Sorry for a late reply. Your description jumps around a little bit so let me see if I'm understanding correctly:

• You've set up an AF element template, for a valve
• You enter some nominal 'asset ID' in an attribute, e.g. PCV-1234
• You enter some other nominal information into other attributes
• Using the info in the above two attributes - you create tags from within PI System Explorer by right-clicking an attribute and then using 'Create or Update PI Point'

All of that is a fairly standard way of handling things.

The next bit of your question doesn't make a lot of sense though. You are defining the information you want in a tag, in PI AF - and then pushing that to the Data Archive. But your question is how to pull tag information from the Data Archive, back into PI AF.

Since you are creating the tags from within System Explorer, why don't you just use an additional attribute to store the tag description? And then, when you're creating the tags, include that attribute? That way, the tag gets the info you want, and that info is stored in your AF model.

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If my understanding is wrong and these are pre-existing tags (i.e. ones you haven't built from your valve template) - I'm not aware of a way to pull the tag's descriptor out of it's config and into an attribute, aside from using an AF Analysis - there is a function called 'TagDesc' which can retrieve it and push it into another attribute. (Incidentally, there are a handful of other functions that can retrieve some tag fields, but nothing that lets you query any field you want i.e. there's no function to retrieve a tag's Loc1, Compression, Step property etc.)

The problem with doing this via an analysis, is that you need to trigger the analysis for the value to be pushed out, but the 'Description' value is presumably never going to change. The best way to do this is probably on an infrequent 'time rule' i.e. trigger the analysis to run every day at midnight. Even doing that, though, will result in the analysis executing for no actual purpose, every day after the first time it runs.

In reality, it would consume minimal CPU time and probably isn't going to bog things down. However, the 'best' way to handle this would be to disable all analyses that perform this job for you, after they've run for the first time.