SIST EN IEC 62541-13:2026

OPC unified architecture - Part 13: Aggregates (IEC 62541-13:2025)

This part of IEC 62541 is part of the overall OPC Unified Architecture specification series and defines the information model associated with Aggregates.
Programmatically produced aggregate examples are listed in Annex A.

OPC Unified Architecture - Teil 13: Aggregation von Daten (IEC 62541-13:2025)

Architecture unifiée OPC - Partie 13: Agrégats (IEC 62541-13:2025)

L'IEC 62541-13:2025 définit le modèle d'information associé aux Agrégats. Des exemples d'agrégats produits par programme sont répertoriés à l'Annexe A. Cette troisième édition annule et remplace la deuxième édition parue en 2020. Cette édition constitue une révision technique.
Cette édition inclut les modifications techniques suivantes par rapport à l'édition précédente:
a) corrections multiples pour le calcul des agrégats
• le bit de statut "Raw" est toujours défini pour les StatusCodes autres que "bad" des agrégats de Début et de Fin;
• les entrées des tableaux d'exemples pour "Interpolative" en A2.2 Historique 1, Historique 2 et Historique 3 ont été modifiées pour passer du code de statut "Good" au code de statut "Good, Raw" lorsque l'horodatage correspond à l'horodatage de la source de données;
• des tableaux manquants ont été ajoutés pour DurationInStateZero et DurationInStateNonZero;
• la valeur zéro a été supprimée pour les résultats avec un StatusCode "bad";
• le type de données était indiqué comme étant "Code de statut" alors qu'il est "Double" pour les deux Agrégats d'Écart type et les deux Agrégats de Variance;
• les erreurs d'arrondi dans TimeAverage et TimeAverage2 ont été corrigées;
• les codes de statut ont été corrigés pour les deux derniers intervalles et la valeur a été corrigée dans le dernier intervalle;
• la formulation a été modifiée pour plus de cohérence avec l'outil d'essai de certification;
• UsedSlopedExtrapolation mis à "true" pour Historian2 et tous les emplacements d'exemples nécessitant de nouvelles valeurs ou de nouveaux statuts ont été modifiés,
• les valeurs influencées par PercentGood et PercentBad ont été mises à jour;
• PercentGood/PercentBad sont désormais pris en compte dans le calcul;
• TimeAverage utilise SlopedInterpolation, mais l'agrégat "Time" est autorisé à tort à utiliser SteppedInterpolation;
• le bit Partial est désormais calculé correctement;
• la phrase peu claire a été supprimée;
• les exemples ont été déplacés dans un fichier CSV;
• la valeur et le code de statut d'Historique 3 ont été mis à jour;
• TimeAverage2 (Historique 1) prend désormais en compte les régions incertaines dans le calcul des StatusCodes;
• TimeAverage2 (Historique 2) prend désormais en compte les régions incertaines dans le calcul des StatusCodes;
• Total2 (Historique 1) prend désormais en compte les régions incertaines dans le calcul des StatusCodes;
• Total2 (Historique 2) prend désormais en compte les régions incertaines dans le calcul des StatusCodes;
• Maximum2 (Historique 1) prend désormais en compte les régions incertaines dans le calcul des StatusCodes;
• MaximumActualTime2 (Historique 1) prend désormais en compte les régions incertaines dans le calcul des StatusCodes;
• Minimum2 (Historique 1) prend désormais en compte les régions incertaines dans le calcul des StatusCodes;
• MinimumActualTime2 (Historique 1) présente désormais les StatusCodes calculés en ut

Enotna arhitektura OPC - 13. del: Agregati (IEC 62541-13:2025)

Ta del standarda IEC 62541 je del celotne serije specifikacij OPC Unified Architecture in določa informacijski model, povezan z agregati.
Programersko ustvarjeni primeri agregatov so navedeni v Prilogi A.

General Information

• Status: Published
• Public Enquiry End Date: 30-Mar-2024
• Publication Date: 12-Apr-2026
• ICS: 25.040.40 - Industrial process measurement and control
• ICS: 35.100.05 - Multilayer applications
• ICS: 35.240.50 - IT applications in industry
• Technical Committee: MOV - Measuring equipment for electromagnetic quantities
• Current Stage: 6060 - National Implementation/Publication (Adopted Project)
• Start Date: 24-Feb-2026
• Due Date: 01-May-2026
• Completion Date: 13-Apr-2026
• Mandate: M/490 - Standardisation mandate to the European Standardisation Organisations (ESOs) to support European Smart Grid deployment
• Ref Project: EN IEC 62541-13:2026 - OPC unified architecture - Part 13: Aggregates

