Several minor variations from the OPC HDA specification are documented in the following table.
| Description | OPC HDA specification Expected Value | DeltaV OPC HDA Returned Value |
|---|---|---|
| The time stamp of an interpolated value coincides with that of a raw sample. | 0x400C0 "Raw, Good" | 0x200C0 "Interpolated, Good"
0x800C0 "Calculated, Good" |
| The aggregate time interval starts past the last recorded sample. | 0x20040 "Interpolated, Uncertain" | 0x200C0 "Interpolated, Good" |
| An aggregate value is for a time span that includes a Bad value. | Bad values are omitted from calculation of aggregates. | All values are included, regardless of the FF status. |