IEC 62541-8:2020

OPC Unified Architecture - Part 8: Data Access

IEC 62541-8:2020

Name:IEC 62541-8:2020   Standard name:OPC Unified Architecture - Part 8: Data Access
Standard number:IEC 62541-8:2020   language:English language
Release Date:21-Jun-2020   technical committee:SC 65E - Devices and integration in enterprise systems
Drafting committee:WG 8 - TC 65/SC 65E/WG 8   ICS number:01 - GENERALITIES. TERMINOLOGY. STANDARDIZATION. DOCUMENTATION

IEC 62541-8
Edition 3.0 2020-06
REDLINE VERSION
INTERNATIONAL
STANDARD
colour
inside
OPC unified architecture –
Part 8: Data access




your local IEC member National Committee for further information.

IEC Central Office Tel.: +41 22 919 02 11
3, rue de
CH-1211 Geneva 20
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and withdrawn publications.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.

need further assistance, please contact the Customer Service

.
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
...

  • Relates Information
  • ISO 8130-9:1992

    ISO 8130-9:1992 - Coating powders
    09-28
  • EN 352-2:2020/FprA1

    EN 352-2:2021/oprA1:2023
    09-28
  • IEC TS 61158-4:1999

    IEC TS 61158-4:1999 - Digital data communications for measurement and control - Fieldbus for use in industrial control systems - Part 4: Data Link protocol specification Released:3/24/1999 Isbn:2831847656
    09-28
  • HD 566 S1:1990

    HD 566 S1:1998
    09-28
  • ISO 5131:1982/Amd 1:1992

    ISO 5131:1982/Amd 1:1992
    09-28
  • EN 60598-2-22:1990

    EN 60598-2-22:1996
    09-27
  • ISO 8504-2:1992

    ISO 8504-2:1992 - Preparation of steel substrates before application of paints and related products -- Surface preparation methods
    09-27
  • EN 12165:2024

    prEN 12165:2022
    09-27
  • IEC TS 61158-6:1999

    IEC TS 61158-6:1999 - Digital data communications for measurement and control - Fieldbus for use in industrial control systems - Part 6: Application Layer protocol specification Released:3/24/1999 Isbn:2831847613
    09-27
  • ISO 4252:1992

    ISO 4252:1992 - Agricultural tractors -- Operator's workplace, access and exit -- Dimensions
    09-27