JP2005233285A - Valve positioner and valve-driving actuator - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a valve positioner capable of setting control sensitivity (hysteresis value) for avoiding hunting, with a simple construction requiring no costs, without using dedicated equipment, and a valve-driven actuator applying the valve positioner. <P>SOLUTION: When a user manually operates an operation switching circuit 10, the signal is transmitted to a sensitivity table switching circuit 8. Due to this, when a table number is selected, control sensitivity in a control sensitivity adjusting part T is set to be a hysteresis value forming a pair with the table number. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a valve driving actuator for driving a valve such as a butterfly valve and a ball valve, and a positioner for driving the valve driving actuator, and more particularly to a valve driving actuator having a function for suppressing valve hunting. Etc.

Hunting of the valve can be cited as an example of an abnormality of the valve driving actuator as described above. It detected these were the hunting of the valve automatically, there is for safety, issues an alarm technology (e.g., see Patent Document 1 or 2). The reason why such hunting occurs is because the control sensitivity is too high. That is, when a difference occurs in the actual valve opening relative to the control target value of the valve opening, a control signal for suppressing the difference is output. The speed to actually operate the actuator from the detection direction to eliminate the above-mentioned difference in the difference that the control sensitivity. The higher the control sensitivity, the more agile control is achieved. However, if this control sensitivity is not set appropriately for the machine conditions, hunting due to overshoot occurs. Therefore, in order to prevent hunting, the control sensitivity is deliberately lowered, that is, the control is slowed down. This is called hysteresis setting, and the set delay rate (usually expressed as a percentage). Is called a hysteresis value.
This hysteresis setting is performed using a dedicated device for hysteresis setting, and in order to change this setting, it is currently necessary to bring in the dedicated device. On the other hand, when hunting occurs In addition, there is a technique for detecting this and automatically adjusting the control sensitivity so as to obtain the highest control sensitivity in a range where hunting is not performed (for example, see Patent Document 3).
Japanese Patent No. 3007587 Japanese Patent No. 2977505 JP 2002-315372 A

By the way, if the installation environment of the valve drive actuator is properly managed by adjusting the temperature by air conditioning, adjusting the humidity by the dehumidifier / humidifier, etc., once the control sensitivity suitable for this environment is set, hunting will occur afterwards. It is rare to change the control sensitivity (hysteresis value) setting frequently.
Therefore, in a valve drive actuator that is used in a place where the installation environment is sufficiently controlled, a valve positioner that automatically adjusts the control sensitivity as in the invention described in Patent Document 3 sometimes requires equipment and cost. May be wasted.
On the other hand, if there is no such function to change the control sensitivity setting, if hunting occurs, there is the inconvenience that the setting must be changed using a dedicated device for setting the control sensitivity. There is also a waste of work time.
An object of the present invention is to solve the problems of the prior art as described above.

In order to solve the above problems, the present invention provides an angle detection means for detecting an operating angle of a valve, a control means for controlling a valve driving actuator based on a valve angle detection value by the angle detection means, and the control means. A valve positioner comprising a sensitivity setting means for setting the control sensitivity of the valve, wherein the user comprises a manual sensitivity setting adjustment means for manually changing a sensitivity setting value in the sensitivity setting means. Configured as a positioner. As a result, waste of equipment and costs can be eliminated.
It is desirable to have display means for displaying the control sensitivity set by the manual sensitivity set value adjusting means. This is because the setting can be confirmed visually.
The display means may be composed of one or a plurality of light emitting diodes.
If the mode changeover switch for switching between the sensitivity setting mode for setting the control sensitivity by the manual sensitivity setting means and the normal operation mode is provided, it is possible to change the control sensitivity setting more safely.

  Furthermore, the present invention may be understood as a valve driving actuator comprising the valve positioner as described above.

  As described above, according to the present invention, the control sensitivity setting can be changed without using a dedicated device for setting the control sensitivity, and a valve that does not require a complicated control system for performing the automatic control sensitivity adjustment. Because it is a positioner, it is possible to eliminate waste of equipment and costs. In addition, it is possible to prevent the control system program from growing for a long time, and it is possible to prevent the cause of bugs and the increase in program capacity.

