Unit classes

Unit classes are the logical groupings of like equipment. They define common properties of the like equipment, regardless of individual manufacturers (MIXERS, REACTORS, STORAGE TANKS).

Using unit classes facilitates the creation of units. Each unit is an instance of one class and inherits the common properties of that class. Individual differences (for example, manufacturer specifications) can be defined at the unit level.

An Example of a DeltaV Unit Class

Unit classes have the following properties:

  • Unit parameter definitions

  • Phase class associations

  • Alias names

  • Unit modules (that is, the instantiation of the unit class)

Unit class definitions are located in the DeltaV system library under the Advanced Definitions category. The names are system wide and are shared with other tagged objects. Therefore, the names must be unique through the system.

The following also apply to unit classes:

  • Unit modules are created based on a unit class.

  • Phase classes are associated with a unit class.

  • Control modules are contained by a unit class.

  • Equipment modules are contained by a unit class.

  • A unit module can use the phase algorithm defined by the phase classes that are associated with the module's unit class.