Should an event frame have PI Point attributes?

Discussion created by rdavin Employee on Jun 20, 2013
Latest reply on Jun 24, 2013 by RJKSolutions

In another thread (http://vcampus.osisoft.com/discussion_hall/development_with_osisoft_sdks/f/28/p/4190/22305.aspx#22305) I claimed that it is highly discouraged for an event frame's attributes to be something other than a null data reference.  Certainly that statement has some small exceptions: formulas to quickly calculate something.  But I thought having PI Points or other historical items on an event frame are discouraged.  I thought for sure this was written down somewhere and tried to find something to back up my claim.  I can't find it in writing anywhere but perhaps I am looking in the wrong places.


To me, if you have something historical, it doesn't belong on an event frame.  Rather it should be on an element.  I think of a single PI Value as a value for some point in time.  Likewise I think of attribute values on an event frame as being a value for some vector or segment in time.  If you do have a PI Point on an event frame, is it possible to get values outside the StartTime-EndTime of the frame?


I didn't think there was technically anything stopping someone from having a PI Point on an event frame.  But is it a good or recommended design?