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



Jess
02-06-2015, 08:34 PM
I think theres a little bit of a thing against laptops in the CNC world which comes from the problems you used to get with parallel ports on them
I think the parallel-port-voltage-thing was often solvable using a decent breakout board.

However, there's another reason: system management/maintenance interrupt 'stuff'. It's the utter enemy of anything that needs to be 'real time'. It's the usual reason for, say, a very slight pause every 30 minutes, or a little hitch whenever the processor gets slightly warmer and the fan speed needs to be increased or if there's a battery fault or...

Whilst all new machines seem to have more 'going on' in terms of SMI tasks, laptops tend to lead this trend, so it's just that poor performance or unreliability is more likely with a laptop.

It's less of a problem with a motion control board as that can hide smaller latency based sins but you really don't want to be a few hours into a milling job only for an intermittent computer problem to mess it up.

I did try a laptop, and the latency was fine...except for a very occasional (like once a day) SMI interrupt which put it it 'useless, even with a motion control board'. (You could also trigger it if you used any of the special laptop keys (like the screen brightness ones etc.,).

JAZZCNC
02-06-2015, 09:02 PM
It's less of a problem with a motion control board as that can hide smaller latency based sins but you really don't want to be a few hours into a milling job only for an intermittent computer problem to mess it up.

I did try a laptop, and the latency was fine...except for a very occasional (like once a day) SMI interrupt which put it it 'useless, even with a motion control board'. (You could also trigger it if you used any of the special laptop keys (like the screen brightness ones etc.,).

It's not a problem using a Laptop if you have a good motion control card using Ethernet. I've been running machines from Laptops for years running jobs that last 30+ hrs without stopping and they never fail or drop out. The Same can't be said for USB it's irratic and unpredictable. There's so many things that can affect it IMO it's not a good or suitable connection for reliable Motion control.

Jess
02-06-2015, 11:16 PM
Ethernet really isn't a natural partner for realtime stuff - being irratic and unpredictable was designed in from the beginning (because it's the easiest way to recover from certain network problems). Add newer things like spanning tree rebuilds and it's a big mess.

USB on the other hand, is - in theory at least - much more predictable; the host (the controlling computer) remains in control all the time.

However, despite the intrinsically random behaviour, Ethernet is much more attractive for industrial control: it works over greater distances, can handle multiple control stations and has features like isolation of multiple grounds and differential signalling built in...and it's actually an IEEE standard.

So, it seems likely that the combination of better motion control cards using Ethernet and capabilities for dealing with irratic and unpredictable behaviour having to be better on Ethernet will make Ethernet appear better, simply because Ethernet motion controllers are able to hide things that the USB motion control cards aren't able to.

(Even in the budget area this looks like it's true; unlike the USB smoothstepper, which seems to rely on a microcontroller for everything, the Ethernet smoothstepper adds an FPGA - presumably for offloading the generation of step/direction signals.)

(Also, don't forget that the only way to get an Ethernet port on some laptops is via USB, nor that some devices actually have a USB Ethernet controller on-board)

JAZZCNC
03-06-2015, 12:07 AM
So, it seems likely that the combination of better motion control cards using Ethernet and capabilities for dealing with irratic and unpredictable behaviour having to be better on Ethernet will make Ethernet appear better, simply because Ethernet motion controllers are able to hide things that the USB motion control cards aren't able to.

There's No Seems about it. Ethernet is much better than USB for Motion control and I'm going thru experience using Both for CNC from several companys products not Theory or what some Spec sheet says should be better.!! . . . . BUT . . . . We are moving away from OP problem so lets get it back on focus.

Jess
03-06-2015, 02:17 PM
There's No Seems about it. Ethernet is much better than USB for Motion control and I'm going thru experience using Both for CNC from several companys products not Theory or what some Spec sheet says should be better.!!
The danger of relying on experience in this way that find yourself reaching conclusions that your experience does not - and cannot - support. To put it another way; lifting 6 tonnes on rope specified for a safe working load of 1 tonne is a bad idea, even if you've 'done it before lots of times'. In fact, it's increasingly poor idea even as you gain more 'experience' that the rope you're using is 'much stronger than the spec sheet said'.

Why I'm objecting is that, whilst you have a lot of experience, 'Ethernet is much better than USB for Motion control' isn't a statement of your experience - you've extrapolated it into conjecture. You can tell it's not experience, because the existence of even one solid USB motion controller is sufficient to falsify your claim.

...plus, I've had enough 'memorable experiences' with Ethernet to know that Ethernet gear is plenty capable of being 'erratic and unpredictable'!


. . . . BUT . . . . We are moving away from OP problem so lets get it back on focus.
A little off but experience and theory and the spec sheet all seem to indicate that if you've got a USB motion controller and a laptop then that combination might be a source of problems. If the planned for desktop PC happens to be lying in a box somewhere, then it'll surely be worth trying with that; given it'll eliminate using a laptop as a factor.

A useful thing to do is to try to split the problem up; perhaps, it's possible to run the machine with the motor drivers disabled, so we're only exercising up to the motion control board? If that's reliable, then the laptop and inputs to the motion controller are less suspect, if it's unreliable, then we can look harder at the laptop and motion controller.

Other problems could be as simple as the connection to the board being poor - so it might be worth trying other USB ports. This is especially true for older computers where the ports may have got worn - especially with laptops which tend to get more connections and disconnections. Sometimes, a different cable might fix things; worth trying as it's easy; although IME cabling problems are fairly uncommon with USB -I've only had it on bus powered gear and extremely cheap cables). If you do have a cabling problem (or even a wonky device) then you might be able to find messages about usb connections/disconnections/resets/errors in the Windows Event Log.

Trying other ports could also help with a problem that occurs with few older computers is that some equipment has an expectation of USB 2.0, but the USB ports are USB 1.1 (or only one of the USB ports is USB 2.0).

JAZZCNC
03-06-2015, 05:13 PM
The danger of relying on experience in this way that find yourself reaching conclusions that your experience does not - and cannot - support. To put it another way; lifting 6 tonnes on rope specified for a safe working load of 1 tonne is a bad idea, even if you've 'done it before lots of times'. In fact, it's increasingly poor idea even as you gain more 'experience' that the rope you're using is 'much stronger than the spec sheet said'.


Why I'm objecting is that, whilst you have a lot of experience, 'Ethernet is much better than USB for Motion control' isn't a statement of your experience - you've extrapolated it into conjecture. You can tell it's not experience, because the existence of even one solid USB motion controller is sufficient to falsify your claim.

