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Manage the Input Trigger of a MATLAB Function Block

An input trigger is an input that executes the MATLAB Function block when activated. See Using Triggered Subsystems. You can add one input trigger to each MATLAB Function block by using the Ports and Data Manager or the Model Explorer.

To use the Ports and Data Manager, double-click the MATLAB Function block to open the MATLAB Function Block Editor and click Ports & Data Manager. You can return to the block code by clicking the Go to Block Editor button Go to Block Editor button.

To use the Model Explorer, in the Modeling tab, in the Design section, click Model Explorer. In the Model Hierarchy pane, expand the model tree view and select the MATLAB Function block.

When using the Ports and Data Manager or the Model Explorer, you can create, manage, and delete input triggers:

  • Modify the input trigger properties by selecting the input trigger in the left pane of the Ports and Data Manager or the Contents of pane in the Model Explorer.

  • Add an input trigger by clicking Add > Trigger or the Add Trigger button Add Trigger button.

  • Delete the input trigger by selecting the input trigger and clicking Edit > Delete or the Delete button Delete button.

Set Input Trigger Properties

After clicking the input trigger you want to modify in the Ports and Data Manager or the Model Explorer, you can set the following properties.

Name

Specifies the name of the input trigger, following the naming conventions used in MATLAB®.

Port

Specifies the index of the port associated with the input trigger. The property is read-only. Because you can only add one trigger to a MATLAB Function block, this property is always 1.

Trigger

Specifies the type of event that triggers the MATLAB Function block. You can select one of the following types:

Trigger EventDescription
RisingThe trigger signal executes the MATLAB Function block when the signal rises from a negative or zero value to a positive value or from a negative value to zero.
FallingThe trigger signal executes the MATLAB Function block when the signal falls from a positive or zero value to a negative value or from a positive value to zero..
EitherThe trigger signal executes the MATLAB Function block when the control signal is either Rising or Falling.
Function callA trigger signal from a block that outputs function-call events executes the MATLAB Function block.

Description

Specifies the description of the input trigger.

Document link

Specifies the link to the documentation for the input trigger. You can enter a URL address or a MATLAB command that displays documentation, such as an HTML file or text in the MATLAB Command Window. When you click the Document link link, the MATLAB Function block evaluates the link and displays the documentation.

Enable a MATLAB Function Block with an Input Trigger

This example uses a MATLAB Function block that is controlled by an either input trigger.

When the signal from the Square Wave Generator block rises or falls below 0, the MATLAB Function block executes. Double-click the MATLAB Function block to open the code.

function [y1,y2] = fcn(u)
y1 = u;
y2 = u - 1;

The MATLAB Function block outputs the last propagated value until the block triggers again. Run the model and open the Scope block to see the outputs.

See Also

Related Examples

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