Page 251 - ExtendSim User Guide
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Resources and Shifts 225
Modeling resources
• It is more difficult to control the complex scheduling of competing resources across a num- ber of different queues using resource pools.
☞ After learning about resource pools, see “Advanced Resource Management” on page 223 for a more rigorous method of creating resource requirements, scheduling, and tracking resources.
Simple Resource Pool model
The discrete event tutorial on page 113 showed how to use and release resources from resource pools, as does the following example:
Simple Resource Pool model
The Simple Resource Pool model represents a flow of material where each piece requires one laborer for pro- cessing. In the dialog of the Resource Pool block (labelled Labor Pool), the pool of resources is called Labor and the initial number of Labor units is 3, as shown at the right. One piece of material is generated by the Create block about every two minutes. Since this model uses resource pool units, the Queue block’s type is set to resource pool queue. This causes gener- ated material to wait in the Queue until the required Labor is available.
In the Activity block, processing takes 5 minutes and
the capacity is infinite, so any number of pieces can be
worked on at a time. Within the Queue and Resource
Pool Release blocks, the quantity of resources required/released is 1 and the name of the resource pool (Labor) is listed.
Running the model shows that the amount of processing that can occur is constrained by the number of laborers available. Although the Activity has an infinite capacity, the cloned plotter graph shows that there are not enough workers available for much of the simulation.
☞ So that the focus is on the constraining effect of labor resources, the Activity block is set to infinite capacity. This causes the availability of labor, but not the processing of material, to affect the flow of items in the model.
Resource Pool dialog
Discrete Event

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