Is there a way to find out from Datalink whether the tag is calculated / direct tag?...
One can search in SMT filtering by their Point-sources.
There are PointSources reserved for specific type of tags.
You would need to know the PI Pointsource(s) for the Performance Equation scheduler(s), and be able to search any AF Analysis Processors for output attributes that are referencing PI Points. If you're lucky a good system administrator will have set all outputs from AF Analyses to specific PointSource(s), but even then it isn't a guaranteed way to find all calculations. Then you have the possibility of external systems calculating & writing back to the PI Data Archive...but that depends how far back the data chain you want to know where a calculation occurs.
Good tag naming conventions can help aswell!
eg.. TAGNAME.CALC | TAGNAME.TOT | TAGNAME.ACE | TAGNAME.AFCALC
It should be obvious to most people what sort of tag those are!
A more obvious way at least for performance equations/totalizers within datalink, you can either output the tag attribute (using standard datalink functions) exdesc or from the tag search dialogue, right click the tag and check the tag properties. In theory, anything with something like tagavg('tagname'),'*-1d','*') in the exdesc would be a calc tag. Totalizers can be easily identified by the point source T or the various other attributes you will see which are not found in "classic" PI points. If exdesc is empty then check instrument tag and point source, if pointsource is something like OPC and instrument tag something like Node1.30.TI1001.PV then you have a raw tag
This is a narrow view on where calculations can be performed. You have to look much wider in a modern PI System.
I believe that Amit's suggestion should accomplish your goal. That being said, what types of calculated tags do you have? Do you have any AF analyses that are outputting to tags?
Retrieving data ...