IEC 62541-11-2025 PDF

Full title and description

St IEC 62541-11-2025 — OPC unified architecture - Part 11: Historical Access. Defines the OPC UA Information Model and behaviour for discovering, accessing, configuring and managing historical data and historical events (historians, historical configuration, annotations, modified events and aggregates). This edition updates and extends the previous edition with features for modified events, backfill notification, historian configuration and external event collection.

Abstract

IEC 62541-11:2025 specifies the historical access information model for OPC UA, including HistoricalDataNodes, HistoricalEventNodes, configuration objects, references for historical data, annotations, time-stamping and bounding semantics, and support for aggregate computations. Informative annexes provide client conventions and examples. The 2025 text is a technical revision that adds support for modified events, backfill events, a new external-node ReferenceType, default historian configuration and additional configuration options for periodic collection.

General information

• Status: Published (International Standard).
• Publication date: 23 December 2025.
• Publisher: International Electrotechnical Commission (IEC).
• ICS / categories: 25.040.40; 35.100.05.
• Edition / version: Edition 3.0 (2025) — technical revision of the previous edition.
• Number of pages: 73 (standard edition PDF).

Scope

This part of IEC 62541 defines the Information Model associated with Historical Access (HA) for OPC UA servers and historians. It covers the representation of historical time series data and historical event records in the AddressSpace, mechanisms to read raw and processed historical values and events (including modified events), configuration objects for historizing, timestamps and bounding semantics, aggregation behaviour (min/max/avg and other aggregates defined in Part 13) and conventions for clients. Informative annexes provide mapping examples and recommended client behaviours.

Key topics and requirements

• Historical Information Model: HistoricalNodes, HistoricalDataNodes, HistoricalEventNodes, standard properties and attributes for historized items.
• History services and parameters: HistoryRead/HistoryUpdate semantics, continuation points, HistoryReadDetails structures and handling of modified events and annotations.
• Aggregation support: Definitions and behaviour to compute and return aggregates (min, max, average, etc.) in cooperation with IEC 62541-13.
• Configuration objects: HistoricalDataConfigurationType, HistoricalEventConfigurationType and default historian configuration to define collection modes (exception-based and periodic).
• Events and auditing: Backfill notification events, audit events and support for tracking modifications to historical records.
• References and external collection: New ReferenceType for indicating external nodes and ObjectType examples for external event collection.
• Client conventions and examples: Informative guidance for Historical Access clients and example AddressSpace patterns.

Typical use and users

Used by implementers of OPC UA servers, historian vendors, system integrators, automation and process control engineers, SCADA and MES product teams, and application developers who require standardized access to historical time-series data and historical events. Typical deployments include process historians, data archival systems, analytic platforms, and cross-system data exchange where consistent historization semantics and aggregates are required.

Related standards

Closely related IEC 62541 series parts: Part 1 (Overview and concepts), Part 3 (Address Space Model), Part 4 (Services), Part 5 (Information Model), Part 13 (Aggregates). Also aligns with alarm/operational standards and mappings such as IEC 62541-9 (Alarms & Conditions) and IEC 62682 (Alarm management) for interoperable alarm and event handling.

Keywords

OPC UA, Historical Access, historian, historization, historical data, historical events, aggregates, annotations, HistoryRead, HistoryUpdate, backfill, modified events, HistoricalEventConfiguration, HistoricalDataConfiguration.

FAQ

Q: What is this standard?

A: IEC 62541-11:2025 is the OPC Unified Architecture (OPC UA) part that defines the Information Model and behaviour for Historical Access — how historical data and events are represented, accessed and configured in OPC UA AddressSpaces.

Q: What does it cover?

A: It covers historical data/event node types, history services (read/update), annotations, modified-event retrieval, backfill notifications, historian configuration objects, aggregate support (in conjunction with Part 13), and informative client conventions and examples.

Q: Who typically uses it?

A: Historian and OPC UA server implementers, system integrators, automation vendors, SCADA/MES developers and any party needing standardized access to time-series and event history in industrial systems.

Q: Is it current or superseded?

A: This is the published 2025 edition (edition 3.0 as listed by the IEC store) and is the current active international standard for Part 11; it is a technical revision of the earlier edition. Check IEC or your national standards body for confirmations and any national adoption (e.g., EN/BS adoption) if required.

Q: Is it part of a series?

A: Yes — IEC 62541 is a multipart series that defines the OPC UA architecture. Part 11 works together with Parts 1, 3, 4, 5, 9, 13 and others to provide complete OPC UA functionality.

Q: What are the key keywords?

A: OPC UA, Historical Access, historian, historical data, historical events, aggregates, annotations, HistoryRead, HistoryUpdate, backfill, modified events.