EN IEC 62541-6:2020

SLOVENSKI STANDARD
01-december-2020
Nadomešča:
SIST EN 62541-6:2015
Enotna arhitektura OPC - 6. del: Preslikave (IEC 62541-6:2020)
OPC Unified Architecture - Part 6: Mappings (IEC 62541-6:2020)
OPC Unified Architecture - Teil 6: Protokollabbildungen (IEC 62541-6:2020)
Architecture unifiée OPC - Partie 6: Correspondances (IEC 62541-6:2020)
Ta slovenski standard je istoveten z: EN IEC 62541-6:2020
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 62541-6

NORME EUROPÉENNE
EUROPÄISCHE NORM
September 2020
ICS 35.100.05; 25.040.40 Supersedes EN 62541-6:2015 and all of its amendments
and corrigenda (if any)
English Version
OPC Unified Architecture - Part 6: Mappings
(IEC 62541-6:2020)
Architecture unifiée OPC - Partie 6: Mappings OPC Unified Architecture - Teil 6: Protokollabbildungen
(IEC 62541-6:2020) (IEC 62541-6:2020)
This European Standard was approved by CENELEC on 2020-08-17. 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,
Turkey 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
© 2020 CENELEC All rights of exploitation in any form and by any means reserved worldwide for CENELEC Members.
Ref. No. EN IEC 62541-6:2020 E

European foreword
The text of document 65E/718/FDIS, future edition 3 of IEC 62541-6, 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) 2021-05-17
level by publication of an identical national standard or by endorsement
• latest date by which the national standards conflicting with the (dow) 2023-08-17
document have to be withdrawn
This document supersedes EN 62541-6:2015 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 mandate given to CENELEC by the European
Commission and the European Free Trade Association.
Endorsement notice
The text of the International Standard IEC 62541-6:2020 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.cenelec.eu.
Publication Year Title EN/HD Year
IEC/TR 62541-1 -  OPC unified architecture - Part 1: Overview CLC/TR 62541-1 -
and concepts
IEC/TR 62541-2 -  OPC unified architecture - Part 2: Security CLC/TR 62541-2 -
model
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 62541-7 -  OPC unified architecture - Part 7: Profiles EN IEC 62541-7 -
IEC 62541-12 -  OPC unified architecture - Part 12: EN IEC 62541-12 -
Discovery and global services
ISO 8601-1 2019 Date and time - Representations for - -
information interchange – Part 1: Basic rules
XML Schema Part 2 - XML Schema Part 2: Datatypes - -
http://www.w3.org/TR/xmlschema‑2/
SOAP Part 1 - SOAP Version 1.2 Part 1: Messaging - -
Framework
http://www.w3.org/TR/soap12-part1/
SSL/TLS: RFC 5246 - The TLS Protocol Version 1.2 - -
http://tools.ietf.org/html/rfc5246.txt
X.509 v3: ISO/IEC - Information technology – Open Systems - -
9594-8 Interconnection – The Directory: Public-key
and attribute certificate frameworks
HTTP: RFC 2616 - Hypertext Transfer Protocol – HTTP/1.1 - -
http://www.ietf.org/rfc/rfc2616.txt
Publication Year Title EN/HD Year
HTTPS: RFC 2818 - HTTP Over TLS - -
http://www.ietf.org/rfc/rfc2818.txt
Base64: RFC 3548 - The Base16, Base32, and Base64 Data - -
Encodings http://www.ietf.org/rfc/rfc3548.txt
X690: ISO/IEC 8825-1 - Information technology – ASN.1 encoding - -
rules: Specification of Basic Encoding Rules
(BER), Canonical Encoding Rules (CER)
and Distinguished Encoding Rules (DER)
IEEE-754 - Standard for Floating-Point Arithmetic - -
HMAC - HMAC – Keyed-Hashing for Message - -
Authentication
http://www.ietf.org/rfc/rfc2104.txt
PKCS #1: - PKCS #1 – RSA Cryptography - -
Specifications Version 2.0
http://www.ietf.org/rfc/rfc2437.txt
PKCS #12 - PKCS #12 – Personal Information Exchange - -
Syntax v1.1 http://www.ietf.org/rfc/rfc7292.txt
FIPS 180-4 - Secure Hash Standard (SHS) - -
https://csrc.nist.gov/publications/detail/fips/1
80/4/final
FIPS 197 - Advanced Encryption Standard (AES) - -
https://csrc.nist.gov/publications/detail/fips/1
97/final
UTF-8 - UTF-8, a transformation format of ISO - -
10646 http://www.ietf.org/rfc/rfc3629.txt
RFC 3280 - RFC 3280 – X.509 Public Key Infrastructure - -
Certificate and CRL Profile
http://www.ietf.org/rfc/rfc3280.txt
RFC 4514 - RFC 4514 – LDAP: String Representation of - -
Distinguished Names
http://www.ietf.org/rfc/rfc4514.txt
NTP - RFC 1305 – Network Time Protocol (Version - -
3) Specification, Implementation and
Analysis http://www.ietf.org/rfc/rfc1305.txt
Kerberos - Web Services Security – Kerberos Token - -
Profile 1.1
http://docs.oasis-open.org/wss/v1.1/wss-v1.
1-spec-os-KerberosTokenProfile.pdf
RFC 1738 - RFC 1738 – Uniform Resource Locators - -
(URL) http://www.ietf.org/rfc/rfc1738.txt
RFC 2141 - RFC 2141 – URN Syntax - -
http://www.ietf.org/rfc/rfc2141.txt
RFC 6455 - RFC 6455 – The WebSocket Protocol - -
http://www.ietf.org/rfc/rfc6455.txt
Publication Year Title EN/HD Year
RFC 7523 - JSON Web Token (JWT) Profile for OAuth - -
2.0 Client Authentication and Authorization
Grants https://tools.ietf.org/rfc/rfc7523.txt
RFC 6749 - The OAuth 2.0 Authorization Framework - -
http://www.ietf.org/rfc/rfc6749.txt
OpenID-Core - OpenID Connect Core 1.0 - -
http://openid.net/specs/openid-connect-core-
1_0.html
OpenID-Discovery - OpenID Connect Discovery 1.0 - -
https://openid.net/specs/openid-connect-disc
overy-1_0.html
RFC 6960 - RFC 6960 – X.509 Internet Public Key - -
Infrastructure Online Certificate Status
Protocol – OCSP
https://www.ietf.org/rfc/rfc6960.txt

