MATLAB: Simulation Data Inspector plots are missing data

simulink

I have a signal being logged, which is an Accelerometer signal multiplied by a constant number (which is the conversion from Volts to m/s^2). Frequently, I face the issue that when the signal is viewed on the Simulink Data Inspector it looks like a set of stairs/blocky signals. When I export this to the Workspace and plot it using MATLAB it looks fine. Why is this happening?

Best Answer

By default, signals are plotted immediately in the SDI, as they are generated by the SLRT model running in real-time. The SLRT kernel stores the data in a network buffer to send to the desktop computer and plot, this buffer can be overrun, and data lost in the process. Regardless, the data is always saved and stored for later analysis, and all data is being passed between the model's component in real-time. This is why the signal looks different when plotted while simulating vs when plotted after loading to the Workspace.

You can change the plotting mode in SDI for simulations. To read more about this, check this link:

https://www.mathworks.com/help/releases/R2020a/xpc/ug/minimize-data-loss-with-simulation-data-inspector-buffered-mode.html

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MATLAB: Simulink data inspector does not show signals logged in Simulink RT model run on target machine

1) Make sure that the Simulink Data Inspector is working as expected by running the example below which does not use Simulink Real Time.

https://www.mathworks.com/help/releases/R2018a/simulink/ug/visual-inspection-of-signal-data.html

2) Make sure that your current SLRT target and model are properly setup, you can test using the following example to make sure the setup is fully operational and external mode is running correctly.

<http://www.mathworks.com/help/releases/R2018a/xpc/gs/run-a-real-time-application.html#f0-42409>

3) Try the shipped example of logging signal in SDI for RT models.me as your use case.

https://www.mathworks.com/help/releases/R2018a/xpc/ug/inspect-signals-in-external-mode-using-simulation-data-inspector.html

4) If above steps are all good except signal logging in SDI, disabling all antivirus software and firewall on the development machine should resolve the issue.

MATLAB: Does Simulink.sdi.save save incomplete data to a MAT file when starting a simulation by setting the “SimulationCommand” parameter to ‘start’

The issue with the script is the way the simulation is run, i.e:

set_param(gcs,'SimulationCommand','start');

This command starts the simulation. but does not guarantee that the simulation ends before progressing to the subsequent part of the script which writes and saves to SDI. What happens is that the script finishes saving the incomplete data to a MAT file when simulation is still writing to SDI.

As a workaround, you may use the "sim" command to run the simulation. This guarantees that the simulation finishes before progressing to the next line of script.

Best Answer

Related Solutions

MATLAB: Simulink data inspector does not show signals logged in Simulink RT model run on target machine

MATLAB: Does Simulink.sdi.save save incomplete data to a MAT file when starting a simulation by setting the “SimulationCommand” parameter to ‘start’

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