Stop talking Bollocks your twisting things to fit.!! . . . . . Object all you like but end of the day we are talking MOTION CONTROL not Networking etc. I can honestly tell you with Hand on Heart I've never had a Machine stop or Dropout thru Ethernet failing on Any Motion control device I've used and I've used most of those in the Serious Hobby user market and some of the more expensive ones as well.
Like wise I've had many many experiences thru helping others and costly experiences of my own thru lost material and time with USB driven Motion control cards or devices dropping out on Both Box PC's and Laptops. So I must object because My experience is very wide so therefore Valid and very much relavant to CNC MOTION CONTROL.!! . . . . Which is what we are talking about here.!!

No more will say on this because as Said it detracts from OP problem.!!

Jess
03-06-2015, 08:56 PM
I must object because My experience is very wide so therefore Valid and very much relavant to CNC MOTION CONTROL.!! . . . . Which is what we are talking about here.!!
Experience has limitations. You almost seem recognise this when you say 'we are talking MOTION CONTROL not Networking etc.' but in falling over yourself to claim limits to the experience of others, you're forgetting applying it to your own.

It's much derided, but theory is necessary to understand what the limitations of one's experience are; ie., the situations it's useful in, and the claims that that experience allows one to make. It allows one to look at what is going on, rather than be confused by a name. For instance, you can fixate on it being called 'motion control', or you can recognise it being called Ethernet is a pretty big hint - ie., that it's a networking technology for, well, networking things and that it doesn't much care if the device you've plugged in is a desktop running a web browser, a VoIP phone or a motion controller.

Simply put - having used some motion controls doesn't qualify you to say that USB is the problem. For instance, given that USB controls tend to be in the lower end of the market whilst Ethernet motion controls tend to be at least 'serious hobby' - so an alternative conclusion would be that USB motion controls tend to be cheap with performance to match - nothing to do with the cable you used to connect it to your PC.

This difference is important, because if USB is the problem, an ethernet motion controller for side-hobby money is a great deal; if the issue is instead that it's simply unreasonable to expect a decent motion controller to be cheap, then one should be wary of any motion controller for less than serious hobby money.


No more will say on this because as Said it detracts from OP problem.!!
The only reason why I'm even talking about Ethernet is that you brought it up. The only reason I'm still talking about it, is because I'm replying to you.

The majority of my post was, in fact on OP's problem. None of yours was.

To try to get it back on track again, if the USB motion controller is likely to be a problem, could it even be the root of the present issue - as in, something goes wrong (eg., command buffer empties during a run) and the controller goes into e-stop mode? (And that guard switch is sorted?)

JAZZCNC
03-06-2015, 11:37 PM
Simply put - having used some motion controls doesn't qualify you to say that USB is the problem. For instance, given that USB controls tend to be in the lower end of the market whilst Ethernet motion controls tend to be at least 'serious hobby' - so an alternative conclusion would be that USB motion controls tend to be cheap with performance to match - nothing to do with the cable you used to connect it to your PC.

Ok you pushed me that bit more and you Sir trying to put down experience over theory and untested conclusions shows me you are Full of Shit.!! . . . I'll take my Real world experiences using Real world MOTION CONTROL CARDS of all shapes and prices in Real CNC enviroment using most connection types with MACH3 control software (Big Clue here) in a Buffered not realtime windows enviroment over your Theory and untested Conclusions anyday.! . . . Now I'll Jog on.:encouragement:

Jess
04-06-2015, 09:09 AM
over your Theory and untested Conclusions anyday.!
You are the one who is making claims about the performance of motion controls you've not tested simply on the basis that you've used other motion controls that happen to have the same connector on them.

JAZZCNC
04-06-2015, 03:45 PM
You are the one who is making claims about the performance of motion controls you've not tested simply on the basis that you've used other motion controls that happen to have the same connector on them.

FYI with exception of a few Cheap Chinese rubbish USB controllers not worth the effort I've tested and used all Motion control cards that work with Mach3. Because after all we are talking, or I am, about expereices using Motion control cards working with Mach3 and not about the Protocol used to do this. I don't give a toss if I used a piece of string to Talk to Machine in Klingon so long as it's stable and reliable in use. My Experience with USB and Mach3 hasn't been good or stable regardless of Device Supplier or PC.

Regards the Sieg USB device if that's what your refering to as the " Untested" then Chances are it's using one I've already tested or some variant.
I could with a quick phone call findout exactly what or who's device it uses as one of the main developers of the Sieg machines I know quite well.! . . . . Chances are he is the one doing the support in UK.!

Jess
04-06-2015, 04:46 PM
Because after all we are talking, or I am, about expereices using Motion control cards working with Mach3 and not about the Protocol used to do this.
We were both very obviously talking about the connection/protocol. For example; here you are, talking specifically about the protocol used, only a scant few posts ago:


The Same can't be said for USB it's irratic and unpredictable. There's so many things that can affect it IMO it's not a good or suitable connection for reliable Motion control.

Then your very next post; talking about protocol again:

Ethernet is much better than USB for Motion control


My Experience with USB and Mach3 hasn't been good or stable regardless of Device Supplier or PC.
That's fine - that's a claim based on your experience; I'm not trying to argue that you've never used a good or stable one!

However...you're not saying the same thing when your words are about USB as a whole. When you claim that USB is not a 'good or suitable connection for reliable Motion control' you're unavoidably also claiming that it's impossible for a USB motion controller to be reliable, because it uses USB.

JAZZCNC
04-06-2015, 05:33 PM
However...you're not saying the same thing when your words are about USB as a whole. When you claim that USB is not a 'good or suitable connection for reliable Motion control' you're unavoidably also claiming that it's impossible for a USB motion controller to be reliable, because it uses USB.

Twist my words to suite for argument all you like the fact still remains with real world experience in a cnc enviroment using MACH3 with All connection types and just about every Motion control card that works with Mach3. USB is definatlely the one thats given me most unexplained troubles. Ethernet hasn't and that's a fact not theory.!! . . . . . Now I really have done with this pointless argument.!!

Jess
04-06-2015, 06:48 PM
USB is definatlely the one thats given me most unexplained troubles.
Keyword here is 'unexplained'; you don't know the cause.

...which is exactly what I've been arguing all along. There's plenty of other things that can go wrong with a motion controller and you've finally admitted that you do not know what the problem actually is.

Thank you for admitting I was right all along.

cropwell
04-06-2015, 09:17 PM
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JAZZCNC
04-06-2015, 11:54 PM
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GEOFFREY
05-06-2015, 12:04 AM
Go ***REMOVED*** some where else you ***REMOVED***

Jazz, it is a pity that you were forced into a slanging match, but I fully understand why. It is generally accepted that you are one of the most informed and helpful members on this forum, and I am a little suprised that you lasted so long!!! I still love you. G.XXX

JAZZCNC
05-06-2015, 12:24 AM
Jazz, it is a pity that you were forced into a slanging match, but I fully understand why. It is generally accepted that you are one of the most informed and helpful members on this forum, and I am a little suprised that you lasted so long!!! I still love you. G.XXX

Geoff I'm calming down as I'm getting Older but every now again ***REMOVED*** comes along and pushes the Button.
I honestly Don't give a flying F@@ about him I know what I know thru experience of building machines. It's the others reading his theory and untested conclusions drival that I'm more bothered about and it pisses me off when all I'm trying to do is pass on this experience to save others buying what I know to be more trouble some devices.

