IEC 62541-11 ED3

OPC unified architecture - Part 11: Historical access

Scope

IEC 62541-11: 2025 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 IEC 62541‑3. The predefined Information Model is defined in IEC 62541‑5. The Services to detect and access historical data and events, and description of the ExtensibleParameter types are specified in IEC 62541‑4.
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 IEC 62541‑13.
Conventions for Historical Access Clients are informatively provided in Annex A.
This fourth edition cancels and replaces the third edition published in 2020. This edition constitutes a technical revision.
This edition includes the following significant technical changes with respect to the previous edition:
a) a functionality has been added to support retrieving of modified events;
b) an Event has been added to indicate when a backfill occurred;
c) a new ReferenceType that can be used to indicate an external node has been defined;
d) the text has been improved to better explain the concept of annotation and remove conflicting explanations;
e) a default historian configuration (and where to find it) has been defined;
f) HistoricalEventConfigurationType, which provides general configuration information about the historical Event storage, has been added;
g) the text has been updated and optional fields have been added to HA configuration object to allow configuration to be defined for periodic data collection, not just for exception-based collection;
h) an ObjectType that can be used for external event collection has been provided as well as an example how historians can be configured.