different sample rates on the same DAQ device

[tibobo]

Hello,

I have a brand new M-6284 device, using NI-DAQmx base under Labview Mac OSX.

I'd like to acquire analog channels at different sample rates, from 1 S/s to 20 kS/s.

As far as I can see, there is no way to do that simply and I don't want to acquire all channel at 20kS/s.

Do you know any hint to do that ?

Thanks

Boris Matrot

[Dennis_Knutson]

I believe the 6284 has a single A/D and all channels share the same clock so different sample rates are not possible. So, even though you might be sampling some channels faster than you need, that doesn't mean that you have to use all of the samples. For example, you could have a main loop doing the DAQ at the highest rate and writing to a queue. In another loop running at a lower rate, read the queue and extract a single channel.

[tibobo]

Thanks for your reply

Well it's the solution I was thinking about. I hoped it was possible to avoid it. My previous DAQ device was able to acquire at different sample rates (main sample rate then each channel could use a percentage of it) and it seems to not be the case with my new device !
I'll have a problem cause I have about 20 inputs and my board is a 625 kS/s so I'll be limited to 30 kS/s (or even less since it never goes as fast as manufacturer says...). I probably need to do some business more with NI !