I've just come out of workshop after 6 hours of wirng so Maybe it's time for quick Guiness before Bed to Calm me down.!!!

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Lee Roberts
05-06-2015, 03:24 AM
Hi,

Jazzcnc, at no point in the discussion did Jess make personal comments about or to you, in the way you have in reply to Jess, please respect other forum members, as rightly pointed out by GEOFFREY, you are a Forum Superstar http://www.mycncuk.com/images/misc/badges/superstar.png, we know you for greater things ;-).

I've read this discussion from the start and suggest it's now time to move on to other things more deserving of our attention, though I can understand the points both of you are making:

Jazzcnc, I share the same thoughts as you to some extent on this, as in, who cares what is really going on "behind the scenes" so long as the machine is reliable and doing what is required, something's I picked up was that, motion control units that communicate via Ethernet are typically more costly, have a higher level of sophistication and may have the ability to "hide" any problems that may be occurring, giving the effect that everything is "fine and dandy" when actually it may not be, so some form of investigation may not be a bad idea.

Jess, I share the same views as you regarding "treating the cause, not the symptoms" and I'm exactly the type to investigate further myself before moving to a different technology, however, in some circumstances, it may be a better idea to switch to something else, a few of our members use their machines in production environments, so down time would be a major problem. Moving quickly to an Ethernet based system, to get up and running again sooner, may be the way I would choose to go first.

Thank you both for the things you've contributed so far, yet again I've learnt a little more on the CNC subject, which brings us nicely back on topic!

lateAtNight, have you implemented a solution to the problems your having, if so, what did you choose to do? if not, what are you likely to do next?

.Me

JAZZCNC
05-06-2015, 12:15 PM
Hi,

Jazzcnc, at no point in the discussion did Jess make personal comments about or to you, in the way you have in reply to Jess, please respect other forum members, as rightly pointed out by GEOFFREY, you are a Forum Superstar http://www.mycncuk.com/images/misc/badges/superstar.png, we know you for greater things ;-).

You know me Lee I say it the way I see it and he was being a provocative ***REMOVED*** towards me so I said it like it was.! Not often I call someone a Troll on any forum but he showed all the classic signs when he continually argued back against Experience over Theory with a person so experienced when he's only got 20+ posts to his name.!! . . . .(post of them arguing with me.!)
For god sake when things are developed whats the procedure.? First it's theory on paper then it's Tested which is experience. Often the Theory doesn't match the test results I know this all too well building Bespoke machines and several years working in Motor cycle racing R&D.
I help and share what i've learnt thru experience to genuinely help others on forum avoid taking a route I know can or will lead to hassle. It's not to massage my Ego showing off my theory knowledge. Anyone who's dealt with me knows this to be true.!!

The simple matter of fact in this case is that USB motion control devices available for MACH3 are not as stable or reliable compared to there Ethernet brothers for what ever reason.! End of the day it doesn't matter to the end user what the reason is all He and I care about is that the machine is stable and reliable.
Why USB has brain farts is not my concern wounce i've established it's not my work or the setup of the PC or machine. Long ago the USB smooth stepper taught me that chasing Ghosts is time consuming and expensive. In the case of USB smooth stepper it was a design fault BUT. .!! Every USB Motion control device, without exeception, I've used withb Mach3 has at some point dropped out while cutting. No matter the cable quality or length etc. This is not the case with Ethernet.!! . . . Yes occasionally you can have troubles getting it to talk to a device but wounce they are chattering away they keep on and never stop until told to do so.!!

There I'm done and said my piece.

Now Lateatnight if you haven't or can't get to the bottom of this then contact me via PM to stop certain ***REMOVED*** interfering and I'll give you my number. I'll also give a friend a call who I'm sure will know all the tricks the sieg can playup with.!

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Lee Roberts
05-06-2015, 01:39 PM
You know me Lee I say it the way I see it and he was being a provocative Knob towards me so I said it like it was.! Not often I call someone a Troll on any forum but he showed all the classic signs

Yep I do, I disagree though, Jess didn't respond to you in the same way you did to him, so while it may have been the way you perceived it, that doesn't mean your perception of it was correct or the intension of Jess.

You don't need to occupy your judgment with troll like behaviour, that's my job and i'm here for you :), I've said it before, I'm not here to manage peoples personalities - it's their behaviour I'm watching out for and I will step in on behalf of any of you if I think its required.

Allot of thought went into the forum guidelines, a little movement either side of the "line" I'm confident we can all live with from time to time, rude and/or personal comments are way way way to far over the line of acceptable.


I help and share what i've learnt thru experience to genuinely help others on forum avoid taking a route I know can or will lead to hassle. It's not to massage my Ego showing off my theory knowledge. Anyone who's dealt with me knows this to be true.!!

We all know this Dean and thank you for your commitment to helping others, for a very high percentage of your commitment to others, you are able to do so without the need to cross to far over the "line", just because you think it, doesn't mean you have to say it, the point I'm trying to make is, your better than that :thumsup:.

Cool, I cant say I gave your motivations any thought, past what I already know of you generally. What I would say is, given the success you have in helping others...its ok to feel good about yourself :encouragement:

.Me

routercnc
05-06-2015, 02:29 PM
Hi Lee,

I've been close to bringing this to your attention for a while to see if there was a way through (just in terms of giving the OP the post back I mean).

I was going to suggest seperating the thread out into "Best ways to connect to a CNC machine?" [ around post#13? ] where pros and cons of USB vs PP vs Ethernet etc. could be discussed. There are some valid discussions on that topic to be had all round I think, moderation issues aside.

Thanks

Lee Roberts
05-06-2015, 04:20 PM
Yep good call, I'm out on the school run at the mo so will sort it later today [emoji481]

.Me

magicniner
06-06-2015, 06:04 PM
Ethernet really isn't a natural partner for realtime stuff

20 years of 1st to 3rd line IT support and development work in industrial control for Blue Chips strongly suggests otherwise to me.
Have you read up on the error-checking and packet resending features of the Ethernet Protocol?
Where routers are involved information can travel several different routes and still be resolved at the destination, this is why the images which you view in your internet browser show so few errors.
Ethernet is not erratic (or even irratic) it's a very robust communication protocol, if you'd levelled your accusation against Token Ring then you may have had a leg to stand on!
Regards,
Nick

JAZZCNC
06-06-2015, 08:54 PM
then you may have had a leg to stand on!

