Assign Process Instances

A recipe procedure is associated with instances within a process class. For example, the process class Reactors might have two process instances: ReactorA and ReactorB. ReactorA and ReactorB are still class based, but you can independently reference them in the recipe.

You must define multiple process instances when more than one unit from a process class is needed to produce the product defined in the recipe. By default, one process instance is created for each process class. The process instance name defaults to the process class name.

If you require multiple units from the same process class, you must define the appropriate number of process instances. Likewise, you must define the appropriate transfer instances so that a differentiation exists between the resulting transfer instances.

Important: Adding process instances is not necessary if you need only one unit from within the same process class.

Example of Using Process and Transfer Instances

Example 1 shows the necessary equipment requirements for a recipe that uses one process instance per class. Example 2 shows the equipment requirements for a recipe that uses two reactor and hold tank process instances. In Example 1, all process and transfer instances automatically default to the class name. In Example 2, four process class instances are defined and four transfer instances must be defined.

Use the Process Class Instance Editor to define the specific process instances necessary for recipe construction. Instance names must be unique. The editor verifies the name to ensure validity and uniqueness. You use the instance names when you assign phases to an operation during recipe procedure development.

Important: Deleting a process instance also removes all transfer instances that were defined using the deleted process instance. If you delete all of the instances for a process class, no instances are available for assigning operations in the Procedure Editor. You can define new instances, or you can delete the process class and reassign it using the Equipment Requirements Editor to return the default instance name. All of the phases that were assigned to a deleted process instance must be manually deleted from the recipe procedure. The recipe becomes invalid until the phases are removed.

If your recipe procedure requires multiple process instance names, you should first change the name of the default instance, and then add the required instances. Remember that if you delete default process instances, the default transfer instances are deleted as well. Also, if you retain the default instance and name, and do not use it in the procedure, the AVEVA Batch Management System requires an extra unit in the train to initialize the recipe.

Note: Multiple process instances are not required unless you have a batch processing requirement for the simultaneous allocation of more than one unit from the same process class.

To assign process instances

1. On the Equipment Requirements Editor, click Process Instances.

   The Process Class Instances Editor dialog box appears.

   

2. In the Name box, type an appropriate process instance name.

   • You can accept the default instance name, which is the same as the selected process class name. If you need only one unit from the class for the recipe, you can use the default name.

   • If more than one unit is required from the process class, you must define multiple instance names.

3. Select a Selection Mode from the list.

   Selection Mode defines how a single unit is to be selected during batch processing when multiple units within the process class are available in the associated train.

   Selection Mode has two settings; Automatic (the default) and Manual. Automatic mode requires the AVEVA Batch Management System to select the specific unit. Manual mode requires an operator to manually select the specific unit from a list of available units.

   Note: If a specific unit has been assigned to a process instance, you cannot set the selection mode. In this case, the AVEVA Batch Management System allocates the assigned unit when the recipe runs.

4. Optionally select Attributes for the process instance from the list as appropriate. For details, see "Selecting Process Class Instance Attributes".

5. Click Add.