How do I find out the actual acquisition sample rate with C daqmx? (USB-6211)

[AmishDave]

I have a national instruments NI-USB-6211 device, and I want to make my application support this.
I'm writing in C, using NI-DAQMX functions.

I'm doing continuous analog acquisition.  If I ask for a specific rate, such as 20000 or 20005, etc,
how can I find out the actual rate the board is using? (other than measuring against the computer's
clock).

This seems like a very basic thing to want to know, but I can't seem to find anything in the API for this.

Thanks,
--
Amish

[Dennis_Knutson]

Not sure what you are asking for. The stated accuracy of the sample clock on your device is 50 ppm of the programmed sample rate with a resolution of 50 ns. Obviously, trying to use the computer's clock ( 1 msec resolution at best) as a comparison would be futile.

[Ed W]

Hi,

Thank you for posting to the NI forums.  You can view your sample clock source and rate by using the NI-DAQmx C timing property functions.  Open to the DAQmx C Reference and select NI-DAQmx C Properties.  There, you will find the Timing Properties; I would recommend using the following two functions to get your timing information.

DAQmxGetSampClkRate

DAQmxGetSampClkSrc

I hope this helps!

Ed W.

Applications Engineer

National Instruments