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

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@...>
> >
> > 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).