OPC UA Servers and the underlying systems that they expose can be conveniently configured using AutomationML (AML) through the use of standardized AML libraries built to mirror the OPC UA modelling concepts defined in OPC 10000-3 and OPC 10000-5. Table A.1 shows the OPC UA modelling concept and the AML modelling concept used to realize the OPC UA counterpart in the AML libraries.

Table A.1 – Mapping OPC UA modelling concepts to AML

UA Modelling Concept	AML Modelling Concept
DataType	AttributeType
ObjectType	SystemUnitClass
VariableType	SystemUnitClass
Method	SystemUnitClass
InterfaceType	RoleClass plus SystemUnitClass
ReferenceType	InterfaceClass(es)

These mappings are general rules and are not always explicitly followed due to mismatches in the capabilities of OPC UA vs. AML. For instance, ReferenceTypes in OPC UA can be used to connect any two nodes in the UA AddressSpace, but AML InterfaceClasses can only be used within nodes of the InstanceHierarchy or between nodes in a single SystemUnitClass. These mismatches lead to occasional exceptions to these rules and shall be explicitly denoted whenever they occur.

OPC UA Objects, Variables and Methods used in instance declarations are mapped to AML InternalElements in the respective SystemUnitClass.