Alternative to PC based Cnc controllers

[ZebethyalParticipant @zebethyal]

> 2) The Mesa boards seem to be about half the price of the Mach-3/4 based solutions;

I am not really seeing how the LinuxCNC + Mesa solution is half the price of a Mach 3 + Smooth Stepper solution.

Both require a PC of some sort, both will require steppers, stepper drivers, etc, so we will ignore all of that.

For LinuxCNC + Mesa, a base setup would be something like: 5i25/7i76 plug and go – $199.00 + shipping

(Trying to locate what Mesa hardware you actually need is a mission in itself! – the Mesa website offers little help in this regard, plus they claim a 6-8 week lead time from placing an order)

For Mach3 and Smooth Stepper: SmoothStepper $165.00, terminal board $29.55 + shipping

So from a hardware point of view there is nothing in it.

From a software point of view, LinuxCNC is free and Mach3 is $175.00 from ArtSoft (various discounted prices exist all over the web), although not everyone pays for a genuine license and many hacked copies exist (I am not advocating the use of hacked software – just stating what is available if you care to look), so yes, you can argue additional cost here, but not a particularly strong argument. for 50% cheaper from the home cheapskate point of view.

[ZebethyalParticipant @zebethyal]

Posted by blowlamp on 04/10/2016 14:53:40:

Posted by Zebethyal on 04/10/2016 14:00:35:

The Mk3 and Mk3/4 USBCNC boards also appear to use the same chip and mostly the same board layout, so you are effectively just paying to unlock the additional functionality in the software.

The Sky Studio MK1 has a few enhancements over the original MK1 and other 'clones' including optocouplers, separate power supplies, additional regulators and transient voltage suppression, but the same microcontroller, memory and pinout restrictions.

The Mk3 is a 9 Axis board, it also has a network connection option as well as quite a few more features like analogue inputs. I think the software is the same for all controllers.

I agree that the board has additional connectors, but that is merely bringing out the relevant pins from the microcontroller to a header that were ignored on the cheaper board – PCB price difference negligable, additional headers, etc, again negligable since the 4 axis board actually has 2 different sets of header connections for both IDC ribbon and individual wire screw terminals.

Edited By Zebethyal on 05/10/2016 12:24:18

[John Stevenson 1Participant @johnstevenson1]

Everyone says Linux is free, which in monetary terms it is but what about time ?
Ok done people can manage easily but for others and some have posted here it’s been a dead end.

In my case I knew before starting that I would not be able to do this lathe so I paid someone off the Linux forum to come and set this up.

Whole day spent ain setting up, machine had been finished, but no go and it’s still sat here not working

[sam sokolikParticipant @samsokolik60334]

The 5i25/7i76 combo is way more than just the smooth stepper. The 7i76 is in all effects a break out board on steroids. 48 isolated i/o, 1 analog output, 1 high speed encoder counter (ttl/differential) 5 axis of stepper output and expandable.

If you can really even compare – the closest products to the smooth stepper would be

PCI 5i25 for $87.50

PCIe 6i25 for $107

Ethernet 7i92 for $87.50

(sorry – linuxcnc doesn't do any usb interface cards)

So – smoothstepper + mach3 is around $340 vs Linuxcnc with a 7i92 for $89.

sssssit—sssssit–sssssit (broken record)

The motion and realtime is all done in the computer with linuxcnc. The communication to the external interface boards are realtime (not buffered). This allows you to have some really cool access to the realtime subsystem. It allows you to connect the guts of linuxcnc any way you want.. Try to do that with dedicated motion controllers. You are stuck with what is implemented in them.

Lets be real here – for basic 3/4 axis machines that are nothing fancy – almost anything will work to control them. It comes down to what features above and beyond that you want. Linuxcnc is the 'above and beyond'. Gear hobbing? Large machining centers with tool changers and pallets? Threading and Tapping? kinematics? 9 axis tool length compensation? True Closed loop servo control? Open source? Integrated realtime PLC? Real time trajectory planning and path tolerance? and more and more..

sam

Posted by Zebethyal on 05/10/2016 12:12:15:

> 2) The Mesa boards seem to be about half the price of the Mach-3/4 based solutions;

I am not really seeing how the LinuxCNC + Mesa solution is half the price of a Mach 3 + Smooth Stepper solution.

Both require a PC of some sort, both will require steppers, stepper drivers, etc, so we will ignore all of that.

