JP2002039106A - Valve positioner - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a valve positioner capable of achieving high efficiency of automatic tuning by resetting a gain in a section to be controlled, in particular, disturbance of hysteresis acting greatly when performing automatic tuning in the valve positioner. SOLUTION: This valve positioner consists of a position sensor detecting an input signal setting a opening of a valve and the opening of the valve, a control operation part controlling and operating so that the opening of the valve agrees with the input signal based on a deviation between a valve opening signal obtained by the position sensor and the input signal to generate a control signal, an electropneumatic conversion mechanism part generating a flow rate of air based on the control signal, and a pressure amplifier supplying pneumatic pressure based on the flow rate of air generated in the electropneumatic conversion mechanism part to the valve. The section to be controlled which is constituted by the electropneumatic conversion mechanism part, the pressure amplifier, the position sensor, and the valve has a gain measuring means measuring the gain in the section to be controlled when it receives an automatically set signal.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a valve positioner, and more particularly to an automatic tuning function for automatically measuring characteristics of a control target portion and calculating a tuning parameter of a control calculation section from the characteristics of the control target portion by calculation. The present invention relates to a valve positioner newly having a function of measuring an input / output gain of a control target portion.

[0002]

2. Description of the Related Art A conventional valve positioner is
Since control functions such as a central processing unit CPU and a DSP are provided and control algorithms can be realized by software, controllability is greatly improved. On the other hand, control algorithms have become complicated and it has become difficult for humans to tune control algorithms manually. As a solution to this, a positioner has come to have a so-called auto-tuning function of measuring the characteristics of a valve as a control target part and determining a tuning parameter based on the measurement result.

[0003] This conventional automatic tuning function has an I / O
The P module, the response speed measurement of the control target portion, the hysteresis measurement of the control target portion, and the measurement of the valve slip width are performed, and the tuning parameter is determined from the measurement results.

[0004]

However, in the above-mentioned automatic tuning function of the prior art, the loop gain to be tuned is obtained from the measured value of the characteristic of the control target portion. Since the gain is the gain Kp of the unit (controller), there is a problem that the gain information of the control target part is necessary to obtain the gain Kp from the loop gain.

[0005] In the conventional automatic tuning function, the input / output gain of the control target portion is obtained by calculation by instructing the positioner of the type of valve or a parameter relating to the type of valve. For this reason, parameters necessary for calculating the gain of the controlled part from the valve type, such as the rated supply pressure, the spring range, etc., are extracted from the database that the positioner itself has in advance. It is necessary to obtain the value of the gain Kp required for control by calculation. Such a method has the following problems. The operator must teach or enter information about the valve to the positioner. As a result, the man-hour for installation is increased. A human error such as an input error occurs. The set value does not always match the actual gain, and has a variation. Therefore, tuning cannot be performed.

Therefore, there is a problem to be solved in that a more accurate and more efficient automatic tuning method is realized by adding a function of measuring the input / output gain of the control target part to the conventional automatic tuning function. .

[0007]

In order to solve the above problems, a valve positioner according to the present invention has the following configuration.

