Simultaneous Sampling using a DAQ BNC2110

[Luminescence9]

Hey folks,

So I'm trying to take data from two different photo diodes plugged into a NI BNC2110 DAQ but for some reason it's collecting a specified amount of data from one channel then it moves onto the other. I'd like for these to be collected at the same time but cannot figure out how to do it.

I've attached my code as well as a sample of the data I've collected from a HeNe laser power fluctuation. After viewing the image you should see that Channel 2 is distinctly out of phase from Channel 0 whereas these should be directly in phase. Weird.

Any help would be appreciated.

[Luminescence9]

One more thing. I'd also like to modify it so that when I zoom in on one graph it zooms in on all of them at the same time so I can compare identical spots on the graphs. I'm sure there's a property node in there that will do it but I have yet to find it.

[Dennis_Knutson]

It's not at all weird since that is the way you programmed the acquisition. You have one task for one channel that you start and then stop and then you start/stop a task for a different channel. You need to have a single task with both channels specified in the physical channel constant and change from 1Chan NSamp to NChan NSamp.

p.s. You don't have any sort of loop. Please don't say you are using the Run Continuous button. If you are, stop doing that and place a while loop around the code you want to run. The code up to the Start Task and the Clear Task should be outside the loop.

Message Edited by Dennis Knutson on 06-15-2010 02:11 PM

[Luminescence9]

hah, I actually figured out the problem mere moments after I posted the question. Your solution was the answer.

I still have no idea how to couple the zoom on two separate graphs. Any ideas?

[The_Red_Barron]

Howdy Luminescense!

This forum post discusses how to synchronize the zoom between two waveform graphs.

Regards,