Data timestamps

The source PI Server provides a timestamp for each data event. These timestamps may be adjusted to account for time zone differences and clock drift between PI Servers. It is required that each PI Server have the correct system time for the configured time zone.

Timestamps are automatically adjusted for time zone differences when both source and receiving servers are PI3. PI3 timestamps are based on the number of seconds that have elapsed since Jan.1, 1970 UTC (Universal Coordinated Time). Each UTC time stamp contains a time offset from Greenwich Mean Time that represents the local time zone setting.

PI3 data includes time zone information that allows for automatic adjustment to local time.

The interface can also adjust for clock drift between PI Servers. Clock drift is the time offset between PI Servers after accounting for time zone differences. An offset of 15 minutes or less is considered clock drift. When the appropriate timestamp adjustment is configured, the time offset is added to the timestamp provided by the source PI Server adjusting it to receiving PI Server time. Timestamp adjustment is configured on a tag-by-tag basis using the Location2 tag attribute.

Note: All computers (interface node, source and receiving PI Server) must have the correct system time for the configured time zone.