Process and Transfer Instances

In addition to specifying process classes, you can define specific instances of each process class. You must define process multiple instances when your recipe procedure uses more than one unit of the same class. When the recipe is processed, each process instance corresponds to an actual unit. You can assign a specific unit to a process instance, or you can allow the unit to be selected when the recipe runs. When one or more process instances have specific units assigned to them, the recipe is called an equipment dependent recipe. The recipe always uses specific equipment for its processing. When process instances are not assigned to specific units, the recipe is called an equipment independent recipe.

Normally, whenever you define process instances, you also define all the resulting transfer instances. Defining multiple instances enables you to simultaneously process-in or transfer-to multiple units within the same process class. A process instance can have a specific attribute range or it can have a specific unit assignment. Using multiple instances enables you to create recipes that are equipment independent or dependent.