[Ahmed1995]

HI all,
I'm trying to understand the maths behind G codes in general and G02 & G03 in particular. G01 are quite forward where the X and Y numbers are simply converted to steps in a stepper motor. But for a circle, two more parameters are introduced I and J in which they define the center of the circle or the ARC. I am trying to create a g code interpreter in which I have to know what kind of maths are done in the background to create a circle for instance any help is appreciated.

Ahmed

[ger21]

First, it depends on if your using incremental or absolute IJ mode.
The arc starts from the existing position, and ends at the XY coordinates in the G2/G3 comand.
In absolute IJ mode the I is the X coordinate of the arc center, and the J is the Y coordinate of the center.
In In remental mode, the center is specified relative to the end point of the arc.

[Ahmed1995]

Thanks for the reply Gerry, the g code that I generate looks like
G0 X -35.355 Y -35.355
M3 M8
G0 Z 0.000
G1 Z 0.000
F400
G2 X 35.355 Y 35.355 I 35.355 J 35.355
G2 X -35.355 Y -35.355 I -35.355 J -35.355
F0
G1 Z 0.000
G0 Z 0.000
M9 M5
G0 X 0.000 Y 0.000
M2 (Program end)

so I assume this is an absolute mode?
So to draw a circle will I have to create an equation in which the x and y axes are increasing till reaching a specific value? I really don't know how to start so and tiny help is appreciated

Regards
A.