Different sample rates on a single 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

[Dazz]

I am looking forward to seeing a response on this one because I too have the same issue.

[Som Sreedhar]

Hi!

You are correct Boris, there is no direct way to sample at different rates on one board.

I came across a KnowledgeBase that addresses this issue. You may want to take a look at it and see if it helps. The concept will be the same for DAQmx Base.

Sampling Different Channels at Different Rates with NI-DAQmx
http://digital.ni.com/public.nsf/allkb/96FD2F4685065C7686256F25006EE8DE

Regards,

Somendra

[tibobo]

Hi Somendra !

Thanks for your reply.

Unfortunately, this solution doesn't work with NI DAQmxBase since it's impossible to give names to virtual channels (the vi entry exists but, until now, is ignored in DAQmx Base). I receive a "Specified channel cannot be added to the task, because a channel with the same name is already in the task" error (-200489).

It seems there is no way to use different sample rates and ranges on a single DAQ under Mac and Linux..

If somebody knows another "trick"...

Boris Matrot

[WM_John_Weeks]

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@tibobo wrote:

Unfortunately, this solution doesn't work with NI DAQmxBase since it's impossible to give names to virtual channels (the vi entry exists but, until now, is ignored in DAQmx Base). I receive a "Specified channel cannot be added to the task, because a channel with the same name is already in the task" error (-200489).

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Huh. That's odd. I give names to my channels when writing C code.