industrial//industrial data layer//event

An event is a record of something that happens once in a process (MotorStarted, PumpStopped, HighPressureAlarm, ValveFault), stored on its own because not everything in a plant should be stored as a continuous stream of samples.

An event is a record of something that happens once in a process (MotorStarted, PumpStopped, HighPressureAlarm, ValveFault), stored on its own because not everything in a plant should be stored as a continuous stream of samples.

Events feed analysis, maintenance, alarm management, traceability and diagnostics. They are the natural unit for what happened during a shift, where a tag trend is the unit for the value a signal had at 18:03.

Alarms are events with a required human response and their own lifecycle (active, acknowledged, cleared). In a DCS alarm management is a discipline of its own; a badly rationalized alarm list floods operators during the one incident that matters.

On the data layer, events travel well over MQTT and OPC UA's alarms-and-conditions model, and they are the timeline that gives telemetry its context: the sample matters because of the event that framed it.