JP6722500B2 - Positioner - Google Patents

Description

The present invention relates to a positioner that controls the valve opening of a control valve.

BACKGROUND ART Conventionally, a positioner has been used as a device for controlling a valve opening of a control valve used for process control of a flow rate in a chemical plant or the like.
The positioner calculates the deviation between the set value of the valve opening of the control valve instructed by the host device and the measured value of the valve opening of the control valve, and the control signal generated based on the deviation is used to open and close the control valve. The valve opening degree of the control valve is controlled by supplying it to an operating device for operating.

The positioner indicates, for example, an operation amount of the control valve based on an angle sensor that detects the amount of displacement of the valve shaft of the control valve as the angle of a feedback lever connected to the valve shaft and the detection signal of the displacement detector. A controller including a microcomputer that generates an electric signal for converting the electric signal generated by the controller into an air signal, and an electropneumatic converter that supplies the air signal to the controller operating device are housed in a metal housing. It has a structure, and its housing is attached to a control valve for use (see Patent Document 1).

The control valve described above controls the valve opening by determining the amount of displacement of the valve shaft based on the balance between the spring and the air pressure. In order for the positioner to accurately control the valve opening of the control valve, the positioner itself must have information on the actual valve opening of the control valve and information on the position of the valve shaft detected by an angle sensor inside the positioner. Must be aware of the correspondence relationship between. That is, before starting the operation of the control valve in the flow control system, it is necessary to store the correspondence between the actual valve opening of the control valve and the position of the valve shaft in the positioner.

Specifically, information on the position of the valve shaft when the control valve is fully closed (valve opening is 0%), and the position of the valve shaft when the control valve is fully opened (valve opening is 100%). It is necessary to store the information of in the positioner.

JP, 2005-172802, A

By the way, this type of positioner has a function of automatic setup (hereinafter, also referred to as “ASU”) that automatically performs tuning of various control parameters and the like, and the ASU newly attaches the positioner to the valve. This is performed before the control valve (valve) is actually operated when the valve is attached to the valve again after periodic maintenance of the positioner or the like (see Patent Document 1).

In the data processing related to this ASU, various control parameters are tuned by using the above-mentioned information about the position of the valve shaft when the control valve to be controlled is fully closed and fully opened. Therefore, if the precise position of the valve shaft at the time of fully closed and at the time of fully opened is not known before executing the data processing related to ASU, the control parameters will not be tuned properly even if ASU is executed, and manual operation There is a problem that readjustment of the positioner is required. The details will be described below.

FIG. 18 is a diagram showing the relationship between the position of the valve shaft of a general control valve and the valve opening degree.
In general, the position of the valve shaft when fully closed is the position where the control valve is closed, that is, the position where the valve body physically collides with the valve seat, so it can be easily known.

On the other hand, the position of the valve shaft when fully opened is determined so that the amount of displacement from the position of the valve shaft when fully closed is a predetermined amount (rated stroke). As in the case of fully closed, the position where the valve shaft does not physically change further, that is, the pressure of the air signal supplied to the control valve (output air pressure of the positioner) is set to the upper limit value (rated supply pressure). When the position of the valve shaft at this time (position of the valve shaft at full stroke) is set to the position of the valve shaft at full opening, the valve opening degree grasped from the position of the valve shaft due to mechanical variation of parts such as springs. There is a deviation between the actual valve opening and the actual valve opening. If such a deviation occurs in the direction in which the actual valve opening degree becomes smaller than the intended valve opening degree, the desired flow rate cannot be supplied, and there is a possibility that the valve opening degree of 100% cannot be realized.

Therefore, as shown in FIG. 18, the relationship between the valve shaft position (stroke) of a general control valve and the valve opening degree is such that the valve opening degree virtually exceeds 100% at the time of full stroke “(100+α)”. %", the valve shaft displacement (rated stroke) corresponding to a valve opening of 100% is designed to be smaller than the full stroke. Here, “α” may be set in the range of 0 to 10% or 30% for each type of control valve and manufacturer of the manufacturer.

As described above, the positioner must understand the relationship between the valve shaft position of the control valve and the actual valve opening. However, since "α" differs depending on the model and manufacturer, the valve shaft when fully opened. It is not easy to know the exact position of.

Therefore, assuming that α=10%, that is, assuming that the valve opening is 110% when the output air pressure is maximum, the position of the valve shaft when fully opened is calculated and the information is stored in the positioner. When it is attached to a control valve of α=0 to 3%, which is different from the assumption, the control parameter is not tuned properly even if ASU is executed, and the control valve cannot be accurately controlled.

As described above, if the ASU cannot be properly adjusted, it is necessary to manually readjust the positioner, which causes a problem that the work cost is increased. In particular, when the manufacturers procure different control valves and positioners and install them on the user side, the readjustment becomes a heavy burden.

The present invention has been made in view of the above problems, and an object of the present invention is to facilitate adjustment of a positioner when mounting the positioner on a control valve.

A positioner (100) according to the present invention converts an electric signal (MV) indicating a valve opening degree of a control valve (2) into an air signal (So), and the air signal is sent to an operation device (2A) of the control valve. An electropneumatic converter (11) for supplying and operating the valve shaft (2B) of the control valve, a valve shaft position detector (17) for detecting the position of the valve shaft of the control valve, and a target valve for the control valve. A control signal generation unit (20) for generating an electric signal based on the opening degree and the valve shaft position of the control valve detected by the valve shaft position detection unit; and the valve opening degree of the control valve and the valve shaft position. A valve opening position data generation unit (21) that generates valve opening position data (231 to 236, 240 to 243, 241A) indicating a correspondence relationship, and a feedback lever (6) connected to the valve shaft are provided. The valve shaft position detection unit includes an angle sensor that detects a rotation angle of the feedback lever, calculates the position of the valve shaft based on the rotation angle detected by the angle sensor, and calculates the valve opening position. The data generator includes the valve opening position when the valve opening becomes 0% based on the position of the valve shaft detected by the valve shaft position detector when the output air pressure of the air signal is minimized. Generates data and calculates the changing speed of the rotation angle based on time series data of the rotation angle of the angle sensor when the output air pressure is changed at a constant speed from the minimum value to the maximum value, and the change The valve opening position data when the valve opening becomes 50% is generated based on the position of the valve shaft when the speed becomes maximum, and the generated valve opening of the control valve becomes 0%. Based on the valve opening position data when and the valve opening position data when the valve opening is 50%, the valve opening position when the valve opening of the control valve is 100% It is characterized by generating data.