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JAZZCNC
06-06-2015, 09:32 PM
Jess Enough now please your splitting Hairs to suit your unrealistic cause, again detracting from L.A.N problem.!! . . . 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.!!


https://www.youtube.com/watch?v=GNL2XdsJz2E

Jess
06-06-2015, 10:20 PM
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
06-06-2015, 11:10 PM
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.!!


https://www.youtube.com/watch?v=wDHeeU5waC4

Jess
07-06-2015, 12:08 AM
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
07-06-2015, 12:16 AM
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
07-06-2015, 01:02 AM
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.!!:yahoo:

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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Lee Roberts
07-06-2015, 03:48 AM
Hi Lee,

I've been close to bringing this to your attention for a while to see if there was a way through (just in terms of giving the OP the post back I mean).

I was going to suggest seperating the thread out into "Best ways to connect to a CNC machine?" [ around post#13? ] where pros and cons of USB vs PP vs Ethernet etc. could be discussed. There are some valid discussions on that topic to be had all round I think, moderation issues aside.

Thanks

Threads split as suggested, sorry for the delay.

.Me

Jess
07-06-2015, 04:06 AM
Twas a Joke Hence the Jester.!!
Yeah, I saw the jester, but I'm afraid that it didn't entirely put my mind at ease at the time. I guess I'm jaded, heard too many 'jokes' where someone's actually a bit more serious than they're letting on etc., If I actually knew you, of course, I'm sure my interpretation would have been totally different!


arguing something that wasn't relavant and pointless to the discussion.!
From my side, if you're interested:

L.A.N. had just bought a machine with a USB controller, so whatever ethernet ones did was irrelevant; if you've just paid well over 3k for your mill, the last thing you want to see is that you need to go buy a different controller (well, except that it's jammed itself in estop again, of course.)

At this point if I'd read 'The Same can't be said for USB Controllers they've all been irratic and unpredictable...they're just not good or suitable for reliable Motion control', I think we'd have been fine. There's lots of (frankly) crap computer peripherals, so a few dozen more isn't a surprise - especially with USB peripherals where the spec often feels more a guide to how it won't be implemented.

Unfortunately, I read 'The Same can't be said for USB it's irratic and unpredictable...it's not a good or suitable connection for reliable Motion control'...I replied about USB as a connection (I've experience with it on the design side) and the rest is...well...this thread.


Now FFS lets leave it alone.!!:yahoo:
Deal.


Nothing specialised about that tool it's just a T-slot cutter.!!!
It's not fancy, but I think we both know what I was trying to get at there! :tongue: (Also, I'll take an undercut of twice the diameter of your largest t-slot cutter! :rolleyes:)


I get it, Ethernet isn't suitable for something no-one here needs to do, good point(less) well made!
I've found that it's dangerous on forums like these to assume that nobody needs to do it...and exceptionally dangerous to assume that no one wants to do it!


I suspect there is very little TCP/IP-Free Ethernet in use outside industrial applications though.
There's a good bit actually! Ignoring nitpicks like UDP/IP, SCTP/IP etc.,
Just off the top of my head, there's methods of attaching hard disks (like ATA over Ethernet), some thin clients etc., PPPoE does too, and that's used by almost everyone who's got VDSL2 (BT Infinity) or got Virgin Media before they moved supplying an all-in-one.

And of course, some of the industrial standards go and use, say, UDP/IP anyway!


but neither is any other remote communication system - the motion controller deals with closed loop rigid tapping locally.
;-)
If the communication system was explicitly designed for control purposes, you can! If you want to see a video example, the spindle encoder in the earlier rigid tapping video Dean posted is connected over CANbus. I'm sure that you can also do it over other things like Modbus/RS485 too...but I'm not going to bother finding examples.

JAZZCNC
07-06-2015, 10:54 AM
If the communication system was explicitly designed for control purposes, you can! If you want to see a video example, the spindle encoder in the earlier rigid tapping video Dean posted is connected over CANbus. I'm sure that you can also do it over other things like Modbus/RS485 too...but I'm not going to bother finding examples.

There you go splitting hairs again when you actually don't know the full story or have experience of the controller.!!
The only reason it's using CANbus because it's a External I/O module that connects to the Main Controller Via CANbus. Hood could have easily connected straight to the main IP-A controller, but with So much I/O to make the Chiron work he's using the I/O Module.!!. . . The Controller still does all the Work and number crunching. CANbus is just used has an easy and stable way to move I/O modules around large machines to localise I/O and keep short Signal wire runs. Other wise it would mean running long signal wires back thru machines risking EMF issues.


Yeah, I saw the jester, but I'm afraid that it didn't entirely put my mind at ease at the time. I guess I'm jaded, heard too many 'jokes' where someone's actually a bit more serious than they're letting on etc., If I actually knew you, of course, I'm sure my interpretation would have been totally different!

Rest assured your not and never where in any Danger from me ***REMOVED***. And if you was I'm not stupid enough to post my intentions on a Forum. ***REMOVED***

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Create threads and/or posts deemed to be soliciting any kind of harassment, discrimination, flaming, trolling and/or behaviour considered by the site staff as intentionally abusive or inappropriate. Such content will be removed from public viewing.

Jess
07-06-2015, 12:03 PM
There you go splitting hairs again when you actually don't know the full story or have experience of the controller.!!
magicniner claimed that no remote communication system can do rigid tapping. CANbus is a remote communication system, and as hood demonstrates, CANbus can do rigid tapping.

I don't see what the problem is?

JAZZCNC
07-06-2015, 12:35 PM
magicniner claimed that no remote communication system can do rigid tapping. CANbus is a remote communication system, and as hood demonstrates, CANbus can do rigid tapping.

I don't see what the problem is?

Problem is CANbus isn't doing the ridgid tapping the Controller is doing it. CANbus is just shifting data which it does best.!!

I think the Valid point Magicininer was making is that it's not the Communication protocol that does the work on any machine usually it's the main Controller it's self.! . Just Like it's the Encoder module working in conjunction with the Main controller on the Cslabs devise. CANbus just lets them talk to each other, albeit very fast.
Also in this case it's actually the main controller that is doing the coordinated movement between spindle and Axis by controling the Servos (Hood's spindle is Servo driven) which is connected to Control software via Ethernet.
The Encoder module is just reading the High resolution encoders which require high data rates which CANbus is very good at.! The controller deals with these internally and send the relavent signals needed for movement to what ever does the moving or turning.!!

m_c
07-06-2015, 12:35 PM
Would you pair put the handbags down! :)

In terms of Mach3, Ethernet is the more reliable communication method for external motion controllers.
The reason for this, is Mach3 can't handle any errors or glitches in the communication method.
Ethernet handles errors and glitches at a hardware level, it's also an isolated system, so is much more tolerant of external noise, and should a packet fail to reach it's destination, the hardware (ok, it's technically the embedded code in the Ethernet controller if you want to split hairs) will handle the problem and resend it until it reaches it's destination.
USB doesn't have that, so any packet of data that gets corrupted, has to be detected and handled by software. I'm sure if the plugins could be designed to do this, they would, however it's one of the things that Mach3 was never designed to handle, as it was originally written to talk directly to the parallel port.
I think it would be fair to say external motion control, was simply patched onto the Mach3 core.

