The ConnectsTo ReferenceType is a concrete ReferenceType used to indicate that source and target Node have a topological connection. It is NonHierarchical 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 48 and Table 49.

Table 48 – ConnectsTo ReferenceType

Attributes	Value
BrowseName	1:ConnectsTo
Symmetric	True
IsAbstract	False
References	NodeClass	BrowseName	Comment
Subtype of 0:NonHierarchicalReferences ReferenceType defined in OPC 10000-5.
Conformance Units
DI ConnectsTo

Table 49 – ConnectsToParent ReferenceType

Attributes	Value
BrowseName	1:ConnectsToParent
Symmetric	True
IsAbstract	False
References	NodeClass	BrowseName	Comment
Subtype of 1: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