(1) An input signal for setting a valve opening of a valve, a position sensor for detecting the valve opening of the valve, and a deviation between the valve opening signal obtained by the position sensor and the input signal. A control operation unit configured to generate a control signal by performing a control operation so that the valve opening degree of the valve matches the input signal; an electro-pneumatic conversion mechanism unit that generates an air flow rate based on the control signal; A valve positioner comprising a pressure amplifier that supplies air pressure based on the air flow rate generated in the conversion mechanism to the valve, the valve positioner including the electro-pneumatic conversion mechanism, the pressure amplifier, the position sensor, and a valve. The controlled position portion has a gain measuring means for measuring a gain of the controlled portion when receiving an automatic setting signal. (2) In the valve positioner according to (1), the gain measuring unit measures the gain of the control target portion from a control signal of the control calculation unit and a valve opening signal of the position sensor. And a valve positioner. (3) In the valve positioner according to (1), the gain measuring means includes a control signal Mv of the first control operation unit.
(1) is output and the valve opening signal of the position sensor at that time is stored as Pv (1), and the second control signal Mv
(2) is output and the valve opening signal of the position sensor at that time is stored as Pv (2), and the control signals Mv (1) and Mv (1) are stored.
The amount of change in v (2) and valve opening signals Pv (1) and Pv (2)
A gain of the control target portion is measured from a change amount of the valve positioner. (4) In the valve positioner according to (1), the gain measuring means includes an initial value M of a control signal of the control operation unit.
v (0) to output the valve opening signal Pv of the position sensor.
(0) is confirmed to be in the operation area, the control signal Mv (1) of the first control calculation unit is output, the valve opening signal of the position sensor is stored as Pv (1), From the control signal Mv (0) to the control signal Mv (1).
The valve opening degree signal of the position sensor is stored as Pv (2) while being changed in the same direction as the direction in which the control signal Mv is changed.
(1) The change amount of Mv (2) and the valve opening signal Pv (1)
And measuring a gain of the control target portion from a change amount of Pv (2). (5) The valve positioner according to (1), wherein the gain measuring means measures a gain of the control target portion from the input signal and the valve opening signal. (6) In the valve positioner according to (1), the control operation unit performs at least a proportional control operation, and the gain measurement unit supplies the first input signal Sp (1) to the control operation unit, and When the valve opening signal is P
v (1) and stores the second input signal Sp (2)
Is given to the control operation unit, and the valve opening signal is obtained as Pv (2)
A valve positioner which stores the gain of the control target part from the input signals Sp (1) and Sp (2) and the valve opening signals Pv (1) and Pv (2). (7) In the valve positioner according to (1), the control calculation unit performs at least a proportional control calculation, and the gain measuring unit determines an initial value Sp (0) of the input signal.
To the control calculation unit to confirm that the valve opening signal Pv (0) is in the operating region,
p (1) is given to the control operation unit, the valve opening signal Pv (1) at that time is stored, and the second input signal Sp (2)
Is changed in the same direction as the direction in which the input signal Sp (0) is changed to Sp (1), and the valve opening signal Pv (2) at that time is stored, and the input signals Sp (1) and Sp (1) are changed.
(2) A valve positioner characterized by measuring a gain of the control target portion from a valve opening signal Pv (1) and Pv (2).

As described above, by adding the function of measuring the input gain of the control target portion to the conventional automatic tuning function, more accurate and more efficient automatic tuning can be performed.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a valve positioner according to the present invention will be described below with reference to the drawings.

As shown in FIG. 1, the valve positioner 100 includes a signal receiving device 110 for inputting an input signal SP,
The signal received by the signal receiving device 110 (the input signal S
p) and a control operation device 120 that receives the valve opening signal PV as a feedback signal to generate a control signal MV, and an electropneumatic conversion mechanism 2 that adjusts air pressure based on the control signal MV.
10, a pressure amplifier 220 for amplifying the pressure of the converted air pressure, and a position sensor 2 for detecting a displacement signal of the stem.
30. The air pressure amplified by the pressure amplifier 220 is supplied to the valve 310, and the change in the stem (not shown) is transmitted to the position sensor 230 through the link mechanism 320. Among them, the electropneumatic conversion mechanism 210, the pressure amplifier 220, the valve 310, the link mechanism 320, and the position sensor 230 are the control target parts 200. Further, the valve 310 and the link mechanism 320 are the valve mechanism 300 that is actually driven.

FIG. 2 shows the signals generated from the components of the valve positioner having such a configuration by using symbols of a controller (control arithmetic unit) 1.
20 is Kp, the unit of the control signal Mv is mA, the signal output by the electropneumatic conversion mechanism 210 is Gfm, kpa, the pressure amplifier 220 is Gpr, the output is kpa, the valve 310 is Gv, the output unit is mm, and the link is The mechanism 320 is Gln and the unit is deg. The position sensor 230 is Gs and the unit is V.