For LinuxCNC + Mesa, a base setup would be something like: 5i25/7i76 plug and go – $199.00 + shipping

(Trying to locate what Mesa hardware you actually need is a mission in itself! – the Mesa website offers little help in this regard, plus they claim a 6-8 week lead time from placing an order)

For Mach3 and Smooth Stepper: SmoothStepper $165.00, terminal board $29.55 + shipping

So from a hardware point of view there is nothing in it.

From a software point of view, LinuxCNC is free and Mach3 is $175.00 from ArtSoft (various discounted prices exist all over the web), although not everyone pays for a genuine license and many hacked copies exist (I am not advocating the use of hacked software – just stating what is available if you care to look), so yes, you can argue additional cost here, but not a particularly strong argument. for 50% cheaper from the home cheapskate point of view.

[blowlampParticipant @blowlamp]

Posted by Zebethyal on 05/10/2016 12:20:58:

Posted by blowlamp on 04/10/2016 14:53:40:

Posted by Zebethyal on 04/10/2016 14:00:35:

The Mk3 and Mk3/4 USBCNC boards also appear to use the same chip and mostly the same board layout, so you are effectively just paying to unlock the additional functionality in the software.

The Sky Studio MK1 has a few enhancements over the original MK1 and other 'clones' including optocouplers, separate power supplies, additional regulators and transient voltage suppression, but the same microcontroller, memory and pinout restrictions.

The Mk3 is a 9 Axis board, it also has a network connection option as well as quite a few more features like analogue inputs. I think the software is the same for all controllers.

I agree that the board has additional connectors, but that is merely bringing out the relevant pins from the microcontroller to a header that were ignored on the cheaper board – PCB price difference negligable, additional headers, etc, again negligable since the 4 axis board actually has 2 different sets of header connections for both IDC ribbon and individual wire screw terminals.

Edited By Zebethyal on 05/10/2016 12:24:18

 

Charging the equivalent of €20 extra per axis and not even including the other additional features doesn't strike me as expensive or anything other than normal business practice. Actually, when you consider the potential increase in function of a CNC machine per added axis, it's peanuts – it's also no different to what other manufacturers do.

Having recently repaired the wife's 20+ years old mechanical sewing machine, I found a small piece of metal pressed into one of the plastic rotary cams used for selecting stitch styles. I could see it prevented the selector knob from turning fully, so I pulled it out. Doing so, instantly allowed the selection of loads more stitch styles.

If I remember correctly back to when we bought the machine, there were two versions of the same model… we got the cheap one (probably £150 cheaper) with fewer stitches, but it now seems the only material difference was that ours was crippled by the insertion of this blocking-piece.

 

Martin.

Edited By blowlamp on 05/10/2016 15:11:14

[John Stevenson 1Participant @johnstevenson1]

Sam,
Can’t fault that logic or argument at all.
BUT
These features are probably only available to 100 people max who can implement them. I know that you are one of them, seen the video of your large matching centre but you are top shelf with probably thousands of hours delving inside Linux but mere mortals don’t stand a chance.

Personally I’d like to just get a two axis lathe running and threading with something like a Path Pilot screen that will sell to the punters. Sounds easy doesn’t it, but it’s not and wasn’t for a Linux guru either.

Mind you I could put a Chinese lathe controller on it like Steve Blackmor has and just spend a night wiring it up ?

[sam sokolikParticipant @samsokolik60334]

Pathpilot is based on linuxcnc but tormach did a bunch of stuff to personalize it. It is made to work with their line of machines. I have not played with it but have looked a bit in its guts. If someone thought it was linuxcnc and could configure it accordingly they where probably blind sided. Quite a few people now have worked though what needs to be done to configure it for other systems. It certainly isn't as easy as linuxcnc prime to setup. (it wasn't designed to be)

sam

Posted by John Stevenson on 05/10/2016 15:20:47:
Sam,
Can't fault that logic or argument at all.
BUT
These features are probably only available to 100 people max who can implement them. I know that you are one of them, seen the video of your large matching centre but you are top shelf with probably thousands of hours delving inside Linux but mere mortals don't stand a chance.

Personally I'd like to just get a two axis lathe running and threading with something like a Path Pilot screen that will sell to the punters. Sounds easy doesn't it, but it's not and wasn't for a Linux guru either.

Mind you I could put a Chinese lathe controller on it like Steve Blackmor has and just spend a night wiring it up ?

