In one of the profibu slave, CI840 PRIM LED is switching between Primary and Secondary CI840 card. Also under Unit Status tab - Extended Status - I get the following error
"Parameter data fault, Redundant Slave does not exist, Redudant - What could be the issue? Other slaves (clusters) are working fine. Only this cluster CI840 and associated AO cards are not working.
Please let me know what could be the probable causes.