JP5965830B2 - Automatic tuning apparatus and method - Google Patents

Description

  The present invention relates to a technique for adjusting a control parameter value of a positioner that controls the opening of a valve.

  In order to control the valve (control valve), a positioner has been put into practical use. In this case, the control target of the positioner is a valve. Therefore, the positioner has a function of controlling the valve, and in order to realize the control function, the control parameter needs to be tuned according to the characteristics of the valve. An example of the control parameter is a PID parameter for PID control.

  Conventionally, as a positioner automatic tuning technique, a valve is experimentally operated by a positioner, a valve characteristic value (operator size and hysteresis level) for determining a PID parameter value is measured, and a PID parameter table is referred to. Techniques for selecting and setting PID parameter values have been proposed (see Patent Document 1 and Patent Document 2).

JP 7-269505 A Japanese Patent Laid-Open No. 11-166655

  Reference information such as a PID parameter table is substantially advanced with the progress of research and development by engineers of positioner manufacturers. Therefore, it is technically possible to update the reference information such as the PID parameter table. However, when the PID parameter is reset by this update, it is necessary to always restart the automatic tuning. However, automatic tuning, which takes several minutes, may not be restarted because the plant in which the valve is used is continuously operated. If automatic tuning cannot be restarted, as a result, the valve that is in operation cannot cope with the sophistication.

  The present invention has been made to solve the above-described problem. When reference information such as a PID parameter table is updated, the control parameter value of the positioner can be set without restarting automatic tuning that takes several minutes. It is an object of the present invention to provide an automatic tuning apparatus and method that can be updated.

  The automatic tuning apparatus of the present invention includes, as reference information, at least a control parameter table that associates valve characteristic values with positioner control parameter values, and automatic tuning that adjusts the positioner control parameters. When executing the above, the valve is driven via the operating device, the corresponding control parameter value is obtained from the control parameter table based on the measured characteristic value of the valve, and the control parameter value set in the positioner is obtained. Automatic tuning execution means for updating, characteristic value storage means for storing the characteristic value of the valve measured at the time of execution of the automatic tuning, and reference information input from the outside at the time of updating the reference information, Reference information updating means for updating the reference information stored in the reference information storage means When the control parameter is updated after updating the reference information, the characteristic value of the valve stored in the characteristic value storage means is read out, and the corresponding control parameter value is read from the control parameter table based on the characteristic value. And a control parameter value update processing means for updating the control parameter value set in the positioner.

  In one configuration example of the automatic tuning apparatus of the present invention, the control parameter value is a PID parameter value, and the reference information storage unit stores a PID parameter table as the control parameter table and other reference information. As an operating device size-response time table and a hysteresis-error table, the automatic tuning execution means measures response time as a characteristic value of the valve, and responds from the operating device size-response time table. The actuator size that is a characteristic value is acquired, the error of the opening is measured as the characteristic value of the valve, and the hysteresis that is the corresponding characteristic value is acquired from the hysteresis-error table. PID parameter values corresponding to the PID parameter table And the PID parameter value set in the positioner is updated. The characteristic value storage means stores the response time and the opening error as the characteristic value of the valve. The value update processing means reads the response time as the characteristic value of the valve stored in the characteristic value storage means, acquires the corresponding operation device size from the operation device size-response time table, and stores the characteristic value storage The error of the opening degree is read as the characteristic value of the valve stored in the means, the corresponding hysteresis is obtained from the hysteresis-error table, and the PID parameter value corresponding to the actuator size and hysteresis is read from the PID parameter table. Obtaining and updating the PID parameter value set in the positioner It is intended to.

  Further, in one configuration example of the automatic tuning device of the present invention, the reference information storage unit and the reference information update unit are mounted in a host device of the positioner, and the automatic tuning execution unit, the characteristic value storage unit, and the The control parameter value update processing means is mounted on the positioner, and the reference information storage means is shared by a plurality of positioners via a communication function.

