Option 1: Use Root-Level Inport Data
The "From File" block was deprecated in R2020b in favor of using the root-level input port data Simulink feature. It supports almost all Simulink data types and has richer functionality compared to the "From File" block.
The basic steps are as follows:
Step 1: Add Inports to the top level of your model.
Step 2: Use the Root Inport Mapper tool or MATLAB code to perform the initial mapping of data to the root-level inports, as shown in the following examples:
- Define and Update Inport Data using Root Inport Mapper UI
- Define and Update Inport Data using MATLAB Language
For example, to map the variable "waveform" to a single inport, use "ExternalInput". Make sure the "LoadExternalInput" option is enabled. Then, build the real-time application with "slbuild":
>> load waveform.mat;
>> set_param(model,'ExternalInput','waveform');
>> set_param(model,'LoadExternalInput','on');
>> slbuild(model);
The input data files are packaged in the MLDATX file at build time. Unless you explicitly stop stimulation before start, the input data will be applied from T=0 every time you start the real-time simulation.
Step 3: Use updateRootLevelInportData to change the inputs to the real-time application without the need to rebuild:
>> load waveform.mat;
>> app_object = slrealtime.Application(model);
>> updateRootLevelInportData(app_object);
This will update the data contained in the MLDATX file with the new contents of the "waveform" variable. The application must be reloaded to take effect. Unless you explicitly stop stimulation before start, the new input data will be applied from T=0 every time you start the real-time simulation.
Step 4: Use Target.Stimulation objects (R2021a+) and reloadData to start, pause, stop, and restart the stimulation applied to root-level inports at any point T=x while the real-time simulation is running:
>> stop(tg.Stimulation,'all');
>> reloadData(tg.Stimulation,[1], new_waveform);
>> start(tg.Stimulation,'all');
For more details, see: Control and Update Stimulation of Inports to Real-Time Application.
Option 2: Use Playback block
Starting in R2022b, Playback blocks are available as another way to provide external data to applications. Other than Root-Level Inports, Playback blocks can be used at different model hierarchies to provide input data. The stimulation of the Playback block ports can be controlled and updated on target at run-time using the same Target.Stimulation objects as mentioned above. For more information, see: Load Data Using Playback Block
Option 3: Use S-functions (not recommended)
Apart from the workflows mentioned above, Simulink Real-Time does not support loading any data from files located on the target file system into the real-time application. If you wish to implement such functionality, you would have to write your own C-Code S-Function to accomplish this. Details on how to do this are ouside the scope of MathWorks Technical Support. For more information, see the following MATLAB Answer: Can I read from external files or write to them from my model with Speedgoat and Simulink Real-Time for R2020b onwards?
