Quick LED PSU question

aniron

Hi, not strictly Duet related but hopefully someone can help.

My printer was originally a Ormerod 2 with a 200W Meanwell PSU.
This had a wire connecting the negative output with mains ground.

My new Meanwell PSU has the mains connections at one end and the 12V connections at the other.
Should I connect mains ground on the PSU with the negative connector on the 12V side and thus the Duet (0.6) ground?

My printer isn't hooked up to a mains outlet with ground, if it matters.

A Former User

@aniron said in Quick LED PSU question:

My printer isn't hooked up to a mains outlet with ground, if it matters.

then neither does connecting anything else to the mains protected earth; if you did have outlets with PE then its still a can of worms, but as you don't we might as well not go there.

aniron

@bearer
yeah, but A)
I might plug the printer into such a socket in the future.

and B)
I might want to use the old 200W PSU for some other purpose in the future, and it would be nice to know if the GND-negative wire should be retained or removed.

A Former User

the (short) answer is Duet (dc42) recommends doing it, but its not a black and white situation.

https://forum.duet3d.com/post/48107

aniron

@bearer what are the drawbacks of doing it?

A Former User

i do believe one was mentioned in the post linked to, the other reasons are mostly tolls on forums https://forum.duet3d.com/search?term=ground&in=titles

dc42

@aniron said in Quick LED PSU question:

@bearer what are the drawbacks of doing it?

The only drawback I am aware if is that if you connect the Duet to a PC via the USB cable, you will have a ground loop. Normally this doesn't cause any trouble but it can do under two different types of fault condition: (a) a bad connection between PSU negative output and Duet VNI negative input; or (b) powering the PC and the Duet from different sockets, and there is a large difference in ground potential between the two sockets. See https://duet3d.dozuki.com/Wiki/USB_ground_loops.

Danal

There is no absolutely right or wrong answer to "connect circuit ground to earth ground" on Printers and CNC and other motion controlled machines.

I do help a lot of people get the glitches out of their CNC, and I can tell you the policy I've developed over the years:

"Star ground" everything that needs a circuit ground. This is a long topic of its own... the shortest version is: Run a ground wire back to ONE central location for each ground; no chaining".
DO NOT connect circuit ground to Mains (earth, wall) ground. UNLESS the machine still glitches. Then, DO connect them.

How is that for "eat your cake and have it too"??