Error using Battery.lo​adDataFrom​MatFile Unable to locate voltage variable in file '03-11-17_08.47 25degC_5Pu​lse_HPPC_P​an18650PF.​mat'

Hey everyone. I just run the Example_DischargePulseEstimation.m code which is prepared code from MATLAB. To run the code I wrote this to command

open('Example_DischargePulseEstimation.m')

and clicked enter.It worked but I want to use this code for another "*.mat" data file.So I just copy paste a code and adapt it to my data but MATLAB constantly gives error.

The Code That I used for Another data:

psObj = Battery.PulseSequence;
disp(psObj) 
FileName = '03-11-17_08.47 25degC_5Pulse_HPPC_Pan18650PF.mat'; 
[time,voltage,current] = Battery.loadDataFromMatFile(FileName); 
addData(psObj,time,voltage,current); 

The Error It's given:

Error using Battery.loadDataFromMatFile
Unable to locate voltage variable in file '03-11-17_08.47 25degC_5Pulse_HPPC_Pan18650PF.mat' 
Error in Battery.loadDataFromMatFile Error in kod3 (line 33) 
[time,voltage,current] = Battery.loadDataFromMatFile(FileName);

I used the data from Mendeley data: https://data.mendeley.com/datasets/wykht8y7tg

The data in code is in attached file!!

Answer 1

[Gowthami]

Hello Hanife,

It is my understanding that you are getting an error while loading data from MAT file.

I could see that executing the below command returning 'meas: [1×1 struct]' ,

open '03-11-17_08.47 25degC_5Pulse_HPPC_Pan18650PF.mat'

All the fields are present inside the meas struct, Because of this you are getting error as 'Unable to locate voltage variable in file '03-11-17_08.47 25degC_5Pulse_HPPC_Pan18650PF.mat''

The function 'Battery.loadDataFromMatFile(FileName)' is expecting the filed names as current, time, and voltage as shown in the below image,

Please refer to the below link for more information on saving a few specific fields into a MAT file - https://www.mathworks.com/help/matlab/import_export/load-parts-of-variables-from-mat-files.html

[Hanife Güney]

Thank you so much. I solved the problem with this code below:

clear all
close all
psObj = Battery.PulseSequence;
files =  '06-15-17_11.31 n20degC_5Pulse_HPPC_Pan18650PF.mat';
load(files);
fields = ["TimeStamp","Wh","Power","Battery_Temp_degC","Chamber_Temp_degC"];
meas = rmfield(meas,fields);

meas = struct2cell(meas);
meas=cell2mat(meas);

voltage=meas(1:49655,:);
current=meas(49656:99310,:);
Ah=meas(99311:148965,:);
Time=meas(148966:198620,:);
time=Time;

% psObj.addData(Time,Voltage,Current);
psObj.Data(1:49655,1) = time;
psObj.Data(1:49655,2)=voltage;
psObj.Data(1:49655,3)=-current;
psObj.Data(1:49655,4)=Ah;
psObj.Data(1:49655,5)=1-(-Ah/2.9);
psObj.plot()

As you said I convert meas to struct then convert to cell and it worked.