Setting Description
VT_R4,VT_R8,VT_I2, VT_I4 Value represents the interval length in number of seconds. The calculation is performed at evenly spaced intervals of the specified size. Against a PI 3.x server, the intervals are computed as evenly spaced UTC time intervals. Against a PI2.x server, the intervals are computed as evenly spaced wall clock time intervals.
VT_BSTR The string is interpreted as a time interval containing an interval count and the interval type name, for example "1d" or "24h". How the string is interpreted depends on the PI server type and the interval type. See the Remarks section below for details. A blank string has the same meaning as a VT_NULL below.
VT_NULL, VT_EMPTY Calculation interval length is set to the difference between the start time and the end time specified. This provides a quick way for the user to specify a single calculation interval.
Enabling Operational Intelligence