[sam sokolikParticipant @samsokolik60334]

(if you think linuxcnc is hard to configure – pathpilot is doubly so…)

[simondavies3Participant @simondavies3]

Bob Warfield on the CNC cookbook site has some useful background on CNC control systems today:

**LINK**

[John Stevenson 1Participant @johnstevenson1]

Read it and it says nothing. Why is he even discussing Mach 3. It's dead in the water and has been for three years plus. No upgrades, no bug fixes and they are trying to drive Mach 4.

One thing he did mention though was the Siemens controller. Now Siemens have a deal with the Chinese and supply them the 3 axis 804 controller very cheap but this is for OEM fitting on machines for the Chinese market but they can be exported out of China. I was quoted about £1200 for a 3 axis system but it's locked down to one machine and preset at the factory, you tell them the parameters. However they are a very good and robust system.

The dearer Chinese controller mentioned on here are made / resold by many companies as they spot a market.

The original manufactures of these controller GSK have been making these for possibly 8 years and output must be in the tens of thousands id not hundreds of thousands but we never see much of them as they go into the Chinese domestic market on their CNC's. I have seen rows and rows of these making all sort of products that we are buying off our suppliers in this hobby.

[sam sokolikParticipant @samsokolik60334]

Bobs article was originally posted back in 2011….

Note: I originally published this two-part series some time ago, and it has been hugely popular ever since. I recently went through it and added a lot of new information and updates. I am republishing so new folks will get a chance to see it and so folks that have already seen it can take advantage of all the new information.

[Ex contributorParticipant @mgnbuk]

Siemens controller………………..However they are a very good and robust system.

Awful things. If you think Linux CNC is a bear to get up and running, you would be in for an unpleasant suprise if you tried one of Erlangen's "finest". On the one I am lumbered with, it's a bit of a lottery when you press the start button as to whether or not it will deign to start – or keep going if it does start. "Very good and robust" it is not !

Did you find the link to the Chinese turning control manual you mentioned earlier, John ? I would be interested to have a look. Do you have details of the shortcomings of the Chinese USBCNC boards mentioned a few posts up ?

I have one on order (a whole £17 delivered – what have I done ) to try with the demo software. Apart from the Planet CNC denigrating of them, I couldn't find anything specific elseware. For a mill this seems a reasonable solution – at least it supports tool radius comp – even if turning isn't fully supported yet.

[John Stevenson 1Participant @johnstevenson1]

Nigel, Sorry forgot you.

This is the most recent revision and has been altered from Steve Blackmore getting his Orac up and running..

**LINK**

Shortcoming for the USBCNC board was that the Chinese ones were a version or two behind and none of the Chinese ones do lathe.

Can't comment on the other features for mill but dare say they work.

Might be worth looking on the Planet forum for any know bugs

[sam sokolikParticipant @samsokolik60334]

I have a feeling that linuxcnc has a greater user base than you think…

The linuxcnc forum satistics.. (the forum hasn't been around as long as mach)

**LINK**

Look at the youtube videos sorted by upload date. Lots of activity. As of now – someone posted a video within the last 24 hours.

**LINK**

I think more than 100 people are using the advanced features of linuxcnc (it isn't as hard as people make it out)

sam.

Posted by John Stevenson on 05/10/2016 15:20:47:
Sam,
Can't fault that logic or argument at all.
BUT
These features are probably only available to 100 people max who can implement them. I know that you are one of them, seen the video of your large matching centre but you are top shelf with probably thousands of hours delving inside Linux but mere mortals don't stand a chance.

[John Stevenson 1Participant @johnstevenson1]

No Sam you misunderstood. There are probably thousands using Linux but possibly only a hundred or so able to delve inside and change the code.

Again I’m not bashing Linux, far from it but why can’t the masses have access to an easily set up program with a workable GUI. None of the screens I have been pointed to are viable screens to put on a machine to sell to a begineer.

By your own admission it’s not easy to incorporate path pilot with Linux, even though path pilot IS Linux. Does that mean the Tormach guys are better than the Linux guys ?
Because they have done it.

[sam sokolikParticipant @samsokolik60334]

Couple of things…

1) I have not changed the source code of linuxcnc for any of my machines conversions. I used the integrated ladder and the configuration files. (that says a heck of a lot about the flexibility of linuxcnc).

