When you create Stateflow^{®} charts in Simulink^{®}, you can specify data properties in either the Property Inspector or the Model Explorer.
To use the Property Inspector:
In the Modeling tab, under Design Data, select Symbols Pane and Property Inspector.
In the Symbols pane, select the data object.
In the Property Inspector pane, edit the data properties.
To use the Model Explorer:
In the Modeling tab, under Design Data, select Model Explorer.
In the Contents pane, select the data object.
In the Message pane, edit the data properties.
Properties vary according to the scope and type of the data object. For many data properties, you can enter expressions or parameter values. Using parameters to set properties for many data objects simplifies maintenance of your model because you can update multiple properties by changing a single parameter.
You can set these data properties in:
The main and Advanced sections of the Property Inspector.
The General tab of the Model Explorer.
Name of the data object. For more information, see Rules for Naming Stateflow Objects.
Location where data resides in memory, relative to its parent.
Setting  Description 

Local  Data defined in the current chart only. 
Constant  Readonly constant value that is visible to the parent Stateflow object and its children. 
Parameter  Constant whose value is defined in the MATLAB^{®} base workspace or derived from a Simulink block parameter that you define and initialize in the parent masked subsystem. The Stateflow data object must have the same name as the MATLAB variable or the Simulink parameter. For more information, see Share Parameters with Simulink and the MATLAB Workspace. 
Input  Input argument to a function if the parent is a graphical function, truth table, or MATLAB function. Otherwise, the Simulink model provides the data to the chart through an input port on the Stateflow block. For more information, see Share Input and Output Data with Simulink. 
Output  Return value of a function if the parent is a graphical function, truth table, or MATLAB function. Otherwise, the chart provides the data to the Simulink model through an output port on the Stateflow block. For more information, see Share Input and Output Data with Simulink. 
Data Store Memory  Data object that binds to a Simulink data store, which is a signal that functions like a global variable. All blocks in a model can access that signal. This binding allows the chart to read and write to the Simulink data store, sharing global data with the model. The Stateflow object must have the same name as the Simulink data store. For more information, see Access Data Store Memory from a Chart. 
Temporary  Data that persists during only the execution of a function. For C charts, you can define temporary data only for a graphical function, truth table, or MATLAB function. 
Exported  Data from the Simulink model that is made available to external code defined in the Stateflow hierarchy. You can define exported data only for a Stateflow machine. 
Imported  Data parented by the Simulink model that you define in external code embedded in the Stateflow machine. You can define imported data only for a Stateflow machine. 
Index of the port associated with the data object. This property applies only to input and output data. See Share Input and Output Data with Simulink.
Specifies whether a variable updates in discrete or continuous time. This property applies only when the chart is configured for continuoustime simulation. See ContinuousTime Modeling in Stateflow.
Specifies that output or local data explicitly inherits properties from
Simulink.Signal
objects of the same name in the MATLAB base workspace or the Simulink model workspace. The data can inherit these properties:
Size
Complexity
Type
Unit
Minimum value
Maximum value
Initial value
Storage class
Sampling mode (for Truth Table block output data)
This option is available only when you set the model configuration parameter
Signal resolution to a value other than None
.
For more information, see Resolve Data Properties from Simulink Signal Objects.
Size of the data object. The size can be a scalar value or a MATLAB vector of values.
To specify a scalar, set the Size property to 1
or leave the field blank.
To specify an n
by1 column vector, set the
Size property to n
.
To specify a 1byn
row vector, set the
Size property to [1
.n
]
To specify an n
bym
matrix, set
the Size property to [
.n
m
]
To specify an n
dimensional array, set the
Size property to
[
, where
d_{1}
d_{2}
⋯
d_{n}
]d_{i}
is the size of the
i
^{th} dimension.
To configure a Stateflow data object to inherit its size from the corresponding Simulink signal or from its definition in the chart, specify a size of
–1
.
The scope of the data object determines what sizes you can specify. Stateflow data store memory inherits all its properties, including its size, from the Simulink data store to which it is bound. For all other scopes, size can be scalar, vector, or a matrix of ndimensions. For more information, see Specify Size of Stateflow Data.
You can specify data size through a MATLAB expression that evaluates to a valid size specification. For more information, see Specify Data Size by Using Expressions and Specify Data Properties by Using MATLAB Expressions.
Specifies that the data object changes dimensions during simulation. This option is available for input and output data only when you enable the chart property Support variablesize arrays. For more information, see Declare VariableSize Data in Stateflow Charts.
Specifies whether the data object accepts complex values.
Setting  Description 

