IEC 62541-8:2020
(Main)OPC Unified Architecture - Part 8: Data Access
OPC Unified Architecture - Part 8: Data Access
IEC 62541-8:2020 is available as IEC 62541-8:2020 RLV which contains the International Standard and its Redline version, showing all changes of the technical content compared to the previous edition.
IEC 62541-8:2020 is part of the overall OPC Unified Architecture (OPC UA) standard series and defines the information model associated with Data Access (DA). It particularly includes additional VariableTypes and complementary descriptions of the NodeClasses and Attributes needed for Data Access, additional Properties, and other information and behaviour.
The complete address space model, including all NodeClasses and Attributes is specified in IEC 62541-3. The services to detect and access data are specified in IEC 62541-4.
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) added new VariableTypes for AnalogItems;
b) added an Annex that specifies a recommended mapping of OPC UA Dataccess to OPC COM DataAccess;
c) changed the ambiguous description of "Bad_NotConnected";
d) updated description for EUInformation to refer to latest revision of UNCEFACT units.
Architecture unifiée OPC - Partie 8: Accès aux données
IEC 62541-8:2020 est disponible sous forme de IEC 62541-8:2020 RLV qui contient la Norme internationale et sa version Redline, illustrant les modifications du contenu technique depuis l'édition précédente.
L'IEC 62541-8:2020 fait partie intégrante de la série de normes générales sur l'architecture unifiée OPC (OPC UA). Elle définit le modèle d'information associé à l'Accès aux données (DA). Elle spécifie notamment des VariableTypes supplémentaires et fournit des descriptions complémentaires concernant les NodeClasses et attributs nécessaires pour l'Accès aux données, ainsi que des propriétés supplémentaires et d'autres paramètres relatifs aux informations et au comportement.
Le modèle d'espace d'adresses complet, comprenant toutes les NodeClasses et tous les Attributs, est spécifié dans l'IEC 62541-3. Les services de détection et d'accès aux données sont spécifiés dans l'IEC 62541-4.
Cette troisième édition annule et remplace la deuxième édition parue en 2015. Cette édition constitue une révision technique.
Cette édition inclut les modifications techniques majeures suivantes par rapport à l'édition précédente:
a) ajout de nouveaux VariableTypes pour les AnalogItems;
b) ajout d'une annexe qui spécifie le mapping recommandé entre OPC UA DataAccess et OPC COM DataAccess;
c) modification de la description ambiguë de "Bad_NotConnected";
d) mise à jour de la description de EUInformation pour renvoyer à la dernière révision des unités CEFACT-ONU.
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IEC 62541-8 ®
Edition 3.0 2020-06
REDLINE VERSION
INTERNATIONAL
STANDARD
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inside
OPC unified architecture –
Part 8: Data access
All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized in any form
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About the IEC
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International Standards for all electrical, electronic and related technologies.
About IEC publications
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IEC 62541-8 ®
Edition 3.0 2020-06
REDLINE VERSION
INTERNATIONAL
STANDARD
colour
inside
OPC unified architecture –
Part 8: Data access
INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
ICS 25.040.40; 35.100.05 ISBN 978-2-8322-8572-5
– 2 – IEC 62541-8:2020 RLV © IEC 2020
CONTENTS
FOREWORD . 5
1 Scope . 8
2 Normative references . 8
3 Terms, definitions and abbreviated terms . 8
3.1 Terms and definitions . 8
3.2 Abbreviated terms and symbols . 9
4 Concepts . 9
5 Model . 10
5.1 General . 10
5.2 SemanticsChanged . 11
5.3 Variable Types . 11
5.3.1 DataItemType . 11
5.3.2 AnalogItem VariableTypes . 12
5.3.3 DiscreteItemType . 15
5.3.4 ArrayItemType . 18
5.4 Address Space model . 24
5.5 Attributes of DataItems . 25
5.6 DataTypes . 26
5.6.1 Overview . 26
5.6.2 Range . 26
5.6.3 EUInformation . 26
5.6.4 ComplexNumberType . 28
5.6.5 DoubleComplexNumberType . 28
5.6.6 AxisInformation . 29
5.6.7 AxisScaleEnumeration . 29
5.6.8 XVType . 30
6 Data Access specific usage of Services . 30
6.1 General . 30
6.2 PercentDeadband . 30
6.3 Data Access status codes . 31
6.3.1 Overview . 31
6.3.2 Operation level result codes . 31
6.3.3 LimitBits . 33
Annex A (informative) OPC COM DA to UA mapping . 34
A.1 Overview. 34
A.2 Security considerations . 34
