A lightning strike hit close by
Replaced Main Board, Display Board, Loop Card. With Addressable loop connected the display indicates a single fault “FDLC 1 DLC OPEN”. If I remove the addressable loop wiring I get No Responses from all of my devices which makes sense and the FDLC 1 DLC OPEN no longer is indicated. Where should I start looking to fix this? Why don’t you get an FDLC 1 DLC OPEN with any wiring connected to the addressable loop? Any help would be greatly appreciated.
I don’t know much about this panel, but the loop card is probably fried.
Loop Card already replaced… see original post … just trying to understand what on the wiring would cause the fault. The fault doesn’t happen with the wiring totally removed from the loop card.
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So obviously we’ve established that the #1 FDLC card is reporting an open circuit condition. Just to confirm, the panel displays no trouble indication originating from that loop if all system wiring is removed from the FDLC terminals?
It does not appear that the addressable loop utilizes End-of-Line resistors to monitor wiring integrity, therefore I must assume the panel relies on lost communications with field devices to determine if an open condition has occurred. I also do not see a trouble code that corresponds with a failed device, so for that reason it is possible that a failed device on the loop may be reported as a DLC OPEN fault.
It’s possible that one or more of your field devices on the #1 FDLC loop went out with the lightning strike. A good strike could have easily killed the whole loop - transient suppression will only help so much in these situations. If you are still able to poll the devices despite the fault, it may be time to start inspecting each on an individual basis to see if they are responding to the panel.
In addition, based on the descriptions of the odd trouble reporting activity associated with the card, there may also be internal faults remaining in the panel. However, since you did not mention any system board remaining from before the strike, I will not speculate here.
Keep in mind I do not have one of these systems in front of me to offer real-time troubleshooting, therefore I have relied on the MPC-6000 manuals for this post. Copies to the manuals I referenced are available here: http://www.epsohio.com/docs/user_manual/Faraday%20MPC%206000-7000%20O%20-%20I%20Manual.Pdf , System Troubles - Faraday MPC-6000 Installation, Operation And Maintenance Manual [Page 74] | ManualsLib
Thanks for everyone’s help. Started half-splitting the addressable loop and it turned out to be the very last device on the addressable loop. With a lightning strike, in hind-sight it makes sense. Usually on a strike, I’ll see shorts on the loop. This is the first one that caused the entire loop to look like an open. Good learning experience, and hopefully this thread may help someone else in a similar situation.