Page 1 of 1

USB Ground Loop

Posted: Wed Jun 04, 2014 5:30 am
by TheMonkeyStink
Hey All,

In putting together my new SO2 I discovered that there appears to be a pretty big potential difference between the ground plane of the Arduino and my PC. It's so bad that if I plug in the USB cable it triggers a protection circuit in the 24v power supply. Has anybody else seen this? Or did I screw something up?

BTW, I found and ordered a USB ground loop isolator (I didn't even know such a thing existed), I'll report back if that really does solve the problem.

Re: USB Ground Loop

Posted: Wed Jun 04, 2014 9:05 pm
by TheMonkeyStink
Just as a quick update, I got my hands on one of these: ... UTF8&psc=1

And now I can plug in both the 24v power supply and the USB cable without issue. I haven't checked functionality yet, but I think I'm on the right track.

As a note, this specific device is supposed to have a poor quality track record...we'll see if I can talk to the Arduino.

Re: USB Ground Loop

Posted: Fri Jun 06, 2014 2:45 pm
by TheMonkeyStink
Okay, it appears that commands are passing just fine through the USB isolator.

With that being said, I've been browsing the forums and I don't think this is an isolated issue. There are reports of device failures that could very well be attributed to large potential differences between the ground plane of the Arduino and the PC. My question is, where would be a good place to post a warning? Is this post adequate?