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5.8 Alarm model ToC Previous Next

5.8.7 Unsuppress Method ToC Previous Next

The Unsuppress Method is used to clear the SuppressedState of a specific Alarm instance. It is only available on an instance of an AlarmConditionType that also exposes the SuppressedState. This Method can be used to overwrite any suppression cause by an associated AlarmSuppressionGroup. This Method works in parallel with any suppression triggered by an AlarmSuppressionGroup, in that if the Method is used to clear the SuppressedState of an Alarm, any change in an AlarmSuppressionGroup might again suppress the Alarm.

Normally, the NodeId of the ObjectInstance is passed as the ObjectId to the Call Service. However, some Servers do not expose Condition instances in the AddressSpace. Therefore, Servers shall allow Clients to call the Unsuppress Method by specifying ConditionId as the ObjectId. The Method cannot be called with an ObjectId of the AlarmConditionType Node.



Method Result Codes in Table 43 (defined in Call Service)

Table 45 – Unsuppress result codes

Result Code Description
Bad_MethodInvalid The MethodId provided does not correspond to the ObjectId provided. See OPC 10000-4 for the general description of this result code.
Bad_NodeIdInvalid Used to indicate that the specified ObjectId is not valid or that the Method was called on the ConditionType Node.
See OPC 10000-4 for the general description of this result code.


Unsuppress Method applies to an Alarm instance, even if it is not currently active.

Table 44 specifies the AddressSpace representation for the Suppress Method.

Table 46 – Unsuppress Method AddressSpace definition

Attribute Value
BrowseName Unsuppress
References NodeClass BrowseName DataType TypeDefinition ModellingRule
AlwaysGeneratesEvent ObjectType AuditConditionSuppressionEventType Defined in 5.10.4    

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