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COMM_ALM not recognized as a reference

We have configured some conditions to reference the COMM_ALM on controllers and CIOCs. For some reason, the COMM_ALM is no longer recognized across all the controllers and application stations. For instance, in WATCHIT, I can see a controller's FAILED_ALM, MAINT_ALM, ADVISE_ALM but the COMM_ALM shows up as an invalid attribute. Can anyone help with getting the system to recognize COMM_ALM again?

• alarm
• DeltaV #DCS

QuyenDinh

• 14 Jan 2025 6:36 PM
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1 Reply

• Andre Dicaire

  

  • 17 Jan 2025 10:05 PM

  The COMM alarm is generated when a console is unable to communicate with a node. Since the node is not able to communicate, how does the console receive the COM alarm? It doesn't. It generates it on behalf of the non communicating node. The alarm shows up in the alarm system to alert the Operator or Maintenance personnel of a loss of communication, which is typically actionable.
  
  In a control module, if you reference a parameter in another node, the CST status of the parameter (all parameters) will indicate a loss of communication, and .ST will go BAD as well. Controllers and CIOC's have diagnostic parameters on the primary and Secondary comms indicating COMM_Good and COMM_Bad. If COMM GOOD goes to 0, that node is not talking on that network to anyone. If the other network is still good, you can see this, even if the network cable is disconnected. If both networks are bad, your module reference would indicate bad status.
  
  Note that some alarm features are only accessible at the console because they are part of the Alarm System, which serves the HMI. i.e. ALARMS[1] aggregate array for Units and Plant Areas and ThisUSer are not accessible to control modules.
  
  If you could share what you are trying to do, we might be able to offer some suggestions.

  Andre Dicaire

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