In the valve positioner thus represented by the symbol, the gain (Gf
w) can be obtained by the following equation.

Gfw = Gfm × Gpr × Gv × Gln × Gs (V / mA) (Equation 1)

On the other hand, the loop gain Gloop of the system
Can be obtained by the following equation. Group = Kp × Gfw (2)

Accordingly, if the gain Gloop to be set is determined and the gain Gfw of the control target portion 200 is obtained,
The gain Kp of the controller 120 can be obtained by the following equation.

Kp = Group / Gfw (Equation 3)

Now, according to the present invention, when performing automatic tuning, when an automatic setting signal (a signal for performing automatic tuning) is received, the gain Gf
This is to enable automatic tuning by measuring w. There are two methods for obtaining the gain Gfw of the control target portion 200, a first measurement method using the control signal Mv and the valve opening signal Pv, and a second measurement method using the input signal Sp and the valve signal. This is a method of obtaining using the opening signal Pv.

First, the control signal Mv, which is the first measurement technique, is used.
As shown in FIG. 3, a method of obtaining the gain Gfw of the control target part 200 using the control signal Mv which is an output of the controller (electro-pneumatic conversion mechanism) 210 by using the The gain Gfw is obtained by measuring the input / output characteristics of the value of the valve opening signal Pv, which is the output value of the position sensor 230, from the value of. Therefore, the gain Gfw can be obtained by changing the value of the control signal Mv by a certain amount and measuring the amount of change in the valve opening signal Pv. The equation is as follows.

Gfw = (Pv (1) −Pv (2)) / (Mv (1) −Mv (2)) (Equation 4)

However, in this measurement, disturbance may be mixed, so that accurate measurement may not be performed. As a method of canceling the disturbance, as shown in FIG.
It is assumed that (s) to D4 (s) exist.

From the control signal Mv (s), the valve opening signal Pv
The arithmetic expression up to (s) can be obtained by the following expression when there is no disturbance. Pv (s) = Gfm × Gpr × Gv × Gln × Gs × Mv (s) = Gfw × Mv (s) (Equation 5)

The disturbances D1 (s) to D4 shown in FIG.
Assuming that (s) exists, the sum of the disturbances is represented by Dsum, and can be expressed by the following equation.

Dsum (s) = D1 (s) × Gpr × Gv × Gln × Gs + D2 (s) × Gv × Gln × Gs + D3 (s) × Gln × Gs + D4 (s) × Gs ...・ (Equation 6)

Therefore, the valve opening signal Pv (s) can be expressed by the following equation. Pv (s) = Gfw × Mv (s) + Dsum (s) (7)

Considering such an equation, Dsum
If the states of Mv (s) and Pv (s) are changed without changing (s), Dsum (s) can be offset. Specifically, Pv (1) = Gfw × Mv (1) + Dsum (1) (Equation 8) Pv (2) = Gfw × Mv (2) + Dsum (2) (Equation 8) 9)

Now, since Dsum (1) = Dsum (2), Dsum can be canceled from Expressions 8 and 9.

Pv (1) -Pv (2) = Gfw × (Mv
(1) −Mv (2)). Therefore, the gain Gfw is the same as the above-described equation (4).

Here, a method of changing the states of the control signal Mv and the valve opening signal Pv (s) without changing Dsum will be described.

Although various disturbances are assumed for Dsum (s), the disturbance that is considered to have the largest proportion of Dsum (s) is the hysteresis existing in the system. Therefore, before performing the measurement, an operation of resetting the hysteresis may be performed.

The flowchart shown in FIG. 5 shows a procedure for resetting the hysteresis, which will be described below with reference to FIG.

First, the controller (control arithmetic unit) is opened (step ST110). Then, an arbitrary initial value Mv value is given to the control signal Mv (Step S
T120). Then, the value of the valve opening signal Pv, which is a feedback signal, is monitored, and the system waits until the value of the valve opening signal Pv stabilizes (steps ST130 and ST140).

