This part of IEC 62541 is part of the overall OPC Unified Architecture (OPC UA) standard series and defines the information model associated with Data Access (DA). It particularly includes additional VariableTypes and complemental descriptions of the NodeClasses and Attributes needed for Data Access, additional Properties and other information and behaviour. The complete address space model, including all NodeClasses and Attributes, is specified in IEC 62541-3. The services to detect and access data are specified in IEC 62541-4.