Refreshing Plot After Certain Time?

Hi all,

I'm writing a GUI in App Designer to live plot spirometry data from LabChart. The end goal is to have a participant match the square wave by sniffing in. So, I want the data to be plotted live, then reset to the beginning every 6 seconds. My solution below does not work, the data doesn't even plot.

function plotter = plot_data(app,~,~)
    global gLCDoc;
    global gChans;
    global gChansData;
    
    % gChansData is the live Y-axis data pulled from LabChart
    gChansData = gLCDoc.GetChannelData(1,gChans,gLatestBlock+1, length(gChansData(1))+1, -1);
    
    % 6 seconds is an arbitrary number
    % My attempted solution is to clear the data points every 6000 ms
    % To find that, I use an if statement and the modulus of data length and 6000
    if mod(length(gChansData),6000) == 0
        gChansData(1:6000) = [];
        app.UIAxes.cla;
        app.UIAxes.XTick = [0:1000:6000];
        app.UIAxes.XLim = [0 6000]; 
        app.UIAxes.YLim = [-600 800]; 
        
        base_x = [0 2000 2000 4000 4000 6000];  
        base_y = [0 0 450 450 0 0];
       
        plot(app.UIAxes,base_x,base_y);
        %plot
        plot(app.UIAxes,gChansData,'r');
    else 
        plot(app.UIAxes,gChansData,'r');
    end
end

% Another if statement I tried that didn't work:
if ~mod(length(gChansData),6000) > 0

%Timer refreshes axes by calling function every .01 seconds
Timer = timer('ExecutionMode','fixedRate','Period',.01);
Timer.TimerFcn = {@app.plot_data};
start(Timer);

Answer 1

[Mario Malic]

Use function drawnow to refresh the plots.

If I understood the code correctly, you just need to add drawnow somewhere after plots.