Possible Noise Culprit

[Coulton]

Hey folks,

I posted about a week ago regarding issues with my input readings to my DAQ that would randomly drop to near zero and then jump back up to the correct values. I believe I found the reason, but I am unsure of what direction to go in. I have attached three files. The first file is my VI (Yes, it is quite unconventional, but it gets the job done, assuming I get correct readings). I am getting a relatively large amount of noise in my setup when I use my power supply. I am trying to obtain voltage inputs that change anywhere to .5 mV to 5 mV. However, the noise in my system, without any filtering or averaging, is on the scale of ~2 mV. When I filter my input I get better results (With a large phase shift, but this is expected with a filter). However, I am still having issues where at times, the voltage reading after filtering is much less or much more (A factor of 3 or more). I investigated the readings my DAQ was receiving and this is what I came up with. The second file “Bad_Input” is using my power supply at 8V. Is there a reason it drops to zero every so often? The third file “Good_Input” is using a 1.5V AA battery. While the voltage values are much lower they stay constant. Is there a way to duplicate this with the power supply? If you need any more info or have other questions, please let me know. Thanks!

Coulton

[RavensFan]

Please don't create bitmap images, then try to get around the ban on posting .bmp files (it's there because of the large file size) by renaming the files as .png.

When creating images, save them as .png files.

[Coulton]

I am on an ancient computer and when I save paint images it saves as bmp. I tried to fix it by putting the png on there since I knew it was a paint image. I didn't know it was much larger than png.

On a LabVIEW note, solved my problem. Apparently either my power supply or the wall outlet is not grounded correctly.

[AnalogKid2DigitalMan]

You should be grounded for attaching rogue bmp's 😉

-AK2DM

[RavensFan]

You need to save as file type .png when in MS Paint.  Just giving it a .png extension when saving doesn't magically make it a .png.

[Coulton]

My bad guys. Now I know. Thanks.