This document is part of the OPC Unified Architecture standards series and defines the Information Model associated with Historical Access (HA). It particularly includes additional and complementary descriptions of the NodeClasses and Attributes needed for Historical Access, additional standard Properties, and other information and behaviour.

The complete AddressSpace Model including all NodeClasses and Attributes is specified in OPC 10000-3. The predefined Information Model is defined in OPC 10000-5. The Services to detect and access historical data and events, and description of the ExtensibleParameter types are specified in OPC 10000-4.

This document includes functionality to compute and return Aggregates like minimum, maximum, average etc. The Information Model and the concrete working of Aggregates are defined in OPC 10000-13.

Conventions for Historical Access Clients are informatively provided in Annex A.