When the valve opening signal Pv is stable, the control signal Mv is monitored until the valve opening signal Pv changes if the valve opening signal Pv does not change while monitoring this stable state. Change in one direction (step ST150, S
T160, ST170).

In step ST160, if the valve opening signal Pv changes, that is, if the valve opening signal Pv follows the control signal Mv, the change of the control signal Mv that is changing in one direction is stopped ( Step ST180).
In this state, the hysteresis has been reset.

Then, the value of the valve opening signal Pv is monitored again to wait for the valve opening signal Pv to stabilize (step ST1).
90, ST200). When the valve opening signal Pv is stabilized, the values of the control signal Mv (1) and the valve opening signal Pv (1) are measured (steps ST200 and ST210).

Then, the control signal Mv is changed again by a certain amount in the same direction as the changed direction (step ST).
220). Then, the value of the valve opening signal Pv is monitored, and if the value of the valve opening signal Pv does not change, the value of the control signal Mv is changed in the same one direction as the previous time to change the value of the valve opening signal Pv. Monitor the change (steps ST230 and ST24)
0, ST250).

In step ST240, when the value of the valve opening signal Pv has changed by a certain amount or more, the change of the control signal Mv being changed in one direction is stopped (step ST2).
60). Then, while monitoring the change in the value of the valve opening signal Pv again, monitoring is continued until the value of the valve opening signal Pv is stabilized (steps ST270 and ST280).

In step ST280, if the value of the valve opening signal Pv is stabilized, the values of the control signal Mv (2) and the valve opening signal Pv (2) are measured (step ST29).
0). The control signals Mv (1), M thus obtained
Calculation for obtaining the gain Gfw of the control target portion is performed from v (2) and the valve opening signals Pv (1) and Pv (2), and the automatic tuning can be performed by resetting the hysteresis which is a disturbance. (Step ST300).

Even if the hysteresis can be reset in this manner, the hysteresis and dead zone existing in the input / output characteristics may cause the input value to change when reversing the direction in which the output value changes. Even if it does, it has the characteristic that the output does not change. Therefore, in order to reset the hysteresis as described above, the measurement may be performed by changing the Mv value so that the Pv value works in the same direction, but has the following disadvantages.

1) Since the measurement must be performed in an open loop, it is difficult to put the value of the valve opening signal Pv into the measurement range. 2) In the open loop, it takes time for the value of the valve opening signal Pv to stabilize, so that it takes time for measurement. 3) Since the forward gain is usually high, the measurement error increases.

As shown in FIG. 2 described above, the second measuring method for solving such a problem is to perform the measurement in a closed loop, and to proportionally control the controller (control operation unit) 120, and to input the signal Sp. Assuming that (s) is a certain value, the valve opening signal Pv (s) can be obtained by the following equation. At this time, a known value prepared in advance for the measurement is used as the value Kp '.

Pv (s) = {(Kp ′ × Gfm × Gpr × Gv × Gin × Gs) / (1 + Kp ′ × Gfm × Gpr × Gv × Gln × Gs)} × Sp (s) 10)

Gfw = Gfm × Gpr × Gv × Gin ×
Since Gs, Equation 10 can be expressed as the following equation.

Pv (s) = Kp ′ × Gfw / (1 + Kp ′ × Gfw) × Sp (s) · Equation 11

Expression 11 is expressed by the following expression 12 when expressed by the expression of gain Gfw.

Gfw = Pv (s) / (Kp ′ × (Sp (s) −Pv (s)) Equation 12

Here, since the valve opening signal Pv (s), the input signal Sp (s), and Kp 'are known, the gain Gfw can be obtained by calculation.

The measuring principle of the second measuring method is a method of obtaining the gain Gfw of the control target portion using the input signal Sp and the valve opening signal Pv as described above. The input / output characteristic of the value of the valve opening signal Pv which is the output value of the position sensor 230 is measured from the value of the input signal Sp. Therefore, the gain Gfw is obtained by changing the value of the input signal Sp by a certain amount and measuring the amount of change in the valve opening signal Pv.

