time, the inspector uses a stopwatch, etc. to check the control valve 1.
It is calculated by visually measuring the movement of In FIG. 2, numeral 9 indicates a power source for driving the solenoid valve 7.

(Problem to be Solved by the Invention) In the conventional performance testing method described above, most operations, data reading, and result calculations rely on humans, so it takes time to set control signals, and data When reading the information, there are inconveniences such as individual differences, resulting in errors, and there is a problem in that a considerable amount of skill and time are required to properly test the performance.

The present invention has been made to solve these problems, and an object of the present invention is to provide an automatic control valve testing device that can automatically test control valves quickly and accurately.

[Structure of the Invention] (Means for Solving the Problems) The automatic control valve testing device of the present invention includes a control signal generating device;
A function of instructing the set value of the control signal output from this control signal generator, a function of correcting the control signal by a feedback signal of the drive signal actually given to the control valve, and a position feedback signal from the control valve. According to
a programmable calculation device that automatically calculates the operating state of the control valve in response to the drive signal; a recording device that automatically records the calculation results of the programmable calculation device;
It is characterized by having the following.

(Function) The automatic control valve testing device of the present invention uses a position transmitter, a pressure transmitter, and a programmable arithmetic device, and the operating state of the JR control valve in response to a control signal is automatically fed back to the programmable arithmetic device. The performance of the control valve is calculated. Furthermore, since a control signal generator is used and the control valve can be automatically operated in accordance with commands from the programmable arithmetic unit, various performance tests of the control valve can be performed automatically.

(Example) Next, the present invention will be described in detail with reference to the drawings. In FIG. 1, the same parts as in FIG. 2 are given the same reference numerals.

In FIG. 1, an actuator 2 and a positioner 3 for driving the control valve are attached to the upper part of a control valve 1. An electromagnetic valve 7 is inserted into an air signal system that leads air signals to the positioner 3 so that the drive signal for the control valve 1 can be instantaneously switched.

Further, the control valve 1 is connected to a position transmitter 10 that electrically outputs its opening degree. A position signal from the position transmitter 10 and a pressure signal from a pressure transmitter 11 that detects an air pressure signal applied to the control valve 1 are input to a programmable arithmetic unit 12 .

On the other hand, the control signal generator 13 outputs an electric signal for controlling the control valve to the electromagnetic valve 7 and the electric-air converter 14 under the control of the programmable arithmetic unit 12 .

The programmable arithmetic device 12 includes the position transmitter 10 described above.
The control valve opening degree is recorded each time the control signal reaches each set level using two types of feedback signals: the control valve opening signal from the controller and the pressure signal from the pressure transmitter 11. In FIG. 1, reference numerals 15 and 16 indicate a printer and a CRT (cathode ray tube) as an example of a recording device that automatically records the calculation results of the programmable calculation device 12.

Conventionally, the setting points of the control signal are 1%, 2%.
Five points are adopted: 5%, 50%, 75%, and 400%, but since the programmable arithmetic unit 12 is programmable, the set points and scores can be set freely. .

In addition, the programmable arithmetic unit 12 actually includes a control valve 1.
The air pressure applied to is fed back,
This also has the function of finely adjusting the output to the control signal generator 13, and when the control signal reaches an accurate value by repeating feedback, the opening signal of the control valve 1 is recorded, so accurate performance data can be obtained. can be collected automatically.

Next, a performance test of the stroke time and dead time of the control valve will be explained.

As described above, the solenoid valve 7 is turned ON/OFF based on a command from the programmable arithmetic unit 12 and a signal from the control signal generator 13 . For example, when measuring the stroke time, first cut off the switching control signal for the solenoid valve 7, release air to the exhaust side, and leave the control valve 1 free (here, we will use a type of control where the free state is fully open). (explained as a valve). Next, the programmable arithmetic unit 12 issues a command to the control signal generator 13 to output a 100% control signal, which corresponds to full opening, and after confirming that the feedback signal from the pressure transmitter 11 is stable, similarly A switching control signal is issued to the solenoid valve 7, and a fully open signal is input instantaneously. At this time, when the control valve is fully opened in response to a feedback signal from the position transmitter 10, the required time is calculated by a quartz clock or the like built in the programmable arithmetic unit 12 and displayed on the CRT 16 as a stroke time.

Furthermore, dead time is also measured using the same principle.

Next, an example of calculating linearity and hysteresis will be described with reference to FIG. 3.

Figure 3 shows an example of the output displayed on the screen of the CRT 16. The data in frame A in the lower half of the screen is the specified control signal (0%, 25%, 50%) when measuring 5 points. , 75
%, 100%), the valve opening degree when the control valve 1 is opened and the valve opening degree ■ when the control valve 1 is closed are displayed. Using these data, operation chart B in the upper half of the screen is displayed. Here, the solid line ■ and the solid line ■ indicate the relationship between the control signal (%) and the opening degree (%) of the control valve during the valve opening operation and the valve closing operation, respectively, and the chain line ■ indicates the reference value.

In addition, the maximum value of the difference between the solid line ■, ■ and the reference value ■ when the control valve 1 is opened and closed is displayed on the screen as linearity, and the control valve is opened during the open operation ■ and when the control valve is closed ■. The maximum value of the difference in degrees is automatically calculated and displayed on the screen as hysteresis.

The various data displayed on the CRT 16 are printed out on the printer 15 if necessary.

In addition, if there are limit values for the performance of the control valve mentioned above, the limit values are programmed in advance in the programmable arithmetic unit 12, and when the limit values are exceeded, the display data on the CRT 16 and the printout on the printer 15 are changed to red. An alarm may be issued by, for example,

[Effects of the Invention] As explained above, according to the automatic control valve testing device of the present invention, when testing the performance of a control valve, the programmable arithmetic unit performs a! for control commands! Feedback control of the valve opening and control signals allows for accurate testing, and the test can be performed automatically using a preset program, so testing can be performed quickly and without any manual effort. Records can also be automatically created if necessary.

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram showing an embodiment of the automatic control valve testing device of the present invention, FIG. 2 is a schematic diagram showing a conventional example, and FIG. 3 is an explanatory diagram illustrating a CRT display screen in the device of the present invention. 1......Control valve 2...Actuator 3...Positioner 4...Reducing valve 5... ......Pressure gauge 6...Scale 7...Solenoid valve 8...Switch 9... ...Power source 10...Position transmitter 11...Pressure transmitter 12...Programmable arithmetic device 13.
......Control signal generator 14...
...Electricity-air converter 15...Printer 16...CRT

Claims (1)

[Claims] Control signal generating device: A function of instructing the set value of the control signal output from the control signal generating device, and correcting the control signal by a feedback signal of the drive signal actually given to the control valve. With the function and position feedback signals from the control valve,
A control valve comprising: a programmable arithmetic device having a function of automatically calculating the operating state of the control valve in response to the drive signal; and a recording device that automatically records the arithmetic results of the programmable arithmetic device. Automatic test equipment.