It's a little odd, but at the time or writing there is no SnapShot retrieval type available for selection when creating a PHDTOREL query in the PHD Configuration tool (confirmed by Honeywell).

The values available are

Average
Maximum
Minimum
Delta
Raw
Standard Deviation
Regression Constant
Regression Slope
Regression Deviation
First
Last
Value

The description for Value is the same as Raw; "Requests the raw value", however what is actually does is return the first Raw value for that retrieval period.

Despite SnapShot being available for other APIs such as the .Net Wrapper and the PHD OLEDB providor, it is not available in PHDTOREL. Bit of a pain.

The closest to it is Average.