  In the automatic tuning method of the present invention, the valve is driven via the operating unit when the automatic tuning for adjusting the control parameter of the positioner is executed, the characteristic value of the valve is measured, and stored in the reference information storage means in advance. The control parameter table, which is the reference information, is referred to, the control parameter value corresponding to the control parameter table is acquired based on the characteristic value of the valve, and the control parameter value set in the positioner is updated. A tuning execution step, a characteristic value storage step for storing the characteristic value of the valve measured at the time of execution of the automatic tuning in the characteristic value storage means, and at the time of updating the reference information, receiving reference information input from the outside, A reference information update step for updating the reference information stored in the reference information storage means; When updating the control parameter after updating the reference information, the characteristic value of the valve stored in the characteristic value storage means is read, and the corresponding control parameter value is obtained from the control parameter table based on the characteristic value And a control parameter value update processing step of updating the control parameter value set in the positioner.

  In one configuration example of the automatic tuning method of the present invention, the control parameter value is a PID parameter value, and the reference information storage unit stores a PID parameter table as the control parameter table and other reference information. As an operating device size-response time table and a hysteresis-error table, the automatic tuning execution step measures response time as a characteristic value of the valve, and corresponds from the operating device size-response time table. The actuator size that is a characteristic value is acquired, the error of the opening is measured as the characteristic value of the valve, and the hysteresis that is the corresponding characteristic value is acquired from the hysteresis-error table. The PID parameter value corresponding to the PID parameter The characteristic value storage means stores the response time and the opening error as the characteristic value of the valve, and the step of updating the PID parameter value set in the positioner, The control parameter value update processing step reads a response time as a valve characteristic value stored in the characteristic value storage means, acquires a corresponding operation device size from the operation device size-response time table, and The error of the opening is read as the characteristic value of the valve stored in the characteristic value storage means, the corresponding hysteresis is obtained from the hysteresis-error table, and the PID parameter value corresponding to the actuator size and hysteresis is set to the PID PID parameters set in the positioner obtained from the parameter table It is characterized in including the step of updating the value.

  Further, in one configuration example of the automatic tuning method of the present invention, the reference information storage means is mounted on a host device of the positioner, the characteristic value storage means is mounted on the positioner, and the host device is the reference device. An information update step is executed, and the positioner executes the automatic tuning execution step, the characteristic value storage step, and the control parameter value update processing step, and the reference information storage means has a plurality of positioners via a communication function. Shared on.

  According to the present invention, when the automatic tuning is performed, the characteristic value of the valve measured by the automatic tuning is stored, so that even when the reference information is updated after the automatic tuning, the automatic tuning is performed. The control parameter value of the positioner can be updated using the updated reference information without performing the tuning again.

  In the present invention, the reference information storage means is shared by a plurality of positioners, so that it is not necessary to update the reference information for each positioner, and the reference information can be prevented from being diversified by mistake.

1 is a block diagram showing a configuration of a valve control system according to a first embodiment of the present invention. It is a flowchart which shows the operation | movement at the time of automatic tuning execution of the automatic tuning apparatus which concerns on the 1st Embodiment of this invention. It is a figure which shows one example of an operating device size-response time table. It is a figure which shows the example of the step response of a valve opening degree. It is a figure which shows one example of a hysteresis level-error average table. It is a figure which shows one example of a PID parameter table. It is a flowchart which shows the operation | movement at the time of the reference information update of the automatic tuning apparatus which concerns on the 1st Embodiment of this invention. It is a flowchart which shows the operation | movement at the time of the PID parameter update of the automatic tuning apparatus which concerns on the 1st Embodiment of this invention. It is a block diagram which shows the structure of the valve control system which concerns on the 2nd Embodiment of this invention.