One key point to remember, is once you involve Ethernet or USB, you are no longer running realtime. All you're essentially doing is running a faster version of ye olde RS232, in that you send commands to a controller, and the controller (hopefully) tells you it's been done.


However, USB can be used reliably. I run several KFlops, and they are far more stable than my USS ever was with Mach3. My lathe still occasionally locks up Mach3 (my manual lathe is the sole trigger for this!), but no where near as often as the USS ever did.
I am in the process of moving to KMotionCNC, as it can handle communication problems far more gracefully (and it has less issues, but that's for another topic!), and will happily resume once things are back to normal.

m_c
07-06-2015, 12:44 PM
magicniner claimed that no remote communication system can do rigid tapping. CANbus is a remote communication system, and as hood demonstrates, CANbus can do rigid tapping.

I don't see what the problem is?

In the original context of this thread, which was to do with computer to machine controller interfaces, magicniner's claim is correct.
In the case of CS-Labs they use it for inter-module communication, which is where it excels.

CANbus is a very resilient system, and can be very fast, however nobody uses it as a communication method between a computer and CNC machine. You could use it for realtime operation if you designed a suitable internal slot card that the computer could access directly and control in realtime, but you're then into a very glorified parallel port like system.

Jon.
07-06-2015, 12:57 PM
Im with jess on this one, usb is far more reliable.

I run both my machines with uc300's from a laptop. it never looses connection, has an excellent 100khz buffer and has been left on for over a week in the past with no issues.

I also have a wired network with multiple routers tried over the years and they all failed from time to time. I know not the same but doesn't give me much faith.

JAZZCNC
07-06-2015, 01:08 PM
Would you pair put the handbags down! :)

However, USB can be used reliably. I run several KFlops, and they are far more stable than my USS ever was with Mach3.

No my Hand bag is always read for Action.!!. . Lol

Now Come on M_C we both know you are talking about a very High quality product when using Granite's Kflop controller it's not your average USB Mach3 controller.
The point I was making in first place is that USB isn't stable as Ethernet when used with Mach3 which we know thru experience is true. We Have Both pulled our hair out with USS(USB Smooth Stepper for those we are wondering.!!) and I've done much the same with every other run of the Mill USB controller for Mach3.
Ethernet on the Other hand is another ball Game. Classic example is the Pokeys 56/7E and now 57ECNC which do Motion control they are cheap and work great they never Miss a beat. The 56U on the other hand was a pain when used for motion control with Mach3, mainly I think because it relied on USB for 5v but still it couldn't be trusted.!

USB driven card Isn't ok for Motion control unless your prepared to spend on quality devices like Granite's Kflop etc so to me it's not for the average DIY user and best avoided.! And now with Ethernet devices coming more available at sensible money what the point.!

JAZZCNC
07-06-2015, 01:19 PM
II run both my machines with uc300's from a laptop. it never looses connection, has an excellent 100khz buffer and has been left on for over a week in the past with no issues.

See this is the point.!! . . . . I've used the uc300 and it was fine. Untill you turned some high frequency device on near by then it would freakout. (In the USS case next Room.!!)
Yes it can be said it's the Cards fault not USB protocol but this doesn't happen with Ethernet driven devices I've used. They handle EMF and such crazyness much better in my experience.
I'm not into communication and all that goes with it. But I am into CNC and all that goes with that and I know thru experience that Ethernet is better than USB when it comes to running a CNC machine using Mach3..!! . . . Which is what started this whole Hang bag stuff in first place.!
It's just some people have to twwist words and things around to suit there own Ego's!!

Jon.
07-06-2015, 02:40 PM
Both Ethernet and usb are digital so noise is likely to effect both if large enough, i have my uc300 running an inch away from my 2200w vfd and two inches from a honking great 55v toroidal transformer without issue so sounds like your noise may have been in your power supply, were you using ac filters? either that or there was something massively wrong happening in the next room.

Jess
07-06-2015, 02:57 PM
however nobody uses it as a communication method between a computer and CNC machine
Not on Mach 3; but that part of the conversation hasn't been about Mach 3 for several days now! :smile: And, of course, that ethernet motion controller is a computer, but that's not what any of us mean.

On the LinuxCNC side, whilst RS485 is more popular, there's definitely people interfacing their machines to their computers with CANbus.

The hardware's been available for years. There's plug in cards that provide the interfaces plus industrial PC motherboards that already have CANbus and/or RS485 on board.


but you're then into a very glorified parallel port like system.
Rather unfair and misleading. CANbus gives you something much closer to a PCI I/O board in function - you're not having to do software step generation, and you actually have the ability to read encoders.

To seque this into the topic of the thread:

Approaches that allow your computer to more directly control the machine is definitely of huge value if you've got some complicated/non-standard kinematics going on, but even on a standard perpendicular axis mill then there's a potentially a significant financial saving to be made.

The additional costs associated with Mach 3; Windows licenses, Mach 3 licenses and ethernet hardware motion controllers could buy you all the electronics you need to convert something like a Novamill or Triac, even once you've thrown in something like a Mesa Anything I/O.

LinuxCNC on BeagleBone Black? A back of the envelope calculation suggests that I can have my entire dedicated control computer as well as software and breakout for the cost of the Mach 3 license alone; that's a lot of difference.

m_c
07-06-2015, 03:52 PM
I wouldn't normally take the bait, especially from someone who has very little if any practical experience building or running CNC machines, but here goes.


And, of course, that ethernet motion controller is a computer.
No it's not. It'll be an embedded micro-controller, DSP or FPGA, which nobody who deals with such things will class as a computer.


On the LinuxCNC side, whilst RS485 is more popular, there's definitely people interfacing their machines to their computers with CANbus.

The hardware's been available for years. There's plug in cards that provide the interfaces plus industrial PC motherboards that already have CANbus and/or RS485 on board.

But not in the form of communication between a computer and a motion controller. In LinuxCNC the computer is the motion controller. External motion control cards are not available for LinuxCNC, as they defeat the whole purpose of LinuxCNC's realtime kernel.
CANbus/RS485 is just another method of communicating between the controller and drives/IO boards, just like lots of other possible options.



