Last Machine I Built went to Scotland which is a 500mile 10hr round trip. I can't afford for to be running up and down the country chasing ghost problems.
It's a FACT whether you agree or not that USB gives more trouble than Ethernet. Just becuase it's working for you without issue doesn't mean it will or does for others. I know this to be true thru experience dealing with Chasing USB ghost's.
I pride my self on the Quality of my Control box's in comparison to many other builders, (and believe me I've been inside a fair few so called Top rated machines costing Several £1000 more than what I build that I wouldn't even turn on.!!) I use correct filtering and ground techniques inside Industrial Steel cabinets along with shielded cables using differential signaling. So I know it's nothing to do with My end but still USB throws Ghost problems and Lockups that cannot easily be explained.
This I can't and Don't want happening on any machine I put my Name on. This is the reason why EVERY component I use when building a Machine gets tested on my own personal machine and for several Months at a time not just a few hours. Could say I torcher them to death or Glory.! . . . NO USB device as passed the Tig/Plasma test.!! . . . . Yes there well maybe some of the Higher end devices that will pass but why should I bother when I've found Ethernet is consistantly more stable on just about every device that uses it. The Cslabs Controllers I use these days are Bullet proof and Never fail or throw wobblys for unexplained reasons.
AND just to prove that USB freaks out when Ethernet doesn't Purelogics PLCM-E3 and Pokey's 57CNC both come with USB and Ethernet connections. The USB on the PLCM couldn't even handle the Mig test before crazyness happened. Ethernet it didn't flinch and when Tig was used it didn't seem to affect it either unless I went right up next to the Controller.!! . . . Pokey's I'm still torchering.!!
I suspect that the underlying UDP ethernet protocol is nearly as error prone as the USB protocol, however, the TCP/IP layer which sits above it and does the error correction is (as has been pointed out) extremely robust so the end result is much better.
I can see both sides of the argument but theory is worth nothing if it doesn't work in practise...
For what it's worth, I've got a 3D printer which is extremely noise sensitive on the USB connection (to the point I now download the print to a memory card and print from that) and a USB CNC controller which I haven't had a problem with but there are dire warnings on the website about using a good quality cable - see https://www.youtube.com/watch?v=NUu9xwDfJ9k
I good example of usb technology would be an external hard drive ... and in my experience these never loose connection. So what is being compared here is not the technology but the boards themselves as proven everywhere, usb is extremely stable... o hang on my ethernet card needs resetting. damn thing screws up all the time. :P
Last edited by Jon.; 08-06-2015 at 08:23 PM.
What you are losing, of course, is any claim to a real-time protocol, but as the network connection is being used to transfer, typically, high-level movement instructions which can be easily buffered, by buffering a couple of seconds'worth of data you can still withstand a short loss of communication during a noise burst, the TCP stuff does its job and makes sure the data gets there eventually, and the pulse generator bit of the motion controller chunters away happily working from buffered data.
Conclusion - theorist meets practical experience, shakes hands, and goes off for a pint...
Personally, I like learning from experience, and preferably someone else's experience 'cos that costs me less! But trying to relate that back to theory might give a bit more insight sometimes and lead to a better understanding and maybe a way to move forward. Cathedral builders used experience to create magnificent buildings but theory and better understanding of materials gives us skyscrapers. If that is an advance...
There is also the cable length issue with USB (just saying) ..Clive
Theory and Experience work together for advancement but experience "TESTING" ultimately Wins and as the final say on what works and what doesn't.!!!
Last edited by JAZZCNC; 09-06-2015 at 03:47 PM.
Would it be too presumptious that on a forum called mycncuk (which has a "mylittlepony" vibe to the name!), that most are hobbyists? In other words, not everyone wants to go to the far end of a fart over 'ethernet vs USB' (which would need a forum called IusemyCNCmachinetomillindustrialhardenedsteel.co.u k - which granted isn't as catchy)
I'm a dabbler (I use my CNC to make pcbs) & I was pleased to see the back of Mach3 ...putting on those retro stick-on Bradley Wiggen-esque sidebruns & a pair of massive Lionel Blairs just to do a CNC session was a bit much. It was therefore like a breath of fresh air to migrate to cnc-usb, which uses erhm USB ....& I've not had one bit of bother with it. For the sake of balance, that's not to say others haven't has problems, which prompted the owner of cnc-usb to illustrate what a difference the actual usb cable can make...
Last edited by HankMcSpank; 09-06-2015 at 03:17 PM.
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