USB 15 metre limit

[mikehenson]

Is anyone here getting over the 15 metre USB limit by (perhaps) running the USB over ethernet cable and if so what hardware do you use?

I have two Sculpfun lasers and I would like to run them from the same PC using different com ports and two instances of Lightburn but one will be over 15 metres from the computer.

[ednisley]

@mikehenson

getting over the 15 metre USB limit

Based on past experience around here, the “limit” on length is much lower, for several reasons:

• Typical laser controller hardware is mmmm marginal
• Under-specified power supply circuitry
• Electrical interference from high-power laser switching

Active-repeater USB cables with power injection at the laser controller seem to be the least unreliable. Unpowered cables over about two meters generally do not work well at all.

Previous discussions may be informative:

USB Cable Issue

I have just purchased a Gweike Cloud RF laser, using with Lightburn. The supplied USB cable works fine but it’s very short. So I bought a nice long one, 5 metres length. USB C to USB A, I use Macs. It’s a good quality cable, but I don’t seem to be able to make a connection when I plug in to the laser and to my Mac? Any suggestions/fixes most welcomed. I came across a really useful post by @BillieRuben who seems to have knowledge of these machines and setting up, any idea Billie ? tia

Light Burn will not run the layered drawing I have Created in LightBurn - HELP

Hello, I’m a nub to lasers and LightBurn but I have been a CAD operator for 40+ years so I the LightBurn program is not a foreign software to me. I have created a LightBurn drawing that i want to use to test my new laser and figure out power and speed for my laser. When i test my drawing by starting the PREVIEW command, the preview runs perfectly. But, when i send the send the START command to the laser, the laser starts by moving to the first object (a 1/2" diameter circle) to engrave/cut (li…

[MikeyH (Mike Hembrey)]

@mikehenson

the USB over ethernet cable

USB over ethernet cable is still USB. To gain the advantage of ethernet cable, you will need USB-Ethernet converters on each end. I have no idea about the noise immunity of such a setup.

[ClayJar (Nathaniel Klumb)]

I’m only at 10m to go from my workstation up the wall across the ceiling joists down another wall and into an externally-powered USB hub mounted to one of my galvo enclosures. (Externally powered isn’t always a requirement, but the more you hang off the far end of your cable, the more you might want it.)

I’m using an active USB 3.0 cable, and I’ve been running two galvo lasers (a MOPA fiber and a CO2 galvo, plus a couple keyboards/keypads for convenience) with no issues. I’ve used longer active USB 3.0 cables for remote AV devices with my production crew live streaming meetings, and as long as they’re quality active USB 3.0 cables, they’ve been fine. (Cheap USB 2.0 cables or passive cables generally have not proven worthy.)

From US Amazon, something like this (USB 3.0 active 5Gbs):

Amazon.com: BlueRigger USB 3.0 Extension Cable (32FT, Active, 5 Gbps, in-Wall...

[mikehenson]

Thank you Nathaniel, I will follow that up.

[misken (Melvin)]

One remark that is still missing: it’s very dangerous to control a laser that far away. They can catch fire in an instant. Better move the control pc right next to them.

[ClayJar (Nathaniel Klumb)]

That far away could be right there. When I’m using my fiber laser, I’m on my drafting stool right in front of it, with a keyboard and monitor mounted to the enclosure. The fact it’s 10m from the PC as the cable lies is irrelevant.

(Actually, a shorter cable would be a safety issue, since instead of routing around the occupied space, it’d have to go right through the middle.)