[Principle of Invention 1]
In automatic tuning, a PID parameter value is determined with reference to a PID parameter table or the like based on a valve characteristic value measured by a basic operation that takes several minutes. Although the performance of automatic tuning can be improved by updating the PID parameter table, etc., the information recorded in the PID parameter table is only reference information for setting the PID parameter, so the valve characteristics themselves change by updating the table. Focused on not doing. Then, if the valve characteristic value is stored and the PID parameter value is updated using the stored valve characteristic value at the time of updating the table, the PID can be restarted without restarting the automatic tuning when the table is updated. I came up with the idea that parameter values can be updated.

[Principle of Invention 2]
The automatic tuning PID parameter table and the like should be managed as common to a plurality of positioners. If a PID parameter table is provided for each positioner, a different PID parameter table will be held for each model of positioner depending on whether or not the table has been updated. The relationship between the value and the valve characteristic value is excessively diversified. Therefore, it is preferable to manage and update the table update results with a device management system mounted on a host computer (Personal Computer) to which the positioner is connected via the communication function. Alternatively, the table itself may be stored on the upper side, and only the update of the PID parameter value may be performed on the positioner side.

[First Embodiment]
Hereinafter, embodiments of the present invention will be described with reference to the drawings. This embodiment corresponds to Principle 1 of the invention described above. FIG. 1 is a block diagram showing a configuration of a valve control system according to the present embodiment. The valve control system includes a positioner 1 and a valve (control valve) 2 that opens and closes a passage through which fluid flows. The valve 2 includes a valve main body 2a that opens and closes a passage through which fluid flows, and an operating device 2b that operates the valve main body 2a according to the air pressure supplied from the positioner 1.

  The positioner 1 is measured at the time of execution of a basic function unit 10, an automatic tuning execution unit 14 that executes automatic tuning and updates a PID parameter value that is a control parameter value set in the basic function unit 10, and A characteristic value storage unit 15 for storing the characteristic value of the valve, a reference information storage unit 16 for storing reference information such as a PID parameter table, a reference information updating unit 17 for updating reference information such as a PID parameter table, and a PID In response to the parameter update command, the valve characteristic value stored in the characteristic value storage unit 15 is used to update the PID parameter value set in the basic function unit 10 based on reference information such as a PID parameter table. PID parameter value update processing unit 18 (control parameter value update processing means).

  The basic function unit 10 includes a control unit 11, an electropneumatic conversion unit 12, and an angle sensor 13. The control unit 11 calculates the operation amount by PID control calculation so that the opening set value SP input from the outside matches the opening of the valve 2 detected by the angle sensor 13. PID parameters for this PID control calculation are set in the control unit 11. In addition, since PID control is a well-known technique, detailed description is abbreviate | omitted. The electropneumatic converter 12 converts the operation amount (input electric signal) into air pressure and supplies it to the operating device 2b of the valve 2. The operating device 2b operates the valve body 2a in accordance with the air pressure supplied from the electropneumatic converter 12. Thus, the opening degree of the valve 2, that is, the flow rate of the fluid passing through the valve 2 is controlled.

  The automatic tuning execution unit 14, the characteristic value storage unit 15, the reference information storage unit 16, the reference information update unit 17, and the PID parameter value update processing unit 18 constitute an automatic tuning device. The automatic tuning execution unit 14 receives the automatic tuning command of the PID parameter, actually drives the valve 2, and determines the size of the operating device 2b from the response time when the opening position of the valve 2 continuously changes. Further, the hysteresis level of the valve 2 is determined from the step response from the first opening position to the second opening position of the valve 2, and based on the determined size of the operating device 2b and the determined hysteresis level of the valve 2 in advance. A corresponding PID parameter value is selected from the created PID parameter table, and the PID parameter value set in the control unit 11 is updated.

Hereafter, the operation | movement at the time of automatic tuning execution of the automatic tuning apparatus of this Embodiment is demonstrated with reference to FIG.
When an automatic tuning command is input from the outside, the automatic tuning execution unit 14 starts automatic tuning and gives an electric signal to the electropneumatic conversion unit 12 to change the opening position of the valve 2 from 0% position to 100%. The position is continuously changed (step S100 in FIG. 2), and the response time of the valve 2 at this time, for example, the time Tup when the valve 2 shifts from the 10% position to the 90% position is measured (step S101 in FIG. 2).