2) I don't understand why 'none of the gui's' are usable by beginners. They obviously work. It really is your opinion. (and I am sure others). The axis gui that you so hate is all I use. What is it that you don't like about it? it resets the estop, turns on the machine. homes, loads gcode, edits tool table, touches off the coordinate system, runs the gcode and so on. (I think it is a clean interface – but that is my opinion)

3) I am not understanding your last point either. Tormach took linuxcnc and to use a geeky term – 'forked it' They then modified it to their liking. (Because it is open source) They added stuff and removed stuff modified stuff. The side effect of this is the changes they made make hard to bring their gui back into linuxcnc. This is good from Tormach standpoint. They for obvious reasons want to keep their gui out of the main stream for as long as they can. There has been hints that someone is working on integrating tormachs gui back to linuxcnc but who knows how long that will take. The bad thing for tormach is because they based their work on linuxcnc – any changes built upon it needs to be released (which they have). So it is probably only a matter of time before someone works it out.

sam

Posted by John Stevenson on 06/10/2016 17:13:31:
No Sam you misunderstood. There are probably thousands using Linux but possibly only a hundred or so able to delve inside and change the code.

Again I'm not bashing Linux, far from it but why can't the masses have access to an easily set up program with a workable GUI. None of the screens I have been pointed to are viable screens to put on a machine to sell to a begineer.

By your own admission it's not easy to incorporate path pilot with Linux, even though path pilot IS Linux. Does that mean the Tormach guys are better than the Linux guys ?
Because they have done it.

[John Stevenson 1Participant @johnstevenson1]

Sam,

I'm sure it's not me.

I usually go visit someone who wants a machine converting and tell them what their options are and what it will cost.

I then tell them what is available as regards software. Up to a few weeks ago this was Mach3, Linux and Eddings CNC.

They look at the options and usually choose Mach 3 without any prompting. Possibly because they have seen it before ?

No one yet has chosen LinuxCNC, when I ask they seem confused as to how to operate it. A beginner expects buttons to press which frankly are too well hidden in Linux CNC. So you say it's a clean interface but that may be the problem, it's too clean ? However we both have our views and I dare say nothing will change this and I certainly don't want to change yours but I would like the option of offering a version of Linux that the average beginner can use.

This is liable to change though in the very near future in a way not envisaged.

Two weeks ago I was approached by one of the university's at Oxford [ contrary to popular view there are 100's based in Oxford ] Over the years I have done a lot of business with them buying up old Denfords and Boxford CNC's when they have upgraded to newer. I still have 8 or 9 left in the hayloft.

So I was expecting to be asked to quote for clearing out some old non working machines but had a very pleasant surprise when the guy explained that yes they had some, in fact they had also been stock piling them as he knew the time would come when it would pay to upgrade instead of buying new.

I then explained that we could offer the Chinese stand alone controller and this guy wanted to know more and it looks as if end of November, beginning of December it's 10 days down in Oxford to convert 15 machines.

Now these controllers are ARM based, complete stand alone, no PC, no monitor, no keyboard or mouse but they use a version of Debian, which is Linux.

So first Tormach get it working and now the Chinese has it working for less than two Mesa cards.

[BazyleParticipant @bazyle]

Oxford university has to get someone in from Notts to set up a computer They never were a patch on CMBRIDGE

[John Stevenson 1Participant @johnstevenson1]

No Oxford has millions of people who can use computers and finger tips. they just lack people who can use hands

[Rod AshtonParticipant @rodashton53132]

Nigel – I hope you will keep thread readers informed about your experience with your £17 investment. Would make a very interesting post I think!

[ZebethyalParticipant @zebethyal]

@Rod,

Don't forget that without the 69.00 Euro license fee Nigel is restricted to 25 lines of Gcode.

@sam

You say that 5i25/7i76 is an over the top combination and go on to mention that a 7i92 is all that you need, yet this is the combination most mentioned anywhere I look for information on what Mesa boards to use.

I have re-read the description and manual of the 7i92 and yes, it would appear that it can be used stand-alone parallel port replacement – it would still need some form of breakout board even if it is a basic $4.00 Chinese one, since most home-brew conversions aren't parallel port ready

This also re-affirms my earlier point about it being difficult for someone new to work out what Mesa cards they need – no guidance on Mesa's own site, the LinuxCNC Wiki is amazingly vague on the subject, merely mentioning a large number of possibilities that should work and doesn't even mention the 7i92 card!