The positioner further includes a storage unit that stores the valve opening position data when the valve opening is 50%, and the valve opening position data generation unit minimizes the output air pressure of the air signal. Occasionally, the valve opening position data is generated when the valve opening is 0% based on the position of the valve shaft detected by the valve shaft position detector, and the valve opening is 0%. Based on the valve opening position data when the valve opening position is 100% and the valve opening position data when the valve opening position stored in the storage unit is 50%. The opening position data may be generated.

The valve opening position data generation unit estimates the relationship between the valve opening of the control valve and the position of the valve shaft from the plurality of valve openings and the positions of the plurality of valve shafts corresponding to the plurality of valve openings. However, the valve opening position data when the valve opening of the control valve becomes 100% may be generated based on the estimated relationship.

It should be noted that a valve opening data acquisition unit (22) for acquiring a valve opening preset for a position of a predetermined valve shaft of the control valve as a plurality of valve openings is further provided. The generation unit opens the valve when the valve opening of the control valve reaches 100% based on the valve opening (Dmax, Dmin) acquired by the valve opening data acquisition unit and the position of the predetermined valve shaft. Degree position data may be generated.

The valve opening degree data acquisition unit acquires the first valve opening degree (Dmin) and the second valve opening degree (Dmax) different from the first valve opening degree, and the valve opening degree position data generation unit uses the air signal When the valve opening of the control valve becomes the first valve opening by associating the position of the valve shaft detected by the valve shaft position detection unit with the first valve opening when the output air pressure is set to the minimum (Pmin). Valve position data (231) of the control valve is generated, and the position of the valve shaft detected by the valve shaft position detector when the output air pressure is set to the maximum (Pmax) is associated with the second valve opening. Of the valve opening position data (232) when the valve opening degree of the second valve opening degree becomes the second valve opening degree, and the valve opening degree position data when the first valve opening degree becomes the second valve opening degree The valve opening position data (233) when the valve opening becomes 100% may be generated based on the valve opening position data.

In addition , it further has a scale instruction value acquisition unit (25) for acquiring the instruction value of the scale plate indicating the valve opening of the control valve, and the valve opening position data generation unit (21B) minimizes the output air pressure of the air signal. The valve opening position data (240) when the valve opening becomes 0% is generated based on the valve shaft position detected by the valve shaft position detection unit when (Pmin) is set, and the valve opening is also set. Based on the valve shaft position detected by the valve shaft position detection unit when the target value of (2) is set to the intermediate opening, the valve opening position data (242 ) Is generated, and the valve opening degree is 100% based on the valve opening degree position data when the valve opening degree is 0% and the valve opening degree position data when the valve opening degree indicated by the indication value of the scale plate is obtained. The valve opening position data (241A) at the time of becoming% may be generated.

The scale instruction value acquisition unit may acquire the instruction value of the scale plate based on the image data (Dim) obtained by photographing the scale plate (2D).

In the above description, the reference numerals in the drawings corresponding to the constituent elements of the invention are described in parentheses as an example.

As described above, according to the present invention, it becomes easy to adjust the positioner when mounting the positioner on the control valve.

It is a figure which shows the structure of the valve control system containing the positioner which concerns on Embodiment 1. It is a figure which shows the positional relationship of an angle sensor and a control valve. 3 is a diagram showing a configuration of a data processing control unit 10 of the positioner according to the first embodiment. FIG. It is a figure for demonstrating the generation method of the valve opening position data 233 at the time of valve opening position 100% by the valve opening position data generation part 21. It is a figure which shows an example of the valve opening position data 233 produced|generated by the valve opening position data production|generation part 21. FIG. 6 is a flow chart for explaining a flow of processing for generating valve opening position data at the time of fully closing and at the time of fully opening by the positioner according to the first embodiment. FIG. 6 is a diagram showing a configuration of a valve control system including a positioner according to a second embodiment. FIG. 9 is a diagram showing a configuration of a data processing control unit 10A of the positioner according to the second embodiment. It is a figure for demonstrating the production|generation method of the valve opening position data 235 at the time of valve opening 50% by the valve opening position data generation part 21A. It is a figure for demonstrating the production|generation method of the valve opening position data 236 at the time of valve opening 100% by the valve opening position data generation part 21A. FIG. 9 is a flow chart for explaining a flow of a process of generating valve opening position data at the time of fully closing and at the time of fully opening by the positioner according to the second embodiment. It is a flow chart for explaining the flow of generation processing of valve opening position data 235 when the valve opening is 50%. FIG. 13 is a diagram showing a configuration of a valve control system including a positioner according to the third embodiment. It is a figure for demonstrating the positional relationship of the imaging device 7 and the scale plate 2D. FIG. 6 is a diagram showing an example of image data Dim by the imaging device 7. It is a figure which shows the structure of the data processing control part 10B of the positioner which concerns on Embodiment 3. FIG. 11 is a flow chart for explaining a flow of processing for generating valve opening position data at the time of fully closing and at the time of fully opening by the positioner according to the third embodiment. FIG. 18 is a diagram showing a relationship between a valve shaft displacement amount and a valve opening degree in a general control valve.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the following description, the same reference numerals are given to the components common to the respective embodiments, and the repeated description will be omitted.

<<Embodiment 1>>
FIG. 1 is a diagram showing a configuration of a valve control system including a positioner according to an embodiment of the present invention.
The valve control system 100 shown in FIG. 1 includes a control valve (valve) 2, a controller 3, a host device 4, and a positioner 1, and is applied to, for example, a flow control process of a plant or the like.

The control valve 2 is a device that controls the flow of fluid from one flow passage to the other flow passage, and is, for example, a pneumatic direct-acting valve.
The control valve 2 includes an operating device 2A, a valve shaft 2B, and a valve 2C. The operation device 2A is a pneumatic valve actuator, and by displacing the valve shaft 2B in accordance with the pressure of an output air signal So supplied from a positioner 1 described later, the opening degree (valve opening degree) of the valve 2C is changed. adjust. In the present embodiment, the operation device 2A will be described as a single-acting operation device having a structure in which the operation amount of the valve shaft of the control valve 2 is determined according to the pressure of the input output air signal So. ..
Further, in the present embodiment, the control valve 2 will be described as a control valve that is fully closed when the pressure of the output air signal So supplied from the positioner 1 is zero.

