Lesson 2 Step-By-Step Model Construction

Building Model 2

To start building model 2 you will need to load model 1 from the previous lesson.

If at any time you encounter difficulties while building this model, a fully functional tutorial model can be found at http://www.flexsim.com/tutorials

Step 1: Load model 1

If you do not have Model 1 open, load it by clicking the button on the toolbar. Select the file for model 1 (.fsm file) saved from lesson 1.
We want to make our flowitems exit the Source at a faster rate for this lesson. Double-click on the Source to open its Properties window, and under Inter-Arrivaltime change the Scale to 12.

Step 2: Create a dispatcher and 2 operators

The Dispatcher is used to queue up task sequences for a team of operators or transporters. In this case it will be used with 2 operators that will be used to move flowitems from the queue to the testers.

Create a Dispatcher and name it Dispatcher.
Create 2 operators and name them Operator1 and Operator2.

Step 3: Connect the Dispatcher and operators

The queue is going to request an operator to pick up the flowitem and take it to one of the testers. The flow logic has already been set on the queue in lesson 1. You will not need to change the flow logic. You will only need to request an operator to be used for the task. Since we are using 2 operators, we will use a dispatcher to queue the requests and send them to a free operator to perform the task. If we only had 1 operator, we would not need the dispatcher and could connect the operator to the queue directly.

In order to use the dispatcher to direct a team of operators to perform a task, the dispatcher must be connected to the central port of the object requesting the operator. The central port is located in the center bottom position of the object. To connect the central port of the dispatcher to the queue, press and hold the "S" key on the keyboard and then click-and-drag from the dispatcher to the queue. When you release the mouse button a connection from the dispatcher's central port will connect to the central port of the queue. You can also use the Connect Center Ports mode from the Mode Toolbar to do this.

In order for the dispatcher to send tasks to the operators, the dispatcher's output ports needs to be connected to the operators' input ports. This must be done for each operator.

Connect Queue to Dispatcher with a center connection (S key).
Connect Dispatcher to Operator1 and Operator2 with a standard connection (A key).

Step 4: Modify Queue Flow to Use Transport (operators)

The next step is to modify the Queue's flow parameters so it uses the operators.

You may define the Queue's flow and transport options by clicking on the Queue in the 3D view to display its properties in the Quick Properties window.

Alternatively, you can open the object's properties window.

Double-click Queue to open its Properties window.
Click the Flow tab
Check the Use Transport box. The Request Transport From list will become available. This picklist allows you to select which transporter or Operator to move the item based on the center port number. In this case it is the object connected to center port 1 (the Dispatcher) that assigns the operator to the task, so the default settings will work here.
Click OK to close the Properties window.

Step 5: Save the Model, and Test Run

Now we should run the model to make sure that the changes we have made are working.

Reset the model and then Save the model by clicking the button on the toolbar.
Run the model to verify that the operators are moving the flowitems from the queue to the testers.

Step 6: Using operators for the Process Time

In order for the testers to use the operators during processing, a connection must be made between the central ports of each tester to central ports of the dispatcher. Then the process must be changed to require an operator.

Connect Dispatcher to Processor1, Processor2, and Processor3 with center connections (S key).

Double-click Processor1 to open its Properties window.
On the Processor tab, check Use Operator(s) for Process. Number of operators and Pick Operator will become available.

Click OK to close the Properties window.
Repeat this step for Processor2 and Processor3.

Step 7: Disconnect the Conveyors from the Sink

Before adding the conveyor queue it is necessary to disconnect the input and output port connections between the conveyors and the sink. This is done by pressing and holding the "Q" key on the keyboard and then click-and-dragging from the conveyor to the sink.

Disconnect the three conveyors from Sink (Q key).
Create a Queue, place it to the right of the conveyors, and name it conveyorqueue.
Connect the three conveyors to conveyorqueue (A key).
Connect conveyorqueue to Sink (A key).

Now that the layout has been revised and the port connections created, the fork truck can be added.

Step 8: Adding the transporter

Adding the transporter to the model to move flowitems from the conveyorqueue to the sink is exactly the same as adding operators to move flowitems from the input queue to the testers. There will be only 1 transporter in the model, so there is no need for a dispatcher. The transporter will be directly connected to a central port of the conveyorqueue.

Move Sink to the right about 10 units to simulate travel distance.
Create a transporter, place it near conveyorqueue, and name it transporter.
Connect conveyorqueue to transporter with a center connection (S key).

Step 9: Adjust the Queue's Flow Parameters to Use the transporter

You may define the Queue's flow and transport options by clicking on the Queue in the 3D view to display its properties in the Quick Properties window.

Alternatively, you can open the object's properties window.

Double-click conveyorqueue to open its Properties window.
Click the Flow tab and check Use Transport. The central port 1 of the queue is already connected so there is no need for any adjustments.

Click OK to close the Properties window.
Reset and Save the model.

Step 10: Run the Model

Run the model.

This is the rewarding part of building the model. It's time to check the model to see if it is working the way you want. While the model is running, you can use the animation to visually inspect the model to see if everything is working properly.

You should see the operators moving back and forth between the queue and the processors. The transporter should be moving flowitems from the queue to the sink. You will notice that when a processor is waiting for an operator to perform the setup, a yellow square is shown under the processor.

Step 11: Analyzing the Output

Select Dashboard > Add a dashboard from the FlexSim Toolbar. The dashboard window will appear.
Add a line graph by clicking the button. Select Content vs Time. The object selection window will appear.
Click the to add objects to the graph. Add Queue and conveyorqueue. Click Select .
Change the chart name to Queue Content vs Time and click OK. A blank chart should appear in the dashboard.

Add a legend by double-clicking the chart in the dashboard. Select the General tab and check the Show Legend checkbox. Click OK to return to the dashboard.

Now add a bar chart by clicking the button and selecting the State Bar option.
Add all of the processors to the chart.
Change the chart name to Processor State Bar and click OK. Another blank chart should appear in the dashboard.
Add another state bar chart to the dashboard for the operators. Follow the same steps as above, but add all the operators to the chart, instead of processors. Change the chart name to Operator State Bar and click OK.
Reset and Run the model. The graphs will dynamically update.

Hold the mouse over one of the bars in the Processor State Bar graph. A ToolTip will appear and give more information.

It becomes obvious that if you add one more Operator the model will run better. Even though the flowitems may still back up at the input queue it will be in its optimum configuration with the addition of a third operator.

Create an Operator, place near the other two, and name it Operator3.
Connect Dispatcher to Operator3 (A key).
Double-click the Operator State Bar chart and add Operator3.
Reset, Save, and Run the model.

With one more operator, the processor wait time goes down and that the Queue stays a a much lower content level.

This ends Lesson 2. Congratulations! Can you go the extra mile?

To continue the tutorial, go to Lesson 2 Extra Mile.

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