  After the opening position of the valve 2 reaches the 100% position, the automatic tuning execution unit 14 gives an electric signal to the electropneumatic conversion unit 12 to change the opening position of the valve 2 from the 100% position to the 0% position. (Step S102 in FIG. 2), the response time of the valve 2 at this time, for example, the time Tdown when the valve 2 moves from the 90% position to the 10% position is measured (Step S103 in FIG. 2).

Next, the automatic tuning execution unit 14 obtains the response time TRES between the 10% position and the 90% position of the valve 2 as an average value of the time Tup measured in Step S101 and the time Tdown measured in Step S103 (FIG. 2 step S104).
TRES = (Tup + Tdown) / 2 (1)
The reason for obtaining the average value of Tup and Tdown is that there may be a speed difference between the direction in which the opening is increased and the direction in which the opening is decreased. By obtaining the average of Tup and Tdown, a more accurate response time is obtained. Because it can.

  Then, the automatic tuning execution unit 14 refers to the operation unit size-response time table stored in advance in the reference information storage unit 16 and operates the value of the operation unit size SZ corresponding to the response time TRES obtained in step S104. Obtained from the device size-response time table (step S105 in FIG. 2). FIG. 3 shows an example of the controller size-response time table. As shown in FIG. 3, the operating device size-response time table associates the operating device size SZ with the response time TRES. The inside of the operation device 2b is divided into an upper chamber and a lower chamber by a diaphragm. By sending the output air pressure of the positioner 1 to one of the upper chamber and the lower chamber, the diaphragm receives the air pressure and drives the valve shaft of the valve body 2a. The magnitude of the driving force of the operating device 2b depends on the area of the diaphragm, and the driving force increases as the area of the diaphragm increases. Needless to say, the size of the operation device 2b having a large-diameter diaphragm is increased. Thus, the size of the operating unit size SZ represents the size of the diaphragm area (the size of the driving force). In the example of FIG. 3, the operating unit size SZ is divided into three stages.

  Subsequently, the automatic tuning execution unit 14 sets the opening setting value SP to be input to the control unit 11 to 40% (first opening position), for example, and then sets the opening setting value SP to 60% (first), for example. 2 opening position). As a result, as shown in FIGS. 4A and 4B, the opening position of the valve 2 makes a step response from the 40% position to the 60% position (step S106 in FIG. 2). FIG. 4 (A) shows the step response when the hysteresis level indicating the degree of the opening position difference when the opening of the valve 2 is increased and when the opening is decreased is small, and FIG. 4 (B) is when the hysteresis level is large. Step response is shown.

  The automatic tuning execution unit 14 measures the valve opening error area Es during this step response, and obtains the average valve opening error EA from the measured error area Es (step S107 in FIG. 2). The valve opening error area Es can be obtained by the following equation.

In Expression (2), t1 is the time when the opening degree of the valve 2 reaches 60%, and t2 is the time when a certain time has elapsed from the time t1. Further, when the opening degree of the valve 2 detected by the angle sensor 13 is PV, the error E can be obtained as follows.
E = PV-60 [%] (3)
Then, the error average EA can be obtained as follows.
EA = Es / (t2-t1) (4)

Next, the automatic tuning execution unit 14 refers to the hysteresis level-error average table stored in advance in the reference information storage unit 16 and sets the hysteresis level HYS of the valve 2 corresponding to the error average EA obtained in step S107. The value is acquired from the hysteresis level-error average table (step S108 in FIG. 2). FIG. 5 shows an example of a hysteresis level-error average table. As shown in FIG. 5, the hysteresis level-error average table associates the hysteresis level HYS of the valve 2 with the error average EA.
Then, the automatic tuning execution unit 14 stores the measured valve characteristic value, specifically, the response time TRES and the error average EA in the characteristic value storage unit 15 (step S109 in FIG. 2).