The controller 3 is a device that instructs the positioner 1 to open and close the control valve 2 in response to an instruction from the host system 4, for example. Specifically, the controller 3 sets the target value (set value) SP of the valve opening of the control valve 2 so that the control valve 2 has a predetermined valve opening during normal operation of the valve control system 100, for example. Give to. For example, the controller 3 indicates the set value SP of the valve opening degree of the control valve 2 to the positioner 1 with a current signal of 4 mA to 20 mA.

The host device 4 is a device management device on the host side that performs overall management of the valve control system 100 including the positioner 1. The higher-level device 4 gives, for example, the target value SP of the valve opening degree to the controller 3 to the positioner 1, and also instructs the positioner 1 to execute the ASU via the communication line (not shown) or to be described later. Valve opening data Dim and Dmax are given.

The positioner 1 controls opening/closing of the control valve 2 based on the target value SP of the valve opening degree of the control valve 2 given from the controller 3, and executes ASU based on an instruction from the host device 4.

When executing the ASU, the positioner 1 generates valve opening position data indicating the correspondence between the valve shaft position of the control valve and the valve opening, prior to the main data processing such as tuning of various control parameters. One of the features is to do. Hereinafter, the positioner 1 will be described in detail.

As shown in FIG. 1, the positioner 1 includes functional parts such as a valve shaft position detection part 17, a data processing control part 10, an electropneumatic conversion part 11, a plurality of pressure sensors 14 to 16 and a display part 18. .. These functional units are housed inside a housing made of, for example, a metal material having corrosion resistance to the fluid to be controlled by the regulating valve 2.

It should be noted that FIG. 1 mainly shows the functional units necessary to generate the above-described valve opening position data at the time of fully closed and at the time of fully opened, among the various functional units constituting the positioner 1, and other functions. Illustration of functional units for realizing the above is omitted.

The valve shaft position detection unit 17 is a displacement amount detector that detects the displacement amount of the valve shaft and generates a detection signal SEN according to the displacement amount. Examples of the valve shaft position detector 17 include an angle sensor and a magnetic sensor. In the present embodiment, the valve shaft position detection unit 17 will be described as an angle sensor, and the valve shaft position detection unit 17 will be referred to as an angle sensor 17.

FIG. 2 is a diagram showing a positional relationship between the angle sensor 17 and the control valve 2.
As shown in FIG. 2, the positioner 1 has a feedback lever 6 that connects the valve shaft 2B of the control valve 2 and the angle sensor 17. The feedback lever 6 rotates about the center O of the angle sensor 17 as an axis according to the amount of vertical movement (lift position) of the valve shaft 2B. The angle sensor 17 detects the rotation angle (lever angle) of the feedback lever 6 and gives it to the data processing control unit 10 as the detection result SEN.

The data processing control unit 10 is a functional unit that performs overall control of the positioner 1. Specifically, the data processing control unit 10 generates the electric signal MV for operating the control valve 2 based on the target value SP of the valve opening degree given from the controller 3. Further, the data processing control unit 10 executes the ASU in response to a user's operation of an operation button (not shown) of the positioner 1 or an ASU execution instruction Asu input by data communication with the higher-level device 4.

Here, as the data communication between the host device 4 and the controller 3 and the positioner 1, a HART (High Addressable Remote Transducer), a field bus (FIELD BUS) and the like can be exemplified.

When executing the ASU, the data processing control unit 10 performs the data processing related to the tuning of various control parameters for controlling the control valve 2 and the like when the control valve 2 is fully closed (the valve opening is 0%. ) And the data processing for determining the position of the valve shaft when fully opened (valve opening 100%). The specific configuration of the data processing control unit 10 will be described later.

The electro-pneumatic conversion unit 11 is an air circuit that converts the electric signal MV generated by the data processing control unit 10 into an air signal. For example, the electro-pneumatic conversion unit 11 includes a nozzle flapper 12 and a pneumatic pressure amplification unit 13.

The nozzle flapper 12 is a pressure (hereinafter, referred to as “supply air pressure”) Ps of the air (air) 5 supplied to the positioner 1 from an air pressure supply source (not shown) such as a pressure reducing valve provided outside the positioner 1. Is changed according to the electric signal MV to generate an air signal Sc having a pressure according to the electric signal MV.

For example, the nozzle flapper 12 has one end to which the air 5 having the supply air pressure Ps is supplied via a fixed throttle, the other end to output an air pressure signal Sc, a coil for changing a magnetic field according to the electric signal MV, A flapper (iron piece) configured to change the pressure (hereinafter, referred to as "nozzle back pressure") Pn of the air signal Sc output from the nozzle by swinging according to the change of the magnetic field by the coil. There is.

The air pressure amplification unit 13 is a functional unit that amplifies the air signal Sc generated by the electropneumatic conversion unit 11 to generate an output air signal So for driving the operating device 2A. For example, the air pressure amplification unit 13 is a well-known single-acting pilot relay or a pilot relay having a function of switching between single-acting and double-acting, and supplies the air 5 of the supply air pressure Ps to the nozzle back pressure Pn. The output air signal So is generated by adjusting the pressure.

The pressure sensors 14 to 16 are components for measuring various air pressures in the positioner 1. Specifically, the pressure sensor 14 detects the nozzle back pressure Pn, the pressure sensor 15 detects the output air pressure Po, and the pressure sensor 14 detects the supply air pressure Ps.

The display unit 18 is a functional unit that is controlled by, for example, the data processing control unit 10 and displays various types of information. The display unit 18 can be exemplified by a liquid crystal display or the like. The display unit 18 displays information indicating, for example, the operating state of the control valve 2.

Next, a specific configuration of the data processing control unit 10 will be described.
FIG. 3 is a diagram showing the configuration of the data processing control unit 10 of the positioner according to the first embodiment.

The data processing control unit 10 includes a program processing device such as a microcontroller (MCU) equipped with a CPU and various memories such as RAM and ROM, various interface circuits for realizing input and output of signals to the outside, An A/D conversion circuit for converting various analog signals input from the outside into a digital signal and inputting the digital signal to the program processing device, and a digital signal based on a result of data processing by the program processing device is analog of 4 mA to 20 mA. It is realized by an electronic circuit (hardware resource) including a D/A conversion circuit for converting into a signal.

Specifically, as shown in FIG. 3, the data processing control unit 10 includes a control signal generation unit 20, a valve opening position data generation unit 21, a valve opening data acquisition unit 22, and a storage unit 23. Here, the control signal generation unit 20, the valve opening position data generation unit 21, the valve opening data acquisition unit 22, and the storage unit 23 described above cooperate with the above hardware resources and the hardware resources. It is realized by a program (software) that realizes various functions.

