prEN IEC 62541-6:2024

SLOVENSKI STANDARD
01-april-2024
Enotna arhitektura OPC - 6. del: Preslikave
OPC unified architecture - Part 6: Mappings
OPC Unified Architecture - Teil 6: Protokollabbildungen
Architecture unifiée OPC - Partie 6: Mappings
Ta slovenski standard je istoveten z: prEN IEC 62541-6:2024
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.

65E/1063/CDV
COMMITTEE DRAFT FOR VOTE (CDV)
PROJECT NUMBER:
IEC 62541-6 ED4
DATE OF CIRCULATION: CLOSING DATE FOR VOTING:
2024-02-02 2024-04-26
SUPERSEDES DOCUMENTS:
65E/978/RR
IEC SC 65E : DEVICES AND INTEGRATION IN ENTERPRISE SYSTEMS
SECRETARIAT: SECRETARY:
United States of America Mr Donald (Bob) Lattimer
OF INTEREST TO THE FOLLOWING COMMITTEES: PROPOSED HORIZONTAL STANDARD:

Other TC/SCs are requested to indicate their interest, if any,
in this CDV to the secretary.
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CENELEC, is drawn to the fact that this Committee Draft for
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submitting ISC clauses. (SEE AC/22/2007 OR NEW GUIDANCE DOC).

TITLE:
OPC Unified Architecture - Part 6: Mappings

PROPOSED STABILITY DATE: 2026
NOTE FROM TC/SC OFFICERS:
electronic file, to make a copy and to print out the content for the sole purpose of preparing National Committee positions.
You may not copy or "mirror" the file or printed version of the document, or any part of it, for any other purpose without
permission in writing from IEC.

i IEC CDV 62541-6 © IEC 2023
1 CONTENTS
2 Page
4 FIGURES . iv
5 TABLES . iv
6 FOREWORD . viii
7 1. Scope . 1
8 2. Normative references . 1
9 3. Terms, definitions and abbreviated terms . 3
10 3.1. Terms and definitions . 3
11 3.2. Abbreviated terms . 4
12 4. Overview . 5
13 5. Data encoding . 6
14 5.1. General . 6
15 5.1.1. Overview . 6
16 5.1.2. Built-in Types . 6
17 5.1.3. Guid . 7
18 5.1.4. DateTime . 7
19 5.1.5. ByteString . 7
20 5.1.6. Number, Integer and UInteger . 8
21 5.1.7. Structures and Unions . 8
22 5.1.8. ExtensionObject . 8
23 5.1.9. Variant . 9
24 5.1.10. Decimal . 9
25 5.1.11. Null, Empty and Zero-Length Arrays . 10
26 5.1.12. QualifiedName, NodeId and ExpandedNodeId String Encoding . 10
27 5.1.13. Name Encoding Rules . 12
28 5.2. OPC UA Binary . 12
29 5.2.1. General . 12
30 5.2.2. Built-in Types . 13
31 5.2.3. Decimal . 21
32 5.2.4. Enumerations . 21
33 5.2.5. Arrays . 21
34 5.2.6. Structures . 22
35 5.2.7. Structures with optional fields . 25
36 5.2.8. Unions . 26
37 5.2.9. Messages . 28
38 5.3. OPC UA XML . 28
39 5.3.1. Built-in Types . 28
40 5.3.2. Decimal . 33
41 5.3.3. Enumerations . 34
42 5.3.4. Arrays . 34
43 5.3.5. Structures . 35
44 5.3.6. Structures with optional fields . 35
45 5.3.7. Unions . 35
46 5.3.8. Messages . 36
47 5.4. OPC UA JSON . 36
48 5.4.1. General . 36