Relations

• Refers: SIST EN IEC 62541-5:2020 - OPC Unified Architecture - Part 5: Information Model
• Effective Date: 10-Feb-2026
• Refers: SIST EN IEC 62541-3:2020 - OPC unified architecture - Part 3: Address Space Model (IEC 62541-3:2020)
• Effective Date: 10-Feb-2026
• Refers: SIST EN IEC 62541-11:2020 - OPC Unified Architecture - Part 11: Historical Access (IEC 62541-11:2020)
• Effective Date: 10-Feb-2026
• Refers: SIST EN IEC 62541-8:2020 - OPC Unified Architecture - Part 8: Data Access (IEC 62541-8:2020)
• Effective Date: 10-Feb-2026
• Refers: SIST EN IEC 62541-1:2026 - OPC unified architecture - Part 1: Overview and concepts (IEC 62541-1:2025)
• Effective Date: 03-Feb-2026
• Refers: SIST EN IEC 62541-5:2026 - OPC unified architecture - Part 5: Information model (IEC 62541-5:2026)
• Effective Date: 03-Feb-2026
• Refers: SIST EN IEC 62541-4:2020 - OPC Unified Architecture - Part 4: Services (IEC 62541-4:2020)
• Effective Date: 03-Feb-2026
• Refers: SIST EN IEC 62541-4:2026 - OPC unified architecture - Part 4: Services (IEC 62541-4:2025)
• Effective Date: 03-Feb-2026
• Refers: SIST EN IEC 62541-8:2026 - OPC unified architecture - Part 8: Data access (IEC 62541-8:2025)
• Effective Date: 03-Feb-2026
• Refers: SIST EN IEC 62541-11:2026 - OPC Unified Architecture - Part 11: Historical Access (IEC 62541-11:2025)
• Effective Date: 03-Feb-2026
• Refers: SIST EN IEC 62541-3:2026 - OPC unified architecture - Part 3: Address space model (IEC 62541-3:2025)
• Effective Date: 03-Feb-2026
• Referred By: SIST EN 62541-7:2015 - OPC Unified Architecture - Part 7: Profiles (IEC 62541-7:2015)
• Effective Date: 10-Feb-2026
• Referred By: SIST EN IEC 62541-7:2020 - OPC unified architecture - Part 7: Profiles (IEC 62541-7:2020)
• Effective Date: 10-Feb-2026
• Referred By: SIST EN 62769-7:2015 - Devices and integration in enterprise systems; Field Device Integration - Part 7: Communication Devices (IEC 62769-7:2015)
• Effective Date: 10-Feb-2026
• Referred By: SIST EN IEC 62769-1:2023 - Field Device Integration (FDI®) - Part 1: Overview (IEC 62769-1:2023)
• Effective Date: 10-Feb-2026

Overview

Standard: prEN IEC 62541-13:2024 - OPC Unified Architecture (OPC UA) - Part 13: Aggregates
Organization: CLC / IEC SC 65E

This edition defines the OPC UA information model for Aggregates, specifying how aggregated values (for example averages, totals, minima/maxima, time-based aggregates and quality metrics) are represented, computed and exposed by OPC UA servers. Annex A provides programmatically produced aggregate examples (now distributed as CSV) to support implementation and testing. This edition replaces the previous publication (2020) and constitutes a technical revision with multiple corrections and clarifications to aggregate computations and status handling.

Key topics and requirements

• Aggregate information model: definitions for Aggregate objects including AggregateFunction and AggregateConfiguration types that describe supported aggregate operations and their parameters.
• MonitoredItem AggregateFilter / ReadProcessedDetails: structures and defaults for requesting processed (aggregated) history and monitored data.
• Aggregate data handling & status codes: rules for computing result values and StatusCodes, including operation-level result codes, Aggregate Information Bits (Raw, Partial, etc.) and how uncertain regions affect status calculation.
• Standard aggregate functions: summaries and behavior for aggregates such as TimeAverage, TimeAverage2, Total, Total2, Minimum, Maximum, Range, DurationInStateZero/NonZero, PercentGood/PercentBad, Start/End, Delta, and statistical aggregates (standard deviation/variance).
• Corrections & clarifications in this edition:
  • Multiple fixes for aggregate computations and rounding errors.
  • PercentGood/PercentBad now accounted for in calculations.
  • Raw status bit rules clarified for Start/End aggregates.
  • Partial bit calculation corrected; uncertain regions and TreatUncertainAsBad handling clarified for many aggregates.
  • Examples updated and moved to CSV; wording aligned with certification testing tool.

Applications

• Implementing OPC UA servers that expose aggregated historical or monitored data (e.g., industrial controllers, process historians and edge gateways).
• Developing client applications and analytics tools that request processed/aggregated data from OPC UA servers (SCADA, MES, IIoT platforms).
• Building and running conformance/certification tests and interoperability checks using the example CSVs and clarified status rules.
• Integrators and system architects defining data aggregation policies, bounding/interpolation behavior and quality handling in automation solutions.

Who should use this standard

• OPC UA server and client product developers
• Industrial automation system integrators
• Historian and analytics software vendors
• Conformance and test laboratories
• Standards and safety engineers defining data quality and processing in manufacturing, utilities and process industries

Related standards

• Other parts of the IEC 62541 (OPC UA) series (addressing security, information model, services, and historical access) provide the broader OPC UA framework within which Part 13 applies.

Standards Content (Sample)

SLOVENSKI STANDARD
01-maj-2026
Enotna arhitektura OPC - 13. del: Agregati (IEC 62541-13:2025)
OPC unified architecture - Part 13: Aggregates (IEC 62541-13:2025)
OPC Unified Architecture - Teil 13: Aggregation von Daten (IEC 62541-13:2025)
Architecture unifiée OPC - Partie 13: Agrégats (IEC 62541-13:2025)
Ta slovenski standard je istoveten z: EN IEC 62541-13:2026
ICS:
25.040.40 Merjenje in krmiljenje Industrial process
industrijskih postopkov measurement and control
35.240.50 Uporabniške rešitve IT v IT applications in industry
industriji
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

