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seeking advice on motion control board

Discussion in 'CNC Mills/Routers' started by cyrille07, Jan 29, 2019.

  1. cyrille07

    cyrille07 New
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    Hello,

    I have inherited a 4 axis CNC with a now completely unsupported motion control card and wanted to "make it work" by replacing the motion cart with a new one and am looking for advices.

    I have 2 main priorities:
    - Cost minimization. I would like to minimize the cost of the card+control SW that goes with it.
    - signal compatibility. The current system uses 4 wires per motor: labeled PUL+, PUL- DIR+ DIR- and 4 signals for the VFD labeled: forward on/off, 10V reference, AVI (from 0 to 10V), 0V


    Can you advise on cards that would match these needs?

    Thanks for your help.
    Cyrille
     
  2. Rob Taylor

    Rob Taylor Journeyman
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    Cheapest option is to forego the 4th axis and run it as a traditional 3-axis machine, where you can get out for maybe $25-30 depending on how much electronic detritus you already have lying around. Arduino running grbl (Either genuine for reliability, or I also like the Elegoo version- proper USB controller, pin labelling, etc. but at half the price). That would happily send your step/dir commands to the motor drivers. To get the 0-10V signal from the 5V PWM variable spindle signal coming from pin 11, I'd just use a simple RC filter->op-amp conversion circuit, you can make your own or buy a cheap ready-made one here: https://smile.amazon.com/dp/B06XB6J4FV/

    If you have to have the 4th axis, I'd look into Mach3/4 and SmoothStepper boards, or LinuxCNC and Mesa boards (if you're feeling adventurous). Either one is gonna cost you probably somewhere in the $400 or so region. SmoothSteppers are cheaper than Mesa cards, but Mach 3 and 4 aren't free (and run on Windows, if it matters).

    Depending on what the machine is and what the motors are that it runs, I'd heavily consider ripping even further into it and yanking the drivers in favour of a Gecko G540, which would pair nicely with a Mesa FPGA parallel I/O card. That's probably not gonna work if it's some monster NEMA 34 machine or something though.
     
  3. cyrille07

    cyrille07 New
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    Hello,

    I guess I should have provided some more info here.

    The machine is not a "monster", but a non negligible 60cm*90cm machine with good size engine and stepper motor controller. The whole thing is already nicely wired, so I would rather not have to touch all that.

    At the moment, I am looking at the PoKeys57cnc card, which, at $130 is perfectly in my price range...
    The problem comes when you add the $200 for Mach4... (no reason to go for MAch3 with is a ticking time bomb at this point in time and does not support modern PCs)...
    So, this would be a total of $330, which is rather more than I wanted to spend.

    I am also rather attached to windows as all the rest of the tools that I am using and am familiar with are windows based...

    Hence my question: is there an alternative card/Software combo, which will not require too much effort to put in place that would allow me to reduce my cost to the $200 or less range.

    Thanks for your help!
    Cyrille
     
  4. MaryD

    MaryD OpenBuilds Team
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    You might want to take a look at our FREE control software... it's evolving and adding features too!
     
  5. cyrille07

    cyrille07 New
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    Hello,

    I did download the exe and installed it. I like the fact that it seems very simple and to the point.
    This is a big plus for me as I am not looking at industrial use....
    From what I was able to see, this is a very nice piece of software that you have created.

    However, I have to admit that I have no clue how to connect it to any boards that I am familiar with.
    As far as I know, it seems to only detect com1 as a connection.

    What are the supported boards for this software at this time?
    There is also the issue that I have 4 axes and would like to use all 4 :)

    Thanks,
    Cyrille
     
    #5 cyrille07, Jan 29, 2019
    Last edited: Jan 29, 2019
  6. MaryD

    MaryD OpenBuilds Team
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    OpenBuilds Control supports grbl based boards. It can run standard g-code. so if your CAM post processor (if not using OpenBuilds CAM), can output standard (generic) g-code, you can try running that through the OpenBuilds Control software.
     
    Peter Van Der Walt likes this.
  7. cyrille07

    cyrille07 New
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    Hello,

    OK, thanks...
    Do you know if there are any plans to add a 4th axis to grbl?

    Thanks,
    Cyrille
     
  8. MaryD

    MaryD OpenBuilds Team
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    Officially, Grbl itself will not get 4th axis. However, there are some promising alternatives supporting up to 6 axis but they are still in development by their programmers and not currently supported.
     
    Peter Van Der Walt likes this.
  9. cyrille07

    cyrille07 New
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    OK.
    I understand perfectly.
    Thanks so much for the info/help.

    Cyrille
     
    MaryD likes this.

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