IEC CDV 62541-6 © IEC 2023 ii
49 5.4.2. Built-in Types . 37
50 5.4.3. Decimal . 41
51 5.4.4. Enumerations . 41
52 5.4.5. Arrays . 42
53 5.4.6. Structures . 42
54 5.4.7. Structures with optional fields . 43
55 5.4.8. Unions . 44
56 5.4.9. Messages . 44
57 6. Message SecurityProtocols . 44
58 6.1. Certificates . 46
59 6.1.1. General . 46
60 6.1.2. Application Instance Certificate . 46
61 6.1.3. User Certificates . 47
62 6.1.4. Issuer (CA) Certificates . 48
63 6.1.5. Certificate Revocation List (CRL) . 48
64 6.1.6. Certificate Chains . 48
65 6.2. Time synchronization . 49
66 6.3. UTC and International Atomic Time (TAI) . 49
67 6.4. Issued User Identity Tokens . 49
68 6.4.1. Kerberos . 49
69 6.4.2. JSON Web Token (JWT) . 49
70 6.4.3. OAuth2 . 50
71 6.5. WS Secure Conversation. 52
72 6.6. OPC UA Secure Conversation . 52
73 6.6.1. Overview . 52
74 6.6.2. MessageChunk structure . 52
75 6.6.3. MessageChunks and error handling . 56
76 6.6.4. Establishing a SecureChannel. 57
77 6.6.5. Deriving keys . 58
78 6.6.6. Verifying Message Security . 59
79 6.7. Elliptic Curve Cryptography (ECC) . 60
80 6.7.1. Secure Channel Handshake . 60
81 6.7.2. UserIdentityToken Encryption . 64
82 6.7.3. ECC Encrypted Secret . 65
83 7. TransportProtocols . 66
84 7.1. OPC UA Connection Protocol . 66
85 7.1.1. Overview . 66
86 7.1.2. Message structure. 66
87 7.1.3. Establishing a connection . 69
88 7.1.4. Closing a connection . 71
89 7.1.5. Error handling . 71
90 7.2. OPC UA TCP . 72
91 7.3. SOAP/HTTP . 72
92 7.4. OPC UA HTTPS . 73
93 7.4.1. Overview . 73
94 7.4.2. Session-less Services . 74
95 7.4.3. XML Encoding . 74
96 7.4.4. OPC UA Binary Encoding . 75
97 7.4.5. JSON Encoding . 76

iii IEC CDV 62541-6 © IEC 2023

98 7.5. WebSockets . 76
99 7.5.1. Overview . 76
100 7.5.2. Protocol Mapping . 77
101 7.5.3. Security . 77
102 1.1 Well known addresses . 78
103 8. Normative Contracts . 78
104 8.1. OPC Binary Schema . 78
105 8.2. XML Schema and WSDL . 78
106 8.3. Information Model Schema . 79
107 8.4. Formal definition of UA Information Model . 79
108 8.5. Constants . 79
109 8.6. DataType encoding . 79
110 8.7. Security configuration . 79
111 Annex A (normative) Constants . 80
112 A.1 Attribute Ids . 80
113 A.2 Status Codes . 80
114 A.3 Numeric Node Ids . 80
115 A.4 Media Types . 81
116 Annex B (normative) OPC UA NodeSet . 82
117 Annex C (normative) Type declarations for the OPC UA native Mapping . 83
118 Annex D (normative) WSDL for the XML Mapping . 84
119 D.1 XML Schema . 84
120 D.2 WDSL Port Types . 84
121 D.3 WSDL Bindings . 84
122 Annex E (informative) Security settings management . 85
123 E.1 Overview . 85
124 E.2 SecuredApplication . 86
125 E.3 CertificateIdentifier . 90
126 E.4 CertificateStoreIdentifier . 91
127 E.5 CertificateList . 92
128 E.6 CertificateValidationOptions . 92
129 Annex F (normative) Information Model XML Schema . 94
130 F.1 Overview . 94
131 F.2 UANodeSet . 94
132 F.3 UANode . 96
133 F.4 Reference . 98
134 F.5 RolePermission . 98
135 F.6 UAType . 98
136 F.7 UAInstance . 99
137 F.8 UAVariable . 99
138 F.9 UAMethod . 100
139 F.10 TranslationType . 101
140 F.11 UADataType . 101
141 F.12 DataTypeDefinition . 102
142 F.13 DataTypeField . 103
143 F.14 Variant . 104
144 F.15 Example . 105
145 F.16 UANodeSetChanges. 107

