Hey all. I am becoming increasingly weary of grounding issues (ground loops). More so, my experience in recognizing what might become an issue. I tried to use a few of the online IOT/Arduino circuit builders to see if it was comprehensive enough that it would let me build at least something similar to my setup to see if it could spot check my setup, but unfortunately, there just wasn’t enough similar devices or scenarios that I felt like it could provide meaningful feedback.
I tried to work up a diagram of my current setup, and was wondering if anyone had a few moments and didn’t mind giving it a quick glance to see if anything jumped out as obviously badly configured, or you have any suggestions on a better/more proper way to ground things, I would greatly appreciate it. I would hate to accidentally fry something due to simple oversight or inexperience.
I worked in labs housing multi-million dollar instruments where you are always one step away from being fired for frying a 100k vector analyzer or 200k automated lab sampler.
From the very little I see, there is too much plastic, and not enough grounding. In the labs I worked:
All work benches were entirely metal with antistatic isolation sheets on top. All benches were also “grounded” as in thick litz wires ran to outside buried in the literal ground to an under-ground metal sheet/plate.
Floor was either bare concrete/rebar or also metal. Extreme cases we had special false floors with cabling ran under, and the floor tiles were anti-static.
I had to work in a faraday cage for EMF experiments.
Use antistatic gloves and clothing with grounding wires attached to wrists, and conductive slippers and clothes.
Etc, etc, the rules for a GLP/GMP lab / floor can fill a few volumes.
Your setup looks very cool, and very far developed!
Hey, are you weary of them as in you’re having grounding problems, or wary of them, as in you’re worried about having them?
If you haven’t found anything to be a problem yet, I’d fire everything up and check with the multi-meter for problems
Looks like your PC and the USB connection to it will be the biggest loop anyway? Everything else looks like a kind of star topology from the same AC power source?
My apologies. I should have double-checked my spelling before I hit post. I did mean wary, as in concerned. I have not had any noticeable issues yet, but the more reading I do, the more I come across folks using odrives who have experienced ground loops that end up frying out their devices because voltage took a wrong path.
Yeah, power is a 24v 14.5A supply, with one set of +/- hooked up going to two 5 port wago connection blocks, one for positive, one negative. Then one set of wires goes out to each device from there.
As for the USB connections, I went with a powered hub hoping that it might provide at least some additional protection of my PC. I have a rasp pi 5 I was considering using as a ‘gateway’. Plugging the USB hub into that, and then connecting to it over wifi, just so there was no direct physical connection to it.
The CANAble device was mostly used for monitoring/debugging, but I just finished building a small app that listens for CAN requests to save/load settings from a database for the ESP32’s/motors. That could just run on the Pi as well, though, so there could easily be just one USB hub.
The more time/work/money I put into it, the more paranoid I become, so I am just hoping that I am not doing something obviously wrong (to someone more experienced with this type of thing) that might be a ticking voltage bomb for some reason.
From my very limited knowledge I would say it’s ok.
Since you’re dealing with AC power your primary concern should be to ensure the high voltage cables, plugs and connections are all done with suitable parts and kept covered and protected from accidental contact with your fingers or tools.
I also use a USB hub to protect my computer, I assume it’s better than doing nothing, even if it’s not proper test gear.
If you’re really paranoid you can add isolation between components but that tends to get expensive.
