Page 191 - ExtendSim User Guide
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Routing 165
Items going to several paths
block indicates that 0.50 (50%) of the items will go to the top Queue while the remainder will be distributed equally between the remaining two Queues.
Simple Routing model
Notice that there are queues in front of the machines. If you omitted the queues, there is a pos- sibility that items arriving from the Create block could be blocked. For example, if the second item were destined for the top machine, but that machine was still processing the first item, the other machines would have to wait for items until the top machine finished processing and pulled in its item.
☞ The previous model routed items based on probabilities. To distribute an input item to any available output, in the Select Item Out dialog choose Select output based on: sequential and If output is blocked: item will try unblocked outputs.
Simple Routing One Queue model
A model similar to Simple Routing would be if there were only one queue and it was placed before the Select Item Out block. As mentioned above, however, if two sequential items are destined for the same activity they will block items that arrive behind them. The option If out- put is blocked: item will try unblocked outputs allows the Select Item Out block to try other outputs if the first choice is unable to accept the item.
Simple Routing One Queue model
As seen in the model, even though 50% of the items should be going to the top machine, item distribution is almost even. Because all the machines process items for the same amount of time, the top machine is often busy and, rather than cause the system to be blocked, its intended item is routed to a different machine.
Discrete Event

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