Different sampling frequencies per channel in Data Acquisition Toolbox?

Hi,

I have a NI USB-6009 data acquisition card which is capable of an aggregate 48 kHz. I need two channels--one for a hotwire, one for a pitot-tube. In the Data Acquisition Toolbox (either Legacy or Session-based, either one works with my version) is there a way I can set Channel 1 sampling frequency to 46,000 scans/s and Channel 2 sampling frequency to 2,000 scans/s and have it take data simultaneously?

Thanks for your help.

Answer 1

[Roja]

When a value is specified for the sample rate, the Data Acquisition Toolbox will set the sample rate for all channels on the board to that value.

If your hardware supports multiple assignments to the same channel, then you can get varying sample rates by assigning channels in the appropriate ratio. For example, if you want to sample channel 1 twice as fast as channel 2, you can create channels in this manner:

chan = addchannel(ai,[1 2 1])

This configuration will effectively sample channel 1 twice for every time channel 2 is sampled.

For more information you can refer to the following link:

http://www.mathworks.com/matlabcentral/answers/95503-can-i-assign-different-sampling-rates-to-different-channels-on-a-single-daq-board