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

[Jess]

Jess Enough now please your splitting Hairs to suit your unrealistic cause, again detracting from L.A.N problem.!!

From the perspective of my own experience, the distinctions I'm making are significant.

To try to explain: It's a bit like someone claiming you can do (arbitrary) under cuts on a vertical mill that has 3 axes. If you're a machinist, whether it's a 3, 4 or 5 axis job is a big difference, but to someone who just wants their design made it might seem like a trivial issue after all, it's 'just one more'.

Apologies for the detraction from the L.A.N. problem, though, you're absolutely right. I was erked by someone claiming a couple of decades of experience, but then, making the sort of error that should have been learned on day one. (Like if someone told you they had 20 years of experience as a machinist, but then couldn't explain climb versus conventional milling.)

Drop it sit back and watch this machine running on a CSlabs Ethernet motion controller doing all those things you say Ethernet can't do.!!

It's an example of moving the controller, so Ethernet doesn't have to deal with realtime demands (my point 2). Actually, you made this distinction really well earlier in the thread, when you referred to this kind of setup as 'Buffered not realtime'.

Very cool video too though! :)

[JAZZCNC]

Well I'm not going any deeper because you clearly don't get that Mach3 isn't real time so WTF does it matter.!! . . All I'll say is if it's good enough for them it's good enough for me.!! . . . . . http://www.haas.co.uk/

Check the "Whats Included" list Second from bottom.!!!


Oh and who says you can't undercut with 3 Axis.!!. . . . .. . I've done it many times.!!

[Jess]

Well I'm not going any deeper because you clearly don't get that Mach3 isn't real time so WTF does it matter.!!

I just quoted you on those Ethernet controls (like the CSlab) being 'buffered not realtime' because it's a great way of putting it, so, yes, I definitely get that part!

Oh and who says you can't undercut with 3 Axis.!!

I included the word 'arbitrary' to try to rule out the use of specialised tooling as used in that video (and, of course, to rule out things like tilting tables, vices etc.,)

However, it works just as well as the example: you jumped in with a correction because you saw something you felt to be misleading.

This is exactly the same thing as I've done - difference is that I've been called a fair few names plus suggestions of physical violence for my trouble.

[magicniner]

I get it, Ethernet isn't suitable for something no-one here needs to do, good point(less) well made!
I didn't mention TCP/IP and in that I was wrong, I suspect there is very little TCP/IP-Free Ethernet in use outside industrial applications though.
As for ethernet being unsuitable for rigid tapping and other "closed loop" control processes you are entirely correct and that's why it isn't used for that, but neither is any other remote communication system - the motion controller deals with closed loop rigid tapping locally.
;-)

[JAZZCNC]

This is exactly the same thing as I've done - difference is that I've been called a fair few names plus suggestions of physical violence for my trouble.

Twas a Joke Hence the Jester.!! . . . The names I stand by because to me you where being a ***REMOVED*** for arguing something that wasn't relavant and pointless to the discussion.! My reference to USB motion controllers being troublesome with Mach3 and Ethernet not being was based on Fact thru experience not theory. You where just being provoking IMO.!! . . . I was stupid enough to respond I should have known better.!

Now FFS lets leave it alone.!!

Except this.!!

I included the word 'arbitrary' to try to rule out the use of specialised tooling as used in that video

Nothing specialised about that tool it's just a T-slot cutter.!!!

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[harmo]

Hi all,

Wow, this has been an interesting thread to read, I feel like I turned up a few years late and more dollars short. For anyone still reading this thread, I'm sure parallel, USB, and ethernet all have a role to play. I have found that USB is problematic in some cases, particularly with Stratasys industrial grade 3D printers, while ethernet works really well. On a CNC mill I had to maintain in a previous job, the reverse was true. In managing some laboratory instruments with stepper-driven actuators, parallel was the only choice because the instrument was made in 1987, and to "upgrade" to USB would cost the business over $80K USD... so we said "Windows 3.1, a parallel port, and some floppies are good enough for us thanks".

I get that people want to express their experiences (who doesn't). I'm glad that each person here has a favourite. For me, building my first DIY CNC, I have chosen ethernet because it suits my situation. I'll be really intrigued to see how a Mesa 7I76E card goes. How that will play out... who knows. If it fails miserably, I have a dozen old computers laying about, the ability to crimp and test my own crossover cables, and a lot of networking experience. If all that fails, I have a USB Mach 3 card that I was given.... for reasons I will never understand.... when I was buying some shielded spindle cable. They sent the USB controller instead. When I contacted the seller, they sent me the cable I originally ordered and told me to keep the card.... <insert confused face and shrug here>.

Anyway, thanks to all who have shared their views on the subject, but at the end of the day, we each must choose our own path. I'll let people know how my ethernet controller works out... but it'll take a while.

Take care everyone!
Hamish.

[Robin Hewitt]

A blast from the past.

USB has improved because they have moved the parts that wear out away from the PCB and onto the cable so they are dead easy to replace.

Ethernet is delightful, how could anyone disagree with four twisted pairs in a ready-made, cheap as chips, cable?