The control signal generation unit 20 is a functional unit that generates an electric signal MV as a control signal for controlling the valve opening degree of the control valve 2. For example, the control signal generation unit 20 generates the electric signal MV of a predetermined magnitude when the instruction Asu to execute the ASU is input from the higher-level device 4 or the like, and thereby the vertical axis of the valve shaft 2B of the control valve 2 is increased. Controls the amount of movement in the direction.

In addition, the control signal generation unit 20 controls the valve opening degree based on the detection result SE of the angle sensor 17 and the target value SP of the valve opening of the control valve 2 given by the controller 3 during normal operation of the valve control system 100. The deviation from the actual measured value (PV) of the valve opening of No. 2 is calculated, and the electric signal MV corresponding to the deviation is generated. At this time, the actual measurement value (PV) of the valve opening degree of the control valve 2 is the information of the position of the valve shaft 2B calculated based on the detection result SEN of the angle sensor 17, and the valve opening at the time of fully closing and at the time of fully opening which will be described later. It is determined based on the degree position data.

The valve opening data acquisition unit 22 is a functional unit that acquires the valve opening data Dmin indicating the first valve opening and the valve opening data Dmax indicating the second valve opening. Specifically, the valve opening degree data Dmin is data indicating the valve opening degree when the output air pressure Po is minimum (for example, Po=Pmin=0), and the valve opening degree data Dmax is the maximum output air pressure Po. It is data indicating the valve opening when (for example, Po=Pmax=Ps).

Here, the maximum value of the output air pressure Po is an upper limit value (rated supply pressure) of the output air pressure Po that can be supplied to the control valve 2 at the time of full stroke of the control valve 2, and is described in the specifications of the control valve 2 and the like. It is the value that has been set.

Specifically, the valve opening degree data acquisition unit 22 receives an input when the valve opening degree data Dmin and the valve opening degree data Dmax are input to the positioner 1 by, for example, an operation of an operation button by a user or data communication with the upper level device 4. The stored valve opening data Dmin and valve opening data Dmax are stored in the storage unit 23.

For example, when the output air pressure Po applied to the control valve 2 is the minimum, the valve opening degree is 0%, and when the output air pressure Po applied to the control valve 2 is the maximum, the valve opening degree is 110%. In the case of the control valve designed as described above, the user inputs data indicating “valve opening degree 0%” as the valve opening degree data Dmin to the positioner 1 through the host device 4 and the like, and sets the valve opening degree data Dmax as “valve opening degree data Dmax”. Data indicating the valve opening of 110%” may be input to the positioner 1.

Alternatively, the valve opening degree is 25% when the output air pressure Po applied to the control valve 2 is minimum, and the valve opening degree is 75% when the output air pressure Po applied to the control valve 2 is maximum. In the case of the control valve 2 designed as described above, the user inputs data indicating “valve opening degree 25%” to the positioner 1 as the valve opening degree data Dmin via the host device 4 and the like, and sets it as the valve opening degree data Dmax. It suffices to input data indicating “valve opening degree 75%” to the positioner 1.

The valve opening position data generation unit 21 determines the valve opening of the control valve 2 based on the vertical displacement amount (position of the valve shaft 2B) of the valve shaft 2B calculated based on the detection result SEN of the angle sensor 17. It is a functional unit that generates valve opening position data indicating a correspondence relationship with the position of the valve shaft 2B.

Here, the valve opening position data includes information on the valve opening of the control valve and information on the position of the valve shaft corresponding to the valve opening.

Specifically, the valve opening position data generation unit 21 determines the valve opening of the control valve 2 based on the valve openings of the control valve 2 and the positions of the valve shafts corresponding to the valve openings. The valve opening position data is generated when is 100%.

More specifically, first, the valve opening position data generation unit 21 outputs information on the position of the valve shaft 2B based on the detection result SEN detected by the angle sensor 17 when the output air pressure Po is set to the minimum value Pmin. By associating with the opening degree data Dmin, the valve opening degree position data 231 at the time of fully closing (valve opening degree 0%) is generated.

In addition, the valve opening position data generation unit 21 obtains information on the position of the valve shaft 2B based on the detection result SEN detected by the angle sensor 17 when the output air pressure Po is set to the maximum value Pmax (=Ps). By associating with the data Dmax, the valve opening position data 232 at the time of full stroke, that is, when the virtually maximum valve opening is obtained is generated.

Next, the valve opening position data generation unit 21 determines, based on the valve opening position data 231 when the valve opening is 0% and the valve opening position data 232 when the valve opening virtually reaches the maximum. When the valve is fully opened, that is, when the valve opening is 100%, the valve opening position data 233 is generated.

FIG. 4 is a diagram for explaining a method of generating the valve opening position data 233 when the valve opening position data generator 21 is 100% of the valve opening. Here, the valve opening data Dmin=0% and the valve opening data Dmax=110%.

For example, the valve opening position data generator 21 associates the valve opening position data 231 with the valve opening 0% at the position Y0 of the valve shaft 2B when the output air pressure Po is set to the minimum value Pmin, and the output air pressure Po. Of the valve shaft position of the control valve 2 and the valve opening based on the valve opening position data 232 in which the position Y1 of the valve shaft 2B when 110 is the maximum value Pmax is associated with the valve opening 110%. A characteristic function 500 indicating the relationship is calculated, and based on the characteristic function 500, the position Y2 of the valve shaft when the valve opening is 100% is calculated. Then, the valve opening position data generation unit 21 generates the valve opening position data 233 at the valve opening of 100% by associating the calculated valve shaft position Y2 with the valve opening of 100%.

Here, the characteristic function 500 may be determined based on the specifications of the control valve 2. For example, in the case of the control valve 2 in which the valve opening changes linearly by changing the valve shaft, the characteristic function 500 is set to the valve opening position data 231 and the valve opening position data 232 as shown in FIG. It is also possible to obtain a position Y2 of the valve shaft 2B at which the valve opening becomes 100% by using a linear function connecting the valve opening and the valve opening based on the ratio between the valve opening and the position of the valve shaft 2B. The position Y2 of the valve shaft 2B at which is 100% may be obtained.

