MATLAB: How to access the signals and parameters of referenced models using C-API in Real-Time Workshop 6.2 (R14SP2)

simulink coder

I want to be able to access the signals and parameters of referenced models using C-API.

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The ability to access the signals and parameters of referenced models using C-API is not available in Real-Time Workshop 6.2 (R14SP2).

To work around this issue:

For a top model (e.g. mymodel.mdl) and all its sub models (e.g. mymodel_refmod.mdl),

1) Open the Configuration Parameters > Data Import/Export pane.

2) Select the checkbox “States“.

3) Provide an appropriate variable for storing states, e.g. “xout”.

4) Select "C-API" on the Interface pane Generate GRT code for the top model (mymodel.mdl).

In the generated file mymodel.c, you would see the childMMI array is initialized in the mymodel_initialize function:

 void mymodel_initialize(boolean_T firstTime)  {
 ...
 rtwCAPI_SetChildMMI(mymodel_M->DataMapInfo.mmi, 0, &(mymodel_refmod_M->DataMapInfo.mmi));
 ...
 }

where mymodel_refmod_M->DataMapInfo.mmi is the child MMI corresponding to the referenced model in mymodel.mdl.

Note that the file mymodel_capi.c remains unchanged. The initialization is done in mymodel_initialize() function in mymodel.c

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This enhancement has been incorporated in Release 2007a (R2007a). For previous product releases, read below for any possible workarounds:

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This enhancement has been incorporated in Release 2008b (R2008b) in the following demo 'Target-Based Data Interface: C-API Data Definition File' which can be opened by typing 'rtwdemo_capi' on MATLAB Command Prompt.

For previous product releases, read below for any possible workarounds:

The attached example application logs values of all global signals in a model to a text file. This code is intended as a starting point for gaining access to signal addresses by using the C-API in Real-Time Workshop. You can extend the code to perform signal logging and monitoring. The application:

Uses the "rtmGetDataMapInfo" macro to gain access to the model mapping information (MMI) substructure of the real-time model structure. In the following macro call, rtM is the pointer to the real-time model structure in model.c or model.cpp.

     rtwCAPI_ModelMappingInfo* mmi = &(rtmGetDataMapInfo(rtM).mmi);

Uses custom function "capi_StartBlockIOLogging" to initialize signal logging, custom function "capi_UpdateBlockIOLogging" to log a signal value at each time step, and custom function "capi_StopBlockIOLogging" to terminate logging and write the values to a text file.

The custom functions are integrated with model code by using the TLC file capitestsigfile.tlc. The TLC file places the following function calls in model.c:

     * Call to "capi_UpdateBlockIOLogging()" in the "model_output" function
     * Call to "capi_StartBlockIOLogging()" in the "model_initialize" function
     * Call to "capi_StopBlockIOLogging()" in the "model_terminate" function

To use the example, download the attached files and place them in your current working directory. The attached files include

     * capitestsigfile.tlc
     * capi_BIOSignalLog.h
     * capi_BIOSignalLog.c
     * example_capi.mdl

To configure and build the example, using Real-Time Workshop 6.1 (R14SP1) do the following:

1. Open the model "example_capi.mdl."

2. In the model window, click Simulation > Configuration Parameters.

2. Choose a target file. If you want to use a grt.tlc target file instead of the default ert.tlc target file:

a. In the left pane of the Configuration Parameters dialog box, click Real-Time Workshop.

b. Click Browse to open the System Target File Browser.

c. Select a grt.tlc target.

3. Integrate the custom application code with the generated code, by including the following string in the TLC options field of the Build process section of the Real-Time Workshop pane :

     -acapiSigTestFile="capitestsigfile.tlc"

4. Click Real-Time Workshop > Interface and select "C-API" for the Interface field under Data exchange. For the purpose of this example, you can limit the data exchange to “Signals in C API” only.

5. If you are using an ert.tlc file, select the following options on the Real-Time Workshop Interface pane:

    * Support complex numbers
    * MAT-file logging

6. Return to the Real-Time Workshop pane and clear the "Generate code only" check box. The Build button appears.

7. Click Apply.

8. Click Build. Real-Time Workshop generates an executable file.

To run the executable, type "!example_capi" at the MATLAB prompt. Real-Time Workshop creates the text file example_capi_ BlockIOLog.txt in your working directory. Examine this text file using an editor, such as the MATLAB Editor.

For more information about using the C-API to interface with signals, see the documentation accessed by typing the following at the MATLAB 7.0.1 (R14SP1) prompt:

web([docroot,'/toolbox/rtw/rtw_ug/f6010dfi2.html'])

Best Answer

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MATLAB: Does inconsistent function name mangling occur with resuable subsystems drawn from a custom-made Simulink library model in Simulink 6.4 (R2006a)

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