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EDC PV / PV_STATE Mismatch After CIOC Power Cycle

I power cycled a CIOC yesterday to clear a hardware alarm and found an issue with an EDC block afterward.  I have two fail closed isolation valves without feedback that were open at the time the CIOC was power cycled.  As expected the valves closed on IO power loss (CHARM fail action also set to closed as well).  After restoring power the valves indicated closed in graphics and the EDC1/PV_D indicated closed as well.  Tracking is not enabled so the SP_D retained the OPEN set point.  When the subsequent batch started the sequence got stuck trying to open the valves.  I noticed the PV_STATE of each valve retained the "Confirmed open" state.  I don't fully understand this as the PV_D correctly indicated closed, but I assume it has to do with the fact that there is no feedback and DEVICE_OPTS not configured to track the SP?  Reading BOL and looking at the EDC configuration I believe the correct DEVICE_OPTS configuration would be enabling "Trip" and "SP Track On Trip"?  I don't have a good way to test this without interrupting operations, so I was hoping to get some advice from the experts.  BOL doesn't specifically define if / how "Trip" works when there is no feedback.  Will "Trip" properly track the SP_D in an IO power loss scenario?

Jesse Delanoy

• 4 Jun 2025 1:47 PM
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3 Replies

• Matt Stoner

  

  • 9 Jun 2025 6:30 PM

  If you don't have inputs configured then Trip really doesn't do you much except maybe for this situation which I suspect hasn't been tested. You should log a call on this issue but I will tell you that there is hotfix coming for the EDC block to address some issues that have recently been found but this situation wasn't mentioned but it might be related to those issues. I will look and see calls but they are installing Win11 and it wants to restart...

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• Matt Stoner

  

  • 10 Jun 2025 5:29 PM

  In reply to Matt Stoner:

  The KBA and Hotfix isn't quite ready for release. I'm not sure if it will address your particular issue or not but you should still log a call for the behavior you have experienced.

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• Jesse Delanoy

  

  • 13 Jun 2025 12:09 AM

  In reply to Matt Stoner:

  Thanks for checking on the KBA Matt. I started GSC call for this issue.

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