CONTROLLER, CONTROL METHOD, AND CONTROL PROGRAM

A controller having an auto-tuning function has a manipulated value determination unit that selectively determines 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 a tuning unit that alternately outputs the first manipulated value and the second manipulated value in accordance with the process value, and that determines the parameter from a response characteristic obtained through the alternate output. The tuning unit successively changes 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.