05.15.08
DAQmxReadAnalogF64 Intermittent Warning of 1
I’ve had a very serious problem recently regarding the long term stability of the NI-4462.
Problem:
Everything works fine for about 20-inf secs but then all of a suddent the DAQmxReadAnalogF64 function returns a 1 rather than a 0.
Solution:
The errors were buffer overrun errors (annoying that the 4462 almost always returns 1 as an error. Not very informative!). This, I eventually figured out, seemed to be happening every time my cpu hit 100% load. Then the DAQ would stop acquiring, post an error of 1 and quit. To fix this I manually set the sampsPerChanToAcquire setting in the DAQmxCfgSampClkTiming function.
Just a bit of background, I am using continuous acquiring, so the sampsPerChan… variable set the hardware buffer size. I am also interrupting every 50000 samples. So setting this value to 200000 or above (i.e. 4x your interrupt generation) seems to get rid of all my intermittent problems!! Woo!
Hope this helps someone in the future…