Can anyone explain why you can trend String Type values in PI Processbook and not in PI Vision?
I don't know Processbook, but let's reverse the question: what do you expect for trending of string values? Because i'm clueless.
Can you given an example of what you need?
If you use Digital states / AF Enumerations you can sort-of trend strings, but i'm not sure if that is what you mean.
This is how PARCview does it. Works well.
How is this different from how PI Vision trends string values? It generally works the same way as PI ProcessBook. As Jim Gavigan mentioned, it's rather unpredictable where a value will be shown and enumeration sets are generally a better option.
I have trended string values for a long time in PI Vision. I do find that enumeration sets make the trend more uniform. We do it often for batch phases or status on equipment. For a batch, if I want the idle phase to be "zero," the first phase to be the first "step" on the trend, etc., then enumeration sets configured properly will allow that. If I just use string values for batch phases, it can be a crapshoot on how they show up, depending on when my trend starts/ends, etc. The idle phase might be a middle value in a trend as a for instance and one of the middle phases is on the zero line.
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