MATLAB: How to log a signal for a long run (multiple days) in Simulink Real Time using File Scope

I wanted to run a simulation for few days, so I configure a File Scope on Simulink Real-Time to do so.

The sample time of my model is 5e-4 s so I needed 999 999 999 samples on my FileScope but it saved only 9 999 999 samples (i.e just more than one hour of simulation instead of 5 days).

I wonder if the memory that I wanted to allocated on the target machine would exceed the memory of the target machine.

Best Answer

Instead of logging all data in one file, consider logging the data in multiple files following this example:

https://www.mathworks.com/help/releases/R2016b/xpc/ug/log-signal-data-into-multiple-files-on-the-target-computer.html

In particular, go to the Scope Properties > File section and select Dynamic File Mode and AutoRestart. Then, you can configure Filename to increment dynamically. Use a base file name, an underscore (), and a < > specifier. Within the specifier, enter one to eight % symbols. Each symbol % represents a decimal location in the file name. The specifier can appear anywhere in the file name. For example, the following value for Filename, C:\work\file<%%%>.dat creates file names with the following pattern:

file_001.dat

file_002.dat

file_003.dat

The last file name of this series is file_999.dat. Note that if the block is still logging data when the last file reaches its maximum size, the function restarts and overwrites the first file in the series. If you do not retrieve the data from existing files before they are overwritten, the data is lost.

For more information about parameters in the Real-Time File Scope, please refer to this page:

https://www.mathworks.com/help/releases/R2016b/xpc/api/realtimefilescope-object.html

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MATLAB: Simulink Real-Time Data Logging with File Scope

In the File Scope, specify the full path of the data logging file, e.g. 'D:\data.dat'. If only the file name is entered, the file scope automatically tries to write to the 'C:\' drive. If the target has no 'C:\' drive, the data will not be written anywhere. More information on File Scope usage can be found here:

https://www.mathworks.com/help/releases/R2020a/xpc/ug/file-scope-usage.html

Additionally, if you omit the drive letter from the "dir" command it assumes that the folder path is relative to the default drive. Therefore, please specify the correct drive letter for your computer if it has no "C:\" drive, for example:

>> dir(fsys, 'D:\')

MATLAB: How does the new “File Log” block work in R2020b, and how is it different from the old “File Scope” block in Simulink Real-Time

To write a signal data file log on your target machine SSD hard disk, use the File Log block from R2020b onwards:

https://www.mathworks.com/help/releases/R2020b/slrealtime/io_ref/filelog.html

This article covers the following topics:

How is the File Log block different from the old File Scope block?
How can I turn off the auto-import for File Scopes?
How can I control the number of File Log runs on the target?
How do I I manually import File Logs into MATLAB?
How can I turn off the logging on the target machine?

How is the File Log block different from the old File Scope block?

The File Log block is similar to a signal marked for streaming in ‘Buffered’ mode, which was an R2020a (and earlier) feature and is documented here . The File Log block has the following improved capabilities compared to the old File Scope block:

1. By default, data is moved automatically to the host computer at the end of the simulation. At the end of the simulation, if the host computer is connected, the data is automatically transferred and loaded on the SDI. In addition to this, the data is also downloaded to the MATLAB base Workspace, as shown in the screenshots below. If the host computer is not connected, the data is stored on the target machine

2. The data file is deleted from the target machine after transfer to the host computer. The data file is deleted from the target machine after successful transfer to the host computer. If the transfer is not successful, the data file is not deleted.

Note: This means that you have to remember to save the data from SDI or the base workspace before closing MATLAB. If you close MATLAB without saving the data, your logged data is lost. This behavior will be reviewed in future MATLAB releases.

3. The File Log takes into account custom signal labels. Instead of naming the signals only based on the upstream block name, as was the case with the File Scope block, the signals will now be displayed according to the custom signal name that you specified in your Simulink model.

4. The data file can be transferred to the host machine during runtime. File Scope DAT files could only be copied to the host at the end of the real-time simulation. The File Log block allows import during runtime using the import() function as shown below.

How can I turn off the auto-import for File Scopes?

To disable the automated import of data logs at the end of the Simulation, start the application via the MATLAB API using the command:\n

>> tg.start('AutoImportFileLog',false);

Refer to the following link to learn more about the target object 'start' function:

https://www.mathworks.com/help/slrealtime/api/slrealtime.target.start.html

Note that it is currently not possible to control the behavior when using External mode, or via Simulink Real-Time Explorer.

How do I control the maximum number of logs stored on the target?

By default, the maximum number of file logs stored on the target is set to 1, as per the 'SLRTFileLogMaxRuns' model parameter:

https://www.mathworks.com/help/releases/R2020b/slrealtime/ref/max-file-log-runs.html

After building the application, you can use the 'fileLogMaxRuns' real-time application option to select the number of simulation runs that are stored when file logging is enabled:\n

>> app = slrealtime.Application('slrt_ex_osc');
>> app.Options.set('fileLogMaxRuns',4); % set max number of file logs
>> tg.start('AutoImportFileLog',false); % disable auto-import of file logs

How do I I manually import File Logs into MATLAB?

If the host computer was not connected when the application stopped, or if the auto-import had been disabled, you can use Simulink Real-Time Explorer to import the file logs available on the target machine. Click Import File Log as shown below:

After successful import, the file logs are automatically deleted from the target machine. The imported data is automatically loaded to the SDI. Export the data from the SDI to store the data on the host computer.

The file log import operation can be also done using the MATLAB API. Use the target object to get the list of the file logs available on the target machine. The list includes the name of the application, the start date, and the size:\n

>> tg.FileLog.list

You can selectively import or discard file logs using:\n

>> tg.FileLog.import(2:3)
>> tg.FileLog.discard("slrt_ex_osc")

How can I turn off the logging on the target machine?

The File Log block works in an Enabled Subsystem, but there is also a global switch. Use the MATLAB API to disable or enable the logging on a target machine:\n

>> tg.FileLog.disable
>> tg.FileLog.enable

\nYou can also use an Enable File Log block, as per:

https://www.mathworks.com/help/releases/R2020b/slrealtime/io_ref/enablefilelog.html

Best Answer

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