HEIDENHAIN TNC 407 (280 580) ISO Programming - Manual (Page 34)

TNC 426/TNC 425/TNC 415 B/TNC 407 1-16
1 Introduction
The polar coordinate system can also express both
types of dimensions:
• Absolute polar coordinates always refer to the
pole (I, J) and the reference axis.
• Incremental polar coordinates always refer to
the last nominal position of the tool.
Fig. 1.17: Incremental dimensions in polar coordinates
(designated by G91)
1.2 Fundamentals of NC
X
Y
J = 10 0
°
I = 30
R
R
R
G91R
G91H G91H
H