How to plot different tdms file data on same figure within a loop?

Hello, thanks for taking a look:

I want to plot certain data from LabView tdms files after I convert them to .mat file(s). I have a script to allow the user to select which files to convert. Once the files are selected, a function is called to convert the files, one at a time, to .mat file. Then proceed to plot the power consumption (from tdms file). The script plots the data correctly, but I can either:

-plot on separate figures, or, -have the first figure overwritten by second figure.

Thanks, John

Answer 1

[Jan]

And what do you want to achieve exactly? A Subplot for each file or collecting the data of all files in one diagram using different line colors? Or do the files contain data recorded to different time, such that the new data are appended to the line(s) of the existing diagram?

Please explane the term "same figure" with more details. When you post the relevant code, suggesting a modification is much easier for us and for yourself.

[John]

Thanks Jan, I tried to post the code but previewed below in a confusing way. I'll try again.

I have a script which contains a loop that uses a function to convert .tdms file(s) to .mat files and plots specific data (Power vs. time) one file at a time (within the loop). I want to be able to "keep" that figure (Power vs. Time) from the first data set so that I can overlay another file's data (power vs. time) to compare the n number of data sets.

(Main Script)

 cd('C:\Repository\Testing\FG Current Transient Test\PN_NVX-2047-1_SN_LK0006\20121023');
            d = dir('*.tdms');
            str = {d.name};
            [s,v] = listdlg('PromptString','Select a file:','ListString',str);
            ls=length(s);   

            for ii=1:length(s)
                filepickTDMS(d(ii)).name,ii,ls);               
            end
            hold off

(Function)

 function filepickTDMS(filename,file_no,plot_select,no_files)

        [ConvertedData,ConvertVer,ChanNames] = convertTDMS(1,filename);

      tStep = ConvertedData.Data.MeasuredData(1,end).Property (1,3).Value; 
      tN = ConvertedData.Data.MeasuredData(1,end).Total_Samples;
      tt = ((0:1:(tN-1))*tStep)/60;

HV_Bus_Volt = ConvertedData.Data.MeasuredData(1,4).Data;
M1_Bus_I = ConvertedData.Data.MeasuredData(1,5).Data*10;
M2_Bus_I = ConvertedData.Data.MeasuredData(1,9).Data*10;

bHV_Bus_Volt = ConvertedData.Data.MeasuredData(1,15).Data;
bM1_Bus_I = ConvertedData.Data.MeasuredData(1,16).Data*10;
bM2_Bus_I = ConvertedData.Data.MeasuredData(1,20).Data*10;

Power_FG_A = HV_Bus_Volt.*M1_Bus_I + HV_Bus_Volt.*M2_Bus_I;
Power_FG_B = bHV_Bus_Volt.*bM1_Bus_I + bHV_Bus_Volt.*bM2_Bus_I;

P_tot= Power_FG_A + Power_FG_B;
rmsPwr = sqrt(mean(P_tot.^2))

        if file_no == 1
        figure(1)
             plot(tt,P_tot) 
             hold on
             axis([0 85 0 5000])
             title(filename)
             xlabel('Time [sec]'); 
             ylabel('Power [Watts]');
        end

        if file_no >= 2
        figure(2)
             plot(tt,P_tot) 
             axis([0 85 0 5000])
             title(filename)
             xlabel('Time [sec]'); 
             ylabel('Power [Watts]');
        end
 end

 end

Thanks so much for your help. John

[Jan]

Thanks for the explanations. It is still not clear enough. E.g. what should happen for the title(filename) commands, if you plot in one diagram?

What happens for this:

if file_no == 1
  figure(1)
  AxesH = axes;
  plot(tt,P_tot) 
  hold on
  axis([0 85 0 5000])
  title(filename)
  xlabel('Time [sec]'); 
  ylabel('Power [Watts]');
else
  plot(tt, P_tot, 'Parent', AxesH); 
end

[John]

Hey Jan, thanks for the response.

I implemented the above, and as-is, it doesn't recognize "AxesH" after the else. So I added the "AxesH=axes" and it keeps the axis setting for the first plot, but still overwrites the first set of data and calls itself figure(1). I'll work on it more now. So frustrating because it is such a simple request!

Thanks, John

[John]

I figured it out! Thanks for your help. With the addition of the "hold on" after the else, it kept both files on the same figure!