Stateflow®

Using History Junctions to Extend Charts and States

About History Junctions

History junctions extend the ability of charts and states by recording the activity of substates inside superstates. Use a history junction in a chart or superstate to indicate that its last active substate becomes active when the chart or superstate becomes active.

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Creating a History Junction

To create a junction, do the following:

1. In the Stateflow Editor toolbar, click the History Junction icon .

2. Move your pointer into the Stateflow Editor.

   The pointer takes on the shape of a junction.

3. Click to place a history junction inside the state whose last active substate it records.

To create multiple history junctions, do the following:

1. In the Stateflow Editor toolbar, double-click the History Junction icon.

2. The button is now in multiple object mode.

3. Click anywhere in the drawing area to place a history junction.

4. Move to and click another location to create an additional history junction.

5. Click the History Junction icon or press the Esc key to cancel the operation.

To move a history junction to a new location, click and drag it to the new position.

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Changing History Junction Size

To change the size of junctions, do the following:

1. Select the history junctions whose size you want to change.

2. Place your pointer over one of the junctions and right-click.

3. In the resulting submenu, place your pointer over Junction Size.

   A menu of junction sizes appears.

4. Select a size from the menu of junction sizes.

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Changing History Junction Properties

To edit the properties for a junction, do the following:

1. Right-click a junction.

2. In the resulting submenu, select Properties.

   The History Junction dialog box appears as shown.

   

3. Edit the fields in the properties dialog box, which are described in the following table:

   Field	Description
   Parent	Parent of this history junction; read-only; click the hypertext link to bring the parent to the foreground.
   Description	Textual description/comment.
   Document Link	Enter a URL address or a general MATLAB command. Examples are www.mathworks.com, mailto:email_address, and edit/spec/data/speed.txt.

4. When finished editing, select one of the following:

   • Select the Apply button to save the changes.

   • Select the Cancel button to cancel any changes you've made.

   • Select OK to save the changes and close the dialog box.

   • Select the Help button to display the Stateflow online help in an HTML browser window.

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Extending Stateflow Charts

Using Subcharts to Extend Charts