Emerson Exchange 365

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How to reference comms parameter OINTEG using OPC?

I'm trying to bring back the integrity of individual comms ports on serial cards into out data historian via OPC (OSIsoft PI), but I'm having trouble getting the reference right. I've gone to diagnostics, browsed to the card and the OINTEG parameter, and noted the reference (DV303/IO1/C03/P01/OINTEG.CV) but that doesn't work. We have about 6 serial cards attached to a couple of controllers, so I'm guessing I need to keep the controller reference (DV303 in this case) to distinguish between the various cards. 

Should I be referencing .CV or .CST, and are these values or strings? BOL doesn't state what the OINTEG parameter is in terms of type (float, string, Boolean) so I might be trying to retrieve a string but the OPC interface is looking for a value.

Any help much appreciated!

Thanks

Col

• ointeg
• serial cards
• OPC

Colin Welsh

• 5 Nov 2019 11:47 AM
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4 Replies

• Scott Thompson

  

  • 5 Nov 2019 10:26 PM

  Colin,

  Your path is correct including .CV (Current Value).  I tried a test on a system here with OPCWatchit and was able to get a number of zero for Good on the OINTEG parameter, I was also able to browse to it.  Definitely need the full path including controller name.

  I'm not sure what is up with your connection.  Do you have other data going over to PI via OPC that are working?  You may want to try a test with OPCWatchit to see if you can connect that way.

  By the way, the .CST parameter is for Connection STatus.  It will give a values as the following:

  0	Good
  1	Not Communicating
  -1	Module not configured
  -2	Parameter not configured
  -3	External reference not resolved

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• Paul Redford

  

  • 6 Nov 2019 7:30 AM

  In reply to Scott Thompson:

  I am doing this but i had to build a module in the PP to read the parameters. On downlaod the sytem complains but it does work.
  Then get PI to read from the module.
  
  Regards
  Paul

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• Colin Welsh

  

  • 6 Nov 2019 8:48 AM

  Found the issue - a bit of a mistake in the tag upload to the OPC server which stopped the OPC interface from correctly reading the data.
  
  I have ended up bringing back the OINTEG and the STATUS as digital and string values respectively.
  
  What are the values the OINTEG can take? Even though the tag is referenced as a digital in PI, it actually takes a number and coverts that to a state as per a predefined state mask. Currently I only have 2 states; 0 and 1. If OINTEG can be more than those values then I won't get any data when the value is > 1.

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• Scott Thompson

  

  • 6 Nov 2019 12:55 PM

  In reply to Colin Welsh:

  OINTEG is a true digital and only has values of zero (Good) and one (Bad). For other values you can always do a search in Books On-Line to get a description with data type and list of possible values for non-string parameters.
  
  One tip for the path of a diagnostic parameter, if you browse to the parameter in DeltaV Diagnostics, right-click and choose Properties, the dialog will give you the full path that you can copy and paste over to the PI OPC interface. Just remember to add .CV as that is not shown in the Diagnostics Property dialog.

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