29 November 2022
If one CPS has failed (no output power and OK LED is not ON) or there is no supply to it, then the alarm output relay will open on that CPS. This is independent of the other CPS. The second CPS, if operating normally, will have its alarm output closed, regardless of the status of the failed CPS. You can also use the %SW124 bit to give you the status of your redundant power supply pair.