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

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Originally Posted by lateAtNight

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

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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.,).

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Originally Posted by Jess

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.,).

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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.

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)

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Originally Posted by Jess

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.

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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.

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Originally Posted by JAZZCNC

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.!!

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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'!

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Originally Posted by JAZZCNC

. . . . BUT . . . . We are moving away from OP problem so lets get it back on focus.

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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).

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Originally Posted by Jess

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.

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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.!!

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Originally Posted by JAZZCNC

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.!!

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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.

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Originally Posted by JAZZCNC

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

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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?)

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Originally Posted by Jess

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.

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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:

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Originally Posted by JAZZCNC

over your Theory and untested Conclusions anyday.!

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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.

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Originally Posted by Jess

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.

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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.!

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Originally Posted by JAZZCNC

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.

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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:

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Originally Posted by JAZZCNC

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.

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Then your very next post; talking about protocol again:

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Originally Posted by JAZZCNC

Ethernet is much better than USB for Motion control

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Originally Posted by JAZZCNC

My Experience with USB and Mach3 hasn't been good or stable regardless of Device Supplier or PC.

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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.

Quote:

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Originally Posted by Jess

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.

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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.!!

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Originally Posted by JAZZCNC

USB is definatlely the one thats given me most unexplained troubles.

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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.

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Quote:

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Originally Posted by JAZZCNC

Go ***REMOVED*** some where else you ***REMOVED***

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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

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Originally Posted by GEOFFREY

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

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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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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

Quote:

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Originally Posted by Lee Roberts

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 ;-).

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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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Quote:

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Originally Posted by JAZZCNC

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

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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.

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Originally Posted by JAZZCNC

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.!!

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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

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

Yep good call, I'm out on the school run at the mo so will sort it later today [emoji481]

.Me

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Originally Posted by Jess

Ethernet really isn't a natural partner for realtime stuff

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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

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Originally Posted by magicniner

then you may have had a leg to stand on!

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***REMOVED***

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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

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Originally Posted by JAZZCNC

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

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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.)

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Originally Posted by JAZZCNC

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.!!

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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! :)

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

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Originally Posted by 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.!!

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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!

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Originally Posted by JAZZCNC

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

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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.

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.
;-)

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Originally Posted by Jess

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.

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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.!!

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Originally Posted by Jess

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

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

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Quote:

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Originally Posted by routercnc

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

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Threads split as suggested, sorry for the delay.

.Me

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Originally Posted by JAZZCNC

Twas a Joke Hence the Jester.!!

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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!

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Originally Posted by JAZZCNC

arguing something that wasn't relavant and pointless to the discussion.!

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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.

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Originally Posted by JAZZCNC

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

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Deal.

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Originally Posted by JAZZCNC

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

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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:)

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Originally Posted by magicniner

I get it, Ethernet isn't suitable for something no-one here needs to do, good point(less) well made!

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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!

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Originally Posted by magicniner

I suspect there is very little TCP/IP-Free Ethernet in use outside industrial applications though.

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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!

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Originally Posted by magicniner

but neither is any other remote communication system - the motion controller deals with closed loop rigid tapping locally.
;-)

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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.

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Originally Posted by Jess

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.

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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.

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Originally Posted by Jess

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!

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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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Originally Posted by JAZZCNC

There you go splitting hairs again when you actually don't know the full story or have experience of the controller.!!

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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?

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Originally Posted by Jess

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?

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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.!!

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.

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Originally Posted by Jess

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?

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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.

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.

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Originally Posted by m_c

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.

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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.!

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Originally Posted by Jon.

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.

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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!!