Real-Time File Logging and Streaming Workflow

You can get signal data into the Simulation Data Inspector through logging by using a File Log block or through streaming by marking a signal for logging in the model or selecting a signal for streaming in the Simulink Real-Time Explorer.

Signal logging through a File Log block provides options that let you control:

  • The number of file logs that are retained on the target computer

  • Whether file log data is auto imported into the Simulation Data Inspector

  • Whether file log data is exported into the base workspace

You can configure these options by using the option for the real-time application start(tg) function or by using the Run in Real-Time selection in the Simulink Real-Time Explorer or the Simulink Editor. The File Logging and Streaming Workflow figure shows how these options configure operation of the real-time application start(tg) function. Where startRecording and stopRecording appear in the figure, you can use either these functions or the corresponding Start Recording and Stop Recording buttons on the Real-Time tab in the Simulink Editor or in the Simulink Real-Time Explorer.

File Logging and Streaming Workflow

While the real-time application is running, you can control file logging from File Log blocks:

  • Default logging logs signal data for the entire simulation run.

  • Enable or disable file logging by using the Enable File Log block in the model. If the model includes an Enable File Log block, the startRecording function and stopRecording function control only streaming, not logging.

  • Enable or disable file logging by using the startRecording function or stopRecording function. These function also enable or disable streaming. Alternatively, you can use the Start Recording button and Stop Recording button on the Real-Time tab in the Simulink Editor or in the Simulink Real-Time Explorer.

You can stop file logging:

After file logging stops, the setting of the AutoImportFileLog name-value argument determines whether file log data is automatically imported into the Simulation Data Inspector or whether you use the import(tg.FileLog) function to import the data.

Automatic import of the file log is handled differently by the workflows in the Recording Workflow figure:

  • For all of the workflows, the automatic import operation occurs when the real-time application stops.

  • For the Recording workflow, the automatic import operation also occurs when the stopRecording function is called.

Add Signals to Instrument in Real-Time Application

Simulink® Real-Time™ user interfaces help you visualize signals by using:

There are programmatic options for collecting signal data that do not require adding File Log blocks or marking signals for logging in the model. These options include:

  • You can apply the addForFileLog function to add signals to an instrument in a Target object. The instrument transfers the signal data from the target computer to the development computer in the same manner and with the same controls (for example, AutoImportFileLog option for the start function) as when file log data is collected through a File Log block.

  • You can apply the addForSDI function to add signals to an instrument in a Target object. When added to a Target object, the instrument transfers of signal data from the target computer to the development computer in the same manner and with the same controls (for example, the startRecording and stopRecording functions) as streaming signal data. The streaming data is available in the Simulation Data Inspector during the simulation run, and the data is not saved on the target computer.

  • You can apply the addForMATLAB function to add signals to an instrument in a Target object. When added to a Target object, the instrument transfers of signal data from the target computer to the development computer in the same manner and with the same controls as streaming signal data; same as with the addForSDI function. The difference is that the streaming data is accessible through apps written in MATLAB rather than being accessible through the Simulation Data Inspector.

Tip

This additional signal logging and streaming support is dynamic. You can modify signal logging and streaming selections in your real-time application without re-building your model.

These steps show how to add a signal to an instrument then add the instrument to a Target object for file logging.

  1. Create a target object and connect to target computer. Open a model and configure model for target computer. Build a real-time application from the model. Create an instrument object and add a signal from real-time application.

    objTarg = slrealtime;
connect(objTarg);
model = 'slrt_ex_osc';
openExample(model);
modelSTF = getSTFName(objTarg);
set_param(model,"SystemTargetFile",modelSTF);
slbuild(model);
mldatxname = 'slrt_ex_osc.mldatx';
objTargInst = slrealtime.Instrument(mldatxname);
objTargInst.Name = 'TargetInstrument';
addSignal(objTargInst,'SigGen');

  2. Add an instrument to the Target object for file logging.

    addForFileLog(objTarg.Instruments,objTargInst);

  3. Load and run the real-time application. After the simulation runs, import the file log data to the development computer and visualize signals in the Simulation Data Inspector.

See Also

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