Safety controller and safety control method

Abstract

To perform control in synchronization with a control cycle of a control target while maintaining safety. A safety controller includes: a processor; a system program for controlling allocation of an execution time of the processor to tasks; a signal generation unit that generates a periodic carrier signal; a control unit that updates a control content for the control target with a control content instructed by instruction information output from the processor, every first predetermined cycle of the carrier signal, and performs PWM control for the control target; and an interrupt signal generation unit that outputs an interrupt signal to the processor every second predetermined cycle of the carried signal. The processor executes the system program to schedule the tasks in accordance with scheduling information on a safety-related time partition and a normal control time partition, switches the time partitions according to an output of the interrupt signal, and outputs the instruction information to the control unit by a normal control task or a safety-related task.