Matlab gui with pause function

Question

I am using the GUIDE for matlab gui. The gui built in order to communicate with keithley current measurement device through GPIB. When using a toggle button for Current measurement while loop, i am using a pause() function inside the while loop for each iteration and a ytranspose on the y array reading results.

    function Measure_Callback(hObject, eventdata, handles)

    global GPIB1
    global filename
    global timeStep

    disp('Measurement in progress \n stopwatch starts!');
    tic
    x=0;
    n=0;
    while get(hObject,'Value')
       fprintf(GPIB1, 'printnumber(smua.measure.i(smua.nvbuffer1))');
       fprintf(GPIB1, 'printbuffer(1,1,nvbuffer1)');
       A = fscanf(GPIB1);
       if length(A)<20
           x = x+1;
           n = n+1;
           t(n) = toc ;
           y(x) = str2double(A);
           plot(t,y,'-bo',...
                    'LineWidth',2,...
                   'MarkerEdgeColor','k',...
                    'MarkerFaceColor',[.49 1 .63],...
                    'MarkerSize',10);
           grid on
           hold on
       end 
       title('Current vs Time','FontSize', 15)
       xlabel('Time [s]','FontSize', 15)
       ylabel('Current [A]','FontSize', 15)
       a = timeStep;
       pause(a)
    end
    disp('Measurement terminated');
    disp('Elapsed time: ');
    elapsedtime = toc;
    elapsedtime_string = num2str(elapsedtime);
    disp(elapsedtime_string);
    ytrans = transpose(y);
    csvwrite(filename,ytrans);
    fprintf(GPIB1, 'smua.source.output = smua.OUTPUT_OFF');

For the pause function i'm geting error: ?? Error using ==> pause Error while evaluating uicontrol Callback

For the transpose(y) function i'm also getting a error: its undefined y.

Cant understand why are those errors and could use some help. Thank you!

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ninehundred ninehundred · Accepted Answer · 2016-01-11T15:36:40

First off, as people say, post the errors and the code. Do you know if length(A) is smaller than 20 in the first time you run the loop? Because if not, A is not defined and you can't transpose something that is not there. Initialize A before the loop to something and see if the error persists (or print out length(A) to make sure the loop gets entered the first run).

As for the pause error, make sure pause is an int or double, not a string. If you get your global timeStep from the GUI field, it is probably a string and you need to covert it to double first.

Matlab gui with pause function

1 Answers