Through the above processing by the valve opening position data generation unit 21, as shown in FIG. 5, the valve opening position data 231 when fully closed (when the valve opening is 0%) and when the valve is fully opened (when the valve opening is 100%). It is possible to obtain the valve opening position data 233 of ).

Next, in the positioner 1, a flow of processing for generating valve opening position data at the time of fully closing and at the time of fully opening will be described.

FIG. 6 is a flow chart for explaining a flow of a process of generating valve opening position data at the time of fully closing and at the time of fully opening by the positioner according to the first embodiment.

For example, the valve opening data Dmin, Dmax representing the minimum and maximum valve opening virtually set in the control valve 2 in the positioner 1 by the user operating the operation button of the positioner 1 or data communication with the host device 4. When is input, the positioner 1 starts a process of generating valve opening position data at the time of fully closing and at the time of fully opening.

First, in the positioner 1, the valve opening degree data acquisition unit 22 acquires the valve opening degree data Dmin and Dmax and stores them in the storage unit 23 (S10). Here, the valve opening data Dmin=0% and Dmax=110%.

Next, when the instruction Asu to execute the ASU is input to the positioner 1 by, for example, an operation of the operation button of the positioner 1 by the user or data communication with the higher-level device 4, the control signal generation unit 20 causes the output air pressure Po to be the minimum. The electric signal MV is generated so as to have the value Pmin (=0) (S11). As a result, the valve shaft 2B of the control valve 2 moves in the direction of closing the valve 2C.

Next, based on the detection result SEN of the angle sensor 17 when the output air pressure Po has the minimum value Pmin (=0), the valve opening position data generation unit 21 moves the valve shaft 2B in the vertical movement amount (valve The position of the axis 2B) is calculated, and the calculated movement amount and the valve opening data Dmin (=0%) are associated with each other to generate the valve opening position data 231 when the valve is fully closed (0%). It is stored in 23 (S12).

Next, the control signal generator 20 generates the electric signal MV so that the output air pressure Po becomes the maximum value Pmax (S13). As a result, the valve shaft 2B of the control valve 2 moves in the direction to open the valve 2C.

Next, based on the detection result SEN of the angle sensor 17 when the output air pressure Po has the maximum value Pmax, the valve opening position data generation unit 21 moves the valve shaft 2B in the vertical direction (position of the valve shaft 2B). ) Is calculated and the calculated movement amount and the valve opening data Dmax (=110%) are associated with each other to open the valve at the full stroke, that is, at the valve opening of 110% which is virtually the maximum valve opening. The degree position data 232 is generated and stored in the storage unit 23 (S14).

Next, the valve opening position data generation unit 21 uses the above-described method based on the 0% valve opening position data 231 generated in step S12 and the valve opening position data 234 generated in step S14. The valve opening position data 233 when the valve is fully opened (valve opening 100%) is generated (S15).

After that, the positioner 1 uses the fully opened valve opening position data 231 generated in step S12 and the fully opened valve opening position data 233 generated in step S15 to perform data processing related to ASU, for example, various types. Data processing and the like for tuning the control parameters are executed (S16).

As described above, according to the positioner according to the first embodiment, a plurality of valve openings of the control valve 2 and a plurality of valve shaft positions corresponding to the plurality of valve openings are set before the data processing of the ASU is executed. Based on this, the valve opening position data when the valve opening of the control valve 2 becomes 100% (at the time of full opening) is generated. Therefore, by executing ASU, the control parameters of the positioner suitable for the control valve to be combined. Etc. can be adjusted. According to this, it is not necessary to manually readjust the positioner after performing the ASU. Therefore, even when the control valve and the positioner of different manufacturers are installed in combination, for example, when the positioner is attached to the control valve, Adjusting the positioner becomes easy.

<<Embodiment 2>>
FIG. 7 is a diagram showing a configuration of a valve control system including a positioner according to the second embodiment.
The positioner 1A according to the second embodiment does not use the valve opening degree data input from the outside, but determines the valve opening degree of 100% based on the 0% valve shaft position and the 50% valve shaft position. The positioner is different from the positioner 1 according to the first embodiment in that the position of the valve shaft is determined, and the other points are the same as the positioner 1.

FIG. 8 is a diagram showing the configuration of the data processing control unit 10A of the positioner 1A according to the second embodiment.
As shown in FIG. 8, the data processing control unit 10 includes a control signal generation unit 20A, a valve opening position data generation unit 21A, and a storage unit 23. Here, the control signal generation unit 20A, the valve opening position data generation unit 21A, and the storage unit 23 are realized by the above hardware resources and a program that realizes various functions in cooperation with the hardware resources. ing.

Similar to the control signal generation unit 20, the control signal generation unit 20A controls the control valve 2 by generating a predetermined electric signal MV when the instruction Asu for executing the ASU is input from the host device 4 or the like. To do.

The valve opening position data generation unit 21A, based on the position of the valve shaft 2B based on the detection result SEN detected by the angle sensor 17 when the output air pressure Po is set to the minimum value Pmin, when fully closed, that is, the valve opening. The valve opening position data 234 at 0% is generated.

Further, the valve opening position data generation unit 21A generates the valve opening position data 235 when the valve opening is 50%.
FIG. 9 is a diagram for explaining a method of generating the valve opening position data 235 when the valve opening position data generating unit 21A has a valve opening degree of 50%.

For example, when the control valve 2 is a direct acting valve, the valve shaft 2B makes a linear motion in the vertical direction. On the other hand, the angle sensor 17, which is connected to the valve shaft 2B of the direct acting valve via the feedback lever 6, performs a rotary motion in conjunction with the linear motion of the valve shaft 2B. Therefore, the positional relationship between the valve shaft 2B and the feedback lever 6 can be obtained from the speed of the rotation angle of the feedback lever 6 when the valve shaft 2B is moved at a constant speed.

Specifically, when the valve shaft 2B is moved at a constant speed and the feedback lever 6 becomes horizontal, that is, when the angle formed by the valve shaft 2B and the feedback lever 6 becomes 90 degrees, the rotation angle of the feedback lever 6 is changed. The rate of change becomes maximum, and the valve opening of the control valve 2 becomes 50%.

Therefore, the valve opening position data generation unit 21A, as shown in FIG. 9, the time series data of the detection result SEN of the angle sensor 17 when the output air pressure Po is changed from the minimum value Pmin to the maximum value Pmax at a constant speed. Based on the above, the change speed of the rotation angle of the feedback lever 6 is calculated, and the valve opening position data 235 in which the position of the valve shaft 2B when the change speed becomes maximum is the valve opening of 50% is generated.

