Historian Aggregation

[Praveen Kumar Karthikeyan]

Hi Guys
While Aggregating the Values from the historian I am having the option of Sum, Avg, Min, Max. But We Need the Number of Samples and Standard Deviation of all the values that are to be aggregated. Any possible ways to do so?

[ursulak]

I suppose you would need create additional variables, e.g. MATH driver can calculate it in 'statistics' formulas. 
Help: MATHDR32 -> Driver-specific functions -> Formulas -> Float formula -> Statistics 

The Count() formula is detecting and counting limits of source variables. A variable can be linked to rema detecting any value change as limit. Formula counts together on these limits (states in reaction matrix) where property 'State number for counter in the mathematics driver' is used.

Is this Historian recording in cycle or 'on change'?

[Praveen Kumar Karthikeyan]

no its cyclic changing