Re: new paradigm 6+3=9 bits: three S&D drives, 8 axes... , 3 bits spare

Hi Doug,
It is obvious you would need new software. Then why not
just add a second LPT port with an other controller? The software
would then work with both new and old systems.



Bob

--- In CAD_CAM_EDM_DRO@y..., Doug Fortune <pentam@h...> wrote:
> Smoke wrote:
> >
> > I'm guessing your router kit could be set up using four axis and
still
> > leave pinout room for spindle on, etc?
>
> Yes, the 6+3=9 scheme allows for 8 axes. You could have just four,
> and if this 'device' costs less than one driver (because you only
need
> three drivers), you would be ahead. Actually, you'd probably only
need
> two physical drivers, if you moved Z in a block separately from X &
Y.
>
> But I am expecting to have many more than four.... perhaps 6,7 or
8.
> Implicit in my concept, but unstated in my original posting was
that
> when an axis is not active (ie not connected to one of the 3
drivers),
> there is a dummy current fed to it in order for that motor to act
> as a brake and hold its position (especially the vertical axes
which
> like to move on their own from gravity).
>
> > Could it then be used for a milling machine instead and the
> > axis switched as desired via any method we want (I'd switch
> > them using rotary gang switches.
>
> Sure, but you miss my point... I would be switching some of them
> at millisecond intervals (to simulate fulltime control of N axes).
>
> Even cycling the most heavily used axis (say X axis) amongst the
> three drivers to distribute the heat dissipation (and thus increase
> the equipments longetivity) is feasible.
>
> Doug Fortune
> http://www.cncKITS.com
>
>
> > ----- Original Message -----
> > From: "Doug Fortune" <pentam@h...>
> > >
> > > In my upcoming professional CNC router kit, I am
> > > facing the problem of lots of auxiliary axes:
> > > multiple Z heads, dual/triple/quad Y axes,
> > > dual gantries, table raising/lowering etc etc.
> > >
> > > This severely constrains using the parallel port
> > > with its limit of 12 output bits (6 axes max),
> > > and one would desire to reserve some for
> > > spindle ON/OFF, vacuum ON/OFF etc.
> > >
> > > The new idea is to use and power only 3 drivers,
> > > each of which can be electronically 'hooked up'
> > > to any of 8 axes (lets assume bipolar only)....
> > >
> > > As there are 3 S&D drivers hooked up, thats
> > > 2*3 = 6 bits. Using 3 bits for 'assigning axes'
> > > that gives a choice of 2**3 = 8 axes. 6+3=9,
> > > so that leaves 3 output bits spare (for Spindle,
> > > vacuum, etc).