Determine Whether To Use Value Types

You can specify signal properties individually or with a predefined set of property specifications. Depending on your modeling requirement, the way you define a set of signal properties differs.

A value type can define the properties of a signal at an interface. When the ports of model components directly connect to each other, specify the same value type for the blocks that represent those ports. If you specify different value types that have the same properties but different names, the software issues an error. By specifying the same value type at both sides of the interface, you enforce consistency at the interface between the two components. For more information about interface design, see Define Interfaces of Model Components.

The value type propagates through the model until the value type reaches a block that produces new data as output. For example, the value type passes through In Bus Element and Out Bus Element blocks, but it does not pass through Sum or Gain blocks.

When you specify a value type as the data type of a block or object, the properties specified by the value type typically override the properties specified by the block or object.

For example, suppose an Inport block has these settings:

The Inport block uses m/s as the unit.

When you specify a value type as the data type of a Constant block, the value type overrides the minimum and maximum specified by the block and the data type of the constant value. The value type validates the dimensions, complexity, and unit of the constant value. When these properties do not match, the software issues a warning or error. (since R2023b)

For example, suppose a Constant block has these settings:

During model compilation, the software issues a warning about the mismatched units. The Constant block uses ft/s as the unit.

For another example, suppose a Constant block has these settings:

During model compilation, the software issues an error about the mismatched dimensions. Similarly, mismatched complexity results in an error.

Information overlays display the property values, not the value type. Suppose your value type specifies a unit. To see the unit that the model uses, in the Simulink^® Toolstrip, on the Debug tab, select Information Overlays > Units. The unit appears on the related signal line.

Value types do not appear in the generated code. The signal properties that the value types specify appear in the generated code.

Create Value Types

To create or edit value types interactively, use the Type Editor or Model Explorer.

For example, to create a value type in the Type Editor:

To create value types programmatically, use the Simulink.ValueType function.

For example, create a value type for wind velocity.

windVelocity = Simulink.ValueType

windVelocity = 
  ValueType with properties:

          DataType: 'double'
               Min: []
               Max: []
              Unit: ''
        Complexity: 'real'
        Dimensions: 1
    DimensionsMode: 'Fixed'
       Description: ''

To edit the properties of the value type programmatically, use dot notation.

windVelocity.DataType = 'single';
windVelocity.Min = 11;
windVelocity.Max = 17;
windVelocity.Unit = 'm/s';
windVelocity.Dimensions = [2 4 3];
windVelocity.Description = 'Wind velocity value type'

windVelocity = 
  ValueType with properties:

          DataType: 'single'
               Min: 11
               Max: 17
              Unit: 'm/s'
        Complexity: 'real'
        Dimensions: [2 4 3]
    DimensionsMode: 'Fixed'
       Description: 'Wind velocity value type'

Value types created programmatically are initially stored in the base workspace.

Specify Value Types

Use a value type to specify signal properties for these blocks and objects:

To associate a block or object with a value type, set the data type of the block or object to ValueType: <object name> and replace <object name> with the Simulink.ValueType object name.

You can specify a value type as the data type either before or after defining the value type. However, before you simulate the model, the Simulink.ValueType object must be defined and loaded.

During model development, you can modify signals to match value types or modify value types to match signals. If you do not want to change the value type, you can:

When value types do not match at an interface, you can:

Save Value Types

You can save value types to these locations:

If you do not save the value types, then when you reopen a model that uses the value types, you must recreate the Simulink.ValueType objects.

Choose where to store value types based on your modeling requirements.

To save value types stored in the base workspace, you can use any MATLAB technique that saves the contents of the base workspace. However, the resulting file contains everything in the base workspace, not just the value types.

When you modify value types, you must resave them to keep the changes.

Map Value Types to Models

Before you simulate a model, all the value types that the model uses must be loaded into the base workspace or a data dictionary used by the model. Mapping value types to models is important for automation and consistency across models.

To ensure the necessary value types load before model execution, consider these approaches:

To find where a value type is used in an open model, see Finding Blocks That Use a Specific Variable.