  Finally, the automatic tuning execution unit 14 refers to the PID parameter table stored in the reference information storage unit 16 in advance, and the PID parameter value corresponding to the operating unit size SZ and the hysteresis level HYS obtained in steps S105 and S108. Is obtained from the PID parameter table, and the PID parameter value set in the control unit 11 is updated to the value obtained from the PID parameter table (step S110 in FIG. 2). FIG. 6 shows an example of the PID parameter table. As shown in FIG. 6, the PID parameter table associates the operating device size SZ and hysteresis level HYS with the PID parameters (proportional gain KP, integral time TI, derivative time TD). Thus, the operation of the automatic tuning execution unit 14 is completed. Such an automatic tuning method is disclosed in Patent Document 2.

  Next, the operation at the time of updating the reference information of the automatic tuning apparatus according to the present embodiment will be described with reference to FIG. The reference information (operator size-response time table, hysteresis level-error average table, PID parameter table) stored in the reference information storage unit 16 is substantially advanced with the progress of research and development by positioner manufacturer engineers. If it is changed (detailed contents or amended by review), it will be necessary to revise and update.

  When the operator wants to update at least one reference information among the controller size-response time table, hysteresis level-error average table, and PID parameter table, he / she operates the input device (not shown) to input the reference information to be updated. The reference information update unit 17 receives the input reference information (step S200 in FIG. 7), and updates the reference information stored in the reference information storage unit 16 to the received reference information (step S201 in FIG. 7). Such updating of the reference information can be realized by a normal download technique.

Next, the operation at the time of updating the PID parameter after updating the reference information will be described with reference to FIG. When a PID parameter update command is input from the outside, the PID parameter value update processing unit 18 reads a response time TRES that is a valve characteristic value stored in the characteristic value storage unit 15 (step S300 in FIG. 8).
Subsequently, the PID parameter value update processing unit 18 refers to the operating unit size-response time table stored in the reference information storage unit 16, and the value of the operating unit size SZ corresponding to the response time TRES read in step S300. Is obtained from the controller size-response time table (step S301 in FIG. 8).

Next, the PID parameter value update processing unit 18 reads out an average EA of errors that are valve characteristic values stored in the characteristic value storage unit 15 (step S302 in FIG. 8).
Subsequently, the PID parameter value update processing unit 18 refers to the hysteresis level-error average table stored in the reference information storage unit 16 and refers to the hysteresis level HYS of the valve 2 corresponding to the error average EA read in step S302. Is obtained from the hysteresis level-error average table (step S303 in FIG. 8).

  Then, the PID parameter value update processing unit 18 refers to the PID parameter table stored in the reference information storage unit 16, and the PID parameter value corresponding to the operating unit size SZ and the hysteresis level HYS obtained in steps S301 and S303. Is updated from the PID parameter table, and the PID parameter value set in the control unit 11 is updated to the value acquired from the PID parameter table (step S304 in FIG. 8). Thus, the operation of the PID parameter value update processing unit 18 is completed.

  As described above, in the present embodiment, when the automatic tuning is performed, the reference characteristic is updated after the automatic tuning by storing the valve characteristic value measured by the automatic tuning. However, automatic tuning operation (operation to continuously change the opening position of valve 2 from 0% position to 100% position, continuously changing the opening position of valve 2 from 100% position to 0% position The PID parameter value can be updated using the updated reference information without re-executing the operation to be performed and the operation in which the opening position of the valve 2 is step-responsive.

