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Tutorial 109
A basic discrete event model
Place an Executive block (Item library) on the top left corner of the model worksheet
The Executive block does event scheduling and manages discrete event simulations. It must be
present in every discrete event model.
Start small
In building any simulation model, it is easiest to start with a simple subset of the process and add detail until you arrive at a completed model that approximates the system that’s being modeled. This allows you to test at various stages while making the model building process more manageable.
The first step is to model the car wash with one bay that just washes cars. Since there is only one line into the car wash, each car must wait in line for the preceding car to move through the wash before it can enter. When finished with this portion of the tutorial, your model should look like the one shown below.
Modeling a waiting line with a single server
Modeling a waiting line with a single server
The following table lists the blocks that will be added to the worksheet and their use in the model. Except for the Plotter block from the Plotter library, the blocks in the table are from the Item library.
Category:Name (Label)
Routing:Create (Dirty Cars)
Queues:Queue (Entry Line)
Block Function
Generates items or values, either ran- domlyoronschedule.Ifusedtogen- erate items, it pushes them into the simulation and should be followed by a queue-type block.
Acts as a sorted queue or as a resource pool queue. As a sorted queue, holds items in FIFO or LIFO order, or sorts items based on their attribute or priority.
Purpose in Car Wash Model
Generates cars that arrive randomly, approximatelyevery4minutes.
Holds the cars and, when the wash bay is available, releases cars one by one in first-in, first-out order.
Discrete Event

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