Further, the valve opening position data generation unit 21A, based on the valve opening position data 234 when the valve opening is 0% and the valve opening position data 235 when the valve opening is 50%, when fully opened, that is, the valve opening is 100%. The valve opening position data 236 at that time is generated.

For example, as shown in FIG. 10, the valve opening position data generation unit 21A calculates the position Y _L of the valve shaft 2B when the valve opening is 0% and the position Y _M of the valve shaft 2B when the valve opening is 50%. The distance (difference) is calculated and the difference is added to the position Y _M of the valve shaft 2B when the valve opening is 50% to calculate the position Y _H of the valve shaft 2B when the valve opening is 100%.

For example, when the detection result SEN of the angle sensor 17 when the valve opening degree is 0% is “−10°” and the detection result SEN of the angle sensor 17 when the valve opening degree is 50% is “3°”, Since the difference is “13°”, the position of the valve shaft 2B at which the detected value SEN of the angle sensor is “3°+13°=16°” can be estimated as the valve opening degree of 100%. The valve opening position data generation unit 21A generates the valve opening position data 236 when the valve opening is 100% based on the estimated position of the valve shaft 2B.

The method of calculating the position Y _H of the valve shaft 2B when the valve opening degree of 100% is not limited to the above example. For example, as described in the first embodiment, the position of the valve shaft 2B is determined from the position Y _L of the valve shaft 2B when the valve opening is 0% and the position Y _M of the valve shaft 2B when the valve opening is 50%. It is also possible to calculate a characteristic function indicating a correspondence relationship with the valve opening degree and calculate the position of the valve shaft 2B when the valve opening degree is 100% based on the characteristic function.

FIG. 11 is a flow chart for explaining a flow of processing for generating valve opening position data at the time of fully closing and at the time of fully opening by the positioner 1A according to the second embodiment.

For example, when an instruction Asu for executing the ASU is input by the user operating the operation button of the positioner 1A or data communication with the host device 4, the positioner 1A outputs the valve opening position data at the time of fully closing and at the time of fully opening. Start the process to generate.

First, the control signal generation unit 20A in the positioner 1A generates the electric signal MV so that the output air pressure Po becomes the minimum value Pmin (=0) (S20). As a result, the valve shaft 2B of the control valve 2 moves in the direction of closing the valve 2C.

Next, the valve opening position data generation unit 21A determines, based on the detection result SEN of the angle sensor 17 when the output air pressure Po has the minimum value Pmin (=0), the vertical movement amount of the valve shaft 2B (valve The position of the axis 2B) is calculated, and the calculated movement amount and the valve opening degree of 0% are associated with each other to generate the valve opening degree position data 234 at the time of fully closing (0%) and store it in the storage unit 23 ( S21).

Next, the positioner 1A generates the valve opening position data 234 when the valve opening is 50% (S22). Specifically, as shown in FIG. 12, first, the control signal generator 20A generates the electric signal MV so as to change the output air pressure Po at a constant speed (S220). For example, the control signal generation unit 20A changes the value of the electric signal MV so as to change the output air pressure Po from the minimum value Pmin (=0) to the maximum value Pmax.

At this time, the valve opening position data generation unit 21A acquires time series data of the rotation angle of the feedback lever 6 based on the detection result SEN of the angle sensor 17 (S221). Next, the valve opening position data generation unit 21A calculates the change rate of the rotation angle based on the time series data of the rotation angle acquired in step S221 (S222).

After that, the valve opening position data generation unit 21A generates the valve opening position data 235 by setting the position of the valve shaft 2B when the speed of change of the rotation angle calculated in step S222 is maximum to 50% as the valve opening. , In the storage unit 23 (S223).

Next, the valve opening position data generation unit 21A described above, based on the 0% valve opening position data 234 generated in step S21 and the 50% valve opening position data 235 generated in step S22. By the method described above, the valve opening position data 236 at the time of full opening (100% valve opening) is generated (S23).

After that, the positioner 1 uses the fully opened valve opening position data 234 generated in step S21 and the fully opened valve opening position data 236 generated in step S23 to perform data processing relating to ASU, for example, various types. Various data processes for tuning the control parameters and the like are executed (S24).

As described above, according to the positioner according to the second embodiment, similar to the positioner according to the first embodiment, the valve opening of the control valve 2 and the positions of the valve shafts corresponding to the valve openings are set. Based on this, the valve opening position data when the valve opening of the control valve 2 becomes 100% (at the time of full opening) is generated. Therefore, by executing ASU, the control parameters of the positioner suitable for the control valve to be combined. Etc. can be adjusted.

Further, according to the positioner according to the second embodiment, the valve opening position data at the time of fully closing and at the time of fully opening are automatically generated without the user himself/herself inputting information, so that when the user mounts the positioner. Can be saved.

Further, according to the positioner according to the second embodiment, the position where the valve opening becomes 50% is detected, and the valve opening position data at the time of fully opening is generated using the detected value. Even when the valve is not mounted horizontally, it is possible to set a more accurate value in the positioner as the position of the valve shaft when fully opened.

In the above embodiment, the method of generating the valve opening position data when the valve opening is 100% by using the position of the valve shaft 2B where the detected valve opening is 50% has been described. When the feedback lever is mounted so as to be horizontal when the valve opening becomes 50%, the positioner does not detect the position where the valve opening becomes 50%, and the valve stored in advance in the storage unit 23 is not detected. The valve opening position data at the time of 50% opening may be used to generate the valve opening position data at the time of full opening. The details will be described below.

Generally, it is recommended that the positioner be mounted so that the feedback lever becomes horizontal when the valve opening of the control valve reaches 50%. In the positioner thus mounted, the rotation angle of the feedback lever 6 becomes “0°” when the valve opening degree of the control valve is 50%.

Therefore, the valve opening position data 235 that the rotation angle is “0°” when the valve opening is 50% is stored in the storage unit 23 in advance. Then, in the process flow shown in FIG. 11, the positioner 1A reads the valve opening position data 235 at the time of 50% valve opening stored in the storage unit 23 in advance without performing step S22 after step S21. In step S23, the valve opening position data 235 when the valve opening is 50% and the valve opening position data 234 when the valve opening is 0%, which is generated in step S21, are used to perform the valve operation by the above-described method. The valve opening position data 236 at 100% opening may be generated.

