Large file size for continuous monitor DAQ 6052E

[ldrummon]

I am trying to use continuous monitor to acquire data from my two 6052E DAQ cards. I am using traditional daq vi's. The DAQ cards are running simultaneously in a seperate thread in TestStand while the rest of my test is running. The tests get lengthy (20 min) and the file size of the data files also becomes large (there are 32 channels monitored on one card and 4 on the other each monitored at a sample rate of 10k). I have set the write to file in a while loop, but because of the large file size I have stripped off important signals and written them to their own (smaller) file. Problem is, now my system is getting bogged down bc the write to file and data recording is taking a while. My scan backlog continues to g
et larger and the tests in teststand begin to fail (I think this is bc the DMM driver is not getting enough processor time to finish it's operations). How should I deal with monitoring so much data and keeping the file size down? This is obviously not the best way.

[preston_johnson]

What version of LabVIEW and DAQ are you using? With LabVIEW 7.x, we greatly enhanced the effeciency of file writing. Also do write in binary, such as waveform data types.

Can you reduce the data prior to writing to file?

32 channels at 10k/second should not be a problem. With today's fast IDE drives I have seen 56 channels at 16k going to disk while the rest of the application (very processor intensive) is able to keep up.

Preston Johnson

[pops]

If your sure it's file I/O causing the slow down try using a low level write to file vi (yellow color). High level write to file vi's such as write characters to file or write to spreadsheet will privide more functionality but will also cause more overhead to your program. Try to log in binary if your not conserned with writing to a text file.