IEC 62541-3:2025

IEC 62541-3:2025

December 2025
International standard Current

OPC unified architecture - Part 3: Address Space Model

IEC 62541-3: 2025 describes the OPC Unified Architecture (OPC UA) AddressSpace and its Objects. This specification is the OPC UA meta model on which OPC UA information models are based. 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) addition of the concept and modelling elements for Interfaces and AddIns;b) addition of Currency;c) addition of Method Meta Data to define additional attributes for Method Arguments;d) addition of ApplyRestrictionToBrowse bit to AccessRestrictionType;e) addition of a Non-Volatile Storage bit to AccessLevelExType;f) addition of a Constant bit and ConfigurationConstant bit to AccessLevelExType;g) the View NodeClass has been changed to define the EventNotifier as an EventNotifierType in the same way the Object NodeClass defines it;h) correctition of HasNotifier, HasEventSource, and Organizes, to include ObjectType as valid source node;i) NamingRules have become deprecated;j) addition of AssociatedWith ReferenceType.

Main informations

Collections

International IEC standards

Publication date

December 2025

Number of pages

285 p.

Reference

IEC 62541-3:2025

ICS Codes

35.100.05   Multilayer applications
25.040.40   Industrial process measurement and control

Print number

1
Sumary
OPC unified architecture - Part 3: Address Space Model

IEC 62541-3: 2025 describes the OPC Unified Architecture (OPC UA) AddressSpace and its Objects. This specification is the OPC UA meta model on which OPC UA information models are based. 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) addition of the concept and modelling elements for Interfaces and AddIns;
b) addition of Currency;
c) addition of Method Meta Data to define additional attributes for Method Arguments;
d) addition of ApplyRestrictionToBrowse bit to AccessRestrictionType;
e) addition of a Non-Volatile Storage bit to AccessLevelExType;
f) addition of a Constant bit and ConfigurationConstant bit to AccessLevelExType;
g) the View NodeClass has been changed to define the EventNotifier as an EventNotifierType in the same way the Object NodeClass defines it;
h) correctition of HasNotifier, HasEventSource, and Organizes, to include ObjectType as valid source node;
i) NamingRules have become deprecated;
j) addition of AssociatedWith ReferenceType.
Replaced standards (1)
IEC 62541-3:2020
July 2020
International standard Cancelled
OPC Unified Architecture - Part 3: Address Space Model

IEC 62541-3:2020 defines the OPC Unified Architecture (OPC UA) AddressSpace and its Objects. This document is the OPC UA meta model on which OPC UA information models are based. This third edition cancels and replaces the second edition published in 2015. This edition includes the following significant technical changes with respect to the previous edition: a) Added new improved approach for exposing structure definitions. An Attribute on the DataType Node now simply contains a binary description. b) Added new flags for Variables to indicate atomicity when reading or writing. c) Added Roles and Permissions to allow configuration of a role-based authorization. d) Added new data types: “Union”, “Decimal”, “OptionSet”, “DateString”, “TimeString”, “DurationString”, NormalizedString”, “DecimalString”, and “AudioDataType”. e) Added definition on how to use the ModellingRules OptionalPlaceHolder and MandatoryPlaceHolder for Methods. f) Added optional Properties “MaxCharacters” and “MaxByteStringLength” to Variable Nodes.

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