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Labels Step-By-Step Model Construction   

Building Labels Model

Begin a new model by clicking the button on the toolbar. Click OK on the Model Units window – we will use the default units for our model.

Step 1: Create the Objects

  • Drag objects from your Library Icon Grid onto the 3D View to create the model shown below.

Connect all of the objects as shown:

  • Connect Source1 to Queue2Queue3 and Queue4
  • Connect Queue2, Queue3 and Queue4 to Processor5
  • Connect Processor5 to Queue6

Step 2: Setup the Source Properties

All objects can store their own Labels. The Labels tab will allow you to create, view and manipulate the labels on that object.

  • Double-click on the Source to open its properties window.
  • Go to the Labels tab.
  • Check Automatically Reset Labels. This will cause the labels to reset to the value you give it when you reset the model.
  • Click Add Number Label and double click "newlabelname" to rename the label "itemsproduced".

The Source will create items with 3 itemtypes. Each itemtype will be assigned a specific color.

  • Go to the Triggers tab.
  • Click the add button for the OnCreation trigger, and select the Set Item Type and Color pick option.
  • We will be using 3 itemtypes, so keep the Involved and Item Type at their default values.

We also want to increment the "itemsproduced" label to keep track of how many items have been produced by the source.

  • Go to the Triggers tab.
  • Click the add button for the OnExit trigger, and select the Increment Value pick option.
  • In the edit box for Increment replace label(item, "labelname") with label(current, "itemsproduced").
  • Leave the By at 1. This will increment the value of the "itemsproduced" label by 1 on each time an item leaves the Source.

We will also assign items of each itemtype to go to a specific queue based on the itemtype.

  • Go to the Flow tab.
  • Choose By Expression in the Send to Port option. Leave it at the default getitemtype(item).

  • Click Apply to apply the changes you made to the Source.

Reset and run your model. If you go back to the Labels tab of the source and watch your "itemproduced" label, it will update the value as each new flow item is created.

Close the properties window of the Source. It may ask you if you want to "Update Label Reset Values?". Click No. (You want the labels to reset to zero when you reset the model.)

Step 3: Setup the Processor Properties

We want the Processor to grab items from the Queue that has the most items waiting in, or the Longest Queue. Since each of the Queues do not know how many items are in the other Queues, it is works best to have the Processor determine which Queue it will pull an item from.

  • Click on the Processor to open its properties in the Quick Properties window.
  • Click the arrow next to the Input section to expand it.
  • Check the Pull option and set the Pull Strategy to Longest Queue.

Step 4: Customizing Flowitems

We are going to store information on all the flowitems so that they can be accessed throughout the model.

  • Open the Flowitem Bin. (You can get to the FlowItem Bin either through the User Toolbar or through the Toolbox).
  • With Box selected click the under the Labels section of the Quick Properties window and add a number label.
  • Double click "LabelName" to rename the label "itemtypeorder".

We will now have the source increment the "itemtypeorder" label on each flowitem for each specific type of item. This will allow us to know in what order the flowitem was created.

  • Open the properties window for the Source.
  • Go to the Labels tab.
  • Change the label "itemsproduced" to "item1produced".
  • Select the "item1produced" label and hit the Duplicate button twice.
  • Rename the two new labels to "item2produced" and "item3produced".

In order to increment each these labels correctly, we need to customize the OnExit trigger. This will require editing the code manually, but don't worry – writing code is easy!

  • Go into the Triggers tab, and click on the button, located to the left corner of the OnExit Trigger, to open the Code Editor.

  • Click on the remove template button to get rid of the comments.
  • Feel free to delete the "PickOption Start/End" lines.

  • We want this "increment" function to increment each label individually. Write an "if" statement matching each itemtype to its own label. We will also set the new label's value to the flowitem.
if (getitemtype(item) == 1) {  int value = inc(label(current, "item1produced"), 1);  setlabel(item, "itemtypeorder", value);  }
  • Write the same statements for itemtype 2 and 3. The code should look like this when you are done:

  • Click OK to apply and close the Code window.
  • Click OK to apply and close the Properties window.

Step 5: Process the Flowitems

In this step, we will change the way the Processor processes the boxes.

  • Open the Processor's Properties window.
  • Go to the Triggers tab.
  • Click the code edit button next to the OnProcessFinish trigger.
  • Write an if statement that will only allow every tenth item of each type to be set to a specific size:
if (getlabel(item, "itemtypeorder") % 10 == 0) {  setsize(item,1,1,1);  }

Note:You don't need to do this two more times, because it applies to any flowitem with the "itemtypeorder" label.

  • Click OK on the Edit Code window as well as the Properties window.

Reset and Run your model. Your model should begin to look something like this:

This completes the the Labels tutorial. Congratulations!

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paul.t contributed to this article


FlexSim 2016.1