hello,

You must have three points : start point and end point of first move and end point second move.

If you have move from point X=0 Y=0 and

you will do move to point eg X=0 Y=30 and next X=32 R8 then between perpendicular lines you will have radius R8

in Heidenhain eg

...

L X=0 Y=0 RL

L X=0 Y=30

RND R8

L X=32 Y=30

Hi Daniel thank for your answer, actually I am looking for formula on which CNC machine interprets Radius movements.

CNC machine takes radius movement by combined linear motion of X and Y axis, so am looking for the method or formula on which CNC machine divides Radius movement into linear X,Y axis movements.

Hope you got my point .....

I don't understand you.

Do you looking for formula in code of controller (eg Fanuc etc.) or formula for programming a controller of stepper motors which is brain of machine?

I am looking for a formula for programming a controller..... I am developing a PC based controllers for CNC machine.

Upto now my controller moves only in linear directions, I want to enable circular directions.

For example If prog have X=4 Y=5 R8, my controller only moves in X and Y direction, How can I interpret R8???? that what I want to ask?

The procedure used is the DDA algorithms that you can see in any Computer Graphics books that deal with line and circle drawing. The only change that you have to do is the resolution instead of pixel you will use the resolution of the system for example 1 micron.

See also these:

http://www-personal.umich.edu/~ykoren/uploads/CNC_Interpolators-_Algorithms_And_Analysis.pdf

http://en.wikipedia.org/wiki/Bresenham's_line_algorithm

http://onlinemca.com/mca_course/kurukshetra_university/semester5/computergraphics/circle_drawing.php