IEC 62541-6 ®
Edition 3.0 2020-07
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
colour
inside
OPC unified architecture –
Part 6: Mappings
Architecture unifiée OPC –
Partie 6: Mappings
INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
COMMISSION
ELECTROTECHNIQUE
INTERNATIONALE
ICS 25.040.40; 35.100.05 ISBN 978-2-8322-8596-1

– 2 – IEC 62541-6:2020 © IEC 2020
CONTENTS
FOREWORD . 8
1 Scope . 11
2 Normative references . 11
3 Terms, definitions, abbreviated terms and symbols . 13
3.1 Terms and definitions . 13
3.2 Abbreviated terms and symbols . 14
4 Overview . 14
5 Data encoding . 16
5.1 General . 16
5.1.1 Overview . 16
5.1.2 Built-in Types . 16
5.1.3 Guid . 17
5.1.4 ByteString . 17
5.1.5 ExtensionObject . 17
5.1.6 Variant . 18
5.1.7 Decimal . 18
5.2 OPC UA Binary . 19
5.2.1 General . 19
5.2.2 Built-in Types . 19
5.2.3 Decimal . 30
5.2.4 Enumerations . 30
5.2.5 Arrays . 30
5.2.6 Structures . 31
5.2.7 Structures with optional fields . 33
5.2.8 Unions . 35
5.2.9 Messages . 36
5.3 OPC UA XML . 37
5.3.1 Built-in Types . 37
5.3.2 Decimal . 43
5.3.3 Enumerations . 43
5.3.4 Arrays . 44
5.3.5 Structures . 44
5.3.6 Structures with optional fields . 45
5.3.7 Unions . 45
5.3.8 Messages . 46
5.4 OPC UA JSON . 46
5.4.1 General . 46
5.4.2 Built-in Types . 46
5.4.3 Decimal . 52
5.4.4 Enumerations . 52
5.4.5 Arrays . 52
5.4.6 Structures . 53
5.4.7 Structures with optional fields . 53
5.4.8 Unions . 54
5.4.9 Messages . 54
6 Message SecurityProtocols . 55

