HEIDENHAIN PT 880 - Manual (Page 13)

POSITIP 880 13
I – 1 F
u
ndamentals of P
o
sitioning
Setting the Datum
The workpiece drawing (Fig. I.3) identifies a certain point on the
workpiece (usually a corner) as the absolute datum and perhaps one
or more other points as relative datums.
The datum setting procedure establishes these points as the origin of
the absolute or relative coordinate systems: The workpiece, which is
aligned with the machine axes, is moved to a certain position relative
to the tool and the display is set either to zero or to another appropriate
value (e.g., to compensate the tool radius).
Example:
Drawing with several relative datums (ISO 129 or DIN 406 Part 11,
Fig. 171)
Fig. I.3 The workpiece datum represents the origin
of the Cartesian coordinate system