Specify Data Types Using Data Type Assistant

R2026b

The Data Type Assistant is an interactive graphical tool that simplifies the task of specifying data types for blocks and data objects. The assistant appears on block and object dialog boxes, adjacent to parameters that provide data type control, such as the Output data type parameter. For example, it appears on the Signal Attributes tab of the Block Parameters dialog box for the Constant block.

For these objects, access to the Data Type Assistant is from a tool:

• Simulink.BusElement objects — Access is from the Type Editor.

• Simulink.Signal and Simulink.Parameter objects — Access is from Model Explorer.

Show or hide the Data Type Assistant by clicking the applicable button:

• Click the Show data type assistant button to display the assistant.

• Click the Hide data type assistant button to hide a visible assistant.

To use the Data Type Assistant to specify a data type:

1. From the Mode list, select the category of data type that you want to specify. In general, these options are included.

   Mode	Description	Related Information
   Inherit	A rule that determines how the output signal inherits its data type.	Data Type Inheritance Rules
   Built in	A built-in data type for a block or data object.	Built-In Data Types
   Fixed point	A fixed-point data type for a block or data object.	Specify Fixed-Point Data Types Specify Fixed-Point Data Types with the Data Type Assistant (Fixed-Point Designer)
   Enumerated	An enumerated object as a data type for a block.	Use Enumerated Data in Simulink Models
   Bus object	A Simulink.Bus object as a data type for a block or data object.	Simulink.Bus Define Bus Properties for Reuse
   Image	A Simulink.ImageType object as a data type for a block or data object (Computer Vision Toolbox™).	Simulink.ImageType (Computer Vision Toolbox)
   Value type	A Simulink.ValueType object as a data type for a block or Simulink.BusElement object.	Simulink.ValueType Specify Common Set of Signal Properties as Value Type
   Expression	An expression that evaluates to a numeric data type object.	Data Type Expressions

   The assistant changes dynamically to display different options that correspond to the selected mode. For example, setting Mode to Expression in the Block Parameters dialog box for a Constant block updates the values in the boxes next to Output data type and Mode.

   

2. To the right of the Mode list, select or enter a data type.

   For example, suppose you designate the variable myDataType as an alias for a single data type. You create an instance of the Simulink.AliasType class and set its BaseType property by entering these commands.

   myDataType = Simulink.AliasType
   myDataType.BaseType = 'single'

   You can use this data type object to specify the output data type of a Constant block. Enter the data type alias name, myDataType, as the value of the expression in the assistant.

   

3. Click OK or Apply to apply your changes.

   The assistant uses the data type that you specified to populate the associated data type parameter in the block or object dialog box. For example, the Output data type parameter of the Constant block specifies the same expression that you entered using the assistant.

   

For more information about the data types that you can specify using the Data Type Assistant, see Entering Valid Data Type Values. For details about specifying fixed-point data types, see Specify Fixed-Point Data Types with the Data Type Assistant (Fixed-Point Designer).