4 The Interpolation
Further data of the circle may be specified in one of two different ways.
Case 1
At address R where R is the radius of the circle. Now the control will automatically calculate the coordinates of the circle center from the start point coordinates (the point where the control is in the instant of the circle block being entered), the end point coordinates (values defined at addresses Xp, Yp, Zp) and from the programmed circle radius R. Since
two different circles of radius R can be drawn between the start and the end points for a given direction of
circumventing (G02 or G03), the control will interpolate
an arc smaller or larger than 180° when the radius of the circle is specified as a positive or a negative number, respectively. For example:
Arc section 1: G02 X50 Y40 R40
Arc section 2: G02 X50 Y40
Arc section 3: G03 X50 Y40 R40
Arc section 4: G03 X50 Y40
Fig.
Case 2
The circle center is specified at address I, J, K for the Xp, Yp and Zp axes. The values specified at addresses I, J, K are interpreted always incrementally by the control system, so that the vector defined by the values of I, J, K points from the start point to the center of the circle. For example:
With G17:
With G18:
With G19:
Fig. |
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