Off  Data object does not accept complex values. 
On  Data object accepts complex values. 
Inherited  Data object inherits the complexity setting from a Simulink block. 
The default value is Off
. For more information, see
Complex Data in Stateflow Charts.
Index of the first element of the data array. The first index can be any integer. The
default value is 0
. This property is available only for C charts.
Type of data object. To specify the data type:
From the Type dropdown list, select a builtin type.
In the Type field, enter an expression that evaluates to a data type.
Additionally, in the Model Explorer, you can open the Data Type Assistant by clicking the Show data type assistant button . Specify a data Mode, and then specify the data type based on that mode. For more information, see Specify Type of Stateflow Data.
You can specify data type through a MATLAB expression that evaluates to a valid type specification. For more information, see Derive Data Types from Other Data Objects and Specify Data Properties by Using MATLAB Expressions.
If you enter an expression for a fixedpoint data type, you must specify scaling
explicitly. For example, you cannot enter an incomplete specification such as
fixdt(1,16)
in the Type field. If you do not specify
scaling explicitly, an error appears when you try to simulate your model.
Prevents replacement of the current fixedpoint type with an autoscaled type chosen by the FixedPoint Tool. For more information, see Autoscaling Using the FixedPoint Tool (FixedPoint Designer).
Specifies physical units for input and output data. For more information, see Specify Units for Stateflow Data.
Initial value of the data object. The options for initializing values depend on the scope of the data object.
Scope  Specify for Initial Value 

Local  Expression or parameter defined in the Stateflow hierarchy, MATLAB base workspace, or Simulink masked subsystem. When you leave this option blank, the local or output data
resolves to a variable in the base workspace with the same name. When you choose
Parameter the data is tunable. If you choose
Expression the data is not tunable. 
Constant  Constant value or expression. The expression is evaluated when you update the chart. The resulting value is used as a constant for running the chart. 
Parameter  You cannot enter a value. The chart inherits the initial value from the parameter. 
Input  You cannot enter a value. The chart inherits the initial value from the Simulink input signal on the designated port. 
Output  Expression or parameter defined in the Stateflow hierarchy, MATLAB base workspace, or Simulink masked subsystem. When you leave this option blank, the local or output data
resolves to a variable in the base workspace with the same name. When you choose
Parameter the data is tunable. If you choose
Expression the data is not tunable. 
Data Store Memory  You cannot enter a value. The chart inherits the initial value from the Simulink data store to which it resolves. 
If you do not specify a value, the default value for numeric data is 0. For
enumerated data, the default value typically is the first one listed in the
enumeration
section of the definition. You can specify a different default
enumerated value in the methods
section of the definition. For more
information, see Define Enumerated Data Types.
You can specify an initial value through a MATLAB expression. For more information, see Specify Data Properties by Using MATLAB Expressions.
Range of acceptable values for this data object. Stateflow charts use this range to validate the data object during simulation.
Minimum — The smallest value allowed for the data item during simulation. You can enter an expression or parameter that evaluates to a numeric scalar value.
Maximum — The largest value allowed for the data item during simulation. You can enter an expression or parameter that evaluates to a numeric scalar value.
The smallest value that you can set for Minimum is
inf
. The largest value that you can set for Maximum
is inf
.
You can specify the minimum and maximum values through a MATLAB expression. For more information, see Specify Data Properties by Using MATLAB Expressions.
A Simulink model uses the Limit range properties to calculate bestprecision scaling for fixedpoint data types. Before you select Calculate BestPrecision Scaling, specify a minimum or maximum value. For more information, see Calculate BestPrecision Scaling.
Enables watching the data values in the Stateflow Breakpoints and Watch window. For more information, see View Data in the Breakpoints and Watch Window.
In the Model Explorer, when you set the Data Type Assistant Mode to
Fixed point
, the Data Type Assistant displays fields for specifying
additional information about your fixedpoint data.
Specifies whether the fixedpoint data is Signed
or
Unsigned
. Signed data can represent positive and negative values.
Unsigned data represents positive values only. The default setting is
Signed
.
Specifies the bit size of the word that holds the quantized integer. Large word sizes represent large values with greater precision than small word sizes. The default value is 16.
Word length can be any integer from 0 through 128 for chartlevel data of these scopes:
Input
Output
Parameter
Data Store Memory
For other Stateflow data, word length can be any integer from 0 through 32.
You can specify the word length through a MATLAB expression. For more information, see Specify Data Properties by Using MATLAB Expressions.
Specifies the method for scaling your fixedpoint data to avoid overflow conditions and
minimize quantization errors. The default method is Binary point
scaling.
Setting  Description 

