Sampling multiple channels at the same frequency

[Kyle.Kyle]

Dennis,

Company policy does not allow me to post entire programs.  I can either write a reduced program or post another snippet (below).  This code is nothing ground breaking but due to restrictons we are under I can't post an entire program.  All I am doing is reaing a sample from the buffer on each iteration of the loop and graphing it.

I still believe that changing the sample rate on my module from 500 ms to 10 ms will solve the problem.  The other two analog channels in the task sample fine.

Kyle

[Viru]

Hi Kyle.Kyle

I agree with Denis. You have to change your read acquisition vi. I compare your two post images and both are differenet interms of defining the sampling clock. I think you define a wrong sampling rate. So try what i send you and put read acquistion vi in your main while loop. Might be solve your problem because I look at your code image and you are doing lot of analysis within a main while loop. So it may be kill your loop time. So check it and let us know.

Thanks

[Kyle.Kyle]

Viru and Dennis,

Attached is a test driver and its output.  Would one of you be willing to help me set up my 9219 as outlined in this link? 

http://digital.ni.com/public.nsf/allkb/1015F4182FB8A805862572D1006B4CC1

Thanks,

Kyle 

[Kyle.Kyle]

Disregaurd the last vi, I did not save it before posting it.

Kyle

[Viru]

Hi Kyle. Kyle

Please check the image and try to implement your data acquisition system accoring to that. I don't have your hardware but this code which i made based on basic data acquisition fundamentals. In that code, I sample at 5 Hz and I acquire one sample per channels so my loop rate will be 200msec.

It might be fulfill your requirements also you do your analysis inside that loop.

If you have any doubts then let me know.

[Kyle.Kyle · Accepted solution]

Solution:

http://forums.ni.com/ni/board/message?board.id=250&message.id=54007#M54007

Thanks for the help.  I have not implimented this in my main program so I will keep your suggestions in mind if the sample rate again slows down.

Kyle