IEC 62541-6:2020 © IEC 2020 – 3 –
6.1 Security handshake . 55
6.2 Certificates . 56
6.2.1 General . 56
6.2.2 Application Instance Certificate. 57
6.2.3 Certificate Chains . 58
6.3 Time synchronization . 58
6.4 UTC and International Atomic Time (TAI) . 58
6.5 Issued User Identity Tokens . 58
6.5.1 Kerberos . 58
6.5.2 JSON Web Token (JWT) . 59
6.5.3 OAuth2 . 60
6.6 WS Secure Conversation . 62
6.7 OPC UA Secure Conversation . 62
6.7.1 Overview . 62
6.7.2 MessageChunk structure . 62
6.7.3 MessageChunks and error handling . 67
6.7.4 Establishing a SecureChannel . 67
6.7.5 Deriving keys . 69
6.7.6 Verifying Message security . 70
7 TransportProtocols . 71
7.1 OPC UA Connection Protocol. 71
7.1.1 Overview . 71
7.1.2 Message structure . 72
7.1.3 Establishing a connection . 75
7.1.4 Closing a connection . 77
7.1.5 Error handling . 77
7.2 OPC UA TCP . 79
7.3 SOAP/HTTP . 79
7.4 OPC UA HTTPS . 79
7.4.1 Overview . 79
7.4.2 Session-less Services . 81
7.4.3 XML Encoding . 81
7.4.4 OPC UA Binary Encoding . 82
7.4.5 JSON Encoding . 82
7.5 WebSockets . 83
7.5.1 Overview . 83
7.5.2 Protocol Mapping . 84
7.5.3 Security . 84
7.6 Well known addresses . 85
8 Normative Contracts . 86
8.1 OPC Binary Schema . 86
8.2 XML Schema and WSDL . 86
8.3 Information Model Schema . 86
8.4 Formal definition of UA Information Model. 86
8.5 Constants . 86
8.6 DataType encoding . 86
8.7 Security configuration . 86
Annex A (normative) Constants . 87
A.1 Attribute Ids . 87

– 4 – IEC 62541-6:2020 © IEC 2020
A.2 Status Codes . 87
A.3 Numeric Node Ids . 88
Annex B (normative) OPC UA Nodeset . 89
Annex C (normative) Type declarations for the OPC UA native Mapping . 90
Annex D (normative) WSDL for the XML Mapping . 91
D.1 XML Schema . 91
D.2 WDSL Port Types . 91
D.3 WSDL Bindings . 91
Annex E (normative) Security settings management . 92
E.1 Overview. 92
E.2 SecuredApplication . 93
E.3 CertificateIdentifier . 96
E.4 CertificateStoreIdentifier . 98
E.5 CertificateList . 99
E.6 CertificateValidationOptions . 99
Annex F (normative) Information Model XML Schema . 101
F.1 Overview. 101
F.2 UANodeSet . 101
F.3 UANode . 103
F.4 Reference . 104
F.5 RolePermission . 104
F.6 UAType . 104
F.7 UAInstance . 105
F.8 UAVariable . 105
F.9 UAMethod . 106
F.10 TranslationType . 106
F.11 UADataType . 107
F.12 DataTypeDefinition . 108
F.13 DataTypeField . 108
F.14 Variant . 109
F.15 Example. 110
F.16 UANodeSetChanges . 112
F.17 NodesToAdd . 113
F.18 ReferencesToChange . 113
F.19 ReferenceToChange . 114
F.20 NodesToDelete . 114
F.21 NodeToDelete . 114
F.22 UANodeSetChangesStatus . 115
F.23 NodeSetStatusList . 115
F.24 NodeSetStatus . 115
Bibliography . 117

