HEIDENHAIN ITNC 530 - CONVERSATIONAL PROGRAMMING User Manual page 546

Explanation of values saved in the preset table
Simple machine with three axes without tilting device
The TNC saves in the preset table the distance from the workpiece
datum to the reference point (with the correct algebraic sign).
Machine with swivel head
The TNC saves in the preset table the distance from the workpiece
datum to the reference point (with the correct algebraic sign).
Machine with rotary table
The TNC saves in the preset table the distance from the workpiece
datum to the center of the rotary table (with the correct algebraic
sign).
Machine with rotary table and swivel head
The TNC saves in the preset table the distance from the workpiece
datum to the center of the rotary table.
Danger of collision!
Keep in mind that moving an indexing feature on your
machine table (realized by changing the kinematics
description) requires you to redefine any workpiece-based
presets.
546 Manual Operation and Setup