How to periodically change Simulink Output file name?

Hello,

I am trying to periodically output data from Simulink using the "To File" block, and I would like to use the current date and time as the name for each output file. Currently, I am trying to periodically call a function which determines the real-world time, converts that to a string, and uses the set_param command to change the output file name accordingly.

 function [Y, M, D, H, MN, S] = fcn()
   coder.extrinsic('now');
   coder.extrinsic('datevec');
   coder.extrinsic('sprintf');
   coder.extrinsic('set_param');
   [Y, M, D, H, MN, S] = datevec(now,'HH:MM:SS.FFF');
   date_time=[Y M D H MN S];
   fname = sprintf('OutputFile_%04d_%02d_%02d_%02d_%02d_%02f.mat', date_time);
   set_param('untitled/To File','Filename',fname);
 end

Unfortunately, I am receiving the error message "Cannot change parameter 'File name: (Filename)' of 'untitled/To File' while simulation is running".

I have only been able to successfully use the set_param command while Simulink is not running, but I need to change my output file name during simulation. Is this possible? Is there a better way to approach this problem?

Thank you,

Drew

Answer 1

[Prateekshya]

Hello Drew,

You are encountering the error because changing the filename of the "To File" block during simulation in Simulink is not directly supported.

Alternatively, you can use a MATLAB function block to perform this operation by writing your own code. Here is a sample code for the same:

function saveData(u)
    coder.extrinsic('now', 'datevec', 'sprintf', 'save');
    persistent lastSaveTime;
    if isempty(lastSaveTime)
        lastSaveTime = -inf;
    end

    % Define the save interval (e.g., 1 second)
    saveInterval = 1; % seconds

    % Get current time
    currentTime = now;
    [Y, M, D, H, MN, S] = datevec(currentTime);
    timeString = sprintf('%04d_%02d_%02d_%02d_%02d_%02d', Y, M, D, H, MN, floor(S));

    % Check if it's time to save data
    if etime(datevec(currentTime), datevec(lastSaveTime)) >= saveInterval
        % Create filename with timestamp
        fname = sprintf('OutputFile_%s.mat', timeString);

        % Save data to file
        dataToSave = u; % Assuming 'u' is the input data to save
        save(fname, 'dataToSave');

        % Update last save time
        lastSaveTime = currentTime;
    end
end

To know more about MATLAB function blocks, kindly follow this link: https://www.mathworks.com/help/simulink/what-is-a-matlab-function-block.html.

I hope this helps!