EUROPEAN STANDARD EN IEC 62541-13

NORME EUROPÉENNE
EUROPÄISCHE NORM February 2026
ICS 25.040.40; 35.100.05 Supersedes EN IEC 62541-13:2020
English Version
OPC unified architecture - Part 13: Aggregates
(IEC 62541-13:2025)
Architecture unifiée OPC - Partie 13: Agrégats OPC Unified Architecture - Teil 13: Aggregation von Daten
(IEC 62541-13:2025) (IEC 62541-13:2025)
This European Standard was approved by CENELEC on 2026-01-20. CENELEC members are bound to comply with the CEN/CENELEC
Internal Regulations which stipulate the conditions for giving this European Standard the status of a national standard without any alteration.
Up-to-date lists and bibliographical references concerning such national standards may be obtained on application to the CEN-CENELEC
Management Centre or to any CENELEC member.
This European Standard exists in three official versions (English, French, German). A version in any other language made by translation
under the responsibility of a CENELEC member into its own language and notified to the CEN-CENELEC Management Centre has the
same status as the official versions.
CENELEC members are the national electrotechnical committees of Austria, Belgium, Bulgaria, Croatia, Cyprus, the Czech Republic,
Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, the
Netherlands, Norway, Poland, Portugal, Republic of North Macedonia, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland,
Türkiye and the United Kingdom.

European Committee for Electrotechnical Standardization
Comité Européen de Normalisation Electrotechnique
Europäisches Komitee für Elektrotechnische Normung
CEN-CENELEC Management Centre: Rue de la Science 23, B-1040 Brussels
© 2026 CENELEC All rights of exploitation in any form and by any means reserved worldwide for CENELEC Members.
Ref. No. EN IEC 62541-13:2026 E

European foreword
The text of document 65E/1059/CDV, future edition 3 of IEC 62541-13, prepared by SC 65E "Devices
and integration in enterprise systems" of IEC/TC 65 "Industrial-process measurement, control and
automation" was submitted to the IEC-CENELEC parallel vote and approved by CENELEC as
The following dates are fixed:
• latest date by which the document has to be implemented at national (dop) 2027-02-28
level by publication of an identical national standard or by endorsement
• latest date by which the national standards conflicting with the (dow) 2029-02-28
document have to be withdrawn
This document supersedes EN IEC 62541-13:2020 and all of its amendments and corrigenda (if any).
Attention is drawn to the possibility that some of the elements of this document may be the subject of
patent rights. CENELEC shall not be held responsible for identifying any or all such patent rights.
This document has been prepared under a standardization request addressed to CENELEC by the
European Commission. The Standing Committee of the EFTA States subsequently approves these
requests for its Member States.
Any feedback and questions on this document should be directed to the users’ national committee. A
complete listing of these bodies can be found on the CENELEC website.
Endorsement notice
The text of the International Standard IEC 62541-13:2025 was approved by CENELEC as a European
Standard without any modification.
Annex ZA
(normative)
Normative references to international publications
with their corresponding European publications
The following documents are referred to in the text in such a way that some or all of their content
constitutes requirements of this document. For dated references, only the edition cited applies. For
undated references, the latest edition of the referenced document (including any amendments)
applies.
NOTE 1  Where an International Publication has been modified by common modifications, indicated by (mod),
the relevant EN/HD applies.
NOTE 2  Up-to-date information on the latest versions of the European Standards listed in this annex is available
here: www.cencenelec.eu.
Publication Year Title EN/HD Year
IEC 62541-1 - OPC Unified Architecture - Part 1: EN IEC 62541-1 -
Overview and concepts
IEC 62541-3 - OPC Unified Architecture - Part 3: Address EN IEC 62541-3 -
Space Model
IEC 62541-4 - OPC unified architecture - Part 4: Services EN IEC 62541-4 -
IEC 62541-5 - OPC Unified architecture - Part 5: EN IEC 62541-5 -
Information Model
IEC 62541-8 - OPC unified architecture - Part 8: Data EN IEC 62541-8 -
access
IEC 62541-11 - OPC Unified Architecture - Part 11: EN IEC 62541-11 -
Historical Access
IEC 62541-13 ®
Edition 3.0 2025-12
INTERNATIONAL
STANDARD
OPC unified architecture -
Part 13: Aggregates
ICS 25.040.40; 35.100.05 ISBN 978-2-8327-0841-5

IEC 62541-13:2025-12(en)
IEC 62541-13:2025 © IEC 2025
CONTENTS
FOREWORD. 3
1 Scope . 6
2 Normative references . 6
3 Terms, definitions and abbreviated terms . 6
3.1 Terms and definitions . 6
3.2 Abbreviated terms . 9
4 Aggregate information model . 10
4.1 General . 10
4.2 Aggregate Objects . 10
4.2.1 General . 10
4.2.2 AggregateFunction Object . 11
4.3 MonitoredItem AggregateFilter . 13
4.3.1 MonitoredItem AggregateFilter Defaults . 13
4.3.2 MonitoredItem Aggregates and Bounding Values . 13
4.4 Exposing Supported Functions and Capabilities . 14
5 Aggregate specific usage of Services . 15
5.1 General . 15
5.2 Aggregate data handling . 15
5.2.1 Overview . 15
5.2.2 ReadProcessedDetails structure overview . 15
5.2.3 AggregateFilter structure overview . 15
5.3 Aggregates StatusCodes . 16
5.3.1 Overview . 16
5.3.2 Operation level result codes . 16
5.3.3 Aggregate Information Bits . 17
5.4 Aggregate details . 18
5.4.1 General . 18
5.4.2 Common characteristics . 18
5.4.3 Specific aggregated data handling . 21
Annex A (informative) Aggregate examples . 64

