Hi,
I have a modicon premium plc rack with TSX PSY 3610 power supply module. The psy 3610 power supply has an alarm contact and it is used in a loop to energize a hard ware relay for 24VDC supply to the DO module FTA boards. There is a safety button in parallel to the alarm contact so that during startup we can press this button, energies DO module loops and all IO faults cleared and power supply alarm contact latches
The problem is that this power supply alarm contact remains always open even when IO report no faults. The PLC has MAST task only and it is running with no faults. If I jumper the alarm contact all the IO's are healthy .
tried changing the power supply and DO modules. no hope. please help.