Binary point  If you select this mode, the Data Type Assistant displays the Fraction length field, which specifies the binary point location. Fraction length can be any integer. The default value is 0. A positive integer moves the binary point left of the rightmost bit by that amount. A negative integer moves the binary point farther right of the rightmost bit.

Slope and bias  If you select this mode, the Data Type Assistant displays fields for entering the Slope and Bias for the fixedpoint encoding scheme. Slope can be any positive real number. The default value is 1.0. Bias can be any real number. The default value is 0.0. You can enter slope and bias as expressions that contain parameters you define in the MATLAB base workspace. 
Whenever possible, use binarypoint scaling to simplify the implementation of fixedpoint data in generated code. Operations with fixedpoint data that use binarypoint scaling are performed with simple bit shifts and eliminate expensive code implementations required for separate slope and bias values. For more information about fixedpoint scaling, see Scaling (FixedPoint Designer).
You can specify Fraction length, Slope, and Bias through a MATLAB expression. For more information, see Specify Data Properties by Using MATLAB Expressions.
Specifies whether to inherit the data type override setting of the FixedPoint Tool that applies to this model. If the data does not inherit the modelwide setting, the specified data type applies.
Specifies whether to calculate the bestprecision values for Binary
point
and Slope and bias
scaling, based on the values
in the Minimum and Maximum
fields in the Limit range section.
To calculate bestprecision scaling values:
Specify Limit range properties.
Click Calculate BestPrecision Scaling.
The bestprecision scaling values are displayed in the Fraction length field or the Slope and Bias fields. For more information, see Maximize Precision (FixedPoint Designer).
The Limit range properties do not apply to
Constant
and Parameter
scopes. For
Constant
, Simulink software calculates the scaling values based on the Initial
value setting. The software cannot calculate bestprecision scaling for data of
Parameter
scope.
Displays information about the fixedpoint data type that is defined in the Data Type Assistant:
Minimum
and Maximum
show the same values that
appear in the corresponding Minimum and Maximum fields in the Limit range
section.
Representable minimum
, Representable maximum
, and
Precision
show the minimum value, maximum value, and precision that the
fixedpoint data type can represent.
If the value of a field cannot be determined without first compiling the model,
the Fixedpoint details subpane shows the value as
Unknown
.
The values displayed by the Fixedpoint details subpane do not automatically update if you change the values that define the fixedpoint data type. To update the values shown in the Fixedpoint details subpane, click Refresh Details.
Clicking Refresh Details does not modify the model. It changes only the display. To apply the displayed values, click Apply or OK.
The Fixedpoint details subpane indicates any error resulting from the fixedpoint data type specification. For example, this figure shows two errors.
The row labeled Maximum
indicates that the value specified in the
Maximum field of the Limit range section is not
representable by the fixedpoint data type. To correct the error, make one of these
modifications so the fixedpoint data type can represent the maximum value:
Decrease the value in the Maximum field of the Limit range section.
Increase Word length.
Decrease Fraction length.
The row labeled Minimum
shows the error Cannot
evaluate
because evaluating the expression MySymbol
, specified in
the Minimum field of the Limit range section, does