Figure 1 – The OPC UA Stack Overview . 15
Figure 2 – Encoding Integers in a binary stream . 20
Figure 3 – Encoding Floating Points in a binary stream . 20
Figure 4 – Encoding Strings in a binary stream . 21
Figure 5 – Encoding Guids in a binary stream . 22

IEC 62541-6:2020 © IEC 2020 – 5 –
Figure 6 – Encoding XmlElement in a binary stream . 22
Figure 7 – A String NodeId . 23
Figure 8 – A Two Byte NodeId . 24
Figure 9 – A Four Byte NodeId . 24
Figure 10 – Security handshake . 55
Figure 11 – OPC UA Secure Conversation MessageChunk . 63
Figure 12 – OPC UA Connection Protocol Message structure . 72
Figure 13 – Client initiated OPC UA Connection Protocol connection . 76
Figure 14 – Server initiated OPC UA Connection Protocol connection . 76
Figure 15 – Closing a OPC UA Connection Protocol connection . 77
Figure 16 – Scenarios for the HTTPS Transport . 80
Figure 17 – Setting up Communication over a WebSocket . 84

Table 1 – Built-in Data Types . 16
Table 2 – Guid structure . 17
Table 3 – Layout of Decimal . 19
Table 4 – Supported Floating Point Types . 20
Table 5 – NodeId components . 22
Table 6 – NodeId DataEncoding values . 23
Table 7 – Standard NodeId Binary DataEncoding . 23
Table 8 – Two Byte NodeId Binary DataEncoding . 24
Table 9 – Four Byte NodeId Binary DataEncoding. 24
Table 10 – ExpandedNodeId Binary DataEncoding . 25
Table 11 – DiagnosticInfo Binary DataEncoding . 26
Table 12 – QualifiedName Binary DataEncoding . 26
Table 13 – LocalizedText Binary DataEncoding . 27
Table 14 – Extension Object Binary DataEncoding. 28
Table 15 – Variant Binary DataEncoding . 29
Table 16 – Data Value Binary DataEncoding . 30
Table 17 – Sample OPC UA Binary Encoded structure . 32
Table 18 – Sample OPC UA Binary Encoded Structure with optional fields . 34
Table 19 – Sample OPC UA Binary Encoded Structure . 35
Table 20 – XML Data Type Mappings for Integers . 37
Table 21 – XML Data Type Mappings for Floating Points . 37
Table 22 – Components of NodeId . 39
Table 23 – Components of ExpandedNodeId . 40
Table 24 – Components of Enumeration . 44
Table 25 – JSON Object Definition for a NodeId . 48
Table 26 – JSON Object Definition for an ExpandedNodeId . 49
Table 27 – JSON Object Definition for a StatusCode . 49
Table 28 – JSON Object Definition for a DiagnosticInfo . 50
Table 29 – JSON Object Definition for a QualifiedName . 50
Table 30 – JSON Object Definition for a LocalizedText . 50