Figure 1 – Representation of Aggregate Configuration information in the AddressSpace. 14
Figure 2 – Variable with Stepped = False and Simple Bounding Values . 23
Figure 3 – Variable with Stepped = True and Interpolated Bounding Values . 24

Table 1 – Interpolation examples . 7
Table 2 – AggregateConfigurationType Definition . 10
Table 3 – Aggregate Functions Definition . 11
Table 4 – AggregateFunctionType Definition . 12
Table 5 – Standard AggregateType Nodes . 12
Table 6 – ReadProcessedDetails . 15
Table 7 – AggregateFilter structure . 16
Table 8 – Bad operation level result codes . 16
Table 9 – Uncertain operation level result codes . 17
IEC 62541-13:2025 © IEC 2025
Table 10 – Data location . 17
Table 11 – Additional information . 17
Table 12 – History Aggregate interval information . 19
Table 13 – Standard History Aggregate Data Type information . 20
Table 14 – Aggregate table description . 25
Table 15 – Interpolative Aggregate summary . 27
Table 16 – Average Aggregate summary . 28
Table 17 – TimeAverage Aggregate summary . 29
Table 18 – TimeAverage2 Aggregate summary . 30
Table 19 – Total Aggregate summary . 31
Table 20 – Total2 Aggregate summary . 32
Table 21 – Minimum Aggregate summary . 33
Table 22 – Maximum Aggregate summary . 34
Table 23 – MinimumActualTime Aggregate summary . 35
Table 24 – MaximumActualTime Aggregate summary . 36
Table 25 – Range Aggregate summary . 37
Table 26 – Minimum2 Aggregate summary . 38
Table 27 – Maximum2 Aggregate summary . 39
Table 28 – MinimumActualTime2 Aggregate summary . 40
Table 29 – MaximumActualTime2 Aggregate summary . 41
Table 30 – Range2 Aggregate summary . 42
Table 31 – AnnotationCount Aggregate summary . 43
Table 32 – Count Aggregate summary . 44
Table 33 – DurationInStateZero Aggregate summary . 45
Table 34 – DurationInStateNonZero Aggregate summary . 46
Table 35 – NumberOfTransitions Aggregate summary . 47
Table 36 – Start Aggregate summary . 48
Table 37 – End Aggregate summary . 49
Table 38 – Delta Aggregate summary . 50
Table 39 – StartBound Aggregate summary . 51
Table 40 – EndBound Aggregate summary . 52
Table 41 – DeltaBounds Aggregate summary . 53
Table 42 – DurationGood Aggregate summary . 54
Table 43 – DurationBad Aggregate summary . 55
Table 44 – PercentGood Aggregate summary . 56
Table 45 – PercentBad Aggregate summary . 57
Table 46 – WorstQuality Aggregate summary . 58
Table 47 – WorstQuality2 Aggregate summary . 59
Table 48 – StandardDeviationSample Aggregate summary . 60
Table 49 – VarianceSample Aggregate summary . 61
Table 50 – StandardDeviationPopulation Aggregate summary. 62
Table 51 – VariancePopulation Aggregate summary . 63

