We are having some issues with our PI OPC Interface which according to my recent discussion with Tech Support are not issues, but just part of opc protocol.
We regularly (at least weekly) push updates to our OPC Servers for all sorts of reasons. Anytime our OPC configuration is changed in a way where an OPC item is read from, the OPC Item ID of the read-from item changes. For instance, we create a new interlock that is reading data from item1. When the update is pushed, item1's ID changes.
My understanding is that upon loading of the tag (new or change) to the interface, the interface loads the ItemID from the OPC Serving using the instrument tag field which indicates the Item Name. This
action is only done upon tag load. So if the ItemID changes for a given item Name, the tag has to be reloaded in the interface manually either by restart, or changing some value in the tag configuration settings to force reload.
So you can see the problem. We are constantly having to restart our interface or turn scan off/on to reload tags.
Is my understanding of how the OPC interface works correct?
Has anyone else seen this issue or developed a solution?
It seems like the interface should be able to reload the itemid when an itemid not found error is returned. We are also communicating with out OPC Vender on solutions.