Events

Event instances represent individual things that happen, like alarms, alerts, or operational issues, based on event types defined in the schema. The schema describes what an event looks like, but Instance messages capture when an event actually occurs.

Event instances are sent using Instance messages and appear in the Events array. Each event represents a single occurrence and can include lifecycle details such as when the event started and, if applicable, when it ended. Events can also be connected to related entities or data streams using relationships defined in the schema.

Each event instance references an event type defined in the schema and includes:

• A unique event identifier (id)

• A start time and, when applicable, end time

• Optional descriptive fields such as description

• Event-specific property values defined by the event type

An event may remain active (with no end time) or be closed later by updating the same event instance with an end time.

Event instances can be linked to related entities or data streams using instance relationships, making it possible to associate alarms or conditions with the assets or measurements they affect. As with entity instances, these links must conform to schema-defined relationship patterns and are expressed in the Relationships array.

{

"events": [

{

"typeid": "HighPressureAlarm",

"id": "Alarm-HP-Tank1-001",

"starttime": "2024-05-01T14:32:10Z",

"endtime": null,

"description": "High pressure alarm triggered for Tank1",

"properties": {

"AlarmId": "HP-TANK1-01",

"Severity": 3,

"Message": "Pressure exceeds safe operating limits"

}

}

],

"relationships": [

{

"source": {

"collection": "events",

"id": "Alarm-HP-Tank1-001"

},

"target": {

"collection": "entities",

"id": "Plant2.Tank1"

}

}

]

}