Connecting to a CNC machine, pros and cons of USB vs PP vs Ethernet etc.

[Neale]

Ok I'll amend it to what was meant and say Ultimately Experience testing wins.!!. . .

I wasn't being very serious! My personal problem is that anytime someone talks about the value of experience, it reminds me of my father whose attitude was along the lines of, "That's the way I've always done it, so that's the way it has to be done!" Didn't leave him much room for improving anything... I cheerfully admit to stealing the results of other people's experience where they've been kind enough to publish it - which is why I have a CSMIO-IP/M waiting to be installed, complete with Ethernet connection and 24V differential signalling.

My god i must be doing everything badly.. cheap ass 5m usb cable coiled up, wrapped around extension leads and all sorts and running off a laptop. I must be very lucky.

FatFreddie said he had so many problems with USB and his 3D printer that he gave up using USB. I've been using USB with my 3D printer for more than 3 years now and I've never had a problem with it. There's nothing wrong in principle, it's just that the safety margins with respect to noise are much lower than with Ethernet. There are also issues if you rely on the 5V supplied via the USB port as this can be a bit flaky as well. My printer controller has a separate supply - maybe that's why mine is more successful? Don't know but it's a case where experience gives different answers depending on who you ask.

As for theory versus experience - I use Ethernet-over-mains to get a network connection to my garage as the layout of my house makes the wifi signal a bit flaky out there. That signal goes through two ring mains, 3 MCBs, and an RCD. I wouldn't expect anything to get through that lot (based on the principles of high-frequency signals getting through a bunch of inductors), but I tried it, it works, and it's really useful for moving Gcode files around and that kind of thing. Stops working as soon as I turn on the router control box and VFD, though!