IEC 62541-3-2020 OPC unified architecture – Part 3: Address Space Model

IEC 62541-3-2020 OPC unified architecture – Part 3: Address Space Model. The Data Type column contains the name of the DataType of the Attribute or Property. It is not used for References. The Description column contains the description of the Attribute, the Reference or the Property. Only this document may define Attributes. Thus, all Attributes of the NodeClass are specified in the table and can may only be extended by other parts of this series of standards the IEC 62541 series. This document also defines ReferenceTypes, but ReferenceTypes can may also be specified by a Server or by a Client using the NodeManagement Services specified in IEC 62541 ‑4. Thus, the NodeClass tables contained in this document can may contain the base ReferenceType called References identifying that any ReferenceType may be used for the NodeClass, including system specific ReferenceTypes. The NodeClass tables only specify how the NodeClasses can be used as SourceNodes of References, not as TargetNodes. If a NodeClass table allows a ReferenceType for its NodeClass to be used as SourceNode, this is also true for subtypes of the ReferenceType. However, subtypes of the ReferenceType may restrict its SourceNodes. This document defines Properties, but Properties can be defined by other standards organizations or vendors and Nodes can have Properties that are not standardized. Properties defined in this document are defined by their name, which is mapped to the BrowseName having the NamespaceIndex 0, which represents the Namespace for OPC UA. The Use column (optional or mandatory) does not imply a specific ModellingRule for Properties. Different Server implementations will choose to use ModellingRules appropriate for them. 4 AddressSpace concepts 4.1 Overview The remainder of Clause 4 defines the concepts of the AddressSpace. Clause 5 defines the NodeClasses of the AddressSpace representing the AddressSpace concepts. Clause 6 defines details on the type model for ObjectTypes and VariableTypes. Standard ReferenceTypes, DataTypes and EventTypes are defined in Clauses 7 to 9. The informative Annex A describes general considerations on how to use the Address Space Model and the informative Annex B provides a UML Model of the Address Space Model. The normative Annex C defines the OPC Binary Types Description System as a format to specify data type structures and the normative Annex D defines a graphical notation for OPC UA data. 4.2 Object Model The primary objective of the OPC UA AddressSpace is to provide a standard way for Servers to represent...