A.3 COM UA wrapper for OPC DA Server . 34
A.3.1 Information Model mapping . 34
A.3.2 Data and error mapping . 38
A.3.3 Read data . 41
A.3.4 Write Data . 42
A.3.5 Subscriptions . 43
A.4 COM UA proxy for DA Client . 43
A.4.1 Guidelines . 43
A.4.2 Information Model and Address Space mapping . 43
A.4.3 Data and error mapping . 47
A.4.4 Read data . 49
A.4.5 Write data . 50
A.4.6 Subscriptions . 50
Figure 1 – OPC DataItems are linked to automation data . 10
Figure 2 – DataItem VariableType hierarchy . 11
Figure 3 – Graphical view of a YArrayItem . 20
Figure 4 – Representation of DataItems in the AddressSpace . 25
Figure A.1 – Sample OPC UA Information Model for OPC DA . 35
Figure A.2 – OPC COM DA to OPC UA data and error mapping . 39
Figure A.3 – Status Code mapping. 40
Figure A.4 – Sample OPC DA mapping of OPC UA Information Model and Address
Space . 44
Figure A.5 – OPC UA to OPC DA data & error mapping . 47
Figure A.6 – OPC UA Status Code to OPC DA quality mapping . 49
Table 1 – DataItemType definition . 12
Table 2 – AnalogItemType BaseAnalogType definition . 12
Table 3 – AnalogItemType definition . 14
Table 4 – AnalogUnitType definition . 14
Table 5 – AnalogUnitRangeType definition . 15
Table 6 – DiscreteItemType definition . 15
Table 7 – TwoStateDiscreteType definition . 16
Table 8 – MultiStateDiscreteType definition . 16
Table 9 – MultiStateValueDiscreteType definition . 17
Table 10 – ArrayItemType definition . 18
Table 11 – YArrayItemType definition . 19
Table 12 – YArrayItem item description. 21
Table 13 – XYArrayItemType definition . 21
Table 14 – ImageItemType definition . 22
Table 15 – CubeItemType definition . 23
Table 16 – NDimensionArrayItemType definition . 24
Table 17 – Range DataType structure . 26
Table 18 – Range definition . 26
Table 19 – EUInformation DataType structure . 26
Table 20 – EUInformation definition . 27
Table 21 – Examples from UNECE Recommendation N° 20 . 27
Table 22 – ComplexNumberType DataType structure . 28
Table 23 – ComplexNumberType definition . 28
Table 24 – DoubleComplexNumberType DataType structure . 28
Table 25 – DoubleComplexNumberType definition . 29
Table 26 – AxisInformation DataType structure . 29
Table 27 – AxisScaleEnumeration values. 29
Table 28 – AxisScaleEnumeration definition . 30
– 4 – IEC 62541-8:2020 RLV © IEC 2020
Table 29 – XVType DataType structure . 30
Table 30 – XVType definition . 30
Table 31 – Operation level result codes for BAD data quality . 31
Table 32 – Operation level result codes for UNCERTAIN data quality . 32
Table 33 – Operation level result codes for GOOD data quality . 32
Table A.1 – OPC COM DA to OPC UA Properties mapping . 37
Table A.2 – DataTypes and mapping . 40
Table A.3 – Quali
...
IEC 62541-8 ®
Edition 3.0 2020-06
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
colour
inside
OPC unified architecture –
Part 8: Data access
Architecture unifiée OPC –
Partie 8: Accès aux données
All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized in any form
or by any means, electronic or mechanical, including photocopying and microfilm, without permission in writing from
either IEC or IEC's member National Committee in the country of the requester. If you have any questions about IEC
copyright or have an enquiry about obtaining additional rights to this publication, please contact the address below or
your local IEC member National Committee for further information.
Droits de reproduction réservés. Sauf indication contraire, aucune partie de cette publication ne peut être reproduite
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Switzerland
About the IEC
The International Electrotechnical Commission (IEC) is the leading global organization that prepares and publishes
International Standards for all electrical, electronic and related technologies.
About IEC publications
The technical content of IEC publications is kept under constant review by the IEC. Please make sure that you have the
latest edition, a corrigendum or an amendment might have been published.
IEC publications search - webstore.iec.ch/advsearchform Electropedia - www.electropedia.org
The advanced search enables to find IEC publications by a The world's leading online dictionary on electrotechnology,
variety of criteria (reference number, text, technical containing more than 22 000 terminological entries in English
committee,…). It also gives information on projects, replaced and French, with equivalent terms in 16 additional languages.
and withdrawn publications. Also known as the International Electrotechnical Vocabulary
(IEV) online.
