When I use GetPIarchiveData with "retrievaltype="interpolated" and an "AF:" path, I seem to get "Data query Mode not supported", unless the attribute is a straight-forward "pi-point" attribute.
I tested it with a paths to
- a formula data reference which is dividing a pi value by 2
- a pipoint attribute with a relative time offset
- a static value
these all worked for "retrievalmode= compressed" but gave "Data query Mode not supported" when "retrievaltype="interpolated"
am I doing something wrong or is this expected behaviour?
I'm looking for something like the the functionality of OLEDB-E InterpolateRange() - to return values of an attribute at fixed interval within a time range - calling attribute.Getvalues.
Is there any way of doing this ? or should I write my own web-service calling OLEDB-E or even direct to AF-Sdk ?