History recovery

AVEVA™ PI System Connector 3 (PSC3) supports history recovery. The start time for the initial backfill of each point can be set using the History Recovery Start Time field located in the Shared Data Source Options tab.

If the PSC3 Windows service is stopped and restarted, the connector performs history recovery to obtain any of the events it missed during the downtime. In some cases, the history recovery will include/send the previous snapshot value the destination PI Server already received and archived, and this event may be resent by the real-time replication resulting in the same data event being stored twice. If this occurs, a [-109] Value at This Time Already Exists error could appear on the broker log.

Other data replication [-109] Value at This Time Already Exists errors may be generated as the result of changes to compression settings, to the gap in archive times indicated by archive markers, or to system shutdowns.

See Show or hide archive gaps in the PI System Management Tools Guide for additional information.