hi

My project is "Conversion of a conventional lathe to the CNC lathe,
by using PC based motion control unit" The programming language is
Turbo Pascal. PC is sending signals to parallel port. Then a driver
is sending this signals to 2 step motors. One of them is acting on X-
direction and the other Y-direction of the lathe. I write a programm.
But is it not finished. In this programm, x1 and y1 (start point)are
entered and then x2 and y2 (finish point) are entered. If this is a
linear line, then my programm is successful (y=mx*i) either m>1 or
m<1 (m=slope). But I can not do it for a circle. (x^2 + y^2 = r^2)
I want to move the step motors like a quarter circle for example for
a shaft. Look the figure below. I update the program to the FILES.
You know any programm like this? Or can please help me!?

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C______
______S
_____C

Thanks
SEMIH DIKEN