Rather unfair and misleading. CANbus gives you something much closer to a PCI I/O board in function - you're not having to do software step generation, and you actually have the ability to read encoders.

And what exactly is a parallel port?
Last I checked, it was simply a bunch of I/O pins conveniently arranged in a standard format, that can be accessed directly by software (I know windows blurs this, but the principle is still there), just like a PCI IO card does.
If you really wanted, you could make a parallel to CANbus to BOB setup, and it would give you a similar setup to using a direct CANbus PCI card, just with more limited IO and speed.



To seque this into the topic of the thread:

Approaches that allow your computer to more directly control the machine is definitely of huge value if you've got some complicated/non-standard kinematics going on, but even on a standard perpendicular axis mill then there's a potentially a significant financial saving to be made.

The additional costs associated with Mach 3; Windows licenses, Mach 3 licenses and ethernet hardware motion controllers could buy you all the electronics you need to convert something like a Novamill or Triac, even once you've thrown in something like a Mesa Anything I/O.

LinuxCNC on BeagleBone Black? A back of the envelope calculation suggests that I can have my entire dedicated control computer as well as software and breakout for the cost of the Mach 3 license alone; that's a lot of difference.

And this argument over cost will rumble on indefinitely.
The fact remains for your typical DIY CNC enthusiast, the familiarity of windows based computer systems, means they'll remain the most popular option for the foreseeable future, despite the additional cost.
You've got to remember, a lot of people who build CNC machines, are not computer or electronic geeks.

For me personally, time is money, so although I may save on licenses, the extra time familiarising myself with a new operating system/hardware, is time that could be spent making money. For me running Dynomotion products, a KFlop costs about 230 delivered. For that I get nearly everything needed for a motion controller including some very reliable software, and only need to add a windows PC, which can be picked up for very little. I can have the controller configured and ready to go in a couple hours. If the computer fails (which lets be honest, is usually the weakest link), I swap the configuration files onto a new computer, and away I go again.

Add something like Mesa cards into the mix, and you've then got to start swapping parts around, and hope they didn't get killed when the computer died.

m_c
07-06-2015, 04:21 PM
Both Ethernet and usb are digital so noise is likely to effect both if large enough, i have my uc300 running an inch away from my 2200w vfd and two inches from a honking great 55v toroidal transformer without issue so sounds like your noise may have been in your power supply, were you using ac filters? either that or there was something massively wrong happening in the next room.

I suspect Jazz's source of interference was a HF Plasma Cutter, or HF TIG welder, both of which will produce and emit interference that will far exceed anything a properly wired VFD will.
If you get the chance, you might want to try firing one up next to your machine, and see if it still remains as stable, as there's nothing quite like a few hundred volt high frequency unsheilded arc to highlight the slightest deficiency in your shielding/grounding/power filtering/communications.

Jon.
07-06-2015, 04:34 PM
Be interesting to find out. Though a grounded metal enclosure around the controller, which should be general practice, would most likely solve the issue. If it didnt id be suprised and very much suprised if the etherenet controller wasnt effected by such levels of noise.

m_c
07-06-2015, 04:53 PM
It probably would be, however Ethernet is far better at handling and recovering from noise problems, as it can handle and resend lost data packets, whereas USB doesn't have that capability. I do suspect USB comms could be improved to handle these situation better, but it'll add cost, complexity, and processing overheads.

I know from various USS discussions, Greg struggled to fit all functionality into the USS, so I suspect it was having to do the bare minimum to handle communication. When it came to the ESS, Greg used a larger FPGA, and I do suspect there may be more going on within it to handle communication problems.

I also suspect other manufacturers have looked at the issues from the USS, and implemented strategies to better handle communication faults, as other good quality USB controllers don't seem to suffer from anywhere near as many communication faults.
You have to remember USS was the first successful USB external motion controller for Mach3, and it did achieve a lot, however I do think it's probably time to retire it, or at least update the hardware.

JAZZCNC
07-06-2015, 04:53 PM
Both Ethernet and usb are digital so noise is likely to effect both if large enough, i have my uc300 running an inch away from my 2200w vfd and two inches from a honking great 55v toroidal transformer without issue so sounds like your noise may have been in your power supply, were you using ac filters? either that or there was something massively wrong happening in the next room.


No offense meant to you Jon but I'm doing this all the time and know all about what or not to do. The particular "next room" incident was actually a Compressor with faulty starter but the more the problem was the USB Smooth stepper had a design flaw so didn't take much to upset it. (It was one of the very first models.!! I've since tried newer versions but still had problems.!)

Regards the uc300 then fire up a Tig or Plasma cutter up near by and see how it reacts.! Vfd's and torodial supplys are nothing and it would be very bad state if they couldn't live along side one or both.
It's the things that go off around the machine that seem to affect USB/PC but what exactly I'm yet to determine and believe me I've looked and tried to put my finger on what causes it.!

End of the day I'm into building and using a CNC machine and haven't got time to chase the many things that can bring it down. What I can do is eliminate using those that don't meet the mark by testing them as I go along building machines.
First test is the Tig/Plasma test and then I work backwards from there.!!. . Very few USB devices Pass this test.!



LinuxCNC on BeagleBone Black? A back of the envelope calculation suggests that I can have my entire dedicated control computer as well as software and breakout for the cost of the Mach 3 license alone; that's a lot of difference.

Ah ah now we get to the meet of the Beef.!! . . . Linux Geek. . . Wanting to Pick a fight with Mach user's.!! . . . . Well Not happening I'm afraid been there too many times.! . . . Jog on.!

JAZZCNC
07-06-2015, 05:10 PM
Be interesting to find out. Though a grounded metal enclosure around the controller, which should be general practice, would most likely solve the issue. If it didnt id be suprised and very much suprised if the etherenet controller wasnt effected by such levels of noise.

All the machines I build use Metal Enclosures and believe me it doesn't help much. Ethernet isn't affected nearly as much and better Motion devices like CSlabs it doesn't affect at all.
I'm just currently testing the Pokey's 57CNC which uses Ethernet and it survived the Tig test but then funnily enough it threw a little wobbly by E-stoping when I was using the Mig welder.? It's behaved since thou so could have been that and the fact i'm using the 5V signal for E-stop. (plus it's rough wired on the bench)

Boyan Silyavski
07-06-2015, 05:27 PM
That thread made me laugh, really. How did i miss it. There is no respect for experience it seems. "Knowledge|" without experience is just a collection of facts or suggestions, from here and there.


I don't know what the hassle is about? Most expensive motion controllers have tried USB and then upgraded to Ethernet controllers. See Galil for example. Even cheap controllers have done the same. So there must be a reason for that.


What happens at low level / cheap/ controllers is that they do the same just like a follow up , after a couple of years, when parts are already cheaply available for the low end market.


