Why do I get errors when I simulate a model that contains a referenced model using the SIM command from a MATLAB function and obtain parameter values from the current workspace in Simulink 7.2 (R2008b)?

I want to run a Simulink model from a MATLAB function. The Simulink model contains a model reference block.

However, when I execute the following commands in my MATLAB function:

opt = simset('SrcWorkspace','Current');

sim('MainTest',1,opt);

I get the following error message:

 ??? Error using ==> RunTheModel at 6

 Error due to multiple causes:

 --> Error using ==> tlc_c at 116

 Error evaluating parameter 'Gain' in

 'ReferedTest/Gain': Error using ==> rtwgen

 Undefined function or variable 'a'.

 --> Error while bringing model references of model

 MainTest up to date: Error using ==> tlc_c at 116

 Error evaluating parameter 'Gain' in

 'ReferedTest/Gain': Error using ==> rtwgen

 Undefined function or variable 'a'.

 Caused by:

     Error using ==> RunTheModel at 6

     Error using ==> tlc_c at 116

     Error evaluating parameter 'Gain' in

     'ReferedTest/Gain': Error using ==> rtwgen

     Undefined function or variable 'a'.

     Error using ==> RunTheModel at 6

     Error while bringing model references of model

     MainTest up to date: Error using ==> tlc_c at 116

     Error evaluating parameter 'Gain' in

     'ReferedTest/Gain': Error using ==> rtwgen

     Undefined function or variable 'a'.

Answer 1

[MathWorks Support Team]

The ability to define the "Source Workspace" for referenced models is not available in Simulink 7.2 (R2008b).

To work around this limitation, setup the model to obtain parameter values from a MAT-file instead. This can be done by using Model Explorer to set the source of the Model Workspace for the Simulink model to a MAT-file. The MATLAB function / script can then be used to create / modify the MAT-file and execute the following lines of code to load the fresh data into the Model Workspace before running the simulation:

load_system(RefModelName)

hws = get_param(RefModelName, 'modelworkspace'); 

hws.reload;

Please see the attached files for an example.