Recommendations on motion control boards & Single Board Computer

Hi everybody,

Hopefully this is the right forum for this question. There are so many sub-forums, confusing as to which is the correct one.


Looking for a single board computer / motion control card recommendations for my CNC build.

i'm retrofitting an old Dyna 2400 machine with servo motors and gecko G320x servo drives. The G320x treats servos just like steppers, needing a step and direction signal.

I'm looking for recommendations on:
- Motion control card (Ethernet Smoothstepper, UC100, Dynomotion Kflop, multiple options from Galil, etc...)
- Single board computer recommendation (there are a LOT out there)
- Which OS to run on my SBC



I want to use a real motion controller, not depend on a parallel port. Plus i want more I/O than a single port can provide
It looks like LinuxCNC doesn't work with any of the motion control cards above? so looks like i'm stuck with Mach3 (or mach4)? the LinuxCNC supported hardware page lists a bunch of seemingly older, and expensive hardware for this LinuxCNC Documentation Wiki: LinuxCNC Supported Hardware
Since i'm stuck with Mach3, i assume Win XP or Win 7 (32 bit) for the OS?
Which SBC should i use? Seems like there's 100 different ones available. With a motion control card, doesn't seem like a ton of work for the PC. I don't want to just randomly pick one. What devices have other people used successfully?

Thanks,
Mike

LinuxCNC needs real time hardware so in general will not work with most buffered motion control cards like the ones above

LinuxCNC does support most of our ( Mesa's ) Ethernet connected control cards such as these:

7I92 2x Parallel port type motion card needs breakout(s)
7I80DB 4x Parallel port type breakout needs breakout(s)
7I76E Ethernet+breakout for step/sir 5 axis 10 MHz step/dir, spindle encoder, isolated analog spindle control 16x 12/24V outputs 32x 12/24V inputs 2x parallel port expansion
7I96 Ethernet+breakout for step/dir 5axis 10 MHz step/dir, spindle encoder, 6 isolated 2A outputs, 11 isolated 3..24V inputs 1x parallel port expansion

Whay are you "stuck" with Mach3? Do you already own a license?

Imo, Mach3 is obsolete, but there are many other options out there.

Linux CNC with a Mesa card, which are not expensive.

Most of the competition make both the hardware and software.

UCCNC
PlanetCNC
Eding CNC
Centroid Acorn

First, what's your budget for the controls end of your project?

Then let's look at the required I/O, how much do you need? That will narrow the field a bit. Dynomotion Kflop is well supported and has expandable I/O. Dynomotion KMotionCNC might be worth a look also. You might also look at Centroid Acorn, I don't know much about it.

I have successfully used the little fanless micro computers for machine operation, in fact I'm just getting ready to order one for a 5 axis project. They normally come with Win10 installed, but you may be able to order one with Win7. Using one of those you will want a USB or Ethernet motion controller.

If you use Mach3, the computer is doing all of the heavy lifting as far as the motion control. It's what Mach3 does so you will want a computer that will keep up. When Mach3 is connected to a Galil board it turns the really intelligent Galil into a zombie, and Mach3 still does all of the heavy lifting. A bit of a waste IMHO.

I normally use Galil products in my projects just because I have been installing them for at least 20 years, so I don't have to learn new stuff and I'm getting old :) Oh, and they work well.

i guess "stuck" with Mach is not the right way to say it. As to some background, I'm really considering only the few most popular systems out there at this point (Mach3 and LinuxCNC) i value proven reliability over the latest thing / advanced features.

I know mach3 has been replaced by Mach4, but 4 to have a very small installed base. Same thing with UCCNC & others. When large numbers of people are successfully using something else, then i'll try it. In the meantime, i'll let someone else figure it all out.


The Mesa cards (with LinuxCNC) are interesting, and budget friendly. I hadn't run across them in my (limited) searching on the subject. I think that might be a new avenue for research.



my budget isn't a hard number, but trying to keep it under $500. I don't need a lot of I/O, but more than 1 parallel port will provide. I'm planning on 4 axes, all with limit switches, spindle control, and tool length probing.

On further research, looks like most of Galil is out of my budget

Linuxcnc hardware is inexpensive and expandable/scalable. (also linuxcnc has been around and is getting new features all the time)

You are correct that all the motion controllers you mentioned in the first post don't work with linuxcnc. This is because linuxcnc doesn't use external motion controllers. (buffered systems) Linuxcnc has the motion controller running realtime in the computer. It communicates with the external 'interface' devices (mesa, printer port, pico systems etc...) in realtime.

sam

What about a DSP based system?

A RichAuto system might be ok for your needs (not understood). Give it your verified G-Code on a USB stick and let it run after co-ordinate setup.

Some issues as "inconvenient" are the DSP handle is a "stand-alone" control unit and although it can connect to a PC via USB - you must power-cycle the unit to change "modes". The pendant itself is quite cool and convenient to use but not so much for manual cutting.


Cheers,

HarryE.
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Quote:

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I know mach3 has been replaced by Mach4, but 4 to have a very small installed base. Same thing with UCCNC & others. When large numbers of people are successfully using something else, then i'll try it

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How do you know how big the user bases actually are? I think that UCCNC has a much larger user base than you think. No, not tens of thousands like Mach3, but many thousands, and growing rapidly.
If you are comparing to Mach3, even LinuxCNC has a small user base.

