2 Replies Latest reply on May 15, 2015 7:50 AM by Karl.Hodgkiss

    Alternate OPC Addresses

    Steve Boyko

      One of our clients uses the OPC server included with the Foxboro AIM Historian to get PI data. They have two redundant workstations (call them AW1 and AW2) that supply data to PI. If you browse the OPC server you can see that the OPC tags are named AW1\TAG1 and AW2\TAG2, meaning the computer name is part of the OPC item ID name. This has forced us to create aliases on both OPC servers to map these computer-specific item IDs to the same OPC item ID so PI can find it, regardless of which OPC server is in control. Maintaining this alias file is a big pain and adds work to the "put a new tag in PI" process.


      Is there any way to overcome this?

        • Re: Alternate OPC Addresses

          Unfortunately, I don't think there is. The OPC Interface treats InstrumentTag as a string. If the InstrumentTag doesn't exactly match the ItemID, the interface just rejects the tag. There is no configuration to make this mechanism smarter. Perhaps you could contact tech support and create an enhancement request.

          • Re: Alternate OPC Addresses

            Only other way I've seen this overcome before is to collect both sets of data then have another tag (PE or AF) sat on top which determines which value to collect based on the active server. That's ok for a small system but not so good if you have a limited tag license and is also a pain if you need to add more (Excel concatenations can help though ).