Gentleman, I thank you in advance for your response. I have two racks with S7410-5H PLC, I want to transfer the redundancy from rack1 to rack0 but there is no switch in front of the PLC to do so. Please guide me to put rack0 back into master mode, maybe through software?

Hi

If you mean that you want to change which cpu has taken the role of primary cpu, then you set the primary cpu to stop and the other will become primary.

Then you warm restart the one you stopped and it will stay secondary.

Regards

Michael