Recovery Time

Recovery Time is the time into the past starting from current time that the interface should attempt to recover events for each PIUnit.

When the interface is shutdown for a certain period of time and restarted, it attempts to recover batches occurred during the shutdownperiod. The recovery is done by checking the archivedvalues for the Active Points. Recovery Time is the time that the interface looks back into the past from the restart time of the interface for the archived events. Some batch data may not be generated if the Recovery Time is shorter than the shutdown period.

During recovery, if there is a running PIUnitBatch, the recovery starts from the start time of that running PIUnitBatch irrespective of the Recovery Time specified.

If there is no running PIUnitBatch, the interface searches for PIUnitBatches on the PIUnit up to Recovery Time into the past. If the search finds PIUnitBatches within that period, recovery is done from the end time of the last PIUnitBatch.

If there are no PIUnitBatches in the search results, then recovery is done for Recovery Time into the past. For example, if the Recovery Time is 4 days, and if the shutdown period is less than 4 days and the last PIUnitBatch on a PIUnit was 2 days ago, then the recovery for that PIUnit is done only for the past 2 days. In this case, the recovery for each PIUnit depends on when the last PIUnitBatch started.

If the shutdown period is 7 days, then PIBaGen will recover batch data only for the past 4 days. There will be no batch recovery for the first 3 days of the shutdown period. This option helps in reducing the time it takes to recover if the shutdown time is long and recovery during the entire shutdown time is not critical. The default recovery time is 4 days.