08-11-2017 09:55 AM
The NI 9239 user guide said the lowest sample freq is ~1.6kHz.
And I need to log the data to PC's HD for more than 5hours.
When I start the .vi, buffer overflow error occurs.
Wondering is there any method to reduce the sample freq or use some soft timer to trigger the 9239 in ~10Hz.
I only have the cDAQ slot, no cRIO slot.
Any suggestion would be helpfull.
08-14-2017 12:06 AM
The main reason for this problem is that the sampling speed does not match the speed of data read. That is to say you do not read the data in time to cause a buffer overflow.You can set up the speed of data read in the program.
08-14-2017 09:29 AM
If you read at 1.6 kHz and only need data @ 10Hz you can
-only record every 160 value and ignore the rest
-or take the mean of 160 values .. and store that value (in signal processing you find resample / decimation vis that do the job)
the PC will be bored anyway with such low samplerates 😄
08-14-2017 08:20 PM
Is not your problem overflowing the cache? The reason why the cache will overflow is that you do not read the data in time, and the sampling rate is actually have no relationship.