Real-Time Windows Target

Types of Parameters

You can change parameter values while running the real-time application by changing the values in

• Block parameters -- Change block parameters by changing the values in the dialog boxes associated with the Simulink blocks. Once you change a value, and click Apply or OK, the new value immediately replaces the existing parameter while the real-time application continues to run.
• Block parameters for masked subsystems -- Change block parameters in the user-created dialog boxes associated with a subsystem.
• MATLAB variables -- Change MATLAB variables by entering the changes through the MATLAB command line, and then press Ctrl+D for the changes to be downloaded to your executable. An alternative method to download parameters is to click Update Diagram from the Edit menu in your Simulink window. Simply changing the value of the MATLAB variable at the MATLAB command line is not sufficient for Simulink to know that the value has changed.

Simulink external mode also supports side-effects functions. For example, given an expression in a Gain block of 2*a+b, the expression is evaluated and the resulting value is exported to the real-time application during execution.

When a parameter in a Simulink model is changed, the communication module rtwinext.dll transfers the data to the external real-time application and changes the model parameters. Only the parameters that do not result in model structure modification can be changed. If the structure is modified, you must recompile the model. Model structure changes are detected automatically using model checksum and reported to the MATLAB command window to avoid conflicts.

Parameter Tuning

Changing Model Parameters