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AUTOSAR.DualScaledParameter

Specify computation method, calibration value, data type, and other properties of AUTOSAR dual-scaled parameter

For run-time calibration of AUTOSAR data, R2018b and R2019a introduced graphical mapping of model elements to AUTOSAR component parameters and variables. In the Code Mappings editor, you select a Simulink® model-workspace parameter or internal signal, state, or data store. You map the selected element to an AUTOSAR component parameter or variable and modify its AUTOSAR calibration attributes. If you currently model AUTOSAR parameters or variables by using AUTOSAR parameter or signal objects in the base workspace, consider migrating to the Code Mappings editor workflow. For more information, see Map AUTOSAR Elements for Code Generation.

Description

This class extends the AUTOSAR.Parameter class so that you can define an object that stores two scaled values of the same physical value. For example, for temperature measurement, you can store a Fahrenheit scale and a Celsius scale with conversion defined by a computation method that you provide. Given one scaled value, the AUTOSAR.DualScaledParameter can compute the other scaled value using the computation method.

A dual-scaled parameter has:

  • A calibration value. The value that you prefer to use.

  • A main value. The real-world value that Simulink uses.

  • An internal stored integer value. The value that is used in the embedded code.

You can use AUTOSAR.DualScaledParameter objects in your model for both simulation and code generation. The parameter computes the internal value before code generation via the computation method. This offline computation results in leaner generated code.

If you provide the calibration value, the parameter computes the main value using the computation method. This method can be a first-order rational function.

y=ax+bcx+d

  • x is the calibration value.

  • y is the main value.

  • a and b are the coefficients of the CalToMain compute numerator.

  • c and d are the coefficients of the CalToMain compute denominator.

If you provide the calibration minimum and maximum values, the parameter computes minimum and maximum values of the main value. Simulink performs range checking of parameter values. The software alerts you when the parameter object value lies outside a range that corresponds to its specified minimum and maximum values and data type.

Creation

Create an AUTOSAR.DualScaledParameter object by using the AUTOSAR.DualScaledParameter function described below.

Description

example

DSParam = AUTOSAR.DualScaledParameter returns an AUTOSAR.DualScaledParameter object with default property values.

Open the workspace object to view and modify its properties.

Properties

The Main Attributes tab shows the properties inherited from the AUTOSAR.Parameter class. For more information, see AUTOSAR.Parameter.

The Calibration Attributes tab shows calibration properties for the dual-scaled parameter.

Calibration value

Calibration value of the parameter. The value that you prefer to use. The default value is [] (unspecified). Specify a finite, real, double value.

Before specifying Calibration value, you must specify CalToMain numerator and CalToMain denominator to define the computation method. The parameter uses the computation method and the calibration value to calculate the real-world value that Simulink uses.

Calibration minimum

Minimum value for the calibration parameter. The default value is [] (unspecified). Specify a finite, real, double scalar value.

Before specifying Calibration minimum, you must specify CalToMain numerator and CalToMain denominator to define the computation method. The parameter uses the computation method and the calibration minimum value to calculate the minimum or maximum value that Simulink uses. A first order rational function is strictly monotonic, either increasing or decreasing. If it is increasing, setting the calibration minimum sets the main minimum value. If it is decreasing, setting the calibration minimum sets the main maximum.

If the parameter value is less than the minimum value or if the minimum value is outside the range of the parameter data type, Simulink generates a warning. In these cases, when updating the diagram or starting a simulation, Simulink generates an error.

Calibration maximum

Maximum value for the calibration parameter can have. The default value is [] (unspecified). Specify a finite, real double scalar value.

Before specifying Calibration maximum, you must specify CalToMain numerator and CalToMain denominator to define the computation method. The parameter uses the computation method and the calibration maximum value to calculate the corresponding maximum or minimum value that Simulink uses. A first order rational function is strictly monotonic, either increasing or decreasing. If it is increasing, setting the calibration maximum sets the main maximum value. If it is decreasing, setting the calibration maximum sets the main minimum.

If the parameter value is less than the minimum value or if the minimum value is outside the range of the parameter data type, Simulink generates a warning. In these cases, when updating the diagram or starting a simulation, Simulink generates an error.

CalToMain compute numerator

Specify the numerator coefficients a and b of the first-order linear equation:

y=ax+bcx+d

The default value is [] (unspecified). Specify finite, real double scalar values for a and b. For example, [1 1] or, for reciprocal scaling, 1.

Once you have applied CalToMain compute numerator, you cannot change it.

CalToMain compute denominator

Specify the denominator coefficients c and c of the first-order linear equation:

y=ax+bcx+d

The default value is [] (unspecified). Specify finite, real, double scalar values for c and d. For example, [1 1].

Once you have applied CalToMain compute denominator, you cannot change it.

Calibration name

Specify the name of the calibration parameter. The default value is ''. Specify a text value, for example, 'T1'.

Calibration units

Specify the measurement units for this calibration value. This field is intended for use in documenting this parameter. The default value is ''. Specify a text value, for example, 'Seconds'.

