Originally Posted by

**FrankAarre** all mathematical functions i use are included in the programming software library. i use omron plc and program in structured text.

floating point

yes i continually monitor the values of x and y and calculate the angle relating to circle center.

startradians:=deg_to_rad(startgrader); /* deg_to_rad() is the included function in software

XyRad:= ATAN(y_pos/x_pos);

yep, errors are consistent and only for the 4 extremities of the circle, if i have 89,999 degrees i get an accurate x,y posistion

Frank