However, even in this measuring method, FIG.
As shown in (1), if there is no disturbance such as hysteresis in the system, the gain Gfw can be calculated by this method. In fact, there are many disturbances.

D1 (s), D2 (s), D3 (s), D
Assuming that 4 (s) is a disturbance, these are aggregated and Dsu
Assuming that m (s), Expression 6 ′ that is the same as Expression 6 described above can be obtained.

Dsum (s) = D1 (s) × Gpr × Gv × Gln × Gs + D2 (s) × Gv × Gln × Gs + D3 (s) × Gln × Gs + D4 (s) × Gs ...・ (Equation 6 ′)

By substituting equation (6 ') into equation (12), the following equation (13) can be obtained. Pv (s) = (Kp ′ × Gfw × Sp (s) + Dsum (s)) / (1 + Kp ′ × Gfw) (Equation 13)

Therefore, since Dsum (s) is unknown, the gain Gfw cannot be obtained. If the conditions of the valve opening signal Pv (s) and the input signal Sp (s) are changed without changing Dsum (s), Dsum (s) can be canceled.

That is, when the above equation 13 is represented by the equation of Dsum (s), the following equation 14 is obtained. Dsum (s) = Pv (s) −Kp ′ × Gfw × (Sp (s) −Pv (s)) (Equation 14)

In the equation (14), the first state is represented by the input signal Sp (1), the valve opening signal Pv (1), and the Dsum (1).
And the second state is the input signal Sp (2) and the valve opening signal P
If v (2) and Dsum (2), the following Expression 15 and Expression 1
6 can be obtained.

Dsum (1) = Pv (1) −Kp ′ × Gfw × (Sp (1) −Pv (1)) (Equation 15) Dsum (2) = Pv (2) −Kp ′ × Gfw × (Sp (2) -Pv (2)) (Equation 16)

Since the states of the input signal Sp and the valve opening signal Pv are changed so that Dsum does not change, Dsum (1) = Dsum (2). Therefore, ((Equation 15)-(Equation 16)) is: Pv (1) −Pv (2) −Kp ′ × Gfw × ｛(Sp
(1) -Pv (1))｝-｛(Sp (2) -Pv
(2))｝ = 0

Therefore, Gfw = {Pv (1) −Pv (2)} / [{Sp (1) −Pv (1)} − {Sp (2) −Pv (2)}] × Kp ′ (Equation 17)

Further, the steady state error Err (s) = Sp (s)
Since −Pv (s), Expression 17 becomes Expression 18 below.

Gfw = {Pv (1) −Pv (2)} / {Err (1) −Err (2)} × Kp ′ (Equation 18)

That is, the meaning of the equation 18 means that the gain Gfw can be obtained from the variation of the value of the valve opening signal Pv and the variation of the steady-state deviation. Therefore, Ds
In order to measure the gain of the control target portion by changing the states of the input signal Sp (s) and the valve opening signal Pv (s) without changing um (s), it is necessary to use Ds among various disturbances.
It is only necessary to reset the hysteresis existing in the system that is considered to have the largest proportion of um (s).

A specific method of resetting the hysteresis, that is, a method of obtaining the gain Gfw of the control target portion 200 from the input signal Sp and the valve opening signal Pv is described with reference to FIG. This will be described below.

First, the controller (control arithmetic unit) is set to proportional control, and an input signal Sp of an initial value is given (steps ST310 and ST320). Then, the value of the valve opening signal Pv, which is a feedback signal, is monitored, and the system waits for the value of the valve opening signal Pv to stabilize (steps ST330 and ST330).
T340).

If the valve opening signal Pv is stable in step ST340, the input signal Sp is moved in one direction until the valve opening signal Pv changes while monitoring the value of the stable valve opening signal Pv. (Step ST35)
0, ST360, ST370).

In step ST360, if the valve opening signal Pv changes, the input signal Sp that is changing in one direction is stopped (step ST380).

