Emerson Exchange 365

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Why am I getting "Write Failed" for quality?

I am attempting to write data from a deltaV tag, with a good quality string to an empty tag using a pipe.  I can see the empty tag in Matrikon OPC explorer with Quality "Good, non-specific", and I can set up the pipe and validate it, with both points being good, however, the value of the deltaV tag isn't written over to the blank point.  Any idea why this is?

Canonical type of deltaV tag is VT-BSTR, and empty tag is VT_EMPTY.

• write failed
• OPC Mirror

rummeln

• 27 May 2016 5:25 PM
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4 Replies

• Rachelle McWright

  

  • 27 May 2016 9:16 PM

  Hi rummeln. We are approaching a holiday weekend here in the states, but I hope by moving this to the (Missing Group) group we might be able to garner a quicker response...experts around the globe, unite!

  Best Regards,

  Rachelle McWright: Business Development Manager, Dynamic Simulation: U.S. Gulf Coast

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• Andre Dicaire

  

  • 27 May 2016 9:52 PM

  In reply to Rachelle McWright:

  Are both OPC Servers on the same machine? It appears you are using OPC Mirror. where is it running? Do you have any other DeltaV parameters that write successfully, or is this the first one you try.
  
  If this is the first pipe, it may be related to security on the other server and not having write access for the OPC MIrror user account. Can you use an OPC client and manually write to the parameter successfully?
  With OPC Watchit, you'll get a fail code that might help clarify what the issue is.

  Andre Dicaire

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• rummeln

  

  • 27 May 2016 10:16 PM

  In reply to Andre Dicaire:

  The servers are on separate machines. The OPC Mirror is running on the DeltaV server, whereas the other server is from Cogent Datahub. I have a number of pipes setup on the DeltaV server already and they are communicating fine (but to a different OPC server). I am unable to get any pipes to write to the Cogent Datahub server. However, I can:
  1. Change the values in Matrikon Explorer on the Cogent Datahub server and see the values updated on the DeltaV server
  2. Use OPC Watchit on the DeltaV server and write to the Cogent Datahub points on the Cogent Datahub server.
  
  But for whatever reason, the OPC Mirror pipe can't write to the Cogent Datahub points...

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• Andre Dicaire

  

  • 27 May 2016 10:43 PM

  In reply to rummeln:

  So as not to assume anything, your OPC Mirror is licensed for three servers?
  
  I don't know what the issue is, so I'm hoping some one else will jump on soon. Typically OPC Mirror is running off a service account, while OPCWatchit would be using the interactive user. Is it possible the OPC Mirror user account does not have the required access on the Cogent Datahub server? Is there a domain involved, or two? or are the computers workgroup with local accounts? I would use local accounts with matching passwords for the OPC connections.
  
  I've never used this Cogent Datahub server. If it is not related to the user security on the OPC server end, I don't have any other suggestions. Sorry.

  Andre Dicaire

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