IEC CDV 62541-6 © IEC 2023 iv
146 F.17 NodesToAdd . 107
147 F.18 ReferencesToChange . 108
148 F.19 ReferenceToChange . 108
149 F.20 NodesToDelete . 108
150 F.21 NodeToDelete . 109
151 F.22 UANodeSetChangesStatus . 109
152 F.23 NodeSetStatusList . 109
153 F.24 NodeSetStatus . 110
156 FIGURES
158 Figure 1 – The OPC UA Stack Overview . 5
159 Figure 2 – Encoding Integers in a binary stream . 13
160 Figure 3 – Encoding Floating Points in a binary stream . 13
161 Figure 4 – Encoding Strings in a binary stream . 14
162 Figure 5 – Encoding Guids in a binary stream . 15
163 Figure 6 – Encoding XmlElement in a binary stream . 15
164 Figure 7 – A String NodeId . 16
165 Figure 8 – A Two Byte NodeId . 16
166 Figure 9 – A Four Byte NodeId . 17
167 Figure 10 – Security handshake when Creating a Session. 45
168 Figure 11 – MessageChunk for Unauthenticated Encryption Algorithms . 52
169 Figure 12 – MessageChunk for Authenticated Encryption Algorithms . 53
170 Figure 13 – ECC Key Negotiation . 60
171 Figure 14 – Signing and Encryption with Authenticated Encryption . 63
172 Figure 15 – Signing and Encryption with Unauthenticated Encryption . 63
173 Figure 16 – ECC CreateSession/ActivateSession Handshake . 64
174 Figure 17 – OPC UA Connection Protocol Message structure . 66
175 Figure 18 – Client initiated OPC UA Connection Protocol connection . 70
176 Figure 19 – Server initiated OPC UA Connection Protocol connection . 70
177 Figure 20 – Closing a OPC UA Connection Protocol connection . 71
178 Figure 21 – Scenarios for the HTTPS Transport . 73
179 Figure 22 – Setting up Communication over a WebSocket . 77
182 TABLES
183 Table 1 – Built-in Data Types . 6
184 Table 2 – Guid structure . 7
185 Table 3 – Layout of Decimal . 9
186 Table 4 – Additional ABNF Core Rules . 10
187 Table 5 – ABNF Description for a NodeId . 10
188 Table 6 – ABNF Description for a ExpandedNodeId. 11
189 Table 7 – ABNF Description for a QualifiedName . 11

v IEC CDV 62541-6 © IEC 2023
190 Table 10 – Examples of XML Encoded Names . 12
191 Table 11 – Supported Floating Point Types . 13
192 Table 12 – NodeId components . 15
193 Table 13 – NodeId DataEncoding values . 16
194 Table 14 – Standard NodeId Binary DataEncoding . 16
195 Table 15 – Two Byte NodeId Binary DataEncoding . 16
196 Table 16 – Four Byte NodeId Binary DataEncoding . 17
197 Table 17 – ExpandedNodeId Binary DataEncoding . 17
198 Table 18 – DiagnosticInfo Binary DataEncoding . 18
199 Table 19 – QualifiedName Binary DataEncoding . 18
200 Table 20 – LocalizedText Binary DataEncoding . 19
201 Table 21 – Extension Object Binary DataEncoding . 19
202 Table 22 – Variant Binary DataEncoding . 20
203 Table 23 – Data Value Binary DataEncoding . 21
204 Table 24 – Inline Matrix DataEncoding . 22
205 Table 25 – Sample OPC UA Binary Encoded structure . 23
206 Table 26 – DataTypeDefinition for “Type1” from Sample. 24
207 Table 27 –DataTypeDefinition for “Type2” from Sample. 25
208 Table 28 – Sample OPC UA Binary Encoded Structure with optional fields . 26
209 Table 29 – Sample OPC UA Binary Encoded Structure . 27
210 Table 30 – XML Data Type Mappings for Integers . 29
211 Table 31 – XML Data Type Mappings for Floating Points . 29
212 Table 32 – Components of Enumeration . 34
213 Table 33 – JSON Object Definition for a NodeId . 38
214 Table 34 – JSON Object Definition for an ExpandedNodeId . 38
215 Table 35 – JSON Object Definition for a StatusCode . 39
216 Table 36 – JSON Object Definition for a DiagnosticInfo . 39
217 Table 37 – JSON Object Definition for a QualifiedName . 40
218 Table 38 – JSON Object Definition for a LocalizedText. 40
219 Table 39 – JSON Object Definition for an ExtensionObject . 40
220 Table 40 – JSON Object Definition for a Variant . 41
221 Table 41 – JSON Object Definition for a DataValue . 41
222 Table 42 – JSON Object Definition for a Decimal . 41
223 Table 43 – JSON Encoding Rules for Structures . 42
224 Table 44 – JSON Object Definition for a Structures with Optional Fields. 43
225 Table 45 – JSON Encoding Rules for Structures with Optional Fields . 43
226 Table 46 – JSON Object Definition for a Union . 44
227 Table 47 – SecurityPolicy . 45
228 Table 48 – Application Instance Certificate . 47
229 Table 49 – User Certificate . 48
230 Table 50 – Issuer Certificate . 48
231 Table 51 – Certificate Revocation List Extensions . 48
232 Table 52 – JWT UserTokenPolicy . 50