IEC 62541-13:2025 © IEC 2025
INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
OPC unified architecture -
Part 13: Aggregates
FOREWORD
1) The International Electrotechnical Commission (IEC) is a worldwide organization for standardization comprising
all national electrotechnical committees (IEC National Committees). The object of IEC is to promote international
co-operation on all questions concerning standardization in the electrical and electronic fields. To this end and
in addition to other activities, IEC publishes International Standards, Technical Specifications, Technical Reports,
Publicly Available Specifications (PAS) and Guides (hereafter referred to as “IEC Publication(s)”). Their
preparation is entrusted to technical committees; any IEC National Committee interested in the subject dealt with
may participate in this preparatory work. International, governmental and non-governmental organizations liaising
with the IEC also participate in this preparation. IEC collaborates closely with the International Organization for
Standardization (ISO) in accordance with conditions determined by agreement between the two organizations.
2) The formal decisions or agreements of IEC on technical matters express, as nearly as possible, an international
consensus of opinion on the relevant subjects since each technical committee has representation from all
interested IEC National Committees.
3) IEC Publications have the form of recommendations for international use and are accepted by IEC National
Committees in that sense. While all reasonable efforts are made to ensure that the technical content of IEC
Publications is accurate, IEC cannot be held responsible for the way in which they are used or for any
misinterpretation by any end user.
4) In order to promote international uniformity, IEC National Committees undertake to apply IEC Publications
transparently to the maximum extent possible in their national and regional publications. Any divergence between
any IEC Publication and the corresponding national or regional publication shall be clearly indicated in the latter.
5) IEC itself does not provide any attestation of conformity. Independent certification bodies provide conformity
assessment services and, in some areas, access to IEC marks of conformity. IEC is not responsible for any
services carried out by independent certification bodies.
6) All users should ensure that they have the latest edition of this publication.
7) No liability shall attach to IEC or its directors, employees, servants or agents including individual experts and
members of its technical committees and IEC National Committees for any personal injury, property damage or
other damage of any nature whatsoever, whether direct or indirect, or for costs (including legal fees) and
expenses arising out of the publication, use of, or reliance upon, this IEC Publication or any other IEC
Publications.
8) Attention is drawn to the Normative references cited in this publication. Use of the referenced publications is
indispensable for the correct application of this publication.
9) IEC draws attention to the possibility that the implementation of this document may involve the use of (a)
patent(s). IEC takes no position concerning the evidence, validity or applicability of any claimed patent rights in
respect thereof. As of the date of publication of this document, IEC had not received notice of (a) patent(s), which
may be required to implement this document. However, implementers are cautioned that this may not represent
the latest information, which may be obtained from the patent database available at https://patents.iec.ch. IEC
shall not be held responsible for identifying any or all such patent rights.
IEC 62541-13 has been prepared by subcommittee 65E: Devices and integration in enterprise
systems, of IEC technical committee 65: Industrial-process measurement, control and
automation. It is an International Standard.
This third edition cancels and replaces the second edition published in 2020. This edition
constitutes a technical revision.
IEC 62541-13:2025 © IEC 2025
This edition includes the following technical changes with respect to the previous edition:
a) Multiple fixes for the computation of aggregates
• The Raw status bit is always set for non-bad StatusCodes for the Start and End
aggregates.
• Entries in the Interpolative examples Tables A2.2 Historian1, Historian2, and Historian3
have been changed from Good to Good, Raw status codes when the timestamp matches
with the timestamp of the data source.
• Missing tables have been added for DurationInStateZero and DurationInStateNonZero.
• The value of zero has been removed for results with a StatusCode of bad.
• Data Type was listed as "Status Code" when it is "Double" for both Standard Deviation
and both Variance Aggregates.
• Rounding Error in TimeAverage and TimeAverage2 have been corrected.
• The status codes have been corrected for the last two intervals and the value has been
corrected in the last interval.
• The wording has been changed to be more consistent with the certification testing tool.
• UsedSlopedExtrapolation set to true for Historian2 and all examples locations needed
new values or status' are modified.
• Values affected by percent good and percent bad have been updated.
• PercentGood/PercentBad are now accounted for in the calculation.
• TimeAverage uses SlopedInterpolation but the Time aggregate is incorrectly allowed to
used Stepped Interpolation.
• Partial bit is now correctly calculated.
• Unclear sentence was removed.
• Examples have been moved to a CSV.
• The value and status code for Historian 3 have been updated.
• TimeAverage2 Historian1 now takes uncertain regions into account when calculating
StatusCodes.
• TimeAverage2 Historian2 now takes uncertain regions into account when calculating
StatusCodes.
• Total2 Historian1 now takes uncertain regions into account when calculating
StatusCodes
• Total2 Historian2 now takes uncertain regions into account when calculating
StatusCodes
• Maximum2 Historian1 now takes uncertain regions into account when calculating
StatusCodes
• MaximumActualTime2 Historian1 now takes uncertain regions into account when
calculating StatusCodes
• Minimum2 Historian1 now takes uncertain regions into account when calculating
StatusCodes
• MinimumActualTime2 Historian1 now has the StatusCodes calculated while using the
TreatUncertainAsBad flag.
• Range2 Historian1 now looks at TreatUncertainAsBad in the calculation of the
StatusCodes.
• Clarifications have been made to the text defining how PercentGood/PercentBad are
used. The table values and StatusCodes of the TimeAverage2 and Total2 aggregates
have been corrected.
IEC 62541-13:2025 © IEC 2025
The text of this International Standard is based on the following documents:
Draft Report on voting
65E/1059/CDV 65E/1098/RVC
Full information on the voting for its approval can be found in the report on voting indicated in
the above table.
The language used for the development of this International Standard is English.
This document was drafted in accordance with ISO/IEC Directives, Part 2, and developed in
accordance with ISO/IEC Directives, Part 1 and ISO/IEC Directives, IEC Supplement, available
at www.iec.ch/members_experts/refdocs. The main document types developed by IEC are
described in greater detail at www.iec.ch/publications.