[Second Embodiment]
Next, a second embodiment of the present invention will be described. This embodiment corresponds to Principle 2 of the invention described above. FIG. 9 is a block diagram showing the configuration of the valve control system according to the present embodiment. The same components as those in FIG. 1 are denoted by the same reference numerals. The valve control system of the present embodiment provides reference information common to a plurality of positioners 1-1 and 1-2, a plurality of valves 2-1 and 2-2, and a plurality of positioners 1-1 and 1-2. And a device management system 4 to be managed. The valves 2-1 and 2-2 operate the valve bodies 2a-1 and 2a-2 according to the air pressures supplied from the valve bodies 2a-1 and 2a-2 and the positioners 1-1 and 1-2. It is comprised from the operation devices 2b-1 and 2b-2.

Each of the positioners 1-1 and 1-2 includes a basic function unit 10, an automatic tuning execution unit 14, a characteristic value storage unit 15, and a PID parameter value update processing unit 18.
The device management system 4 includes a reference information storage unit 16 and a reference information update unit 17.

  In the present embodiment, the reference information storage unit 16 and the reference information update unit 17 described in the first embodiment are provided in the device management system 4 that is a higher-level device of the positioners 1-1 and 1-2. Yes, the reference information storage unit 16 and the reference information update unit 17 are shared by a plurality of positioners 1-1 and 1-2 via a communication function. This configuration eliminates the need to update the reference information for each positioner.

Since the processing flow of this embodiment is the same as that of the first embodiment, the operation of the valve control system of this embodiment will be described with reference to FIGS. 2, 7, and 8.
When the positioners 1-1 and 1-2 use the reference information storage unit 16 of the device management system 4 in the processing at the time of automatic tuning execution (steps S105, S108, and S110 in FIG. 2), and the PID parameter is updated after the reference information is updated. When the positioners 1-1 and 1-2 use the reference information storage unit 16 of the device management system 4 in the time processing (steps S301, S303, and S304 in FIG. 8), the processing is performed via the communication function. .

Further, the process at the time of updating the reference information (steps S200 and S201 in FIG. 7) is performed on the device management system 4 side.
Thus, in this embodiment, the same effect as that of the first embodiment can be obtained, and reference information can be prevented from being diversified by mistake.

  Each of the positioner 1 and the device management system 4 described in the first and second embodiments is based on a computer having a CPU (Central Processing Unit), a storage device and an interface, and a program for controlling these hardware resources. Can be realized. The CPU of each device executes the processing described in the first and second embodiments in accordance with a program stored in the storage device.

  The present invention can be applied to a technique for adjusting a control parameter value of a positioner.

  1, 1-1, 1-2 ... positioner, 2, 2-1, 2-2 ... valve, 2a, 2a-1, 2a-2 ... valve body, 2b, 2b-1, 2b-2 ... actuator, DESCRIPTION OF SYMBOLS 4 ... Device management system, 10 ... Basic function part, 11 ... Control part, 12 ... Electropneumatic conversion part, 13 ... Angle sensor, 14 ... Automatic tuning execution part, 15 ... Characteristic value storage part, 16 ... Reference information storage part, 17: Reference information update unit, 18 ... PID parameter value update processing unit.

Claims (6)