– 6 – IEC 62541-6:2020 © IEC 2020
Table 31 – JSON Object Definition for an ExtensionObject . 51
Table 32 – JSON Object Definition for a Variant . 51
Table 33 – JSON Object Definition for a DataValue . 52
Table 34 – JSON Object Definition for a Decimal . 52
Table 35 – JSON Object Definition for a Structure with Optional Fields . 53
Table 36 – JSON Object Definition for a Union . 54
Table 37 – SecurityPolicy . 56
Table 38 – Application Instance Certificate . 57
Table 39 – Kerberos UserTokenPolicy . 59
Table 40 – JWT UserTokenPolicy . 59
Table 41 – JWT IssuerEndpointUrl Definition . 60
Table 42 – Access Token Claims . 61
Table 43 – OPC UA Secure Conversation Message header . 63
Table 44 – Asymmetric algorithm Security header . 64
Table 45 – Symmetric algorithm Security header . 65
Table 46 – Sequence header . 65
Table 47 – OPC UA Secure Conversation Message footer . 66
Table 48 – OPC UA Secure Conversation Message abort body . 67
Table 49 – OPC UA Secure Conversation OpenSecureChannel Service . 68
Table 50 – PRF inputs for RSA based SecurityPolicies . 70
Table 51 – Cryptography key generation parameters . 70
Table 52 – OPC UA Connection Protocol Message header . 72
Table 53 – OPC UA Connection Protocol Hello Message . 73
Table 54 – OPC UA Connection Protocol Acknowledge Message . 74
Table 55 – OPC UA Connection Protocol Error Message . 74
Table 56 – OPC UA Connection Protocol ReverseHello Message . 75
Table 57 – OPC UA Connection Protocol error codes . 78
Table 58 – WebSocket Protocols Mappings . 84
Table 59 – Well known addresses for Local Discovery Servers . 85
Table A.1 – Identifiers assigned to Attributes . 87
Table E.1 – SecuredApplication . 94
Table E.2 – CertificateIdentifier . 97
Table E.3 – Structured directory store . 98
Table E.4 – CertificateStoreIdentifier . 99
Table E.5 – CertificateList . 99
Table E.6 – CertificateValidationOptions . 100
Table F.1 – UANodeSet . 102
Table F.2 – UANode . 103
Table F.3 – Reference . 104
Table F.4 – RolePermission . 104
Table F.5 – UANodeSet Type Nodes. 104
Table F.6 – UANodeSet Instance Nodes . 105
Table F.7 – UAInstance . 105

IEC 62541-6:2020 © IEC 2020 – 7 –
Table F.8 – UAVariable . 106
Table F.9 – UAMethod . 106
Table F.10 – TranslationType . 107
Table F.11 – UADataType . 108
Table F.12 – DataTypeDefinition . 108
Table F.13 – DataTypeField . 109
Table F.14 – UANodeSetChanges . 112
Table F.15 – NodesToAdd . 113
Table F.16 – ReferencesToChange . 113
Table F.17 – ReferencesToChange . 114
Table F.18 – NodesToDelete . 114
Table F.19 – ReferencesToChange . 114
Table F.20 – UANodeSetChangesStatus . 115
Table F.21 – NodeSetStatusList . 115
Table F.22 – NodeSetStatus . 116

– 8 – IEC 62541-6:2020 © IEC 2020
INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
OPC UNIFIED ARCHITECTURE –
Part 6: Mappings
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) Attention is drawn to the possibility that some of the elements of this IEC Publication may be the subject of
patent rights. IEC shall not be held responsible for identifying any or all such patent rights.
International Standard IEC 62541-6 has been prepared by subcommittee 65E: Devices and
integration in enterprise systems, of IEC technical committee 65: Industrial-process
measurement, control and automation.
This third edition cancels and replaces the second edition published in 2015. This edition
constitutes a technical revision.
This edition includes the following significant technical changes with respect to the previous
edition:
a) Encodings:
• added JSON encoding for PubSub (non-reversible);
• added JSON encoding for Client/Server (reversible);
• added support for optional fields in structures;
• added support for Unions.
IEC 62541-6:2020 © IEC 2020 – 9 –
b) Transport mappings:
• added WebSocket secure connection – WSS;
• added support for reverse connectivity;
• added support for session-less service invocation in HTTPS.
c) Deprecated Transport (missing support on most platforms):
• SOAP/HTTP with WS-SecureConversation (all encodings).
d) Added mapping for JSON Web Token.
e) Added support for Unions to NodeSet Schema.
f) Added batch operations to add/delete nodes to/from NodeSet Schema.
g) Added support for multi-dimensional arrays outside of Variants.
h) Added binary representation for Decimal data types.
i) Added mapping for an OAuth2 Authorization Framework.
The text of this International Standard is based on the following documents:
FDIS Report on voting
65E/718/FDIS 65E/734/RVD
Full information on the voting for the app
...