Share Parameters with Simulink and the MATLAB Workspace

A parameter is a constant data object that you can:

Define in the MATLAB^® base workspace.
Derive from a Simulink^® block parameter that you define and initialize in a mask.
Derive from a data dictionary that you add to the parent Simulink model of the chart.

Use parameters to avoid hard-coding data values and properties. Share Simulink parameters with charts to maintain consistency with your model.

You can access parameter values in multiple Stateflow^® objects in a chart such as states, MATLAB functions, and truth tables. You can include parameters in expressions defining data properties such as:

Size
Type
Initial Value
Minimum and Maximum
Fixed-Point Data Properties

For more information, see Specify Data Properties by Using MATLAB Expressions

Initialize Parameters from the MATLAB Base Workspace

You can initialize a parameter by defining it in the MATLAB base workspace and in the Stateflow hierarchy.

Define and initialize a variable in the MATLAB base workspace.
In the Stateflow hierarchy, define a data object with the same name as the MATLAB variable.
Set the scope of the Stateflow data object to Parameter.

When the simulation starts, data resolution occurs. During this process, the Stateflow parameter gets its value from the associated MATLAB variable.

Share Simulink Parameters with Charts

You can share a parameter from a Simulink subsystem containing a Stateflow chart by creating a mask for the subsystem.

In the Simulink mask editor for the parent subsystem, define and initialize a Simulink parameter.
In the Stateflow hierarchy, define a data object with the same name as the Simulink parameter.
Set the scope of the Stateflow data object to Parameter.

When the simulation starts, Simulink tries to resolve the Stateflow data object to a parameter at the lowest-level masked subsystem. If unsuccessful, Simulink moves up the model hierarchy to resolve the data object to a parameter at higher-level masked subsystems.

Add Data Dictionaries to Charts

To add a data dictionary to a Stateflow chart, import the data dictionary into the Simulink model that contains the chart. The data dictionary appears in multiple locations in the Model Explorer:

Under the Simulink Root component.
Inside the chart workspace, under the External Data component.

For instructions on importing a data dictionary into a model, see Import and Export Dictionary Data (Simulink).

To read an entry from an imported data dictionary, add the entry to the Symbols pane as a parameter. The entry and parameter must have identical names. For instructions, see Add Stateflow Data.