Re: CAM Software Advice for Shopmaster CNC

--- In CAD_CAM_EDM_DRO@yahoogroups.com, John Dammeyer <johnd@...> wrote:

>
> Hi Wayne,
>
> > John:
> >
> > The buffer board with the PIC16F877 can generate a step
> > every 20uSec. However, I'm not sure that there is any
> > realistic way to ramp a stepper up to that speed. I
> > think a step every 100uSec is a more realistically
> > obtainable rate -- call it 10KHz step rate. It won't
> > win any of the Inch/Min. derbies out there, but quite
> > respectable for a table top machine.
> >
>
> I have my ELS running a 10 uStep/Step at 20kHz which is
> 50uS per step maximum. It used to be 25kHz (40 uS) but
> I just ran out of processor time since the interrupt
> routine is also doing the micro-stepping support for
> the LMD18245 drivers.

These 8-bit micros are nice, but they sure do not seem
to be increasing in speed very fast.

[snip]

> Microchip has just announced (no samples yet) the 32
> bit MIPs series processors pin compatible with some
> of their dsPIC processors. They are making available
> the various stacks and FAT16 file code. Makes my tray
> of 16F877 PICs even older and sadder...

That sounds real interesting.

> > After that, I intend to tackle the bandwidth bottleneck
> > and switch over to 10MB Ethernet using a Microchip
> > ENC28J60 chip. After that, I would speed up the
> > microcontroller again, -- either an ARM or an FPGA.
> > I'm leaning towards the FPGA, since they are kind of
> > neat devices I've always wanted to figure out.
> >
> > Does that answer your questions?
>
> I've always got lots more questions. <grin> But for now
> I've got so many work-work projects on my plate in addition
> to the ELS that I have to hold myself back from getting
> started on yet something else. The layout of the latest
> ELS rev is done and I'm just prettying it up a bit
> -- consistent trace widths and spacing etc. Prototype
> boards will be ordered this week; schematic has already
> been posted.
>
> I still have 3 more castings to make so that I can mount
> up the bits and pieces for my ELS (Rev 0.1 prototype)
> controlled back fence for my 3:1 shear/brake/roller.
> Haven't even started on the software for that. Can't
> wait till I can key in in a shear dimension or bend
> dimension and have the fence move to the right spot.

I'm in the same boat. Too many projects and not nearly
enough time.

-Wayne