According to this, since the process for detecting the position where the valve opening degree is 50% is unnecessary, the load of data processing by the data processing control unit 10A is reduced and the valve opening position data at the time of full opening is automatically calculated. Can be generated.

<<Embodiment 3>>
FIG. 13 is a diagram showing a configuration of a valve control system including a positioner according to the third embodiment.
The positioner 1B according to the third embodiment has a valve opening degree of 100% based on the instruction value of the scale plate of the positioner when the target value SP of the valve opening degree of the control valve is set to the intermediate opening degree. It differs from the positioner 1A according to the second embodiment in that the valve opening position data is generated, and is the same as the positioner 1A in other respects.

As shown in FIG. 13, the valve control system 100B further includes an imaging device 7.
The imaging device 7 is a camera that is attached to the control valve 2 and captures a scale plate 2D that indicates the valve opening of the control valve 2. As shown in FIG. 14, the imaging device 7 is attached to a position where the scale plate 2D can be photographed. The imaging device 7 generates image data Dim obtained by photographing the scale of the scale plate 2D and the indicator needle 2E as shown in FIG. The image data Dim is captured by the positioner 1B and stored in the storage unit 23 of the data processing unit 10B.

FIG. 16 is a diagram showing the configuration of the data processing control unit 10B of the positioner 1B according to the third embodiment.
As shown in FIG. 16, the data processing control unit 10B includes a control signal generation unit 20B, a valve opening position data generation unit 21B, a storage unit 23, and a scale instruction value acquisition unit 25. Here, the control signal generation unit 20B, the valve opening position data generation unit 21B, the storage unit 23, and the scale instruction value acquisition unit 25 perform the above-mentioned hardware resources and various functions in cooperation with the hardware resources. It is realized by the program to be realized.

Similar to the control signal generation unit 20, the control signal generation unit 20B controls the control valve 2 by generating a predetermined electric signal MV when the instruction Asu for executing the ASU is input from the host device 4 or the like. To do.

The scale instruction value acquisition unit 25 is a functional unit that acquires the instruction value of the scale plate 2D. Specifically, the scale instruction value acquisition unit 25 reads the instruction value of the scale plate 2D from the image data Dim captured from the imaging device 7 and generates the scale instruction value data 243.

The valve opening position data generation unit 21B generates the valve opening position data 240 when the valve opening is 0% based on the position of the valve shaft 2B when the output air pressure Po is the minimum value Pmin.

Further, the valve opening position data generation unit 21B determines the temporary position of the valve shaft 2B when the valve opening is 100% based on the position of the valve shaft 2B when the output air pressure Po is the maximum value Pmax. The temporary valve opening position data 241 shown is generated.

Further, the valve opening position data generation unit 21B has the scale instruction value data 243 when the target value SP of the valve opening is set to an intermediate opening other than 0% and 100%, and the valve opening is 0%. Based on the valve opening position data 240 at this time, the true valve opening position data 241A when the valve opening is 100% is generated.

For example, suppose that the indication value of the scale plate 2D of the control valve 2 is "60%" when the control valve 2 is operated by setting "50%" as the intermediate opening degree to the target value SP of the valve opening degree. The valve opening position data 242 of the intermediate opening (valve opening 60%) is generated by associating the position of the valve shaft 2B (the detection result SEN of the angle sensor 17) at that time with the valve opening 60%. After that, the valve opening degree is 100% based on the valve opening degree position data 242 when the valve opening degree is 60% and the previously generated valve opening degree position data 240 when the valve opening degree is 0%. True valve opening position data 241A is generated.

Here, the method of generating the true valve opening position data 241A is similar to the valve opening position data generation unit 21 according to the first embodiment, that is, the valve opening position and the valve opening at 60% valve opening. A characteristic function showing the correspondence between the position of the valve shaft 2B and the valve opening is calculated from the two points of the valve opening at 0%, and the valve shaft when the valve opening is 100% is calculated from the characteristic function. May be calculated to generate the true valve opening position data 241A. Similarly to the valve opening position data generation unit 21A according to the second embodiment, the valve opening at 60% valve opening may be calculated. Even if the true valve opening position data 241A is generated by calculating the position of the valve shaft when the valve opening is 100% from the difference between the position of the valve opening and the position of the valve opening when the valve opening is 0%. Good.

FIG. 17 is a flow chart for explaining the flow of the process of generating the valve opening position data at the time of fully closing and at the time of fully opening by the positioner 1B according to the third embodiment.

For example, when an instruction Asu for executing an ASU is input by a user operating the operation buttons of the positioner 1 or performing data communication with the host device 4, the positioner 1B generates valve opening position data at the time of fully closing and at the time of fully opening. To start the process.

First, the control signal generator 20B in the positioner 1 generates the electric signal MV so that the output air pressure Po becomes the minimum value Pmin (=0) (S30). As a result, the valve shaft 2B of the control valve 2 moves in the direction of closing the valve 2C.

Next, based on the detection result SEN of the angle sensor 17 when the output air pressure Po is the minimum value Pmin (=0), the valve opening position data generation unit 21B causes the valve shaft 2B to move vertically (valve The position of the axis 2B) is calculated, and the calculated movement amount and the valve opening degree of 0% are associated with each other to generate the valve opening degree position data 240 at the time of fully closing (0%) and store it in the storage unit 23 ( S31).

Next, the control signal generator 20B generates the electric signal MV so that the output air pressure Po becomes the maximum value Pmax (S32). As a result, the valve shaft 2B of the control valve 2 moves in the direction to open the valve 2C.

Next, based on the detection result SEN of the angle sensor 17 when the output air pressure Po is the maximum value Pmax, the valve opening position data generation unit 21B causes the valve shaft 2B to move vertically (the position of the valve shaft 2B. ) Is calculated, and the calculated movement amount and the valve opening degree of 100% are associated with each other to generate temporary valve opening degree position data 241 at the time of fully closing (0%) and store it in the storage unit 23 (S33). ..

Next, the positioner 1B controls the control valve 2 based on the fully closed valve opening position data 240 generated at step S31 and the fully opened temporary valve opening position data 241 generated at step S33. To do. Specifically, the control signal generation unit 20B generates the electric signal MV so that the target value SP of the valve opening becomes the intermediate opening (for example, 50%) (S34). As a result, the valve shaft 2B of the control valve 2 moves in the direction of closing the valve 2C by 50%.

