Simulates a first-in-first-out (FIFO) queue for buffering items needed by machines, conveyors, or batching operations. The maximum length, which determines how many items the buffer can hold, can be set in the dialog.
The instantaneous buffer length and wait time can be monitored at the L and W connectors, respectively. The L and W connectors output a noValue when data is not valid.
When full, the buffer will not receive any more items until an item has been removed from the buffer output; alternately, you can specify in the dialog that the simulation should stop when the buffer is full. In the dialog you can view the average and maximum buffer length and wait time, the number of items that have entered and left the buffer, and utilization of the buffer.
Dialog Choices
Arrivals: Number of items that have entered the block.
Average length: Average number in the activity. This is a time-weighted average.
Average wait: Average time an item spends in this block.
continuous: The L and W outputs are always available for viewing and decisions.
Departures: Number of items that have left the block.
histogram: The L and W outputs are only available when queue events occur. Use this choice only if these connectors are connected to a Histogram plotter.
Maximum buffer length: Maximum number of items the activity can hold. This determines the “blocking” of the queue.
Max. length: Longest length of the queue during this simulation.
Max. wait: Longest wait in the queue during this simulation.
Stop simulation when the buffer is full: Normally, this is not selected. When the buffer fills the F connector goes to 1 and no more entities are allowed in the queue. This can be used for “balking”. If this option is selected, a full buffer will stop the simulation immediately.
Utilization: The percentage of time the block was in use over the course of the simulation run. The total time that items were in the block is used in the calculation, including the time items were blocked from leaving because the next block could not pull them in.
Connectors
The input is items to be buffered.
The output is the items from the buffer.
F: Outputs 1 when the block is full, otherwise outputs 0.
L: Number of items in the buffer.
W: Wait time for items leaving the buffer.
Animation
Flashes when an item arrives and when an item leaves, and shows the number of items available in the block.
