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Autoscaling Using the Fixed-Point Tool

The Fixed-Point Tool automates the task of specifying fixed-point data types in a Simulink® model. This process is also known as autoscaling. The tool can collect range data for model objects from:

  • Design minimum and maximum values that objects specify explicitly

  • Logged minimum and maximum values that occur during simulation

  • Minimum and maximum values derived using range analysis

Based on these values, the tool proposes fixed-point data types that maximize precision and cover the range.

Workflow for Automatic Data Typing

Before you begin conversion, you need to set up the model in Simulink. For more detail, see Set up the model.

Data Typing

  1. Select system under design

  2. Collect ranges

    1. Range collection using simulation—Using this method, collect ideal ranges for objects in your model by overriding your model with double-precision data types, and then simulate the model.

    2. Range collection using derived range analysis—Using this method, the Fixed-Point Tool uses range analysis to derive minimum and maximum values for objects in your model. Range analysis works only for compatible models. For more information, see Model Compatibility with Range Analysis.

  3. Propose data types

  4. Examine results to resolve conflicts

  5. Apply proposed data types


  1. Verify new settings

    1. Set range collection using specified types

    2. Simulate using fixed-point data types

    3. Compare runs in the Simulation Data Inspector

  2. Clean Up Model Settings

To begin the fixed-point conversion process, see Set Up the Model.

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