EventCategories in the A&E COM Serverare represented in the UA Serveras ObjectTypeswhich are subtypes of BaseEventType. The BrowseNameand DisplayNameof the ObjectType Nodefor Simple and Tracking EventTypes are constructed by appending the text ‘EventType’ to the Description of the EventCategory. For Condition EventTypes the text ‘AlarmType’ is appended to the ConditionName.
These ObjectType Nodes have a super type which depends on the A&E EventType, the EventCategory Description and the ConditionName; however, the best mapping requires knowledge of the semantics associated with the EventCategories and ConditionNames. If an A&E COM UA Wrapper does not know these semantics then Simple EventTypes are subtypes of BaseEventType, Tracking EventTypes are subtypes of AuditEventTypeand Condition EventTypes are subtypes of the AlarmType. Table D.1defines mappings for a set of “well known” Category description and ConditionNames to a standard super type.
Table D.1– Mapping from standard Event categories to OPC UA Event types
|
COM A&E Event Type |
Category Description |
Condition Name |
OPC UA EventType |
|
Simple |
--- |
--- |
BaseEventType |
|
Simple |
Device Failure |
--- |
DeviceFailureEventType |
|
Simple |
System Message |
--- |
SystemEventType |
|
Tracking |
--- |
--- |
AuditEventType |
|
Condition |
--- |
--- |
AlarmType |
|
Condition |
Level |
--- |
LimitAlarmType |
|
Condition |
Level |
PVLEVEL |
ExclusiveLevelAlarmType |
|
Condition |
Level |
SPLEVEL |
ExclusiveLevelAlarmType |
|
Condition |
Level |
HI HI |
NonExclusiveLevelAlarmType |
|
Condition |
Level |
HI |
NonExclusiveLevelAlarmType |
|
Condition |
Level |
LO |
NonExclusiveLevelAlarmType |
|
Condition |
Level |
LO LO |
NonExclusiveLevelAlarmType |
|
Condition |
Deviation |
--- |
NonExclusiveDeviationAlarmType |
|
Condition |
Discrete |
--- |
DiscreteAlarmType |
|
Condition |
Discrete |
CFN |
OffNormalAlarmType |
|
Condition |
Discrete |
TRIP |
TripAlarmType |
There is no generic mapping defined for A&E COM sub-Conditions. If an EventCategory is mapped to a LimitAlarmTypethen the sub Conditionname in the Eventare be used to set the state of a suitable State Variable. For example, if the sub-Conditionname is “HI HI” then that means the HighHighstate for theLimitAlarmTypeis active
For Condition EventTypes the EventCategory is also used to define subtypes of BaseConditionClassType.
Figure D.1illustrates how ObjectType Nodescreated from the EventCategories and ConditionNames are placed in the standard OPC UA HasNotifierhierarchy.
