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Tune and Monitor Model Running on Gumstix Overo Hardware

Overview of Using External Mode

You can use External mode to tune parameters and monitor a model running on your target hardware.

External mode enables you to tune model parameters and evaluate the effects of different parameter values on model results in real time. Doing so helps you find the optimal values to achieve desired performance. This process is called parameter tuning.

External mode accelerates parameter tuning because you do not have to rerun the model each time you change parameters. You can also use External mode to develop and validate your model using the actual data and hardware for which it is designed. This software-hardware interaction is not available solely by simulating a model.

This workflow lists the tasks usually required to tune parameters with External mode:

  1. In the model on your host computer, enable External mode.

  2. Optional: Place one or more sink blocks in your model. For example, use Display or Scope blocks to visualize data, or use a To File block to log signal data.

  3. Give Simulink® software the command to run the model on the target hardware.

  4. Optional: Observe data External mode sends from the target hardware to sink blocks in the model on the host computer.

  5. Change and apply parameter values in the model on your host computer.

  6. Find the optimal parameter values by making adjustments and observing the results.

  7. Save the new parameter values, disable External mode, and save the model.

Run Your Simulink Model in External Mode

  1. Create a network connection between the Overo® hardware and your host computer. See Configure Network Settings on Gumstix Overo Hardware.

  2. On the model toolbar, set Simulation mode to External.

  3. Set the Simulation stop time parameter, located to the left of Simulation mode on the model toolbar. The default value is 10.0 seconds. To run the model for an indefinite period, enter inf.

  4. Click the Run button.

    If your model does not contain a sink block, the MATLAB® Command Window displays a warning message. For example:

    Warning: No data has been selected for uploading. 
    > In C:\Program Files (x86)\MATLAB\R2013a Student1\toolbox\
    extModeAutoConnect at 17
    realtime\realtime\sl_customization.p>myRunCallback at 149

    You can disregard this warning or add a sink block to the model.

    After several minutes, Simulink starts running your model on the board.

  5. Change parameter values in the model on your host computer.

    Observe the corresponding changes in the model running on the hardware.

    If your model contains blocks from the Simulink Sinks block library, the sink blocks in the model on your host computer display the values generated by the model running on the hardware.

    Note:   External mode increases the processing burden of the model running on the board. If the software reports an overrun, disable External mode.

    Note:   If you have the Embedded Coder® or Simulink Coder™ software, you can use External mode with a model that contains Model blocks (uses the "Model reference").

Stop External Mode

To stop the model running in External mode, click the Stop button located on the model toolbar.

If the Simulation stop time parameter is set to a specific number of seconds, External mode stops when that time elapses.

When you are finished using External mode, set Simulation mode back to Normal.

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