I'm using a MATLAB function block within a Simulink model. I build this model and run it on a dspace system with 1 kHz. To evaluate my experiment I need the data (20x20 double array) that is calculated in my MATLAB function block. Is it possible to export the data to the base workspace?
To read a variable from your system, the easiest way to do so is using ControlDesk. Create a project and download/start your experiment using ControlDesk, then it is automatically aware of the running application and can read the variable. You now have to configure a Measurement (or Capture in old versions) and export the results to MAT. You can find detailed instructions in the documentation from dSPACE, called HelpDesk.
Alternatively you can use the XIL-API or HIL-API to automate the above steps.
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Context: I have a huge Simulink Model that is going to be used for automated simulations on a Debian 10. Therefore it has to be built as standalone C-Code using the Matlab Coder. This code is then called to start the simulation.
What I need: I need to find a way to initialize my built model with ~500 parameters. These change with each simulation run and are stored in a SQLite file. The goal is to have parameters written to the database, then start the Model which reads the parameters from SQLite during initialization (presumably using the InitFcn Model Callback, although I'm open to alternatives).
What I have tried:
Direct SQL interface: I tried to use a direct Matlab-SQL interface such as JDBC (since I don't have access to the Database-toolbox) but those are not supported for Code generation.
Write a C-function that reads the SQLite file, then call the function during initialization in the InitFcn Callback using coder.ceval like this:
data = 0;
err = coder.ceval('read_function',4, 2, 12, coder.wref(data));
parameter = data;
Problem here is that coder.wref is not supported in Matlab and therefore doesn't work in the InitFcn. (Please correct me if I'm wrong)
This only seems to work inside a Matlab-Function-Block:
Error evaluating 'InitFcn' callback of block_diagram 'Model'.
Caused by:
The coder.wref function is not supported in MATLAB.
So my problem with the second approach is, that I can't call the C-function during initialization.
Using a Matlab-function-Block to read the parameters isn't really an option, since I would have to route all the signals out which makes maintaining and further development of the model really hard. Also my suggestion is, that the model would not even run because the parameters are needed to initialize the model.
Questions:
Is there a way to make one of the above approaches work? If yes, how? Where is my mistake?
Is there another (simpler) option to pass the data as an array or struct to my model?
Database looks like this:
Identifier Default
latitude 52.5
longitude 13.4
electricity_consumption 4000.0
ventilation_stream 50.0
PV_peak 30.0
PV_orientation 0.0
no_vessels 28.0
heatpump_exists 1.0
hotwater_consumption 1000.0
.
.
.
After having spent so much time on this issue, I would like to share my experience on this problem:
SQLite: This approach did not work out for me because the direct SQL-Matlab interfaces are not supported for code generation.
It is in fact possible to write a C-function, that reads from SQLite and call that function in a Matlab-function-block via coder.ceval wich allows to read in a signal during simulation. This works for code generation (Simulink coder) as well. However this will not work for initialization (see question).
So none of my original approaches ended up working.
Workaround: I ended up switching to an approach based on the Simulink RSIM-target wich generates code (also for Linux) and can be parametrized via a .mat file wich contains all the parameters. The .mat file can be modified to update parameters. This required some additional code wich automates this step. Also the model configuration for RSIM is a bit tricky.
I am running Simulink using FastRestart, as I need to start and stop the simulation multiple times changing parameters. When I run Simulink from the main script, there are no problems. However, as soon as I make the script a function so that I can run it for different input data, I get an error that is clearly related to Simulink not seeing the Matlab workspace within the function.
To be more precise, say sfile is my Simulink file, then I run the following lines AFTER having initialized all variables I need in structures in Matlab:
load_system(sfile);
set_param(sfile,'FastRestart','on');
set_param(sfile,'SaveFinalState','on');
set_param(sfile,'SaveCompleteFinalSimState','on');
set_param(sfile,'SimulationCommand','update');
At the last line, I get the error that Simulink does not recognize mdl.tStep (which is the time step), as mdl is not a recognized structure. In fact, it is and if I run Simulink from the main script everything is fine.
Now, in the past, I would have used
options = simset('SrcWorkspace','current');
However, an expert I know has advised me against simset (as it may get deprecated in the future) and encouraged me to use set_param instead. I have
looked up the options for set_param on-line, but I could not find the setting for the Matlab workspace.
Any help would be greatly appreciated. Thank you in advance!
