Saving fast acquired data, reading it later

[usuario]

Hello,

I am acquiring 7 channels at 10kHz and 1 channel at 100kHz. Because of already existing postprocessing code, I will treat the acquired signals in MatLab. I am also pretty new in LV, want to learn.

So, since 7*10kHz + 1*100kHz is quite a lot of data, I have chosen to write it as TDMS files (1 for the 7 channels, 1 for the other one). I am trying to get the data once recorded... but can't, I am not able. I have gone through the LV Basics course lessons, read about TDMS format, tried with LV examples. I have also seen a code for MatLab to read tdms files, but won't make it work (I have 64bit xp).

Now I am thinking on saving one file per channel, just the data (no headers, author, fs, date, ...) so as to be easily read afterwards with MatLab, but I find myself that can't write a file and then read it even with LV's examples.

Any suggestions please?

[srikrishnaNF]

Hi usuario,

  Whether are you trying to read the tdms files in matlab or are you unable to read in labview itself?

T hanks and regards,

srikrishnaNF

[usuario]

Hello,

I haven't tried with MatLab yet, not until I can check the data in LV.

I attach some acquired files.

What do you think about writing one binary file per channel, just data (no headers...)? What data format should I use?

[srikrishnaNF]

Hi usario,

  I can able to read your tdms files...why are you bothering about the  data format?Please refer the examples..

Thanks and regards,

srikrishnaNf

[usuario]

Hi,

I think I haven't explained it good enough, sorry. If I use the TDMS File Viewer block I am able to see the data. But only that way, I cannot graph it; nor be able to access it so that I can then write a separate binary file to be read from MatLab for example. Also, 'I cannot' means 'I don't know how please help'.

Examples I have tried: 

Read TDMS file.vi

TDMS - Express read data (time domain).vi

Also:

Express Read Meas File block

Yet also:

many tries with open/creat file, read file, close file, ... blocks.

By the way, thank you very much for your effort and attention.

[FHM]

try with this Example VI. I could read the tdms File correctly and display the signals.

[FHM · Accepted solution]

and in this way you have access to each signal see attached picture!

Message Edited by FHM on 06-10-2010 07:03 AM

[usuario]

Hi,

thanks!! it works great!!

It happened that I just made this code, and this time works to me also (I can't tell why didn't worked before / what was I doing wrong before).

Thanks, your support has been very useful to me. Regards,

usuario