When you configure the Units field of a scaling parameter such as PV_SCALE or OUT_SCALE, DeltaV software has a standard list of engineering unit (EU) descriptors from which to choose. It is possible to add your own custom EU descriptors to this list from DeltaV Explorer.
When exporting and importing the entire DeltaV system for an upgrade or reinstall, select the Include the data for a DeltaV software upgrade check box on the Export and Import dialogs to save and restore custom engineering unit descriptors.