The ConnectsTo ReferenceType is a concrete ReferenceType used 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 Reference exists between a Network and the connected Devices (or their ConnectionPoint, respectively). Browsing a Network returns the connected Devices; browsing from a Device, one can follow the ConnectsTo Reference from the Device’s ConnectionPoint to the Network.

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

The two ReferenceTypes are illustrated in Figure 23.

Figure 23 – Type Hierarchy for ConnectsTo and ConnectsToParent References

The representation in the AddressSpace is specified in Table 39 and Table 40.

Table 39 – ConnectsTo ReferenceType

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

Table 40 – ConnectsToParent ReferenceType

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

Figure 24 illustrates how this Reference can be used to express topological relationships and parental relationships. In this example two Devices are connected; the module DPcomm is the communication Device for the Network.

Figure 24 – Example with ConnectsTo and ConnectsToParent References