Then, the value of the valve opening signal Pv is monitored again to wait for the valve opening signal Pv to stabilize (step ST39).
0, ST400).

In step ST390, when the valve opening signal Pv is stable, the first input signal Sp (1),
The value of the first valve opening signal Pv (1) is measured (step ST410).

Then, the value of the input signal Sp is changed by a fixed amount in the same direction (step ST420). Then, the value of the valve opening signal Pv is monitored, and if the value of the valve opening signal Pv does not change, the value of the input signal Sp is changed in the same direction to monitor the change in the value of the valve opening signal Pv. (Steps ST430, ST440, ST450).

In step ST440, when the value of the valve opening signal Pv has changed by a certain value or more, the change of the input signal Sp in one direction is stopped (step ST460). Then, a change in the value of the valve opening signal Pv is monitored again, and monitoring is continued until the value of the valve opening signal Pv is stabilized (steps 470 and ST480).

In step ST480, if the value of the valve opening signal Pv is stabilized, the second input signal Sp (2)
The value of the second valve opening signal Pv (2) is measured (step ST490).

The input signal Sp thus obtained is
(1), Sp (2), valve opening signal Pv (1), Pv
The calculation for obtaining the gain Gfw of the control target part from (2) is performed (step ST500).

As described above, the hysteresis and dead zone existing in the input / output characteristics have such a property that when the direction in which the output value changes is reversed, the output does not change even if the input value is changed. Therefore, in order to reset the hysteresis, the value of the input signal Sp may be changed so that the value of the valve opening signal Pv acts in the same direction.

As described in the above two measurement methods, it is possible to reset the hysteresis by measuring the gain Gfw of the control target part 200 before the measurement. Can be applied to control systems. In particular, when the system is a servo system, it is important and effective to know the forward gain for tuning the controller gain.

FIG. 10 is a block diagram of a general control system. The controller 10 generates a control signal Mv by inputting a deviation between an input signal Sp (s) and a valve opening signal Pv (s).
0, a control target portion 200, and a feedback 400 that generates a valve opening signal Pv (s) based on a signal from the control target portion 200.

When a control system having such a configuration is actually constructed, the gain of the feedback 400 can be determined by a design value or a set value, but the gain of the control target portion 200 cannot be specified in many cases. When the information on the gain of the control target part 200 is lacking, the entire loop gain is not known, so that the gain tuning of the controller 100 becomes intuitive and the adjustment becomes difficult. In such a case, tuning can be performed more easily and accurately by measuring the gain of the control target portion 200 using the above two measurement methods.

[0076]

As described above, the valve positioner of the present invention has the following effects by measuring the gain of the control target portion. 1) The operator does not need to input the characteristics of the valve and the like, and the man-hour for installing the positioner can be reduced. 2) Since the actual control target part is measured, accurate tuning can be performed. 3) No human error such as incorrect input.

The following effects can be obtained by performing the measurement of the control target part in a closed loop of the proportional control. 1) It becomes easy to put the value of the valve opening signal Pv into the measurement range. 2) Since the proportional control is performed, the time required until the valve opening signal Pv becomes stable can be shortened. 3) Since the gain Gfw of the control target portion is calculated backward from the value of the input signal Sp and the value of the valve opening signal Pv, the measurement error is reduced.

[Brief description of the drawings]

FIG. 1 is a block diagram of a valve positioner according to the present invention.

FIG. 2 is a block diagram showing the valve positioner in a signal system.

FIG. 3 is a block diagram for obtaining a gain Gfw of a control target portion in an open loop, which is the first measurement method.

FIG. 4 is a block diagram showing a state of a disturbance generated in the open loop.

FIG. 5 is a flowchart for performing measurement in an open loop to reset disturbance (mainly hysteresis) before the measurement.

FIG. 6 is a graph showing a relationship between a control signal Mv and a valve opening signal Pv when measuring in an open loop in FIG. 5 on a time axis.

FIG. 7 is a block diagram showing a state of a disturbance when performing measurement by proportional control, which is the second measurement method.

