Waveform File Size

[tritone]

Hello, I am acquiring data from 3 PCI-6052E cards, at a rate of 10kHz.

I am using the low-level waveform file VIs (open / write / close) to write the waveforms I acquire to a file, and these files are massive (about 3 MB per second of logging). Is there a way to cut this down, and still have a valid timestamp to plot against?


Any help would be GREATLY appreciated! Thanks!

[alipio]

Hi again tritone

By default, waveforms are DBL data format ( see Application note 154). One way to cut size down and keep using waveform data type is:
1- scale waveform for 16 bits.
2 extract Y ( dbl)
3 conver Y to I16
3 insert into waveform
The new waveform will be I16 data (1/4 of DBL)and you will keep all waveform attibutes.
It should decrease file size
Hope this helps.
Alipio

[tritone]

Thanks for your reply .. this seems like what I want to do, however I am not sure what you mean by "scale waveform for 16 bits". Could you explain? Thanks!

[alipio]

Hi Tritone

Your DAQ card is 16 bits converter, so you have to scale you V range to 16 bits to keep relationship.

See attached example

Hope it helps. you can achieve a data reductio to 1/4 of original, without loosing data and keeping timestamp.

Alipio

[tritone]

That's great, I got it working .. my files are now about 1/3 the size they were .. thanks!

[Fantester]

Could you send this in V6.1 ?

[AlanArmstead]

Here is the VI saved in LV 6.1.