Controller, control method, and control program

A control method in a controller having an auto-tuning function, comprising:

• selectively determining a first manipulated value for causing a first change in a controlled value of a controlled object or a second manipulated value for causing a second change opposite to the first change in the controlled value, in accordance with a preset parameter, so that a process value obtained from the controlled object follows a target value;
• and
• alternately outputting the first manipulated value and the second manipulated value in accordance with the process value and determining the parameter from a response characteristic obtained through the alternate output,
• wherein the determining the parameter includes successively changing a magnitude of the first manipulated value each time output is switched during the alternate output of the first manipulated value and the second manipulated value, and
• wherein the determining the parameter includes determining the parameter from a response characteristic obtained when it is determined that the first change in the controlled value to the first manipulated value has linearity.

A non-transitory storage medium comprising a control program for implementing a controller having an auto-tuning function, the control program causing a processor to perform:

• selectively determining a first manipulated value for causing a first change in a controlled value of a controlled object or a second manipulated value for causing a second change opposite to the first change in the controlled value, in accordance with a preset parameter, so that a process value obtained from the controlled object follows a target value;
• and
• alternately outputting the first manipulated value and the second manipulated value in accordance with the process value and determining the parameter from a response characteristic obtained through the alternate output,
• wherein the step of determining the parameter includes successively changing a magnitude of the first manipulated value each time output is switched during the alternate output of the first manipulated value and the second manipulated value, and
• wherein the determining the parameter includes determining the parameter from a response characteristic obtained when it is determined that the first change in the controlled value to the first manipulated value has linearity.