Or you say people who make industrial control are stupid and don't know their business.


My blue Makita drill worth 360euro drills holes in steel and my friends green Bosch worth 50 euros drill holes in steel. My Makita can drill 10 years everyday without a glitch and the Bosch will die in month of industrial environment.


As i have pure HF plasma at home let me clear something. Glitches come from not good home grounding, the non shielded mouse and other Pc cables, not from USB or Ethernet cable if they are shielded and all electronics are in a shielded box. So basically both should work if everything to the last detail is well done.


Well Jess, now we know you . You have well presented yourself here. I am half expecting soon to hear that RP is better than ball screw and that HD alu profile gantry is stronger than steel one..

Jon.
07-06-2015, 09:22 PM
Really id say its down to personal preference. I think if your using an Ethernet controller over usb because of noise its because you haven't taken the correct steps to shield the controller and that you are also happy to have your controller bombarded with noise, just because it can it doesn't mean it should. You may be correct in that ethernet has better protection against noise but that is providing the noise is entering via its ports. If your talking about noise that is infact capable of entering a grounded enclosure then there's no telling how that noise is going to enter the board, but you say it does fair better but with the correct steps either can work so again personal preference.

Bearing in mind a pc usually has multiple usb ports, but can only handle a single ethernet port so its restrained in that respect.

m_c
08-06-2015, 12:29 AM
It is down to personal preference.
.
However most experienced machine builders, will recommend Ethernet over USB. Over 99% of USB users never have any problems, even when questionable wiring techniques have been used, yet others, even with proper wiring techniques will have endless problems.
The fact is though, the only threads over on the Mach forum about intermittent communication issues are all about USB controllers. I personally cannot remember seeing any involving Ethernet, apart from initial setup problems.
.
PCs can have more than one Ethernet port installed, it's just not a common thing to need. There are people who run Ethernet devices over a full network, but ideally you should be dedicating a computer to running a machine and connecting directly, with the same advice applying to USB.

Jess
08-06-2015, 03:28 AM
There is no respect for experience it seems.
I respect experience. What has seemingly confused you is that I believe that respecting experience means you respect both what it tells you and what it doesn't.


"Knowledge|" without experience is just a collection of facts or suggestions, from here and there.
The collorary to that is: "Experience" without "Knowledge" is just half truths and old wives tales. You need both of them.

I'd have liked to present a more continuous narrative, but that's just not possible when the topic is getting changed enough times that we somehow got from the relative sophistication of ethernet and USB controllers to talking about connecting to a machine with a parallel port CANbus adaptor! :grumpy:


and then upgraded to Ethernet controllers. See Galil for example. Even cheap controllers have done the same. So there must be a reason for that.
Simple; the cost of doing it compared with the profit of doing it.

With the integration level of modern microcontrollers, an Ethernet port costs about the same to put on a board as a properly isolated USB port. Given there's also a willingness to pay a small premium for Ethernet it's not surprise that things are moving that way.


I am half expecting soon to hear that RP is better than ball screw and that HD alu profile gantry is stronger than steel one..
Don't worry, I'm not going to tell you to use coat hangers as rails for your X axis!

...I just wish people had done me the same courtesy on this topic. Especially given that later posts have now repeatedly confirmed what I've been getting shouted down for saying is correct!

Jon.
08-06-2015, 06:48 AM
Well Jess, now we know you . You have well presented yourself here. I am half expecting soon to hear that RP is better than ball screw and that HD alu profile gantry is stronger than steel one..

What sort of steel are you talking about here? Heat treated stress relieved steel.. by far much stronger. Mild steel simply welded up and painted that will change shape over the years then going on its working life span, Aluminum will retain shape and last longer if built well. Hense why production machines always use heat treated steel or aluminum, but you still see people forking out thousands building machines from mild steel obviously going off your assumption, knowing one day they might wake up to find their machine is jammed.

Boyan Silyavski
08-06-2015, 08:58 AM
What sort of steel are you talking about here? Heat treated stress relieved steel.. by far much stronger. Mild steel simply welded up and painted that will change shape over the years then going on its working life span, Aluminum will retain shape and last longer if built well. Hense why production machines always use heat treated steel or aluminum, but you still see people forking out thousands building machines from mild steel obviously going off your assumption, knowing one day they might wake up to find their machine is jammed.

I will reply in you build thread, cause I see you took that personally. I am also making machines from aluminum just right now.

Robin Hewitt
08-06-2015, 10:55 AM
I had experience of USB a few years back and it was not good, in fact I think the whole USB thing is a scam. The idea was good, every USB device had it's own unique ID number, you plugged it in , the computer asked, "What are you", it replied. "I am a 12345B". The computer searches itself for the driver named "12345B" and runs it. If it cannot find 12345B it asks you where it should look.

The unique ID numbers are free, but, you have to join the USB club before they can be given to you and joining the club is hideously expensive.

To get around that manufacturers used a loophole, instead of coming up and saying, "I am a Model J CNC Controller from Choppit Ltd" they come up and say, "I am a Windows device, usually a serial port or a disk drive". The Choppit CNC control software then has to rummage among the available ports and drives looking for it's controller.

USB does not usually shine because for CNC it is fettered by all sorts of 3rd party software impersonating other things. There was a company called something like "Metrologie" who joined the club and sold their unique ID's at around 10 for 120. They got stomped on PDQ but cheap ID's are still out there if you look :thumsup:

Jon.
08-06-2015, 11:14 AM
lol.. you what?? so you went on to get ethernet from the tackle shop yeah?

m_c
08-06-2015, 11:32 AM
What sort of steel are you talking about here? Heat treated stress relieved steel.. by far much stronger. Mild steel simply welded up and painted that will change shape over the years then going on its working life span, Aluminum will retain shape and last longer if built well. Hense why production machines always use heat treated steel or aluminum, but you still see people forking out thousands building machines from mild steel obviously going off your assumption, knowing one day they might wake up to find their machine is jammed.

Jon, you do realise silyavski was taking the michael?
Although I'm not sure about ballscrews being better than RP... :joker:

Jon.
08-06-2015, 11:45 AM
He might have been but he had just made a patronizing comment about heavy aluminum on a thread of mine seconds before he wrote that one.

m_c
08-06-2015, 12:29 PM
He might have been but he had just made a patronizing comment about heavy aluminum on a thread of mine seconds before he wrote that one.
I don't see anything patronizing about his comments. There is a bit of misunderstanding due to Silyavski's English, but both his suggestions were valid given the information provided before those posts.

Boyan Silyavski
08-06-2015, 01:24 PM
Jon,
it was a suggestion, not patronizing. I saw the need to say to you about strengthening the gantry at glance. But plus that, i spend 2 hours at least thinking about your problem, your machine strength and making calculations, comparing your alu profile data and transferring that data to find the comparative steel profile, then i started calculating deflection and so on...

