Derive Ranges

  1. Verify that your model is compatible with range analysis.

  2. In Simulink®, open your model and set it up for use with the Fixed-Point Tool. For more information, see Set Up the Model.

  3. From the Simulink Analysis menu, select Fixed-Point Tool.

  4. In the Fixed-Point Tool Model Hierarchy pane, select the system or subsystem of interest.

  5. Use the Fixed-Point Advisor to prepare the model for conversion.

    1. In the Fixed-Point Tool Fixed-point preparation for selected system pane, click the Fixed-Point Advisor button.

    2. Run each task in the Fixed-Point Advisor. For more information, see Preparation for Fixed-Point Conversion.

    The Fixed-Point Advisor:

    • Checks the model against fixed-point guidelines.

    • Identifies unsupported blocks.

    • Removes output data type inheritance from blocks.

    • Allows you to promote simulation minimum and maximum values to design minimum and maximum values. This capability is useful if you have not specified design ranges and you have simulated the model with inputs that cover the full intended operating range. For more information, see Specify block minimum and maximum values.

  6. In the Settings for selected system pane, set Data type override to Double, then click Apply.

    This global override of the fixed-point data types using double-precision numbers avoids quantization effects.

  7. Optionally, in the Data collection pane Store results in run field, specify a run name. Specifying a unique run name avoids overwriting results from previous runs.

  8. In the Fixed-Point Tool, click the Derive min/max values for selected system button.

    The analysis runs and tries to derive range information for objects in the selected system. Your next steps depend on the analysis results.

    Analysis ResultsFixed-Point Tool BehaviorNext StepsFor More Information

    Successfully derives range data for the model.

    Displays the derived minimum and maximum values for the blocks in the selected system.

    Review the derived ranges to determine if the results are suitable for proposing data types. If not, you must specify additional design information and rerun the analysis.

    View Derived Ranges in the Fixed-Point Tool

    Fails because the model contains blocks that the software does not support.

    Generates an error and provides information about the unsupported blocks.

    To fix the error, review the error message information and replace the unsupported blocks.

    Model Compatibility with Range Analysis

    Cannot derive range data because the model contains conflicting design range information.

    Generates an error.

    To fix this error, examine the design ranges specified in the model to identify inconsistent design specifications. Modify them to make them consistent.

    Fixing Design Range Conflicts

    Cannot derive range data for an object because there is insufficient design range information specified on the model.

    Highlights the results for the object.

    Examine the model to determine which design range information is missing.

    Providing More Design Range Information

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