The Alarm and Condition model extends the OPC UA base Event model by defining various Event Types based on the BaseEventType. All of the Event Types defined in this standard can be further extended to form domain or Server specific Alarm and Condition Types.

Instances of Alarm and Condition Types may be optionally exposed in the AddressSpace in order to allow direct access to the state of an Alarm or Condition.

The following sub clauses define the OPC UA Alarm and Condition Types. Figure 8 informally describes the hierarchy of these Types. Subtypes of the LimitAlarmType and the DiscreteAlarmType are not shown. The full AlarmConditionType hierarchy can be found in Figure 8



Figure 8 – ConditionType hierarchy