Page 143 - ExtendSim User Guide
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Final model
For your reference, the com- pleted model, titled Final Car Wash, is located in the folder \Examples\Tutorials\Discrete Event\Car Wash. This model also has buttons for running the model and turning animation on and off. For information about adding buttons to models, see “Creating a dashboard interface” on page 584.
Further exploration
Final Car Wash model
Tutorial 117
Further exploration
There are many other ways to modify the model shown in this section. Some possible varia- tions are:
• Havethewashorwash/waxtimesbedynamicratherthanstatic.Thereareseveralwaysto do this:
• SpecifythatthedelayintheActivityblockisfromadistribution.Thiswouldcausethe processing times to be random, rather than fixed as shown in “Random processing time” on page 183.
• UseaLookupTableblocktoschedulethewashorwash/waxtimestobedependenton the time of day, as seen in “Scheduled processing time” on page 182.
• Have an Equation block (Value library) calculate a wash time based on model condi- tions. Then connect the Equation’s output to the Activity block’s D input.
• Assignattributestothecarstorepresenttheexpectedtimetoprocessit,witheachtype of car requiring a different processing time. This is especially useful in a manufactur- ing environment where there are several types of products that require different process times.
• Add more wash or wax bays, then use the Select Item Out block to give preference to spe- cific bays rather than just letting cars randomly go to any available bay.
• Have arriving cars look at the waiting line and not enter the car wash if the line is too long (balking) or leave the line after arrival if the wait time reaches a certain point (reneging). These concepts are discussed more in “Queueing considerations” on page 143.
• Modelotheraspectsofthecarwash,suchasthelimitedcapacityofaparkinglottoholdcars after the wash process. To do this, use the Resource Pool block to represent the total number of parking spaces available. Then set the Queue block as a Resource Pool queue to hold cars waiting for a parking space. The Resource Pool Release block would release parking spaces as the cars pass through it.
• ConsiderusingahierarchicalblockfromtheTemplateslibrarytoreplacesomeofthefunc- tionality in this model. For example, the “Create - Arrivals Vary by Time” template would be helpful if you had a historical record of car arrivals.
Discrete Event

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