Script for CSV processing

Question

Antonio Jayena 2015-3-23

0
链接

此问题的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/184618-script-for-csv-processing

评论： dpb 2015-3-23

Hi friends.

First of all I apologize for my bad English.

I tell you my problem. I was working with an osciloscope and I take around 500 measures (Voltage/Time) in CSV files. The signal is a pulse train with only the 1% of the period crossing the zero.I want to measure with matlab, for each csv, which is the value of x axis (time) for exactly 25 pulses of the whole train.

Doing this with cursors is a very hard work. I'm trying to build a Script. My main idea (because of the small time that the signal cross the zero) is to make a FOR loop, with a IF loop inside that, when Y axis have crossed the zero 25 times, the script catchs the value of the X axis in a new variable. This operation, with the bucle, for all the CSV files.

This is my idea, but Im new in Matlab and is costing me a lot.

Anyone can help me? Thank you very much.

1 个评论
显示 -1更早的评论隐藏 -1更早的评论

Antonio Jayena 2015-3-23

在 MATLAB Online 中打开

Im trying to go in other way, but I'm faling in the sintax

j=1
i=1 
for i=1:30
     s=csvread('scope_0_1.csv',2,0);
if (r2==0)  % when signal cross zero
     j=j+1
else 
if (j==25)  % finding the 25th zero crossing
disp('s');
j=0;
i=i+1;
end

Any help plis?

请先登录，再进行评论。

请先登录，再回答此问题。

Answer 1

dpb 2015-3-23

0
链接

此回答的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/184618-script-for-csv-processing#answer_172406

在 MATLAB Online 中打开

s=csvread('yourfile.csv');   % read the signal
ix=find([0 diff(s>0)==1,25); % locate first 25 zero crossings

The above works by turning the input signal into a 0/1 pulse train, then looks for the positive crossing locations (where the 0 turns to 1 is a +1 difference).

The ix index vector is the position in the original vector of those crossings, specifically it will be the index of the first positive location after the zero-crossing.

0 个评论
显示 -2更早的评论隐藏 -2更早的评论

请先登录，再进行评论。

Answer 2

Antonio Jayena 2015-3-23

0
链接

此回答的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/184618-script-for-csv-processing#answer_172429

在 MATLAB Online 中打开

Im trying to go in other way, but I'm faling in the sintax

j=1
i=1 
for i=1:30
     s=csvread('scope_0_1.csv',2,0);
if (r2==0)  % when signal cross zero
     j=j+1
else 
if (j==25)  % finding the 25th zero crossing
disp('s');
j=0;
i=i+1;
end

Any help plis?

3 个评论
显示 1更早的评论隐藏 1更早的评论

Antonio Jayena 2015-3-23

在 MATLAB Online 中打开

I´m trying but I get errors.

Error using horzcat
Dimensions of matrices being concatenated are not
consistent.
Error in Matlab (line 2)
ix=find([0 diff(s>0)==1,25]);

Mi CSV has 2 colums (voltage and time)...is here my error? I make a loop because I have a lot of CSV files, and Im triying to get the value of each one printing in each iteration with

disp('s')

Thank you for your effort.

dpb 2015-3-23

在 MATLAB Online 中打开

OK, I presumed a row vector in s; for a Nx2 array then for the voltage column it would be

ix=find([0; diff(s(:,1)>0)==1,25]);

again assuming the data array is s; obviously use whatever you use in your script.

For processing multiple files, you might look at the File Exchange function filefun that applies a function "automagically" to each function. It's at <Apply a function to files>

请先登录，再进行评论。