HEIDENHAIN TNC 640 (34059x-02) Cycle programming - Manual (Page 68)

Using Fixed Cycles
2.4 Point tables
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TNC 640 | User's Manual Cycle Programming | 5/2013
Effect of the point tables with Cycles 210 to 215
The TNC interprets the points as an additional datum shift. If you
want to use the points defined in the point table as starting-point
coordinates, you must define the starting points and the workpiece
surface coordinate (Q203) in the respective milling cycle as 0.
Effect of the point tables with Cycles 251 to 254
The TNC interprets the points of the working plane as coordinates
of the cycle starting point. If you want to use the coordinate
defined in the point table for the spindle axis as the starting point
coordinate, you must define the workpiece surface coordinate
(Q203) as 0.