Create an Interruptible Work Center

Prerequisites:

This discussion assumes that you already have a basic understanding of how to set and use labels. For more complete information on these topics, see our book Learning SIMUL8: The Complete Guide, or ask about our training programs.

Description:

An interruptible work center will accept higher priority work items in the middle of a cycle. Sometimes referred to as 'preemption,' this option causes the work center to set aside the work item it is currently processing to select the higher priority item, process it, then reselect the previous item where it left off. It is a bit tricky to get this act of 'preemption' to work properly.

The concepts that are required for this undertaking are slightly more advanced; following is a list of the steps required in order to create an Interruptible work center:

1. Select the work center that you want interrupted and click the Interruptible Routing-in option found under the Options tab.
2. Select the storage bin that will hold the interrupted work items in the Storage Area Objects dialog.
3. Ensure that you directly connect a second work center to the interruptible work center. This second work center causes the interruption to occur by pushing work items upon the interruptible work center.
4. Create a label named 'Priority.' This determines whether an interruption will occur. If the work item that is currently being processed by the interruptible work center has a lower Priority label value than the item on route to it, then the interruption is successful.
5. Observe that SIMUL8 creates another label called 'Due.' This records the amount of processing time that remains on the interrupted work item.

A sample model for this example is available for download.