If you feel i am not right, just ignore what i said, anyway its not an attack or anything personal

Lee Roberts
08-06-2015, 01:32 PM
Really id say its down to personal preference. I think if your using an Ethernet controller over usb because of noise its because you haven't taken the correct steps to shield the controller and that you are also happy to have your controller bombarded with noise, just because it can it doesn't mean it should. You may be correct in that ethernet has better protection against noise but that is providing the noise is entering via its ports. If your talking about noise that is infact capable of entering a grounded enclosure then there's no telling how that noise is going to enter the board, but you say it does fair better but with the correct steps either can work so again personal preference.

My thoughts are the same, +1 for this post.

If people stoped for a second and actually read what was being said, then...never mind... I guess we are all limited in some ways to our own experiences, a level of understanding for things and struggle with other things.

.Me

JAZZCNC
08-06-2015, 03:53 PM
Really id say its down to personal preference. I think if your using an Ethernet controller over usb because of noise its because you haven't taken the correct steps to shield the controller and that you are also happy to have your controller bombarded with noise, just because it can it doesn't mean it should. You may be correct in that ethernet has better protection against noise but that is providing the noise is entering via its ports. If your talking about noise that is infact capable of entering a grounded enclosure then there's no telling how that noise is going to enter the board, but you say it does fair better but with the correct steps either can work so again personal preference.

Bearing in mind a pc usually has multiple usb ports, but can only handle a single ethernet port so its restrained in that respect.

This is the situation Jon from my point of view has someone who Builds machines for others compared to someone like your self who just uses a Machine in a DIY capacity or maybe even Small business venture.
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.!!

FatFreddie
08-06-2015, 09:43 PM
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

Jon.
08-06-2015, 09:57 PM
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

Neale
09-06-2015, 08:35 AM
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

Looking at a USB cable, it appears to use ground, power, and data in and data out. So, single-ended connections. Typical Ethernet connections use twisted-pair and, presumably, differential signalling. That suggests that Ethernet, at a hardware level, should be intrinsically more noise-resistant (although my own 3D printer has run for many, many hours over USB without any problem, although that is in a domestic environment without machine tools and EMI generators nearby). I think FatFreddie has it right with reference to TCP, though. A typical USB connection will be using an application-specific protocol that assumes a reliable connection (I know my 3D printer does this as I've looked at the code) so any data corruption or loss will be catastrophic, where the TCP protocol gives a highly reliable connection; any packet loss or corruption short of losing the whole connection will be detected and corrected by resending packets. Ethernet-connected motion controllers appear to use IP as they need network addresses and I presume they also use TCP over this - why shouldn't they? So, an error-correcting protocol over a more noise-resistant hardware connection gives so much more safety margin than a simple protocol over less-protected hardware. Be interesting to see the Ethernet-level error counts in a noisy environment, though.
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...

Lee Roberts
09-06-2015, 10:10 AM
Looking at a USB cable, it appears to use ground, power, and data in and data out. So, single-ended connections. Typical Ethernet connections use twisted-pair and, presumably, differential signalling. That suggests that Ethernet, at a hardware level, should be intrinsically more noise-resistant (although my own 3D printer has run for many, many hours over USB without any problem, although that is in a domestic environment without machine tools and EMI generators nearby). I think FatFreddie has it right with reference to TCP, though. A typical USB connection will be using an application-specific protocol that assumes a reliable connection (I know my 3D printer does this as I've looked at the code) so any data corruption or loss will be catastrophic, where the TCP protocol gives a highly reliable connection; any packet loss or corruption short of losing the whole connection will be detected and corrected by resending packets. Ethernet-connected motion controllers appear to use IP as they need network addresses and I presume they also use TCP over this - why shouldn't they? So, an error-correcting protocol over a more noise-resistant hardware connection gives so much more safety margin than a simple protocol over less-protected hardware. Be interesting to see the Ethernet-level error counts in a noisy environment, though.
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...
Really well said Neale.

Clive S
09-06-2015, 12:12 PM
There is also the cable length issue with USB (just saying):whistle: ..Clive

JAZZCNC
09-06-2015, 03:07 PM
Cathedral builders used experience to create magnificent buildings but theory and better understanding of materials gives us skyscrapers. If that is an advance...

Yes very well said but just one small detail.? . . . Those Skyscrapers where built by Master builders with years of experience.! Those builders would not use inferior products and therefore make sure those products where well tested by people experienced in testing material Theory.!!

Theory and Experience work together for advancement but experience "TESTING" ultimately Wins and as the final say on what works and what doesn't.!!!

Neale
09-06-2015, 04:58 PM
Theory and Experience work together for advancement but experience ultimately Wins and as the final say on what works and what doesn't.!!!

I'm not sure that I agree with that (I think that testing has the ultimate say) but that statement is only based on my experience and there's no theory to back it up...

HankMcSpank
09-06-2015, 05:14 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...


https://www.youtube.com/watch?v=NUu9xwDfJ9k

JAZZCNC
09-06-2015, 05:46 PM
I'm not sure that I agree with that (I think that testing has the ultimate say) but that statement is only based on my experience and there's no theory to back it up...

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

Jon.
09-06-2015, 06:45 PM
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.

Neale
09-06-2015, 10:49 PM
Ok I'll amend it to what was meant and say Ultimately Experience testing wins.!!. . .:smiley_simmons:

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!

JAZZCNC
09-06-2015, 11:10 PM
I wasn't being very serious! Yes I knew that neil, I wasn't exactly being too serious my self.! . . . And regards your Father experience then I fully it get it.!
To me it comes close or equal to "Can't teach Old Dog new tricks" in terms of irritation.! . . . .I'm so far removed from both it gets me in trouble at times But Experience applied with intelligence along with a good dose of common sense win every time over theory alone in my book.! . . . . But . . . . All my best ideas and achievements started with " In theory it should work" but it does take certain amount of experience to allow the theory to evolve.!! . . . .Chicken and Egg maybe.?

GEOFFREY
13-06-2015, 11:40 PM
Yes I knew that neil, I wasn't exactly being too serious my self.! . . . And regards your Father experience then I fully it get it.!
To me it comes close or equal to "Can't teach Old Dog new tricks" in terms of irritation.! . . . .I'm so far removed from both it gets me in trouble at times But Experience applied with intelligence along with a good dose of common sense win every time over theory alone in my book.! . . . . But . . . . All my best ideas and achievements started with " In theory it should work" but it does take certain amount of experience to allow the theory to evolve.!! . . . .Chicken and Egg maybe.?

Sadly I learned long ago that "common sense" is not so common!!! G.