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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
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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
...