not return a numeric value. When an expression does not evaluate successfully, the
Fixedpoint details subpane shows the unevaluated expression (truncating
to 10 characters as needed) in place of the unavailable value. To correct this error, define
MySymbol
in the base workspace to provide a numeric value. If you click
Refresh Details, the error indicator and description are removed and
the value of MySymbol
appears in place of the unevaluated text.
You can set logging properties for data in:
The Logging section of the Property Inspector.
The Logging tab of the Model Explorer.
Saves the data value to the MATLAB base workspace during simulation. For more information, see Log Simulation Output for States and Data.
Designates the data as a test point. A test point is a signal that you can observe in a Floating Scope block in a model. Data objects can be test points if:
Scope is Local
.
Parent is not a Stateflow machine.
Data type is not ml
.
For more information, see Monitor Test Points in Stateflow Charts.
Specifies the name associated with logged signal data. Simulink software uses the signal name as its logging name by default. To specify a custom
logging name, select Custom
from the list box and enter the new name
in the adjacent edit field.
Limits the amount of data logged to the most recent samples.
Limits the amount of data logged by skipping samples. For example, a decimation factor of 2 saves every other sample.
You can set additional data properties in:
The Info tab of the Property Inspector.
The Description tab of the Model Explorer.
Assigns the value of the data object to a variable of the same name in the MATLAB base workspace at the end of simulation. This option is available only in the Model Explorer for C charts. For more information, see Model Workspaces (Simulink).
Units of measurement associated with the data object. The unit in this field resides with the data object in the Stateflow hierarchy. This property is available only in the Model Explorer for C charts.
Description of the data object. You can enter brief descriptions of data in the hierarchy.
Link to online documentation for the data object. You can enter a web URL address or a MATLAB command that displays documentation in a suitable online format, such as an HTML file or text in the MATLAB Command Window. When you click the Document link hyperlink, Stateflow evaluates the link and displays the documentation.
When you leave a property field blank, Stateflow assumes a default value.
Property  Default Value  

Size 
 
First Index  0  
Initial Value  0.0  
Limit Range  Minimum  inf 
Maximum  inf  
FixedPoint Data Properties  Word length  16 
Fraction length  0  
Slope  1.0  
Bias  0.0 
In the Property Inspector and Model Explorer, you can enter MATLAB expressions as values for these properties:
Minimum
Maximum
Word length
Fraction length
Slope
Bias
Limit Range: Minimum and Maximum
FixedPoint Data Properties: Word length, Fraction length, Slope, and Bias
Expressions can contain a mix of numeric values, constants, parameters, variables, arithmetic operations, parameters, constants, arithmetic operators, and calls to MATLAB functions. For example, you can use these functions to specify data properties.
Property  Function  Description 

Size  size  Returns the size of a data object 
fi  Returns a fixedpoint numeric object  
Type  type  Returns the type of a data object 
fixdt  Returns a Simulink.NumericType object that describes a fixedpoint
or floatingpoint data type  
Minimum  min  Returns the smallest element or elements of an array 
Maximum  max  Returns the largest element or elements of an array 
For more information, see Specify Data Size by Using Expressions and Derive Data Types from Other Data Objects.