Next, embodiments of the present invention will be described with reference to the accompanying drawings to help understand the present invention. It should be noted that the following embodiments and examples are examples embodying the present invention and do not limit the technical scope of the present invention.
FIG. 1 is a control block diagram of a positioner for a valve driving actuator according to an embodiment of the present invention, and FIG. 2 is a conceptual diagram showing an example of a control sensitivity (hysteresis value) table.
As shown in FIG. 1, a positioner A for a valve drive actuator (not shown) according to this embodiment is configured around a determination circuit 1.
Valve opening setting value signal from the target value setting section outside the figure, is input from the setting value input circuit 2 to the positioner A. The input set value signal is converted to a digital signal by the first A / D converter 3 and then input to the determination circuit 1 through the control sensitivity adjustment unit T.
On the other hand, the valve angle signal detected by the operating angle feedback signal generator 4 which is an example of the angle detecting means attached to the output shaft of the motor M is inputted to the feedback input circuit 5 and then the second A / D converter. After being converted into a digital signal at 6, it is inputted to the determination circuit 1.
The determination circuit 1 calculates the difference between the digital signals from the first and second A / D converters 3 and 6 and sends it to the motor drive circuit 7. Motor drive circuit 7 drives the motor M in accordance with the difference. As a result, the motor M rotates in the direction in which the difference becomes smaller, and the valve is driven so as to approach the target opening degree via the valve driving actuator connected to the motor.
The control sensitivity adjustment unit T sets the speed at which the difference between the set value and the actual measured value of the motor M is applied, that is, the control sensitivity (hysteresis value). The control sensitivity adjustment unit T further includes control sensitivity. A sensitivity table switching circuit 8 storing a (hysteresis value) table is connected. As shown in FIG. 2, the control sensitivity (hysteresis value) table is composed of storage means for storing a multistage hysteresis value and a table number indicating each hysteresis value as a pair. When the user manually operates the operation switching circuit 10 from an operation unit (not shown), the signal is transmitted to the sensitivity table switching circuit 8, and when the table number is selected, the control sensitivity in the control sensitivity adjustment unit T is changed. And the determination circuit 1 delays the control based on this hysteresis value.

Here, as shown in FIG. 1, a display circuit 9 may be connected to the control sensitivity (hysteresis value) adjusting unit T. For example, a configuration in which a display unit (equivalent to display means) such as a monitor is provided to display the input sensitivity table number and sensitivity selected by the user is conceivable.
This makes it possible to change the setting while visually confirming the setting of the hysteresis value, and to prevent setting errors.
Furthermore, the display means may be composed of one or a plurality of light emitting diodes (hereinafter referred to as LEDs). If the LED with n color mode to constitute a display means with the m n ^m street (if LED off state also used as a display unit (n + 1) ^m street) capable of displaying the set value of This is preferable because a simpler configuration is sufficient.
For example, as shown in FIG. 3, by combining three LEDs (LED1, LED2, LED3) having three coloring modes (red, blue, orange), the selected hysteresis value table number is 3 ³ = 27 ( When the LED is turned off as display means, (3 + 1) ³ = 64 ways) can be displayed.
For example, if LED1 displays information about the environment, LED2 displays information about the motor, and LED3 displays the information on the valve side in color, the operating status of the actuator can be externally determined by combining the colors of LEDs 1-3. Can be displayed. The user has a list of combinations of such colors and the meaning of the situation, or the user can stick to the actuator to detect the operating status of the actuator at a glance from the outside. It is possible to prevent failure.

Further, as shown in FIG. 1, the operation switching circuit 10 is connected to the sensitivity table switching circuit 8 (mode changeover switch), and the control sensitivity (hysteresis value) setting mode is switched between the normal operation mode and the hysteresis during normal actuator operation. It is possible to prevent the setting of the value from being changed, and it is possible to prevent the error that the setting is changed during the operation and to change the setting of the hysteresis value more safely.
If the operation switching circuit 10 is connected to the display circuit 9 as in the embodiment shown in FIG. 1, the display means indicates whether the control sensitivity (hysteresis value) setting mode or the normal operation mode is set. Can also be displayed.

  Further, the valve positioner A according to the present invention can be applied to a valve driving actuator as it is.

The block diagram which shows the control system of the valve positioner concerning one Embodiment of this invention. The conceptual diagram which shows an example of a hysteresis value table. The conceptual diagram which shows an example of the hysteresis value table number display by the display part comprised combining LED.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Judgment circuit 2 ... Setting value input circuit 3 ... A / D converter 4 ... Operation angle feedback signal generator 5 ... Feedback input circuit 6 ... A / D converter 7 ... Motor drive circuit 8 ... Sensitivity table switching circuit 9 ... Display circuit 10 ... Operation switching circuit A ... Valve positioner M ... Motor T ... Control sensitivity adjustment section

Claims (5)

An angle detection means for detecting an operating angle of the valve; a control means for controlling the valve drive actuator based on a detected value of the valve angle by the angle detection means; and a sensitivity setting means for setting the control sensitivity of the control means. In the valve positioner
A valve positioner comprising a manual sensitivity setting adjusting means for a user to manually change a sensitivity setting value in the sensitivity setting means.   3. The valve positioner according to claim 1, further comprising display means for displaying the control sensitivity set by the manual sensitivity set value adjusting means.   The valve positioner according to claim 2, wherein the display means comprises one or a plurality of light emitting diodes.   4. The valve positioner according to claim 1, further comprising a mode changeover switch for switching between a sensitivity setting mode in which control sensitivity is set by the sensitivity setting means and a normal operation mode.   5. A valve drive actuator comprising the valve positioner according to claim 1.

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