So I’m trying to work with intermittent communication with my plcs and to solve the problem I want to get the last good value if the current state is bad quality. I wrote a script that will get me either the current value if it’s good or the last historical if its not.
But here’s my problem. If I make an expression tag that is set to this value then I have to get the full tag path to the OPC tag that contains the value using expressions and I can’t figure out what the reference is for that.