Next, the scale instruction value acquisition unit 25 acquires the instruction value of the scale based on the image data Dim of the scale plate 2D captured by the imaging device 7, and generates and stores the scale instruction value data 243 at the intermediate opening degree. The data is stored in the unit 23 (S35).

In addition, the valve opening position data generation unit 21 calculates the valve shaft based on the detection result SEN of the angle sensor 17 when the target value SP of the valve opening is set to the intermediate opening (for example, 50%) in step S34. The valve opening position data 242 of the intermediate opening is generated by associating the vertical movement amount of 2B (position of the valve shaft 2B) with the valve opening of the scale instruction data 243 generated in step S35 (S36). ).

For example, when the target value of the valve opening is set to 50% in step S34 and the indication value of the scale acquired in step S35 is 60%, the target value of the valve opening is set to 50% in step S34. By associating the rotation angle of the feedback lever 6 (position of the valve shaft 2B) detected when set to 60% with the valve opening degree of 60%, the valve opening degree of 60% is obtained as the valve opening degree position data 242 of the intermediate opening degree. The valve opening position data at the time is generated.

Next, the valve opening position data generation unit 21 described above based on the 0% valve opening position data 240 generated in step S31 and the intermediate valve opening position data 242 generated in step S36. By the method described above, the true valve opening position data 241A when fully opened (valve opening 100%) is generated (S37).

After that, the positioner 1 does not use the temporary valve opening position data 241 generated in step S33, but the true valve opening position data 241A when fully opened generated in step S37 and the valve opening position data fully closed generated in step S31. Main data processing of the ASU, for example, various data processing for tuning various control parameters is executed using the opening position data 231 (S38).

As described above, according to the positioner according to the third embodiment, similar to the positioner according to the first embodiment, the valve opening of the control valve 2 and the positions of the valve shafts corresponding to the valve openings are set. Based on this, the valve opening position data when the valve opening of the control valve 2 becomes 100% (at the time of full opening) is generated. Therefore, by executing ASU, the control parameters of the positioner suitable for the control valve to be combined. Etc. can be adjusted.

Further, according to the positioner according to the third embodiment, it is not necessary for the user to input information by himself/herself, as in the positioner according to the second embodiment, so that the user can save time and effort when attaching the positioner.

Further, according to the positioner according to the third embodiment, since the indication value of the scale plate attached to the control valve 2 is used, the correspondence relationship between the rotation angle of the feedback lever 6 and the valve opening degree of the control valve 2 is used. You can know more accurately. This makes it possible to set a more accurate value for the positioner as the position of the valve shaft when fully opened.

Although the invention made by the present inventors has been specifically described based on the embodiments, the present invention is not limited thereto and needless to say, various modifications can be made without departing from the scope of the invention. Yes.

For example, in the above embodiment, the electropneumatic conversion unit 11 may have any configuration as long as it can generate the air signal Sc and the output air signal So, and is not limited to the above-described configuration (see FIG. 1 ). ..

Further, in the third embodiment, the case of inputting the image data Dim photographed by the image pickup device 7 in order to acquire the indication value of the scale plate has been described as an example, but the present invention is not limited to this, and adjustment is performed by means other than the image pickup device 7. You may acquire the indication value of the scale plate of the valve 2.

Further, in the above-described embodiment, the case where the control valve that is fully closed when the pressure of the output air signal So is zero and the positioners 1, 1A, 1B are combined is illustrated, but the present invention is not limited to this, and the output air signal So is not limited thereto. The control valve that is fully opened when the pressure is zero and the positioners 1, 1A and 1B may be combined.

100, 100A, 100B... Valve control system, 1, 1A, 1B... Positioner, 2... Control valve, 2A... Operator, 2B... Valve shaft, 2C... Valve, 2D... Scale plate, 3... Controller, 4... Upper device 5... Air (air), 7... Imaging device, 10, 10A, 10B... Data processing control part, 11... Electro-pneumatic conversion part, 12... Nozzle flapper, 13... Air pressure amplification part, 14, 15, 16... Pressure sensor, 17... Angle sensor, 18... Display unit, SP... Target value of valve opening, MV... Electric signal, Pn... Nozzle back pressure, Ps... Supply air pressure, Po... Output air pressure, So... Output air signal, Sc... Air signal , SEN... Detection signal, 20, 20A, 20B... Control signal generation section 21, 21A, 21B... Valve opening position data generation section, 22... Valve opening data acquisition section, 23... Storage section, 25... Scale instruction value Acquisition unit, 231, 232, 233, 234, 235, 236, 240, 241, 241A, 242... Valve opening position data, 243... Scale instruction value data, Dmin, Dmax... Valve opening data.

Claims (2)

An electropneumatic converter that converts an electric signal indicating the valve opening degree of the control valve into an air signal and supplies the air signal to the controller of the control valve to operate the valve shaft of the control valve.
A valve shaft position detector that detects the position of the valve shaft of the control valve;
A control signal generation unit that generates the electric signal based on a target valve opening degree of the control valve and the position of the valve shaft of the control valve detected by the valve shaft position detection unit;
A valve opening position data generation unit that generates valve opening position data indicating the correspondence between the valve opening of the control valve and the position of the valve shaft ,
A feedback lever connected to the valve shaft,
Equipped with
The valve shaft position detection unit includes an angle sensor that detects a rotation angle of the feedback lever, and calculates a position of the valve shaft based on the rotation angle detected by the angle sensor,
The valve opening position data generation unit,
The valve opening position data when the valve opening becomes 0% is generated based on the position of the valve shaft detected by the valve shaft position detecting unit when the output air pressure of the air signal is minimized. , A change speed of the rotation angle is calculated based on time series data of the rotation angle of the angle sensor when the output air pressure is changed at a constant speed from a minimum value to a maximum value, and the change speed becomes maximum. The valve opening position data when the valve opening becomes 50% based on the position of the valve shaft at
Based on the generated valve opening position data when the valve opening of the control valve is 0% and the generated valve opening position data when the valve opening is 50%, Generating the valve opening position data when the valve opening becomes 100%
Positioner that is characterized . The positioner according to claim 1,
A storage unit that stores the valve opening position data when the valve opening is 50%,
The valve opening position data generation unit determines when the valve opening is 0% based on the position of the valve shaft detected by the valve shaft position detection unit when the output air pressure of the air signal is minimized. The valve opening position data is generated, and the valve opening position data when the valve opening is 0% and the valve opening when the valve opening stored in the storage unit is 50%. A positioner characterized by generating the valve opening position data when the valve opening is 100% based on the degree position data .