Event Log

An event log is the time ordered record of what a control system noticed: alarms raised and cleared, devices lost and recovered, mode changes, and limits reached.

Where the historian stores continuous measurements and the audit log stores human actions, the event log stores the discrete things that happened at the plant. Read as a timeline next to the measurement charts it answers what happened and when: the inverter faulted at 14:02, the battery hit its reserve at 14:05, the peak was missed at 14:15. Daily records summarize the same data one day at a time for reporting.

Also called: Alarm log, Event timeline