The task of modelling an Asset is more than just describing a single simple Asset. It is modelling the relationships between the Assets. In OPC UA, relationships can be modelled as References, where a Reference provides semantic information about the relationship. OPC UA has defined a number of References in OPC 10000-23 that can be used for modelling Assets. This list is extended by this document. The following ReferenceTypes will be illustrated in various examples in this annex:
- HasContainedComponent indicates that an Asset has another Asset contained in it.
- HasBuiltInAsset indicates that an Asset has an integrated Asset, which is not removable.
- HasPart indicates that an Asset has another Asset which can be removed.
- HasAttachedComponent indicates that an Asset has physically/mechanically attached an Asset.
- IsPhysicallyConnectedTo (symmetric) indicates that two Assets are physically connected to each other.
- ConnectedTo (symmetric) indicates that two Assets are connected to each other by an electrical cable.
- IsPartOfRedundantAssetSet indicates that an Asset is part of a group of Assets that form a redundant Asset.
Additional References may be defined or used to show additional relationships.