The ConnectsTo ReferenceTypeis a concrete ReferenceTypeused to indicate that source and target Node have a topological connection. It is both hierarchical and symmetric, because this is natural for this Reference. The ConnectsTo Referenceexists between a Networkand the connected Devices(or their ConnectionPoint, respectively). Browsing a Networkreturns the connected Devices; browsing from a Device, one can follow the ConnectsTo Referencefrom the Device’s ConnectionPointto the Network.

The ConnectsToParent ReferenceTypeis a concrete ReferenceTypeused to define the parent (i.e. the communication Device) of a Network. It is a subtype of The ConnectsTo ReferenceType.

The two ReferenceTypesare illustrated in Figure 23.

Figure 23– Type Hierarchy for ConnectsTo and ConnectsToParent References

The representation in the AddressSpaceis specified in Table 42and Table 43.

Table 42– ConnectsTo ReferenceType

Attributes	Value
BrowseName	ConnectsTo
Symmetric	True
IsAbstract	False
References	NodeClass	BrowseName	Comment
Subtype of 0:HierarchicalReferences ReferenceType defined in OPC 10000-5.
Conformance Units
DI ConnectsTo

Table 43– ConnectsToParent ReferenceType

Attributes	Value
BrowseName	ConnectsToParent
Symmetric	True
IsAbstract	False
References	NodeClass	BrowseName	Comment
Subtype of ConnectsTo ReferenceType
Conformance Units
DI ConnectsTo

Figure 24illustrates how this Referencecan be used to express topological relationships and parental relationships. In this example two Devicesare connected; the module DPcomm is the communication Devicefor the Network.

Figure 24– Example with ConnectsTo and ConnectsToParent References