Losing PM 866 Controller redundancy due to Modulebus connectivity issue.
Configuration : Red. PM 866 Controllers with 6 Clusters in Modulebus (TB840A)
Note: The PM 866 controller are replaced with the new ones after the recent field alert.
The controllers are getting out of redundancy very frequently. On checking the controller log, found out that the one of the cluster is not visible in the backup controller. The customer has brought the optic fibre technician and he checked the signal, re polished the cables and put it back in service. It worked for 2 -3 days. forgot to say that this is a marine project (vessel). Now again the problem started, I have attached the controller logs of primary and backup just after resetting the backup controller (which was in fault state). My question is
1. Is the any possible reason for this other than cable issue. The customer is challenging my finding, saying that the cable continuity and signal strength has been tested and values were good enough.
2. Is there any filter time for controller to wait for the signal to be back.
1. Yes. Lots. Pretty much the entire hardware chain could be suspect. Without a drawing of exactly what is installed its not possible to say.
2. No. There is a setting for Module Bus scan rate which "might" help but could instead make things worse. Its not possible to say if you can change this without knowing the details of your application software. In any case - it's just hiding the problem. The modulebus should be stable and the communications to the cluster should not stop.
You say you've checked the Fibre connections, but what about the pre-made POF cables ? Modems etc ?
At one of our customer site i am also facing same issue of cluster no 6 invisibility and controller went to fault state.
We have checkcd all the power supply,also replace TB826,TU841,TB840,But still problem is there.
So have u worked out anything for the solution of this problem??
Pls give suggestions for this issue as i got stuck with this issue and we are facing this issue with most critical Loadshedding controller.