Obsolete tags
Is there a way to restore tags that have been accidentally obsoleted fro the historian?
5 replies
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Hi bblakely ,
If you start logging data to the obsoleted tag, it in a sense resurrects that tag from obsoletion.
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, what if it doesn't resurrect them?
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Hi , I think the original post was from a pre-24 version using Sender/Receiver, not SaF. I was able to replicate the same error, but that may be the expected behavior with the new SaF service. Development will need to decide if they want to support this scenario the same way it was with the Sender/Receiver. For now, if you force the Historian to roll over the DataSet, it will create a new file without that tag in it, but then it should come right back once the buffer flushes.
What was the reason to obsolete the tag in the first place? If you delete the calculation and check the box to "Remove calc data" it will rename the tag and mark it for obsoletion. You can then recreate the calc and start fresh with the original tag name.
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The use case is me developing a calc using trial and error and needing to constantly create, rename, and delete tags - and move them between calcs. I'm guessing during one of these operations I didn't check that obsolete box.
I tried to rename the obsoleted tag so calcs could recreate it. But it errored out saying it couldn't because the tags was being logged to or accessed. Which didn't make sense because the calc service was off and the SaF session was purged. Now I'm thinking maybe I had the trend up in Axiom. Would that have locked it?
After I came back after a while I was able to rename the obsoleted trouble tag. And interestingly enough, renaming it made it unobsolete. Is that expected?
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I'm not sure what would've been holding on to an obsoleted tag. Once a tag is flagged for obsoletion, it is no longer available to clients.
Similarly, I don't know what is the expected behavior when you rename an obsoleted tag. That would not be a common use case. If anything, a tag would be renamed before being obsoleted. That is essentially what the calc service does when you delete the calculation and check the box to remove calculated data.
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