Re: Re: How does G02 & G03 work?

Fred Smith wrote:

> From: "Fred Smith" <imserv@...>
>
>
> > From: Jon Elson <jmelson@...>
> >
> > Therefore, it doesn't need
> > any sign information on the I J K words. Allen-Bradley never used
> signs
> > on their I J K
> > words, either.
> >
>
> This is incorrect. On the Allen-Bradley 8400 in incremental mode(G91)
> the
> IJK arc centers were signed, and in absolute mode (G90) the arc
> centers were
> the actual coordinates of the arc centers.
>
> Darn, I hate to be on the same side as Darrell. ;-)
>
> My own mathematical analysis when I was writing a runtime calculation
> program that analyzed arcs, was that if an arc is less than 180
> degrees, the
> sign of the IJK is not necessary, but if arcs are accepted that are
> greater
> than 180 degrees, the sign becomes important.

Right, I think that is the key, there. If arcs are less than 180
degrees!

Jon