Event category mapping – OPC Unified Architecture

D.3.4 Event category mapping

Each A&E Event type (e.g. Simple, Tracking, Condition) has an associated set of Event categories which are intended to define groupings of A&E Events. For example, Level and Deviation are possible Event categories of the Condition Event type for an A&E COM Server. However, since A & C does not explicitly support Event categories, the A&E COM UA Proxy uses A & C Event types to return A&E Event categories to the A&E COM Client. The A&E COM UA Proxy builds the collection of supported categories by traversing the type definitions in the address space of the UA A & C Server. Figure D.3 shows the mapping as follows:

A&E Tracking categories consist of the set of all Event types defined in the hierarchy of subtypes of AuditEventType and TransitionEventType, including AuditEventType itself and TransitionEventType itself.
A&E Condition categories consist of the set of all Event types defined in the hierarchy of subtypes of ConditionType, including ConditionType itself.
A&E Simple categories consist of the set of Event types defined in the hierarchy of subtypes of BaseEventType excluding AuditEventType and ConditionType and their respective subtypes.

Figure D.3 – Example mapping of UA Event Types to COM A&E categories

Category name is derived from the display name Attribute of the Node type as discovered in the type hierarchy of the UA A & C Server.

Category description is derived from the description Attribute of the Node type as discovered in the type hierarchy of the UA A & C Server.

The A&E COM UA Proxy assigns Category IDs.