The ReferenceDescriptionVariableTypeis a subtype of the BaseDataVariableType. It is used as container to expose additional information of a Reference. The Valuecontains the description of the Referencethe Variablerepresents.

The Referenceas defined in the Valueshall be exposed in the OPC UA Server containing the Variable. The IsForwardfield in the Valueindicates the browsable direction of the Reference. It is not required that the opposite direction is browsable. The VariableTypeis formally defined in Table 14.

Table 14– ReferenceDescriptionVariableType Definition

Attribute

Value

BrowseName

ReferenceDescriptionVariableType

IsAbstract

FALSE

ValueRank

−1 (−1 = Scalar)

DataType

ReferenceDescriptionDataType

References

NodeClass

BrowseName

DataType

TypeDefinition

Other

Subtype of the BaseDataVariableType defined in OPC 10000-5

HasProperty

Variable

ReferenceRefinement

ReferenceListEntryDataType[]

PropertyType

O

Conformance Units

Base Info ReferenceDescription

The optional Property ReferenceRefinementcontains an array of Referencesrefining the original Referencerepresented by an instance of ReferenceDescriptionVariableType. Each entry in the array contains the ReferenceType, direction and TargetNode. The SourceNodeof the first entry in the array is the SourceNodeof the Valueof the instance of ReferenceDescriptionVariableType. The SourceNodeof all other entries is the TargetNodeof the previous entry. The TargetNodeof the last entry shall be the TargetNodeof the instance of ReferenceDescriptionVariableType.