CPU Transitions

CPU commands that change states:

Command

Description

STOP CPU

CPU tasks go to the STOP state.

RUN CPU

CPU tasks go to the RUN state.

RUN Task

The relevant tasks and the CPU go to the RUN state.

STOP Task

The relevant task goes to the STOP state. The CPU goes to the STOP state if this task was the last task in the RUN state.
NOTE:

  • When the CPU switches from RUN to STOP, the output modules in RIO drops associated with this task go to the configured fallback state. Input values associated with this task in the CPU memory image are interpreted as 0.

  • When the CPU switches from STOP to RUN, data received from the CPU are applied to the physical outputs associated with this task. Input images in the CPU are updated with physical inputs associated with this task.

  • Refer to the Modicon M580 Hardware Reference Manual for CPU configuration options that help prevent remote commands from accessing the Run/Stop modes.

  • Refer to the Modicon M580 Hot Standby System Planning Guide for Frequently Used Architectures.