We are creating an application that predicts a tag's next value. One of the inputs to the algorithm is based on several of the tag's recent values. As I understand it, if I as for the value of a regular archived point for "now" or for "now+ some small delta", I get Pi's estimate for the value as long as the last good value in the cache is "close enough" to "now+delta". In other words:
given a good reading at time T1 < '*', I can still ask for (and receive) the value TagVal(mytag,'*') as long as '*'-T1 is < some maximum delta (call it Max_delta).
1) What is Max_delta?
2) How big can delta be to create a No Data error for TagVal(mytag,'*+d')?