Queues

A queue is a location that imitates the progressive movement and queuing of waiting lines. When an entity enters a queue, ProModel executes any operation logic for the entity and then moves it to the end of the queue. To have processing logic execute after an entity arrives at the end of a queue, use a MOVE statement in the operation logic. A move statement causes the entity to move to the end of the queue where any additional operation logic defined will be processed. Operation logic following a MOVE statement actually gets processed after the elapsed time that the entity would have reached the very end of the queue if no other entities were ahead of it. Following a MOVE statement, any operation statement is valid except for CREATE, SPLIT AS, UNGROUP, UNLOAD, or another MOVE statement.

If a MOVE statement is specified that includes a move time (e.g., MOVE for 5.2 sec), the entity speed and length of the queue are ignored. If a move time is not included with the MOVE statement, the move time is based on the entity speed and length of the queue (if no queue length or entity speed is defined, the move time is zero).

Entities in a queue may not be preempted by other entities and, once entities begin movement in a queue, are not allowed to pass each other. After the specified move time, however, entities continue processing any additional operation and output logic. A "No Queuing" rule specified for a queue location allows entities to depart in any order after completing their move time.

Queues are drawn from the beginning to the end of the center-line and are assigned a default length based on the graphic scale. However, the default queue length may be overridden by entering a different length. When a queue is modified graphically, the length will automatically be recalculated based on the graphic scale unless you checked the "Recalculate path lengths when adjusted" option. You can access this option from the Tools menu under Options.