Throughout this document and the other parts of the IEC 62541 series, certain document
conventions are used:
Italics are used to denote a defined term or definition that appears in the "Terms and definitions"
clause in one of the parts of the IEC 62541 series.
Italics are also used to denote the name of a service input or output parameter or the name of
a structure or element of a structure that are usually defined in tables.
The italicized terms and names are, with a few exceptions, written in camel-case (the practice
of writing compound words or phrases in which the elements are joined without spaces, with
each element's initial letter capitalized within the compound). For example, the defined term is
AddressSpace instead of Address Space. This makes it easier to understand that there is a
single definition for AddressSpace, not separate definitions for Address and Space.
A list of all parts in the IEC 62541 series, published under the general title OPC Unified
Architecture, can be found on the IEC website.
The committee has decided that the contents of this document will remain unchanged until the
stability date indicated on the IEC website under webstore.iec.ch in the data related to the
specific document. At this date, the document will be
– reconfirmed,
– withdrawn, or
– revised.
IEC 62541-13:2025 © IEC 2025
1 Scope
This part of IEC 62541 is part of the overall OPC Unified Architecture specification series and
defines the information model associated with Aggregates.
Programmatically produced aggregate examples are listed in Annex A.
2 Normative references
The following documents, in whole or in part, are normatively referenced in this document and
are indispensable for its application. For dated references, only the edition cited applies. For
undated references, the latest edition of the referenced document (including any amendments
and errata) applies.
IEC 62541-1, OPC Unified Architecture - Part 1: Overview and Concepts
IEC 62541-3, OPC Unified Architecture - Part 3: Address Space Model
IEC 62541-4, OPC Unified Architecture - Part 4: Services
IEC 62541-5, OPC Unified Architecture - Part 5: Information Model
IEC 62541-8, OPC Unified Architecture - Part 8: Data Access
IEC 62541-11, OPC Unified Architecture - Part 11: Historical Access
3 Terms, definitions and abbreviated terms
3.1 Terms and definitions
For the purposes of this document, the terms and definitions given in IEC 62541-1,
IEC 62541-3, IEC 62541-4, and IEC 62541-11 and the following apply.
ISO and IEC maintain terminology databases for use in standardization at the following
addresses:
– IEC Electropedia: available at https://www.electropedia.org/
– ISO Online browsing platform: available at https://www.iso.org/obp
3.1.1
ProcessingInterval
timespan for which derived values are produced basedNo terms and definitions are listed in this
document
Note 1 to entry: The total time domain specified for ReadProcessed is divided by the ProcessingInterval. For
example, performing a 10-minute Average over the time range 12:00 to 12:30 would result in a set of three intervals
of ProcessingInterval length, with each interval having a start time of 12:00, 12:10 and 12:20 respectively. The rules
used to determine the interval Bounds are discussed in 5.4.2.2.
3.1.2
Interpolated data
data that is calculated from data samples
Note 1 to entry: Data samples can be historical data or buffered real time data. An interpolated value is calculated
from the data points on either side of the requested timestamp.
IEC 62541-13:2025 © IEC 2025
3.1.3
EffectiveEndTime
time immediately before endTime
Note 1 to entry: All Aggregate calculations include the startTime but exclude the endTime. However, it is sometimes
necessary to return an Interpolated End Bound as the value for an Interval with a timestamp that is in the interval.
Servers are expected to use the time immediately before endTime where the time resolution of the Server determines
the exact value (do not confuse this with hardware or operating system time resolution). For example, if the endTime
is 12:01:00, the time resolution is 1 second, then the EffectiveEndTime is 12:00:59. See 5.4.2.4.
If time is flowing backwards, Servers are expected to use the time immediately after endTime where the time
resolution of the Server determines the exact value.
3.1.4
Extrapolated data
data constructed from a discrete data set but is outside of the discrete data set
Note 1 to entry: It is similar to the process of interpolation, which constructs new points between known points, but
its result is subject to greater uncertainty. Extrapolated data is used in cases where the requested time period falls
farther into the future than the data available in the underlying system. See example in Table 1.
3.1.5
SlopedInterpolation
simple linear interpolation
Note 1 to entry: Compare to curve fitting using linear polynomials. See example in Table 1.
3.1.6
SteppedInterpolation
Interpolation holding the last data point constant or interpolating the value based on a horizontal
line fit
Note 1 to entry: Consider the following Table 1 of raw and Interpolated/Extrapolated values:
Table 1 – Interpolation examples
Timestamp Raw Value Sloped Interpolation Stepped Interpolation
12:00:00 10
12:00:05 15 10
12:00:08 18 10
12:00:10 20
12:00:15 25 20
12:00:20 30
SlopedExtrapolation SteppedExtrapolation
12:00:25 35 30
12:00:27 37 30
IEC 62541-13:2025 © IEC 2025
3.1.7
bounding values
values at the startTime and endTime needed for Aggregates to compute the result
Note 1 to entry: If Raw data does not exist at the startTime and endTime a value shall be estimated. There are two
ways to determine Bounding Values for an interval. One way (called Interpolated Bounding Values) uses the first
non-Bad data points found before and after the timestamp to estimate the bound. The other (called Simple Bounding
Values) uses the data points immediately before and after the boundary timestamps to estimate the bound even if
these points are Bad. Entries 3.1.8 and 3.1.9 describe the two different approaches in more detail.
In all cases the TreatUncertainAsBad (see 4.2.1.2) flag is used to determine whether Uncertain values are Bad or
non-Bad.
If a Raw value was not found and a non-Bad bounding value exists the Aggregate Bits (see 5.3.3) are set to
‘Interpolated’.
When calculating bounding values, the value portion of Raw data that has Bad status is set to null. This means the
value portion is not used in any calculation and a null is returned if the raw value is returned. The status portion is
determined by the rules specified by the bound or Aggregate.
The Interpolated Bounding Values approach (see 3.1.8) is the same as what is used in Classic OPC Historical Data
Access (HDA) and is important for applications such as advanced process control where having useful values at all
times is important. The Simple Bounding Values approach (see 3.1.9) is new in this standard and is important for
applications which shall produce regulatory reports and cannot use estimated values in place of Bad data.
3.1.8
interpolated bounding values
bounding values determined by a calculation using the nearest Good value
Note 1 to entry: Interpolated Bounding Values using SlopedInterpolation are calculated as follows:
• if a non-Bad Raw value exists at the timestamp then it is the bounding value;
• find the first non-Bad Raw value before the timestamp;
