Control device and control method

A control method of a control device, the control device comprising:

• a controller configured to control machines to be controlled;
• a power shutdown detection circuit configured to detect a power shutdown in which power supply from a power supply to the controller is cut off;
• a power supply holding circuit configured to supply power to the controller at the time of the power shutdown;
• and
• a power detection circuit configured to detect a power amount held in the power supply holding circuit,
• the control method comprising:
• executing a termination process with the power supplied from the power supply holding circuit in a case where the power shutdown detection circuit has detected the power shutdown;
• executing a restart process on condition that the power supply holding circuit holds the power amount equal to or greater than a reference amount based on the power detection circuit in a case where the power shutdown detection circuit has detected a return of the power supply from the power shutdown;
• setting a determination timing for whether to execute the restart process after a se of a certain period of time from a start of the termination process;
• and
• determining the return of the power supply from the power shutdown and the power amount of the power supply holding circuit at the determination timing.