If your limiting yourself to Mach3 or LinuxCNC, than LinuxCNC all day. I can't recommend Mach3 to anyone anymore. No development, no bug fixes, no support. Still full price. LinuxCNC and a Mesa card is still a lot cheaper than the Mach3 license alone.

Quote:

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I'm planning on 4 axes, all with limit switches, spindle control, and tool length probing.

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This requirement can be handled with one parallel port: Each parallel port has 12 outputs and 5 inputs, so:

Outputs:
1. Xdir
2. Xstep
3. Ydir
4. Ystep
5. Zdir
6. Zstep
7. Adir
8. Astep
9. Spindle Dir
10. Spindle PWM
11. Drive Enable
12. Something else

Inputs:
1. X-limits combined (Can also be used as home switch)
2. Y limits combined (Can also be used as home switch)
3. Z limits combined (Can also be used as home switch)
4. A limits combined (Can also be used as home switch)
5. Probe input

Each parallel port gives another 12 outputs and 5 inputs and doing 2 is super easy and handled by the stepper configuration wizard.

I personally have run my mill with LinuxCNC and it has performed flawlessly. The only issue is getting a PC with low latency. This is perhaps the most problematic thing about LinuxCNC. This is not to mean you need bleeding edge PC requirements. Quite the contrary. I use an old Pentium 4 PC that in the computing world is considered pure junk but it runs LinuxCNC fine. The current PC has OK latency numbers and can step at about 28 kHz which for my machine equates to about 210 IPM on my mill. I actually have it set for 120 IPM currently I have another machine under construction and have a PC selected for this one too and it is also an old Pentium 4 but has lower latency yet, and should be able to provide 45 kHZ from the parallel port. I could get 300 IPM out of this, but will likely keep it around 200.

However, take that first PC which just had its HDD go out last week.. I get 28 kHz running LinuxCNC 2.5 on Ubuntu, an older version, with decent latency numbers. With the latest version of linuxCNC on Debian Wheezy the latency numbers skyrocketed to the point that the LinuxCNC on Wheezy isn't usable. Same computer, 2 different versions. I haven't had a chance, but intend to try the new version on Ubuntu to see if this computer just doesn't like Debian Wheezy. This scenario could present itself if you just go out and buy a PC. The linuxCNC folks can recommend PC's combos that yield low latency, or you could do like me and hunt in your basement for old pc's that can still be put to good use. To put in perspective how old the PC's I'm using are, they both have 3-1/2" floppy disk drives installed.

Getting to cost, you can't get any cheaper than my setups above because I got these computers for free from a local company that was upgrading their PC's and they were going to have to pay a disposal fee for each. They were happy to let me take a few, including keyboards, mouses, and 15" LCD's. The only caveat was they didn't have hard drives as those were shredded for security reasons. I had some old HDDs lying around so still no out of pocket cost, and the one has been running since 2012 with only the recent HDD failure.

I wasn't previously aware that there were 2 classes of motion control boards. Buffered, and real-time. That one bit of information has been very helpful

I think i'm going to go with LinuxCNC and one of the Mesa boards. I'm a fan of open source vs proprietary anyway.

Now, back to the original question, which Single-board computer will work with this combination? (i'm trying to pack everything into the original Dyna cabinet, which means SBC, not full size PC)



BTW, regarding the question/commment about installed base, of course i don't know for sure. I'm basing this on both the CNCCookbook survey, as well as the amount of general questions/amount of chatter online. I'm not interested in determining the exact base, nor is this intended to be a project in figuring out how to best build a CNC controller. i want something i can just put together, and get it working with as little fuss as possible. I want to make parts with this machine. I know my goal of using only one of the more popular systems is going to piss people off, but whatever. it's my project, and that's my plan.

I'm in a similar boat retrofitting a knee mill with a dead Bandit I control using the original cabinets. I purchased a fanless J1900 based mini-pc:

https://www.aliexpress.com/item/XCY-...331a4c4d5OR6V5

Price has dropped since I ordered it last year. With 4 GB RAM and 60 GB SSD it is currently $161. That is more than sufficient for running LinuxCNC. Installing LinuxCNC wasn't as straight forward as some other systems as it would hang during the install. I ended up having to set some boot options in Linux for it to work (Hopefully I wrote these down...). Latency numbers aren't great (50-100 us peaks under full load with 3d, constant disk reads, ping floods, and youtube playing) but are sufficient when using a Mesa card. I am planning to use it with the 7i92M and 7i77 Mesa boards for controlling a 3 axis brushed DC servo system with analog servo drives and direct encoder feedback. Your setup should be easier with step/dir drive and no axis encoder feedback, so you could use the 7i96 ($119):

7I96 picture

or the 7i76E ($199) if you need more I/O:

7I76E picture

Additional daughter cards could be added to each if you need even more I/O. With the PC above and 7i76E you are looking at $360 for the controller. The PC has both HDMI and VGA so any monitor should be usable (some may require inexpensive adapter). I am going with a 14" IPS laptop display with HDMI driver card which was about $80 or so for both. The 14" display should fit nicely in the Bandit head.

All that said, LinuxCNC isn't what I would consider a get it together with as little fuss as possible type system although there are configuration tools which do simplify this. I found Centroid Acorn to be simpler to get up and running. It did need a better spec PC and Windows 10 though. I'm going with LinuxCNC on this machine because I want the flexibility it brings and I'd rather use Linux than Windows for this type of application.

Some random thoughts... (crappy camera work -sorry)

https://www.youtube.com/watch?v=vzDGVmo3BO4