Safety controller and safety control method

A safety controller comprising:

• a processor that outputs instruction information for instructing a control content for a control target;
• a system program for controlling allocation of an execution time of the processor to a safety-related task for executing processing related to ensuring of functional safety of the control target, and to a normal control task for executing other processing related to control of the control target;
• a signal generation unit that generates a carrier signal;
• a control unit that updates the control content for the control target with a control content instructed by the instruction information output from the processor, every first predetermined cycle of the carrier signal generated by the signal generation unit, and performs PWM (Pulse Width Modulation) control for the control target based on the control content updated;
• and
• an interrupt signal generation unit that generates an interrupt signal to the processor and outputs the interrupt signal to the processor every second predetermined cycle of the carrier signal generated by the signal generation unit, wherein
• the processor executes the system program to schedule the tasks in accordance with scheduling information indicating scheduling contents of a safety-related time partition in which the execution time is allocated to the safety-related task, and of a normal control time partition in which the execution time is allocated to the normal control task,
• the processor executes the system program to switch the time partitions according to an output of the interrupt signal from the interrupt signal generation unit, and
• the processor outputs the instruction information to the control unit by executing one of the normal control task and the safety-related task.