Re: [CAD_CAM_EDM_DRO] Re: Pendant

Terry - (Comments inserted below)

James Owens wrote:

>
> Hi Ballendo,
>
> I think I have covered most of what you ask here in a previous post but I
> should say that in the first instance I am trying to produce something that
> is useable and still affordable. The last thing that I wanted to do is to
> drive the price out of most HSM's budgets.

What Ballendo suggests would probably only require more programming
and about 3 more bits of I/O. (See below)

> >
> > Since you're programming a PIC anyway:
>
> The difficulty here is that of running out of pins on the device, the price
> and the speed of the processor. Not to mention the available the space for
> programming. I am relatively new to PIC's and CNC, the learning curve is
> quite steep.
>

As for the I/O, you can use cascaded shift registers for inputs.
You could get a very high number of inputs with about 2 or 3 pins.
The newer 16F877 chips have about 33 I/O pins (from memory) and quite
a bit program space. Are you programming in Assembly, or a high level
compiled language?

> > How about WE enter our steps per inch/mm/unit. You then allow one of
> > 4 of 12 feedrates (IPM) based on OUR input?
> >
> > Next, how about a 'move' 90 or 45 degree only of a certain Distance
> > (units), based on our steps/unit value?
> >
> > Thes two items will allow much of the functionality of CNC, without
> > the computer, and will be MORE useful,IMO, than just a dumb power
> > feed.
> >
> > Hope this helps.
> >
> > Ballendo
> >
> > P.S. The steps/unit could be 'input' by dipswitches 14 'bits would
> > allow steps/unit up to 16384 per'. The remaining two switches if
> > dip8's are used 'could' select one of four axis combos for output
> > xyxa,xyz,xz,xy?
>
> I am sorry, it is after 2 in the morning here and I can't get my head around
> what you are trying to say here in the PS?

He is saying to use dip switches to set the number of steps per unit in
binary and read it in at power up or reset of the micro. Again, this
could
be done with shift registers to save pins on the micro if needed.

>
> Terry
>

Mike