Showing results for 
Search instead for 
Did you mean: 

NI 6229 Sample Frequence

Generally speaking, the maximum rate can be reached when there is only one channel. As the number of channels increases, the maximum sampling rate decreases correspondingly. But why can NI_6229 achieve the maximum sampling rate of 250KS/s for both single channel and multi-channel? What are its internal processing mechanisms?

0 Kudos
Message 1 of 3

Hi bhyy,


there's just one ADC on this board, and it achieves a max sample rate of 250kHz.

This is valid for one channel, and also for multiple channels ("aggregate")…

Best regards,
CLAD expired, using LV2011SP1 + LV2017 (+LV2019 sometimes) on Win7+cRIO
Kudos are welcome Smiley Wink

0 Kudos
Message 2 of 3

I was in a another recent thread dealing with this term "sampling rate (aggregate)".  I explained it by saying that it defined the maximum rate of A/D *conversions*.  


What makes for some confusion is that DAQmx uses some different terminology and conventions.  DAQmx doesn't give you access to individual conversions, it only gives you access to *samples*.  Under DAQmx, 1 "sample" ALWAYS means 1 A/D conversion for each channel in the task.  A task with 5 channels on a board with a 250 kHz max *aggregate* rate, would have a *sample rate* of 50 kHz.


When you read data using DAQmx, it will always be returned in units of samples which will include 1 A/D conversion for each channel in the task.  You cannot retrieve only the A/D conversions for the 3rd channel out of 5.



-Kevin P

0 Kudos
Message 3 of 3