5.6.4.5 Mapping of IEC 62720 to EUInformation

This clause specifies how to apply the Common Data Dictionary (IEC CDD) published as IEC/TS 62720 by the “International Electrotechnical Commission - IEC” to the EUInformation Structure.

The units and their identifiers, along with their relationships, is maintained in the IEC Common Data Dictionary (CDD): https://cdd.iec.ch/cdd/iec62720/iec62720.nsf/TreeFrameset. Specific units can only be found via search. A ‘*’ as search string will return all units.

Figure 6 specifies the dialog to search for units and optionally export them.

Figure 6 – Searching Units in the IEC Common Data Dictionary

Table 25 contains a small excerpt of the relevant columns in IEC 62720:

Table 26 – Examples from the IEC CDD
Excerpt of Units from IEC/TS 62720
CodeSymbolName
UAA017Ωohm
UAA033°Cdegree Celsius
UAA070μNmicronewton
UAA172Jjoule
UAA539ininch
UAB044in/s2inch per second squared
UAA497g/sgram per second

All units in the IEC CDD have been extracted and mapped to the EUInformation fields. The list is available here:

https://reference.opcfoundation.org/files/IEC62720_to_OPCUA.csv?u=http://opcfoundation.org/UA/

This mapping has been generated as follows:

	Int32 unitId = 0;	Int32 c;	for (i=0; i<6;i++)	{
		c = UnitCode[i] 0x1f;	 	unitId = unitId << 5;		unitId = unitId | c;	}