IEC Just Published - webstore.iec.ch/justpublished
Stay up to date on all new IEC publications. Just Published IEC Glossary - std.iec.ch/glossary
details all new publications released. Available online and 67 000 electrotechnical terminology entries in English and
once a month by email. French extracted from the Terms and Definitions clause of
IEC publications issued since 2002. Some entries have been
IEC Customer Service Centre - webstore.iec.ch/csc collected from earlier publications of IEC TC 37, 77, 86 and
If you wish to give us your feedback on this publication or CISPR.
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IEC 62541-8 ®
Edition 3.0 2020-06
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
colour
inside
OPC unified architecture –
Part 8: Data access
Architecture unifiée OPC –
Partie 8: Accès aux données
INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
COMMISSION
ELECTROTECHNIQUE
INTERNATIONALE
ICS 25.040.40; 35.100.05 ISBN 978-2-8322-8464-3
– 2 – IEC 62541-8:2020 © IEC 2020
CONTENTS
FOREWORD . 5
1 Scope . 7
2 Normative references . 7
3 Terms, definitions and abbreviated terms . 7
3.1 Terms and definitions . 7
3.2 Abbreviated terms . 8
4 Concepts . 8
5 Model . 9
5.1 General . 9
5.2 SemanticsChanged . 10
5.3 Variable Types . 10
5.3.1 DataItemType . 10
5.3.2 AnalogItem VariableTypes . 11
5.3.3 DiscreteItemType . 14
5.3.4 ArrayItemType . 17
5.4 Address Space model . 23
5.5 Attributes of DataItems . 24
5.6 DataTypes . 25
5.6.1 Overview . 25
5.6.2 Range . 25
5.6.3 EUInformation . 25
5.6.4 ComplexNumberType . 27
5.6.5 DoubleComplexNumberType . 27
5.6.6 AxisInformation . 28
5.6.7 AxisScaleEnumeration . 28
5.6.8 XVType . 29
6 Data Access specific usage of Services . 29
6.1 General . 29
6.2 PercentDeadband . 29
6.3 Data Access status codes . 30
6.3.1 Overview . 30
6.3.2 Operation level result codes . 30
6.3.3 LimitBits . 32
Annex A (informative) OPC COM DA to UA mapping . 33
A.1 Overview. 33
A.2 Security considerations . 33
A.3 COM UA wrapper for OPC DA Server . 33
A.3.1 Information Model mapping . 33
A.3.2 Data and error mapping . 37
A.3.3 Read data . 40
A.3.4 Write Data . 41
A.3.5 Subscriptions . 42
A.4 COM UA proxy for DA Client . 42
A.4.1 Guidelines . 42
A.4.2 Information Model and Address Space mapping . 42
A.4.3 Data and error mapping . 46
A.4.4 Read data . 48
A.4.5 Write data . 49
A.4.6 Subscriptions . 49
Figure 1 – OPC DataItems are linked to automation data . 9
Figure 2 – DataItem VariableType hierarchy . 10
Figure 3 – Graphical view of a YArrayItem . 19
Figure 4 – Representation of DataItems in the AddressSpace . 24
Figure A.1 – Sample OPC UA Information Model for OPC DA . 34
Figure A.2 – OPC COM DA to OPC UA data and error mapping . 38
Figure A.3 – Status Code mapping. 39
Figure A.4 – Sample OPC DA mapping of OPC UA Information Model and Address
Space . 43
Figure A.5 – OPC UA to OPC DA data & error mapping . 46
Figure A.6 – OPC UA Status Code to OPC DA quality mapping . 48
Table 1 – DataItemType definition . 11
Table 2 – BaseAnalogType definition . 12
Table 3 – AnalogItemType definition . 13
Table 4 – AnalogUnitType definition . 13
Table 5 – AnalogUnitRangeType definition . 14
Table 6 – DiscreteItemType definition . 14
Table 7 – TwoStateDiscreteType definition . 15
Table 8 – MultiStateDiscreteType definition . 15
Table 9 – MultiStateValueDiscreteType definition . 16
Table 10 – ArrayItemType definition . 17
Table 11 – YArrayItemType definition . 18
Table 12 – YArrayItem item description. 20
Table 13 – XYArrayItemType definition . 20
Table 14 – ImageI
...
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