If I specifically search for the 7i92 card, I see very few posts about it, and many of those I do find are from the LinuxCNC forum which seem to be cries for help with using one – hardly a great advert.

To buy one I would need to order from the US, not necessarily an issue, but Mesa quote 6-8 week lead times, EUsurplus have no stock, and I have yet to find a UK supplier.

I like the idea of this board in that it de-couples from the required PC, making some form of laptop more of an option, or a mini PC that can fit behind the monitor.

One thing I am not so keen on with the Mesa breakout boards is that their screw terminals are too close to each other to use crimped ferrules, and pretty awful from a strain relief point of view – 90 degree plug in screw terminals would be a better option in that regard.

Edited By Zebethyal on 07/10/2016 09:33:53

[MuzzerParticipant @muzzer]

Well those are the wrong crimps. The approved terminations would be "bootlace ferrule" crimps such as this from RS, although you can get them from CPC and other outlets. IIRC, you want the 1mm2 size (red) for those terminals, which fit easily into the space. Whoever terminated those wires used the wrong crimps. You will find pics on the LinuxCNC site if you have time to kill. You can also prewire the terminals and then plug them into the headers of course.

These terminal blocks are designed to take stranded wire directly but if you choose to do so, do NOT solder tin them first. Solder suffers from "cold creep" when under pressure, resulting in intermittent connections after time. Not a fire hazard in this instance but it can be if you are talking about higher voltages and currents.

As far as I know, you can only buy Mesa boards from 2 outlets in the US, plus Eurospares in Portugal. Availability seems to be hit and miss to say the least. I guess I was lucky.

[J A Harvey-SmithParticipant @jaharvey-smith]

A very interesting thread, thanks to all contributors.

In my workshop LinuxCNC is the clear leader at the moment but yes, I do find it tedious getting the setup right and the keyboard and mouse are a pain. I ditched Mach3 the last time the KX3 mill caused grief, wasted a little time playing with Arduinos and Pis, but produced some seriously capable hardware using cheap ARM Cortex boards using the free mbed.org online compiler, along with Altera FPGAs. However, this was all for academic interest as I was never going to write software to create a full CNC controller, I don't have the years left and no desire to reinvent the wheel.

I work in an engineering workshop of a heritage railway. Last year we got a "new" (which in heritage railway parlance means post WW II) Harrison 500 CNC lathe. Lovely !! – for a week until the electronics failed. I'll steer clear of railway politics, but a year on it ain't fixed. The computer part of the control electronics was a DOS pc with obsolete proprietary plugin boards, this no longer talks to the considerably older servo drives which take +/- 10V signals to control axis velocity, position encoders feeding back to computer to close the loop. The spindle and axis encoders are good, the servos work (as proved using AA cell as signal source). I would not waste my time trying to persuade management to let me loose on the machine with a LinuxCNC system – nobody but me would ever use it (or feel confident with it), but I'll be reading through the manual for the 990TDB which (unless I've missed something obvious) just might be sellable to them.

If anyone can spot why this won't work, please advise. Thanks again.

Jon

[MuzzerParticipant @muzzer]

Unless I've misread the manuals I've got for these, they are intended to generate step / dir position outputs rather than analogue servo (+/-10V) velocity outputs. They tend to have one or two analogue outputs as well but these are for single or dual spindle speed control (ie to drive a VFD), rather than axis position control.

If you want to use a modern controller with analogue servos, I believe you will need a "positioner". This takes the step / dir demand information from the controller and the positional feedback from the encoder to generate an analogue drive (error) signal for the servos. There is a PID controller in there typically. The servo motor will probably incorporate a velocity sensor as well as an incremental position encoder but this typically provides feedforward info into the servo drive, not the positioner.

Somebody may correct me but that's how I understand it t the moment.

I suspect your Harrison has just converted itself into a very large piece of scrap!

Edited By Muzzer on 07/10/2016 11:57:01

[Jat GrewalParticipant @jatgrewal91795]

Hi All,

Been reading everyones comments and its such a great feedback.

Keeping things simple has been the key issue and also getting rid of the computer based OS. I have gone through the same issues while making the CNC machines for hobby.

And thats why I started making a non OS controller that is only made to run a CNC machine. Having custom built hardware means full control of hardware design and custom software that for the hardware.

I will appreciate everyones views and comments as I would like to keep adding more features to the design.

[Author]

Posts