RE: [CAD_CAM_EDM_DRO] G02 - G03 - an aside

EMC handles it by generating an error message and aborting the program. It
is pretty picky about these parameters all being correct. The standing joke
is they have to be right to the micron level.

Tim
[Denver, CO]

> -----Original Message-----
> From: Kevin P. Martin [mailto:kpmartin@...]
> Sent: Monday, August 21, 2000 11:51 AM
> To: CAD_CAM_EDM_DRO@egroups.com
> Subject: [CAD_CAM_EDM_DRO] G02 - G03 - an aside
>
>
> This brings up a question I have often wondered about. Given
> that the parameters
> to G02 and G03 include the starting position (implicitly), an
> ending position, a
> center point position *and* a radius, what do controllers do
> if these are
> inconsistent values?
> For instance if the distance between the initial position and
> the center point
> is not equal to the radius? Of if the ending point isn't on
> the arc defined by
> the start point, center point, and radius?
>
> Even if the G-code writer correctly calculates all these
> values, all coordinates
> and distances are expressed as finite precision values, so it
> would seem to me
> that this would be an unavoidable problem with anything other
> than arcs that are
> multiples of 90 degrees. So the controller can't just call it
> an error condition
> and stop.
>
> If I were writing a G-code interpreter, I could invent several ways of
> gracefully handling the error, but I was wondering what real, existing
> controllers do...
> -Kevin Martin