How can I read from two channels with different rates?

[Jick]

I have a DAQ card NI PCI-6111 (https://www.ni.com/en-us/support/model.pci-6111.html)

I am  trying to read from two input channels at the same time and with different rates (100k and 1k).

As far as I know I should be able to do this because the card has 2 simultaneously-sampled analog inputs.

The question is how?

I have attached a sample vi and there is the place marked where I get an error.

Kudos for any good help! 🙂

[MikeS81]

Hi Jick,

you can use only one task. The inputs are multiplexed. You should read both inputs with the higher sample rate.

Mike

[Jick]

I am not sure how to do it if I want both "Rate" and "Number of samples per channel" to be controllable for both channels. Could you modify my example to show how to do that? Thanks a lot!

[ZachHindes]

Like was already mentioned, this is not possible on your hardware.  Despite having simultaneously sampled inputs, the device has only one timing engine to drive them.  The best bet is to sample them at the highest rate that you need, and pull out the data you need in software.  In your case, you said you have one channel going 100k and one going 1k.  Simply run both at 100k, and pull out 1 of every 100 samples from the second channel.