G-Code G02...

hi all.
I'm new in this forum .
on first sorry for me eanglish.
I create own procejct to control small CNC machine.
now I use MACH3 but create firware for LPC2148 to controll cnc.
I want add G-Code and HPGL to my firmware for easy comunication with cnc.
there is my machine:
and ther is me proto board. board is routed by cnc (eagle+MACH3):



and question is if use command like G02 X Y and use I and J parameter I can find center of arc or circle but how to work if know only radius???
from I and J prameter can calculate radius (=sqrt(x^2+y^2).
I look to code to G02 and G03 function and there don't work with only R radius parameter.
can some help with this????

You know that the center of the arc (I,J) is R distance from both the current position (call that x1,y1) and X,Y (the destination point). Find the points where a circle of radius R around x1,y1 intersects a circle of radius R around X,Y. Those two points are the possible locations of I,J.

It's not clear how you pick which of the two to use as the center of the arc... You can draw a clockwise arc from one endpoint to the other using either center. One arc will typically be less than 180

Your milled PCB looks very good! I'm trying to get milling working with my RepRap and G-Code myself. It all seems pretty promising!

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Regards,

Erik de Bruijn
[Ultimaker.com] - [blog.erikdebruijn.nl]

I found the answer to my quandry in:

[www.isd.mel.nist.gov]

Appendix B
B.4 Milling Arcs
B.4.1 Radius Format Arc
"A positive radius indicates that the arc turns through 180 degrees or less, while a negative radius indicates a turn of 180 degrees to 359.999 degrees."

hi
i am sada previous i am using Delcam make any hole, now days at new work place dont have cam software please any send example of circular interpolation programe exapmles