In many instances it is better to use the Model Workspace rather than the Base Workspace:
hws = get_param(model, 'modelworkspace');
hws.assignin('mdl',mdl);
At least be aware that this option exists.
A solution to your problem might be to use the assignin-function to all the variable whose value you want to pass to simulink in your matlab base workspace. To do so just use
assignin('base','mdl',mdl)
Having the variable in your base workspace should allow simulink to see it.
I have a Simulink model, the purpose of which is automated code generation.
My model uses S-functions (developed by another party), which has hard-coded assumptions about the path. For instance, several external data files are needed, which are referenced in the S-function via a relative path like ..\Bin\data\datafile.bin. This makes it necessary to set MATLAB's current working directory to a specific path before the model can be run.
I can automatically check and set the correct path via model callback functions. However, all model callback functions only seem to be related to the simulation process, not the build process. That means that I can run the model irrespective of what directory I'm in, but when I try to build the model, it always fails unless I manually navigate MATLAB back to the correct directory.
Needless to say, that's quite annoying. So I was wondering if there is something like a "preBuildFcn" callback fnuction, a function that is run before starting the build process? Any other solution (that does not involve modifying the S-function) is also very welcome.
There are plenty of hooks into the build process of Simulink / Embedded Coder ('entry', 'before_tlc', 'after_tlc', 'before_make', 'after_make', 'exit', and 'error'). I assume you want an 'entry' hook.
All you need to do is write an M-function with the name your_system_target_file name_make_rtw_hook, as explained in the documentation Customize Build Process with STF_make_rtw_hook File.
In case you can't open the online documentation (login required), here is the path to the HTML in your MATLAB installation: MATLAB root\help\rtw\ug\customizing-the-target-build-process-with-the-stf-make-rtw-hook-file.html
I am not sure whether building simulink models is sufficiently similar to building regular MATLAB programs, but here is what I used in the past:
Set up the project manually
Build the project programmatically
The program that is used to build the project should be able to set the path or do other custom things.
Disclaimer: I'm not a professional simulink/matlab programmer
If I've opened simulink and created a model, then i want to save it from the commandline in matlab. The save_system works, but I also want to specify a filename, for this i need to use save_system(sys, newsysname.slx)
I can't seem to find a function to get sys. How can I get the same sys as save_system() uses?
Use gcs to get the current system or bdroot to get the top-level of the model. find_system may also be useful.
I am using Matlab 2012a and the Simulink Coder (aka Real-Time Workshop). I want to compile the model using Simulink Coder but preserve the functionality of model callbacks.
Consider the following simple example. I have a Simulink model, callBackTest, which reads in a constant and outputs to a since. input1 is defined in myValues.m and loaded into the model workspace using the PreLoadFcn model callback. The PreLoadFcn callback is executed when the model is first opened. By using the PreLoadFcn callback, input1 will automatically be defined every time the model is opened.
Suppose myValues.m is originally coded as input1=1. When you run the simulation, yout will be an array of 1s. Also if I compile the model using the Simulink coder, the output will also be an array of 1s. However if I modify myValues.m so that input1 = 2 and do not recompile, the realtime output is still 1. This is wrong, so how can I read variables from a file into the model workspace with a compiled model?
You cannot generate code for model callbacks. If you do not want to regenerate code every time you change your input you can try using "From File" block which can read data from a .mat file. When you want to change your data you can then run your MATLAB code and save the output data into the same .mat file. There are some restrictions on what kind of data is supported for code generation from this block. Check out the doc for that block for details.
If your data is not too big you can also edit the generated source to modify the data. Data from Constant block is usually in-lined in the generated source code. After editing you can compile the generated code to produce new binary.
Another approach is to write your custom C S-Function where you can read from your own data sources. You need to write a TLC file to support code generation for this S-Function.
You need to recompile your model if these does not work for you. Documentation at http://www.mathworks.com/help/simulink/ug/importing-signal-data-in-simulink.html lists different ways of importing signal data into Simulink.
This does not answer your question about Model callbacks, but it might be helpful anyway.
If the "Inline Parameters" option is checked in:
Preferences -> Optimization -> Signals and Parameters
there is no way to change values in an already compiled model because they are hardcoded. Once you have this option turned off and you have recompiled, you could for example connect with external mode and run your myValues.m script and the values will be updated (unless you have marked them as non-tuneable).