This is a subtype of AuditHistoryUpdateEventType and is used for categorization of history value update related Events. This type follows all the behaviour of its parent type. Its representation in the AddressSpace is formally defined in Table 17.

Table 17 – AuditHistoryValueUpdateEventType definition

Attribute	Value
BrowseName	AuditHistoryValueUpdateEventType
IsAbstract	False
References	NodeClass	BrowseName	DataType	TypeDefinition	ModellingRule
Subtype of the AuditHistoryUpdateEventType defined in OPC 10000-3, i.e. it has HasProperty References to the same Nodes.
HasProperty	Variable	UpdatedNode	NodeId	PropertyType	Mandatory
HasProperty	Variable	PerformInsertReplace	PerformUpdateType	PropertyType	Mandatory
HasProperty	Variable	NewValues	DataValue[]	PropertyType	Mandatory
HasProperty	Variable	OldValues	DataValue[]	PropertyType	Mandatory
ConformanceUnits
Historical Access Data Audit Events

This EventType inherits all Properties of the AuditHistoryUpdateEventType. Their semantic is defined in OPC 10000-3.

The UpdatedNode identifies the Attribute that was written on the SourceNode.

The PerformInsertReplace enumeration reflects the parameter on the Service call.

The NewValues identify the value that was written to the Event.

The OldValues identify the value that the Event contained before the write. It is acceptable for a Server that does not have this information to report a null value. In the case of an insert it is expected to be a null value.

Both the NewValues and the OldValues will contain a value in the DataType and encoding used for writing the value.