• find the first non-Bad Raw value after the timestamp;
• draw a line between before value and after value;
• use point where the line crosses the timestamp as an estimate of the bounding value.
The calculation can be expressed with the following formula:
V = (T – T ) × (V – V ) / (T – T ) + V
bound bound before after before after before before
where V is a value at ‘x’ and T is the timestamp associated with V .
x x x
If no non-Bad values exist before the timestamp the StatusCode is Bad_NoData. The StatusCode is
Uncertain_DataSubNormal if any Bad values exist between the before value and after value. If either the before
value or the after value are Uncertain the StatusCode is Uncertain_DataSubNormal. If the after value does not exist
the before value shall be extrapolated using SlopedExtrapolation or SteppedExtrapolation.
The period of time that is searched to discover the Good values before and after the timestamp is Server dependent,
but if a Good value is not found within some reasonable time range then the Server will assume it does not exist.
The Server as a minimum should search a time range which is at least the size of the ProcessingInterval.
Interpolated Bounding Values using SlopedExtrapolation are calculated as follows:
• find the first non-Bad Raw value before timestamp;
• find the second non-Bad Raw value before timestamp;
• draw a line between these two values;
• extend the line to where it crosses the timestamp;
• use the point where the line crosses the timestamp as an estimate of the bounding value.
The formula is the same as the one used for SlopedInterpolation.
The StatusCode is always Uncertain_DataSubNormal. If only one non-Bad raw value can be found before the
timestamp then SteppedExtrapolation is used to estimate the bounding value.
IEC 62541-13:2025 © IEC 2025
Interpolated Bounding Values using SteppedInterpolation are calculated as follows:
• if a non-Bad Raw value exists at the timestamp then it is the bounding value;
• find the first non-Bad Raw value before timestamp;
• use the value as an estimate of the bounding value.
The StatusCode is Uncertain_DataSubNormal if any Bad values exist between the before value and the timestamp.
If no non-Bad Raw data exists before the timestamp then the StatusCode is Bad_NoData. If the value before the
timestamp is Uncertain the StatusCode is Uncertain_DataSubNormal. The value after the timestamp is not necessary
when using SteppedInterpolation; however, if the timestamp is after the end of the data then the bounding value is
treated as extrapolated and the StatusCode is Uncertain_DataSubNormal.
SteppedExtrapolation is a term that describes SteppedInterpolation when a timestamp is after the last value in the
history collection.
3.1.9
simple bounding values
bounding values determined by a calculation using the nearest value
Note 1 to entry: Simple Bounding Values using SlopedInterpolation are calculated as follows:
• if any Raw value exists at the timestamp then it is the bounding value;
• find the first Raw value before timestamp;
• find the first Raw value after timestamp;
• if the value after the timestamp is Bad then the before value is the bounding value;
• draw a line between before value and after value;
• use point where the line crosses the timestamp as an estimate of the bounding value.
The formula is the same as the one used for SlopedInterpolation in 3.1.5.
If a Raw value at the timestamp is Bad the StatusCode is Bad_NoData. If the value before the timestamp is Bad the
StatusCode is Bad_NoData. If the value before the timestamp is Uncertain the StatusCode is
Uncertain_DataSubNormal. If the value after the timestamp is Bad or Uncertain the StatusCode is
Uncertain_DataSubNormal.
Simple Bounding Values using SteppedInterpolation are calculated as follows:
• if any Raw value exists at the timestamp then it is the bounding value;
• find the first Raw value before timestamp;
• if the value before timestamp is non-Bad then it is the bounding value.
If a Raw value at the timestamp is Bad the StatusCode is Bad_NoData. If the value before the timestamp is Bad the
StatusCode is Bad_NoData. If the value before the timestamp is Uncertain the StatusCode is
Uncertain_DataSubNormal.
If either bounding time of an interval is beyond the last data point, then the Server can use extrapolation or return
an error. If extrapolation is used by the server the type [SteppedExtrapolation or SloppedExtrapolation] of
extrapolation is server specific.
In some Historians, the last Raw value does not necessarily indicate the end of the data. Based on the Historian's
knowledge of the data collection mechanism, i.e. frequency of data updates and latency, the Historian can extend
the last value to a time known by the Historian to be covered. When calculating Simple Bounding Values the Historian
will act as if there is another Raw value at this timestamp.
In the same way, if the earliest time of an interval starts before the first data point in history and the latest time is
after the first data point in history, then the interval will be treated as if the interval extends from the first data point
in history to the latest time of the interval and the StatusCode of the interval will have the Partial bit set (see 5.3.3.2).
The period of time that is searched to discover the values before and after the timestamp is Server dependent, but
if a value is not found within some reasonable time range then the Server will assume it does not exist. The Server
as a minimum should search a time range which is at least the size of the ProcessingInterval.
3.2 Abbreviated terms
DA Data Access
HA Historical Access (access to historical data or events)
HDA Historical Data Access
UA Unified Architecture
IEC 62541-13:2025 © IEC 2025
4 Aggregate information model
4.1 General
IEC 62541-3 and IEC 62541-5 standards define the representation of Aggregate historical or
buffered real time data in the OPC Unified Architecture. This includes the definition of
Aggregates used in processed data retrieval and in historical retrieval. This definition includes
both standard Reference types and Object types.
4.2 Aggregate Objects
4.2.1 General
4.2.1.1 Overview
OPC UA Servers can support several different functionalities and capabilities. The following
standard Objects are used to expose these capabilities in a common fashion, and there are
several standard defined concepts that can be extended by vendors.
4.2.1.2 AggregateConfigurationType
The AggregateConfigurationType defines the general characteristics of a Node that defines the
Aggregate configuration of any Variable or Property. AggregateConfiguration Object represents
the browse entry point for information on how the Server treats Aggregate specific functionality
such as handling Uncertain data. It is formally defined in Table 2.
Table 2 – AggregateConfigurationType Definition
Attribute Value
BrowseName AggregateConfigurationType
IsAbstract False
References NodeClass BrowseName DataType TypeDefinition ModellingRule
Subtype of the BaseObjectType defined in IEC 62541-5
HasProperty Variable TreatUncertainAsBad Boolean PropertyType Mandatory
HasProperty Variable PercentDataBad Byte PropertyType Mandatory
HasProperty Variable PercentDataGood Byte PropertyType Mandatory
HasProperty Variable UseSlopedExtrapolation Boolean PropertyType Mandatory
Conformance Units
Aggregate Master Configuration

