Hi John; I've a small Unimat SL that I've CNC'd (and talked about it at the last CNCWorkShop back in June, and in my blog)
Some random thoughts: 1) Beaglebone is fine. Sure, graphics is slow, but so what? Change "Axis" to the DRO display and you are fine. 2) My OLD Unimat has a not so great spindle, which is a bit of a problem. And an old motor, which is very weak. 3) Currently, I have no spindle feedback for threading. 4) Others have used stepper motors for spindle control on Unimats; one chap in Germany, and, maybe Cecil on this list? 5) I've a larger, stronger lathe (a big brother to the Unimat - an Emco Compact-8) that is my target lathe for CNC; not sure if I'm going to develop the Unimat further. I have the Xylotex cape, with the Beaglebone direct from them, pushing a Gecko G540. Look at cnc-for-model-engineers.bogspot.com and top left corner is a search box, put "Unimat" in there. Maybe it'll give you some ideas. John. On Wed, Aug 12, 2015 at 5:45 AM, andy pugh <bodge...@gmail.com> wrote: > On 12 August 2015 at 09:37, John Dammeyer <jo...@autoartisans.com> wrote: > > The lack of a spindle input or PWM output on the Probotix cape and the > > higher price of the PMDX cape rules out the Beagle for any sort of Linux > CNC > > at the moment. That and what appears to be a lack of continuing support > for > > the Beagle and LinuxCNC. > > I think you may be misinterpreting the situation. > > Machinekit seems to be committed to the Beaglebone, and the Machinekit > flavour of LinuxCNC will work just as well as old-school LinuxCNC with > a lathe. > > All you need to do is set up one of the step generators in the PRU in > velocity mode and connect then "net spindle-speed > motion.spindle-speed-out-rps => ****.stepgen.02.velocity-cmd" > > (*** because I don't know the BBB PRU Hallname). > > That gives you a working lathe, though it doesn't give you an index, > so threading won't work initially. > However, this does not mean that threading can't work. It should be > possible to configure a synthetic index in HAL. But I suggest you talk > to the Machinekit folks about that. > ( www.machinekit.io ) > > As for the Probotix cape not having a PWM output, you can use a > step-dir output. PWM is just another aspect of the PRU driver. > If you want to convert that PWM to analogue voltage then some external > components might be needed, but this can be as simple as a resistor > and capacitor. Or, off the shelf, > > http://store.mesanet.com/index.php?route=product/product&path=74_78&product_id=205 > > > -- > atp > If you can't fix it, you don't own it. > http://www.ifixit.com/Manifesto > > > ------------------------------------------------------------------------------ > _______________________________________________ > Emc-users mailing list > Emc-users@lists.sourceforge.net > https://lists.sourceforge.net/lists/listinfo/emc-users > ------------------------------------------------------------------------------ _______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