FIG. 8 is a flowchart when measuring by proportional control to reset disturbance (mainly hysteresis) before the measurement.

FIG. 9 is a graph showing the relationship between the input signal Sp and the valve opening signal Pv when measuring by the same proportional control on the time axis.

FIG. 10 is a block diagram of a general control system.

[Explanation of symbols]

100; valve positioner, 110; signal receiving device, 1
Reference Signs List 20: control operation device (controller), 200: control target part, 210; electro-pneumatic conversion mechanism part, 220; pressure amplifier, 230; position sensor, 300; valve mechanism, 31
0; valve, 320; link mechanism

Claims (7)

[Claims] An input signal for setting a valve opening of a valve; a position sensor for detecting the valve opening of the valve; and a deviation between the valve opening signal obtained by the position sensor and the input signal. A control operation unit that generates a control signal by performing a control operation so that the valve opening of the valve matches the input signal; an electro-pneumatic conversion mechanism unit that generates an air flow rate based on the control signal; A valve positioner including a pressure amplifier that supplies air pressure based on an air flow rate generated in a mechanism unit to the valve, the valve positioner including the electropneumatic conversion mechanism unit, the pressure amplifier, the position sensor, and a valve. A valve positioner, wherein the control target portion has gain measuring means for measuring a gain of the control target portion when receiving an automatic setting signal. 2. The valve positioner according to claim 1, wherein said gain measuring means measures said gain of said controlled object part from a control signal of said control calculation part and a valve opening signal of said position sensor. A valve positioner characterized by the following. 3. The valve positioner according to claim 1, wherein said gain measuring means outputs a control signal Mv (1) of said first control operation section and outputs a valve opening signal of said position sensor at that time. Pv (1), outputs the second control signal Mv (2), stores the valve opening signal of the position sensor at that time as Pv (2), and outputs the control signal Mv
(1) A valve positioner, wherein a gain of the control target portion is measured from a change amount of Mv (2) and a change amount of the valve opening signals Pv (1) and Pv (2). 4. The valve positioner according to claim 1, wherein said gain measuring means outputs an initial value Mv (0) of a control signal of said control operation section to output a valve opening signal Pv (0) of said position sensor. Is in the operating range, the control signal Mv (1) of the first control operation unit is output, the valve opening signal of the position sensor is stored as Pv (1), and the second control signal Mv (2) is converted from the control signal Mv (0) by M
v (1), the valve opening signal of the position sensor is stored as Pv (2), and the control signals Mv (1) and Mv (2) are changed. Opening signal P
A valve positioner characterized in that a gain of the control target part is measured from a change amount of v (1) and Pv (2). 5. The valve positioner according to claim 1, wherein said gain measuring means measures a gain of said controlled part from said input signal and said valve opening signal. 6. The valve positioner according to claim 1, wherein said control operation unit performs at least proportional control operation, and said gain measuring means outputs said first input signal S.
p (1) is given to the control calculation unit, the valve opening signal at that time is stored as Pv (1), and the second input signal Sp (2) is given to the control calculation unit to open the valve. The degree signal is stored as Pv (2), and the input signals Sp (1) and Sp (1) are stored.
(2) A valve positioner characterized in that the gain of the control target portion is measured from the valve opening signals Pv (1) and Pv (2). 7. The valve positioner according to claim 1, wherein the control operation unit performs at least a proportional control operation, and the gain measuring unit supplies an initial value Sp (0) of the input signal to the control operation unit. The valve opening signal P
After confirming that v (0) is in the operation region, the first input signal Sp (1) is supplied to the control operation unit, and the valve opening signal Pv (1) at that time is stored, and The second input signal Sp (2) is changed in the same direction as the direction in which the input signal Sp (0) is changed from Sp (0) to Sp (1), and the valve opening signal Pv (2) at that time is stored. Input signal Sp
(1) and Sp (2), valve opening signal Pv (1) and Pv
(2) A valve positioner for measuring the gain of the control target portion from the following.