IEC CDV 62541-6 © IEC 2023 vi
233 Table 53 – JWT IssuerEndpointUrl Definition . 50
234 Table 54 – Access Token Claims . 51
235 Table 55 – OPC UA Secure Conversation Message Header . 53
236 Table 56 – Asymmetric algorithm Security header . 54
237 Table 57 – Symmetric algorithm Security header . 55
238 Table 58 – Sequence header . 55
239 Table 59 – Message Footer for Unauthenticated Encryption Algorithms. 56
240 Table 60 – Message Footer for Authenticated Encryption Algorithms. 56
241 Table 61 – OPC UA Secure Conversation Message abort body . 57
242 Table 62 – OPC UA Secure Conversation OpenSecureChannel Service . 57
243 Table 63 – PRF inputs for RSA based SecurityPolicies . 59
244 Table 64 – Cryptography key generation parameters . 59
245 Table 65 – Deriving Client Keys from Keying Material . 62
246 Table 66 – Deriving Server Keys from Keying Material . 62
247 Table 67 – Creating a Mask for the Initialization Vector . 64
248 Table 68 – Additional Header Key Names . 65
249 Table 69 – Deriving Keys from Keying Material . 66
250 Table 70 – OPC UA Connection Protocol Message header . 67
251 Table 71 – OPC UA Connection Protocol Hello Message. 67
252 Table 72 – OPC UA Connection Protocol Acknowledge Message . 68
253 Table 73 – OPC UA Connection Protocol Error Message . 68
254 Table 74 – OPC UA Connection Protocol ReverseHello Message . 69
255 Table 75 – Client and Server Handshake during Reverse Connect . 70
256 Table 76 – OPC UA Connection Protocol error codes . 72
257 Table 77 – WebSocket Protocols Mappings . 77
258 Table 78 – Well known addresses for Local Discovery Servers. 78
259 Table A.1 – Identifiers assigned to Attributes . 80
260 Table A.2 – Media Types Assigned to OPC UA Document Formats . 81
261 Table E.1 – SecuredApplication. 87
262 Table E.2 – CertificateIdentifier . 90
263 Table E.3 – Structured directory store . 91
264 Table E.4 – CertificateStoreIdentifier . 92
265 Table E.5 – CertificateList . 92
266 Table E.6 – CertificateValidationOptions . 93
267 Table F.1 – UANodeSet. 95
268 Table F.2 – UANode . 97
269 Table F.3 – Reference . 98
270 Table F.4 – RolePermission . 98
271 Table F.5 – UANodeSet Type Nodes . 99
272 Table F.6 – UANodeSet Instance Nodes . 99
273 Table F.7 – UAInstance . 99
274 Table F.8 – UAVariable . 100
275 Table F.9 – UAMethod . 100

vii IEC CDV 62541-6 © IEC 2023

276 Table F.10 – TranslationType . 101
277 Table F.11 – UADataType . 102
278 Table F.12 – DataTypeDefinition . 102
279 Table F.13 – StructureType Enumeration Mapping . 103
280 Table F.14 – DataTypeField . 104
281 Table F.15 – UANodeSetChanges . 107
282 Table F.16 – NodesToAdd . 108
283 Table F.17 – ReferencesToChange . 108
284 Table F.18 – ReferencesToChange . 108
285 Table F.19 – NodesToDelete . 109
286 Table F.20 – ReferencesToChange . 109
287 Table F.21 – UANodeSetChangesStatus . 109
288 Table F.22 – NodeSetStatusList . 110
289 Table F.23 – NodeSetStatus . 110
IEC CDV 62541-6 © IEC 2023 viii

