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Mapping System Object Code to MATLAB System Block Dialog Box

The System object™ source code controls the appearance of the block dialog box. This section maps the System object code to the block dialog box. This example code snippet uses two System objects, one that uses default System object to block dialog box mapping, and one that uses a custom mapping.


You can also change the appearance of a MATLAB System block dialog box using the Mask Editor. For more information, see Customize MATLAB System Icon and Dialog Box Using Mask Editor.

System Object to Block Dialog Box Default Mapping

The following figure shows how the source code corresponds to the dialog box elements when you do not customize the dialog using the getHeaderImpl or getPropertyGroupsImpl methods. (The link to open the source code and the Simulate using parameter appear on all MATLAB System block dialog boxes.)

Default mapping between the source code and dialog box elements

The Delay block from the example model snippet uses a System object that draws the dialog box using the default mapping. This block has one input and one output.

This block uses a System object that has direct feedthrough set to false (nondirect feedthrough). This setting means that the System object does not directly use the input to compute the output, enabling the model to use this block safely in a feedback system without introducing an algebraic loop. For more information on nondirect feedthrough, see Use System Objects in Feedback Loops.

Created Widget Types MATLAB System block

For an example of a custom block dialog box, see System Object to Block Dialog Box Custom Mapping.

System Object to Block Dialog Box Custom Mapping

The LMS Adaptive block is an example of a block with a custom header and property groups. The System object code uses the getHeaderImpl and getPropertyGroupsImpl methods from matlab.System to customize these block dialog elements.

The LMS Adaptive Filter block estimates the coefficients of an unknown system (formed by the Unknown System and Delay blocks). Its inputs are the desired signal and the actual signal. Its outputs are the estimated signal and the vector norm of the error in the estimated coefficients. It uses the lmsSysObj System object.

Source code and dialog box mapping with custom header title, description and tabs group

The source code for this System object also defines two input and output ports for the block.

Source code describing input and output ports for system block

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