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How to get the last known value after a Scan Timeout on Data link

Question asked by PIAdminEnelGP on Jul 25, 2019
Latest reply on Jul 29, 2019 by rschmitz

Hello PI Square,


We are currently using DataLink to report the production of our machines. The production tag is a counter of the monthly produced energy and is updated each 10 minutes. We need to get the last value from the previous day, however when the machine is in maintenance the tag shows Scan Timeout , as the last known value is "frozen". However if the machine gets its maintenance during the night and they turn it on during the day the tag gets more than 1 Scan Timeout values.



We are using the Archive Value on DataLink and the retrieval mode is the previous value.



For this tag in particular the result would be Scan Timeout. As the last value before midnight is that one, however we have 3 Scan Timeout values but we need the last known value from the day, that in this case would be 104348. Is there is a way with Performance Equations or any other OSIsoft tool to get this Last Known value that is not a 'Scan Timeout' or other value? 


As a side note I could use the same solution on some tags that aren't being updated since a long time as their last value is snapfix and they don't have values since may 2018.



Hopefully you can understand what I'm trying to do and I would appreciate if you can help me to find a solution for it. 



Alan López