293 INTERNATIONAL ELECTROTECHNICAL COMMISSION
294 ____________
296 OPC UNIFIED ARCHITECTURE –
298 Part 6: Mappings
300 FOREWORD
301 1) The International Electrotechnical Commission (IEC) is a worldwide organization for standardization comprising all
302 national electrotechnical committees (IEC National Committees). The object of IEC is to promote international co-
303 operation on all questions concerning standardization in the electrical and electronic fields. To this end and in addition to
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305 Specifications (PAS) and Guides (hereafter referred to as "IEC Publication(s)"). Their preparation is entrusted to technical
306 committees; any IEC National Committee interested in the subject dealt with may participate in this preparatory work.
307 International, governmental and non-governmental organizations liaising with the IEC also participate in this preparation.
308 IEC collaborates closely with the International Organization for Standardization (ISO) in accordance with conditions
309 determined by agreement between the two organizations.
310 2) The formal decisions or agreements of IEC on technical matters express, as nearly as possible, an international
311 consensus of opinion on the relevant subjects since each technical committee has representation from all interested IEC
312 National Committees.
313 3) IEC Publications have the form of recommendations for international use and are accepted by IEC National Committees
314 in that sense. While all reasonable efforts are made to ensure that the technical content of IEC Publications is accurate,
315 IEC cannot be held responsible for the way in which they are used or for any misinterpretation by any end user.
316 4) In order to promote international uniformity, IEC National Committees undertake to apply IEC Publications transparently
317 to the maximum extent possible in their national and regional publications. Any divergence between any IEC Publication
318 and the corresponding national or regional publication shall be clearly indicated in the latter.
319 5) IEC itself does not provide any attestation of conformity. Independent certification bodies provide conformity assessment
320 services and, in some areas, access to IEC marks of conformity. IEC is not responsible for any services carried out by
321 independent certification bodies.
322 6) All users should ensure that they have the latest edition of this publication.
323 7) No liability shall attach to IEC or its directors, employees, servants or agents including individual experts and members
324 of its technical committees and IEC National Committees for any personal injury, property damage or other damage of
325 any nature whatsoever, whether direct or indirect, or for costs (including legal fees) and expenses arising out of the
326 publication, use of, or reliance upon, this IEC Publication or any other IEC Publications.
327 8) Attention is drawn to the Normative references cited in this publication. Use of the referenced publications is indispensable
328 for the correct application of this publication.
329 9) Attention is drawn to the possibility that some of the elements of this IEC Publication may be the subject of patent rights.
330 IEC shall not be held responsible for identifying any or all such patent rights.
331 International Standard IEC 62541-6 has been prepared by subcommittee 65E: Devices and integration
332 in enterprise systems, of IEC technical committee 65: Industrial-process measurement, control and
333 automation.
334 This fourth edition cancels and replaces the third edition published in 2020. This edition constitutes a
335 technical revision.
336 This edition includes the following significant technical changes with respect to the previous edition:
337 a) Added support for ECC to UA Secure Conversation
338 b) Added use of the AuthorityKeyIdentifier extension in Certificate Revocation Lists.
339 c) Enhanced JSON mapping of Unions.
340 d) Added Decimal data type encoding.
341 e) Specified ECC keyUsage rules.
342 f) Added Media assigned by IANA to UANodeSet definition.
343 g) Added requirements for user and issuer Certificates.
344 h) Added rules which specify what happens when DateTime precision is lost.
345 i) Added rules to allow for the truncation of strings containing embedded nulls.

ix IEC CDV 62541-6 © IEC 2023
346 j) Defined a normative string representation for NodeId, ExpandedNodeId and QualifiedName for
347 JSON mapping.
348 k) Require that TAI times be converted to UTC.
349 l) Allow Symbol to be omitted if unknown in JSON encoding.
350 m) Added fields needed to support RolePermissions to the UANodeSet.
352 The text of this International Standard is based on the following documents:
CDV Report on voting
65E/XX/CDV 65E/XX/RVC
354 Full information on the voting for the approval of this International Standard can be found in the report
355 on voting indicated in the above table.
356 This document has been drafted in accordance with the ISO/IEC Directives, Part 2.
357 Throughout this document and the other parts of the IEC 62541 series, certain document conventions
358 are used:
359 Italics are used to denote a defined term or definition that appears in the "Terms and definition" clause
360 in one of the parts of the IEC 62541 series.
361 Italics are also used to denote the name of a service input or output parameter or the name of a
362 structure or element of a structure that are usually defined in tables.
363 The italicized terms and names are, with a few exceptions, written in camel-case (the practice of
364 writing compound words or phrases in which the elements are joined without spaces, with each
365 element's initial letter capitalized within the compound). For example, the defined term is
366 AddressSpace instead of Address Space. This makes it easier to understand that there is a single
367 definition for AddressSpace, not separate definitions for Address and Space.
368 A list of all parts of the IEC 62541 series, published under the general title OPC Unified Architecture,
369 can be found on the IEC website.
370 The committee has decided that the contents of this document will remain unchanged until the
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