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Reading Delta V parameters through OPC with MOCCA (Alarm Management tool)

Hello, good morning. I'm not sure if this section would be the recommended one to this question, so I'm sorry if not (if possible, some moderator could move it to the right place please?).

Well, we have a MOCCA software (Honeywell) that is our Alarm Management tool. It basically reads many Delta V control modules parameters (such as HI_ALM.CV, HI_ALM.OPSUP, engineering units and range, etc), catalogue everything, and we use it also as a tool for alarm rationalization. The problem is that we are not being able to read the MODULE/DESC.CV parameter for some reason. If you check the OPC branches on the OPCWATCHIT, we can't find this parameter there, but if you type it directly to "Type Path", it reads perfectly.

We contacted Honeywell support many many times, but they are unable to solve this issue. Do you guys have any idea about how to fix it? Is there any other path to read the control module description? Why it doesn't appear in the OPC branches? Please see an example below:

• MOCCA
• OPC
• Delta V
• alarm management
• control module description
• DESC.CV

Rafael Rebouças de Araujo

• 17 Oct 2017 2:09 PM
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7 Replies

• Andre Dicaire

  

  • 17 Oct 2017 5:16 PM

  The module description is not stored as a parameter within control modules, and as such is not exposed to the OPC Server Browser.  However, the path is available via the OPC server.   Using the OPCWatchit tool on the DeltaV system, the browser does not show the /DESC parameter.  But manually typing the path will return the module's description, as you have shown abofe.

  The browser functionality of an OPC DA Server is actually an optional feature of the OPC Server, and client applications can only browse what the OPC Server has exposed.  A client application would not be able to overcome this, except by providing an independent method to derive and expose the description parameter. 

  Andre Dicaire

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• Rafael Rebouças de Araujo

  

  • 17 Oct 2017 9:46 PM

  In reply to Andre Dicaire:

  Hi, Andre. Thank you very much for the reply.
  
  Well, we also have a IP.21 Data Historian which is able to read the DESC.CV value through OPC. Do you know why the IP.21 can do that, but the MOCCA can't? I'm typing the path manually in MOCCA just as we do in IP.21.
  
  Best regards,
  
  Rafael

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• Andre Dicaire

  

  • 17 Oct 2017 9:53 PM

  In reply to Rafael Rebouças de Araujo:

  Rafael, I do not know why MOCCA would not accept a manual path for the description. You have confirmed that a non DeltaV OPC Client is able to access this. In the face of mounting evidence that the DESC parameter is accessible, just not browseable, the MOCCA application would appear to be at issue. I have not worked with MOCCA so I cannot speak to that application.

  Andre Dicaire

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• Leo Paradis

  

  • 17 Oct 2017 10:31 PM

  In reply to Andre Dicaire:

  Is it possible that the wrong data type is being asked for. Real or integer instead of ASCII?

  Leo

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• damer.j1975

  

  • 18 Oct 2017 10:14 AM

  Dear My friend.
  I am not sure about the reason of that issue but I have below recommendation as well .
  you can add one internal input parameter inside of your module and link it to the module description parameter then download and try to search that new parameter in OPC .
  B R
  Jefry

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• Youssef.El-Bahtimy

  

  • 19 Oct 2017 3:10 AM

  In reply to Leo Paradis:

  I recently ran into a discrepancy between opc clients and servers where one was expecting/accepting null terminating strings, and the other just plain ascii. Can you read other strings in the system? Does the client keep a debug level log to determine where the process runs into into trouble?

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• Rafael Rebouças de Araujo

  

  • 19 Oct 2017 11:11 AM

  In reply to Youssef.El-Bahtimy:

  Thank you very much for your suggestions, I'll make some tests and update you latter about the results!
  
  Best regards,
  
  Rafael

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