Settings for circle center point correction and radius compensation

A circle that is determined in the NC-program through starting point, end point and middle point is geometrically over determined. In the case of inaccurately programmed circle co-ordinates, the radius of the starting point of the circle and the end of the circle will be different. This problem is solved by correcting the co-ordinates of the center point of the circle and of the radius of the circle. The algorithm of the correction of the center point of the circle has been described in greater detail in [PROG]. The correction algorithm provides a usable result for all and even for geometrically meaninglessly programmed circle co-ordinates. In some cases the deviations between programmed and corrected center point co-ordinates become correspondingly large. Hence, the new, calculated center point co-ordinates are subjected to a plausibility test.

It will be verified whether the center point offset Δm is greater than the maximum center point offset "mittelpkt_diff" laid down as absolute value in the channel parameters.

Δm > sda_mds.mittelpkt_diff ?

and whether the center point offset Δm is greater than the product of "mittelpkt_faktor/1000" and the corrected radius "radius".

Δm > sda_mds.mittelpkt_faktor/1000 * radius ?

If this is the case then an error message occurs. Otherwise the corrected center point co-ordinates will be included. Here, "mittelpkt_diff" should be determined as absolute value, "mittelpkt_faktor" as factor (unit 0,1 %).

The programmed center point co-ordinates must thus lie in a circumcircle around the corrected center point of the circle. The radius of this circumcircle corresponds to the permissible center point offset Δm, which can be set using the two parameters "mittelpkt_diff" and "mittelpkt_faktor" (Fig. 2-2).