Re: G02 Tolerance ?

[edmiller42-at-attglobal.net]

Assuming that you're in absolute coordinate mode for X,Y,Z, your G02 command is
wrong because it defines an arc-center at (20.982085,1.350706), which is
clearly not equidistant from both the start-point at (10.607085,1.350706) and
the end-point at (10.607085,-1.350706).  Perhaps you forgot that the
radius-offset coordinates I & J are always incremental, not absolute.


Hugh & Denise Currin wrote:

> In the last few days I've gotten a foreign knee mill running under CNC, at
> least X & Y.  It's using ball screws, 750 oz-in steppers with 2:1 timing
> belts, Camtronic 5A drivers, opto-isolation from a computer running Red Hat
> 6.2, rtlinux & EMC.  Now that it is functioning I'll have a bushel of
> questions, I hope you guys have some patience.  Thanks. :-)
>
> First, I have a question regarding the g-code G02 command.  The first thing
> I'm doing is machining belt guards for the timing belts.  In checking my
> code I get the error that the radius from the start point is different than
> the radius to the end point.  I thought this was my hand coding and
> rounding to .001 but I just created code using Yeager ACE and can't see any
> problem in the code.  The code that give the error is:
>
> G01 X0.047366 Y2.186987 f40
> G01 Z0.000000
> G01 X0.102140 Y2.880401 Z0.000000
> G01 X10.662027 Y2.046252 Z0.000000
> G01 X10.607085 Y1.350706 Z0.000000
> G02 X10.607085 Y-1.350706 I10.375000 J0.000000
>
> I think the only relevant commands are the last two.  Why does this create
> an error?  Is there a tolerance setting in EMC for this?  I could not see
> one in the '*.ini' file.
>
> The error occurred while running "sim.run" in what I think is the standard
> distrubution.  (Thus explaining the feed rate of 40, visual output via
> backplot no cutting.)
>
> I can work around this using radius R rather than center I&J but would like
> to know how to adjust this tolerance.
>
> Thank you.
>
> Hugh
>
> --------------------------------
>   Hugh & Denise Currin
>     currin-at-cdsnet.net
>     Klamath Falls, Oregon  USA
>     541/884-3023
> --------------------------------