The TreatUncertainAsBad Variable indicates how the Server treats data returned with a
StatusCode severity Uncertain with respect to Aggregate calculations. A value of True indicates
the Server considers the severity equivalent to Bad, a value of False indicates the Server
considers the severity equivalent to Good, unless the Aggregate definition says otherwise. The
default value is True. Note that the value is still treated as Uncertain when the StatusCode for
the result is calculated.
The PercentDataBad Variable indicates the minimum percentage of Bad data in a given interval
required for the StatusCode for the given interval for processed data request to be set to Bad.
(Uncertain is treated as defined above.) Refer to 5.4.3 for details on using this Variable when
assigning StatusCodes. For details on which Aggregates use the PercentDataBad Variable, see
the definition of each Aggregate. The default value is 100.
IEC 62541-13:2025 © IEC 2025
The PercentDataGood Variable indicates the minimum percentage of Good data in a given
interval required for the StatusCode for the given interval for the processed data requests to be
set to Good. Refer to 5.4.3 for details on using this Variable when assigning StatusCodes. For
details on which Aggregates use the PercentDataGood Variable, see the definition of each
Aggregate. The default value is 100.
The following calculations are used to detemine the StatusCode which will be used to calculate
the value of the aggregate. Refer to 5.4.3 for details on using these Variables when assigning
StatusCodes. The PercentDataGood and PercentDataBad shall follow the following relationship
PercentDataGood ≥ (100 – PercentDataBad). If they are equal the result of the
PercentDataGood calculation is used. If the values entered for PercentDataGood and
PercentDataBad do not result in a valid calculation (e.g. Bad = 80; Good = 0) the result will
have a StatusCode of Bad_AggregateInvalidInputs. The StatusCode
Bad_AggregateInvalidInputs will be returned if the value of PercentDataGood or
PercentDataBad exceed 100.
The UseSlopedExtrapolation Variable indicates how the Server interpolates data when no
boundary value exists (i.e. extrapolating into the future from the last known value). A value of
False indicates that the Server will use a SteppedExtrapolation format, and hold the last known
value constant. A value of True indicates the Server will project the value using
UseSlopedExtrapolation mode. The default value is False. For SimpleBounds this value is
ignored.
4.2.2 AggregateFunction Object
4.2.2.1 General
This Object is used as the browse entry point for information about the Aggregates supported
by a Server. The content of this Object is already defined by its type definition. All Instances of
the FolderType use the standard BrowseName of ‘AggregateFunctions’. The HasComponent
Reference is used to relate a ServerCapabilities Object and/or any
HistoryServerCapabilitiesType Object to an AggregateFunction Object. AggregateFunctions is
formally defined in Table 3.
Table 3 – Aggregate Functions Definition
Attribute Value
BrowseName AggregateFunctions
References Node BrowseName DataType TypeDefinition Modelling
Class Rule
HasTypeDefiniti Object FolderType Defined in IEC 62541-5
on
Type
Conformance Units
Historical Access Aggregates
Each ServerCapabilities and HistoryServerCapabilitiesType Object shall reference an
AggregateFunction Object. In addition, each HistoricalConfiguration Object belonging to a
HistoricalDataNode can reference an AggregateFunction Object using the HasComponent
Reference.
4.2.2.2 AggregateFunctionType
This ObjectType defines an Aggregate supported by a UA Server. This Object is formally
defined in Table 4.
IEC 62541-13:2025 © IEC 2025
Table 4 – AggregateFunctionType Definition
Attribute Value
BrowseName AggregateFunctionType
IsAbstract False
References Node BrowseName DataType Type Mod.
Class Definition Rule
Subtype of the BaseObjectType defined in IEC 62541-5
Conformance Units
Historical Access Aggregates
For the AggregateFunctionType, the Description Attribute (inherited from the Base NodeClass),
is mandatory. The Description Attribute provides a localized description of the Aggregate.
Table 5 specifies the BrowseName and Description Attributes for the standard Aggregate
Objects. The description is the localized “en” text. For other locales it shall be translated.
Table 5 – Standard AggregateType Nodes
BrowseName Description
Interpolation Aggregate
Interpolative At the beginning of each interval, retrieve the calculated value from the data points
on either side of the requested timestamp.
Average Retrieve the average value of the data over the interval.
TimeAverage Retrieve the time weighted average data over the interval using Interpolated
Bounding Values.
TimeAverage2 Retrieve the time weighted average data over the interval using Simple Bounding
Values.
Total Retrieve the total (time integral) of the data over the interval using Interpolated
Bounding Values.
Total2 Retrieve the total (time integral) of the data over the interval using Simple Bounding
Values.
Minimum Retrieve the minimum raw value in the interval with the timestamp of the start of the
interval.
Maximum Retrieve the maxi
...