Reference information storage means for storing at least a control parameter table associating valve characteristic values with positioner control parameter values as reference information;
At the time of execution of automatic tuning for adjusting the control parameter of the positioner, the valve is driven via an operating device, and the corresponding control parameter value is acquired from the control parameter table based on the measured characteristic value of the valve, Automatic tuning execution means for updating the control parameter value set in the positioner;
A characteristic value storage means for storing a characteristic value of the valve measured during execution of the automatic tuning;
Reference information updating means for receiving reference information input from the outside at the time of updating the reference information and updating the reference information stored in the reference information storage means;
When updating the control parameter after updating the reference information, the characteristic value of the valve stored in the characteristic value storage means is read out, and the corresponding control parameter value is read from the control parameter table based on the characteristic value. An automatic tuning apparatus comprising: control parameter value update processing means for acquiring and updating a control parameter value set in the positioner. In the automatic tuning device according to claim 1,
The control parameter value is a PID parameter value;
The reference information storage means stores a PID parameter table as the control parameter table, and stores an operating device size-response time table and a hysteresis-error table as other reference information,
The automatic tuning execution means measures a response time as a characteristic value of the valve, obtains an operating device size that is a corresponding characteristic value from the operating device size-response time table, and opens it as the characteristic value of the valve. The hysteresis, which is a characteristic value corresponding to the hysteresis-error table, is obtained from the hysteresis-error table, and the PID parameter value corresponding to the actuator size and hysteresis is obtained from the PID parameter table. Update the set PID parameter value,
The characteristic value storage means stores the response time and the error of the opening as the characteristic value of the valve,
The control parameter value update processing means reads a response time as a valve characteristic value stored in the characteristic value storage means, obtains a corresponding operating device size from the operating device size-response time table, and The error of the opening is read as the characteristic value of the valve stored in the characteristic value storage means, the corresponding hysteresis is obtained from the hysteresis-error table, and the PID parameter value corresponding to the actuator size and hysteresis is set to the PID An automatic tuning apparatus, wherein a PID parameter value acquired from a parameter table and set in the positioner is updated. In the automatic tuning device according to claim 1 or 2,
The reference information storage means and the reference information update means are mounted on a host device of the positioner,
The automatic tuning execution means, the characteristic value storage means, and the control parameter value update processing means are mounted on the positioner,
An automatic tuning apparatus, wherein the reference information storage means is shared by a plurality of positioners via a communication function. When automatic tuning for adjusting the control parameter of the positioner is performed, the valve is driven via the operating unit, the characteristic value of the valve is measured, and a control parameter table that is reference information stored in advance in the reference information storage means is stored. An automatic tuning execution step for obtaining a corresponding control parameter value from the control parameter table based on the characteristic value of the valve and updating the control parameter value set in the positioner;
A characteristic value storage step of storing the characteristic value of the valve measured during execution of the automatic tuning in a characteristic value storage means;
A reference information update step of receiving reference information input from the outside when updating the reference information and updating the reference information stored in the reference information storage means;
When updating the control parameter after updating the reference information, the characteristic value of the valve stored in the characteristic value storage means is read out, and the corresponding control parameter value is read from the control parameter table based on the characteristic value. A control parameter value update processing step of acquiring and updating a control parameter value set in the positioner. The automatic tuning method according to claim 4,
The control parameter value is a PID parameter value;
The reference information storage means stores a PID parameter table as the control parameter table, and stores an operating device size-response time table and a hysteresis-error table as other reference information,
In the automatic tuning execution step, the response time is measured as the characteristic value of the valve, and the actuator size which is the corresponding characteristic value is obtained from the actuator size-response time table, and is opened as the characteristic value of the valve. The hysteresis, which is a characteristic value corresponding to the hysteresis-error table, is obtained from the hysteresis-error table, and the PID parameter value corresponding to the actuator size and hysteresis is obtained from the PID parameter table. Updating a set PID parameter value;
The characteristic value storage means stores the response time and the error of the opening as the characteristic value of the valve,
The control parameter value update processing step reads a response time as a valve characteristic value stored in the characteristic value storage means, acquires a corresponding operation device size from the operation device size-response time table, and The error of the opening is read as the characteristic value of the valve stored in the characteristic value storage means, the corresponding hysteresis is obtained from the hysteresis-error table, and the PID parameter value corresponding to the actuator size and hysteresis is set to the PID An automatic tuning method comprising a step of updating a PID parameter value set in the positioner, obtained from a parameter table. In the automatic tuning method according to claim 4 or 5,
The reference information storage means is mounted on a host device of the positioner,
The characteristic value storage means is mounted on the positioner,
The host device executes the reference information update step,
The positioner executes the automatic tuning execution step, the characteristic value storage step, and the control parameter value update processing step;
An automatic tuning method, wherein the reference information storage means is shared by a plurality of positioners via a communication function.

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