Data duplication while using DAQ

[lanky0211]

Hello all,

I am working on a code in LabVIEW that takes an air velocity measurement from a sensor and converts it to volumetric flow rate (I did not write this code but I am editing it). I'm only working with one sensor now for testing while the code is set up for 4 sensors to run simultaneously. There are four numerical outputs for these four sensors. I get good readings for two of these channels ("Exhaust 2" and "Glovebox Intake"). However, for the remaining two channels ("Intake" and "Exhaust 1"), I get a reading that looks like it maxes out at 2356 but loops infintely. I am newer to LabVIEW but from my research, it most likely has something to do with the 1D arrays that are used in this code (which I don't understand the purpose of). I attached the test of the duplicating data and the VI. Any help at all on this issue or understanding the arrays purpose would be greatly appreciated! Thank you for your time!

[lanky0211]

Stuff didn't attach

[altenbach]

If you are only using one sensor, what's connected to the other inputs? Are these floating?

[lanky0211]

Hello altenbach,

I don't have them connected to anything. The DAQ card is empty for those inputs. I'm using an NI-9209 and my sensor is wired up for the ai0 input. The rest are empty. I don't have the sensors with me to do the proper testing. But I did map out which sensor is rigged to each input if they were connected. 

[altenbach]

If nothing is connected, you should probably terminate them correctly. Don't keep them floating,

[mcduff · Accepted solution]

Can't open your VI, but your DAQ shares an ADC, and ghosting is possible. Check out these links

https://knowledge.ni.com/KnowledgeArticleDetails?id=kA03q000000YHy6CAG&l=en-US

https://forums.ni.com/t5/FlexLogger/Channel-Ghosting-issue/td-p/4440643

[lanky0211]

I believe ghosting was the problem. Took the configuration wire that was unused in the wiring diagram for the sensor and grounded it. Data no longer loops! Thank you both for the help!