Re: CAM Software Advice for Shopmaster CNC

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

>
> Hi Dennis,
>
> OK. Nuff said. Clean slate.
>
> But maybe we need to push for an open source CNC flavoured USB
> interface. Here's my idea on how to do it. Hopefully I won't
> leave the non-electronic/software types behind.
>
> The biggest problem with USB is there is no guarantee when the
> data sent by the application will arrive at the destination.
> IEEE1394 Firewire used for Video Cameras is a bit better and
> faster I believe but still suffers from the same problem.

[snip lots of good stuff]

I have a system that is similar to what John suggests,
but differs in the details. Important features such as
ESTOP are not currently implemented (or even designed.)

The system is broken into to two parts. One piece of software
(called Steps) takes a fairly standard set of CNC codes
and breaks them into timed step codes. A timed step code
is just a timestamp and axis increment/decrement --
(0:12:345.670 +X) (0:12:345.890 -Y). These are merged and
shipped down to a separate buffer board that that has
some memory and an inexpensive microcontroller that can
squirt out the pulses at accurately timed intervals.

Here are the URLs:

Serial => Parallel Buffer Board:
<http://gramlich.net/projects/cnc/buffer/rev_a/index.html>

CNC => step code converter:
<http://gramlich.net/projects/steps/index.html>

By the way, this stuff actually works; it has lots of
rough edges, but it works. In addition, everything
is published -- code, gerber files, parts lists, the
works. It needs another round or two of polishing, tho'.

Is my approach of any interest to other people?

-Wayne