Is configuration valid

Simulink indicates whether the configuration is valid. The default value is true. If Simulink detects an issue with the configuration, it sets this field to false and provides information in the Diagnostic message field. You cannot set this field.

Diagnostic message

If you specify invalid parameter settings, Simulink displays a message in this field. Use the diagnostic information to help you fix an invalid configuration issue. You cannot set this field.

This table shows command-line information for the calibration properties.

Name

Access

Description

CalibrationValue

RW

Calibration value of this parameter. See Calibration value.

CalibrationMin

RW

Calibration minimum value of this parameter. See Calibration minimum.

CalibrationMax

RW

Calibration maximum value of this parameter. See Calibration maximum.

CalToMainCompuNumerator

RW

Numerator coefficients of the computation method. See CalToMain compute numerator.

Once you have applied CalToMainCompuNumerator, you cannot change it.

CalToMainCompuDenominator

RW

Denominator coefficients of the computation method. See CalToMain compute denominator.

Once you have applied CalToMainCompuDenominator, you cannot change it.

CalibrationName

RW

Name of the calibration parameter. See Calibration name.

CalibrationDocUnits

RW

Measurement units for this calibration parameter's value. See Calibration units.

IsConfigurationValid

RO

Information about validity of configuration. See Is configuration valid.

DiagnosticMessage

RO

If the configuration is invalid, diagnostic information to help you fix the issue. See Diagnostic message.

Examples

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Create an AUTOSAR.DualScaledParameter object that stores a value as both time and frequency.

T1Rec = AUTOSAR.DualScaledParameter;

Set the computation method.

T1Rec.CalToMainCompuNumerator = [1];  
T1Rec.CalToMainCompuDenominator = [1 0];

This computation method specifies that the value used by Simulink is the reciprocal of the value that you want to use.

Set the value that you want to see.

T1Rec.CalibrationValue = 1/7
T1Rec = 

  DualScaledParameter with properties:

             CalibrationValue: 0.1429
               CalibrationMin: []
               CalibrationMax: []
      CalToMainCompuNumerator: 1
    CalToMainCompuDenominator: [1 0]
              CalibrationName: ''
          CalibrationDocUnits: ''
         IsConfigurationValid: 1
            DiagnosticMessage: ''
                        Value: 7
                    CoderInfo: [1×1 Simulink.CoderInfo]
                  Description: ''
                     DataType: 'auto'
                          Min: []
                          Max: []
                         Unit: ''
                   Complexity: 'real'
                   Dimensions: [1 1]

The AUTOSAR.DualScaledParameter calculates T1Rec.Value which is the value that Simulink uses. T1Rec.CalibrationValue is 1/7, so T1Rec.Value is 7.

Name this value and specify the units.

T1Rec.CalibrationName = 'T1';
T1Rec.CalibrationDocUnits = 'Seconds';

Set calibration minimum and maximum values.

T1Rec.CalibrationMin = 0.001;
T1Rec.CalibrationMax = 1;

If you specify a value outside this allowable range, Simulink generates a warning.

Specify the units that Simulink uses.

T1Rec.Unit = 'Hz';

Open the AUTOSAR.DualScaledParameter dialog box.

open T1Rec

The Calibration Attributes tab displays the calibration value and the computation method that you specified.

In the dialog box, click the Main Attributes tab.

This tab displays information about the value used by Simulink.

Create a dual-scaled parameter. Configure its storage class so that when you generate code, the exported ARXML code includes the dual-scaled parameter.

Create a dual-scaled parameter.

T1Rec = AUTOSAR.DualScaledParameter;
T1Rec.CalToMainCompuNumerator = [1];  
T1Rec.CalToMainCompuDenominator = [1 0];
T1Rec.CalibrationValue = 1/7;
T1Rec.CalibrationName = 'T1';
T1Rec.CalibrationDocUnits = 'Seconds';
T1Rec.CalibrationMin = 0.001;
T1Rec.CalibrationMax = 1
T1Rec = 

  DualScaledParameter with properties:

             CalibrationValue: 0.1429
               CalibrationMin: 1.0000e-03
               CalibrationMax: 1
      CalToMainCompuNumerator: 1
    CalToMainCompuDenominator: [1 0]
              CalibrationName: 'T1'
          CalibrationDocUnits: 'Seconds'
         IsConfigurationValid: 1
            DiagnosticMessage: ''
                        Value: 7
                    CoderInfo: [1×1 Simulink.CoderInfo]
                  Description: ''
                     DataType: 'auto'
                          Min: 1
                          Max: 1000
                         Unit: ''
                   Complexity: 'real'
                   Dimensions: [1 1]

Set the storage class of the parameter so that the generated ARXML code includes the parameter.

T1Rec.CoderInfo.StorageClass = 'Custom';
T1Rec.CoderInfo.CustomStorageClass = 'InternalCalPrm';

You can now use the parameter in a Simulink model. If you configure the model for AUTOSAR, when you generate code for the model, the code generator produces ARXML code that contains information about the dual-scaled parameter.

Introduced in R2013b