OPC UA defines a preferred namespace for EngineeringUnits. The mapping of IO-Link unitCode to OPC UA EngineeringUnits uses the EngineeringUnits of the preferred OPC UA namespace, when they are also defined. Otherwise, it uses its own namespace. The mapping is defined in a CSV document.

The CSV released with this version of the specification can be found here:

http://www.opcfoundation.org/UA/schemas/IOLink/1.0/EngineeringUnits.csv

NOTE    The latest CSV that is compatible with this version of the specification can be found here:

http://www.opcfoundation.org/UA/schemas/IOLink/EngineeringUnits.csv