A Unit is a group of Tags. The Unit can be any name, but usually corresponds to a physical device (for example MixTank1, MixTank2, MixTank3 etc.) Equipment Lineup and Process Unit are other terms for Unit. The tagnames assigned to the "Unit" provides the link to the physical world.
By defining multiple Units, the same recipe can be downloaded to different groups of tags by operators and users. In selecting a recipe, operators select the recipe and unit to download.