Page 193 - ExtendSim User Guide
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Sequential Ordering model
With the sequential setting, the Select Item Out block will choose outputs in successive order starting from the top output. The block’s dialog is set to If output is blocked: item will wait for blocked output.
Sequential Ordering model
The first two activities are set to process for 1 time unit while the third activity takes only 0.5 time units. For this model, even if the third activity is the first one ready to accept an item, it will only get an item after the first and second activities have pulled in an item. Also note that an item is only pulled from the Queue block when an activity has finished processing, poten- tially causing blocking in the system. The example “Balancing multiple output lines” on
page 171 shows a solution for this.
☞ To distribute an input item to any available output, choose Select output based on: sequen- tial and set the block to If output is blocked: item will try unblocked outputs.
Explicit ordering
If there are several operations, and you prefer certain ones to be active more than others, you can explicitly state which operations have a higher priority for items. This is common when you want to avoid using an operation because it is not as efficient (such as an older piece of equipment) or because it is an uneconomical use of a resource (having a supervisor wait on customers.)
Choosing the selection condition connector priority in its dialog allows the Select Item Out block to be used to specify the priority of each output.
☞ Note that this is different from assigning a priority to an item, since the Select Item Out block essentially prioritizes the output path, not the item.
Routing 167
Items going to several paths
Discrete Event

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