most likely, the SAFE task is in stop after the power cycle. In order to run automatically the SAFE task on power cycle, the CPU setting "automatic start in run" must be checked

Basics :
A power cycle leads to a warm start. By design, the SAFE task cannot perform a "warm" start, but only a "cold" start. On power cycle, if the CPU setting "automatic start in run" is not checked, the MAST task will execute a warm start, therefore the safety task will not be able to proceed, and the user will have to switch the SAFE task to RUN manually using the "PLC screen" Task tab in maintenance mode.

Publié pour: Schneider Electric Belgium