I need to acquire data from multiple channels and wish to perform signal averaging by acquiring many samples from each channel as quickly as possible. There is a limited number of total samples to acquire or a limited time frame over which to acquire these samples. This process will then be repeated some time later (making it sort of like burst mode sampling) or it will be repeated later by restarting again with a software restart. Such a multichannel sampling task can be configured by assigning a physical channel list of ai0:2 and then using DAQmx Timing vi with type Sample Clock to set sample mode of Finite Acquisition with say 100 Samples per Channel. This task however will continuously alternate between channels such as 0,1,2,0,1,2, etc. It is desirable to avoid multiplexer switching and subsequent settling times and instead acquire all samples from channel 0 first, then switch to and acquire all samples from the next channel yielding a channel list of 0,0,0,0...1,1,1,1...2,2,2,2... How can such a task be configured to acquire many samples from one channel and then many samples from another channel ? The channels will need to each have different input ranges or gains (but all samples from a specific channel will have the same input range). It seems the entire channel list must be used an as input to DAQmx Create Virtual Channel. Doing that then requires that a different "name to assign" for every channel in the task including the duplicate channels. How can different input ranges be assigned for each channel, either using Create Virtual Channel or afterwards ? Attached a vi that uses a for loop to generate a list of channels and unique names but is there a better approach ?

Multifunction DAQ

DAQmx AI Task with many samples CH0, then many CH2, then many CH3

To John P.

Thank you for your answer. Only a question. We have only a LV 8.5 installation and we cannot open your examples. Can you please, post your examples in version 8.5?

Best regards,

Beluja

Beluja
"...you see, but you do not observe" (Sherlock Holmes)

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Multifunction DAQ

DAQmx AI Task with many samples CH0, then many CH2, then many CH3

Re: DAQmx AI Task with many samples CH0, then many CH2, then many CH3