CRio data logging too slow

Question

Hi,
I am using a cRio 9074 in scan mode and I have a fairly simple timed loop that should run at 5-10mSec periods to operate a pwm control. I also need to do some data logging and save two input signals (at approx. 1kS/sec). However, when I use write to spreadsheet, the loop speed drops and my timed loop period goes up to 50mSec. How can I speed this up, and what is the efficient way to save data in scan mode.
Thanks.
Solved!
Go to Solution.

Answer 1

The single best way to improve determinism is to divide your acquisition/logging into two distinct producer/consumer loops as VTHokie says. Next best improvement would probably be using a binary format file structure rather than Write to Spreadsheet, which converts all data to ASCII representation prior to writing to file. Writing to ASCII files rather than binary files degrades performance in four ways:
CPU must be used to do the number to text conversion
ASCII represented numbers lose precision and don't exactly convert back to original data
The filesize is larger
When you go to read the file, it's slower for the above three reasons
On the other hand, an ASCII file is more portable - e.g., you can easily import into a third-party spreadsheet analysis program. But who in their right mind would export data OUTSIDE of LabVIEW when it offers best-in-industry analysis tools?
a.lia-user-name-link[href="/t5/user/viewprofilepage/user-id/88938"] {color: black;} a.lia-user-name-link[href="/t5/user/viewprofilepage/user-id/88938"]:after {content: '';} .jrd-sig {height: 80px; overflow: visible;} .jrd-sig-deploy {float:left; opacity:0.2;} .jrd-sig-img {float:right; opacity:0.2;} .jrd-sig-img:hover {opacity:0.8;} .jrd-sig-deploy:hover {opacity:0.8;}