HEIDENHAIN ND 720 v.3 - Manual (Page 6)

6
Absolute workpiece positions
Each position on the workpiece is uniquely defined by its absolute
coordinates.
Example
Absolute coordinates of position 1:
X = 10 mm
Y = 5 mm
Z = 0 mm
If you are working according to a workpiece drawing with absolute
dimensions, then you are moving the tool to the coordinates.
Y
X
Z
10
5
1
Fundamentals
1
Y
X
Z
10
5
10
10
1
2
Relative workpiece positions
A position can also be defined relative to the previous nominal
position. The datum for the dimension is then located at the previous
nominal position. Such coordinates are termed relative coordinates or
chain dimensions. Incremental coordinates are indicated by a
preceding I.
Example
Relative coordinate of position 2 referenced to
position 1 :
IX = 10 mm
IY = 10 mm
If you are working according to a workpiece drawing with incremental
dimensions, then you are moving the tool by the dimensions.
Sign for incremental dimensioning
A relative dimension has a positive sign when the axis is moved in the
positive direction, and a negative sign when it is moved in the
negative direction.
Bateil1.pm6 07.11.2001, 10:36 6