Hi,
Thanks for you quick reply. Yes, cable is correct and plugged in the correct way. Yes, the modules are in same order in HW configuration as they are DIN rail. I can download program to PLC but it's like the plc is not communicating with ex-a1. I have branches off 0v supply to the ex-a1 and v570 - sounds like a longshot but could this be a cause? I originally connected v570 to ex-a1 with a regular cat5 patch cable. Could this have damaged the ex-a1?
Thanks,
Gerard