HEIDENHAIN SW 68894x-02 - Manual (Page 44)

44 Introduction and fundamentals
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7
Fundamentals
Coordinate system
The meanings of the coordinates X, Y, Z, and C are specified in DIN
66 217.
The coordinates entered for the principal axes X and Z are referenced
to the workpiece zero point. The angles entered for the rotary axis (C
axis) are referenced to the datum of the C axis.
The axis designations X and Z describe positions in a two-dimensional
coordinate system. As you can see from the figure to the center right,
the position of the tool tip is clearly defined by its X and Z coordinates.
The CNC PILOT can connect points by linear and circular paths of
traverse (interpolations). Workpiece machining is programmed by
entering the coordinates for a succession of points and connecting the
points by linear or circular paths of traverse.
Like the paths of traverse, you can also describe the complete contour
of a workpiece by defining single points through their coordinates and
connecting them by linear or circular paths of traverse.
Positions can be programmed to an accuracy of 1 µm (0.001 mm). This
is also the accuracy with which they are displayed.
Absolute coordinates
If the coordinates of a position are referenced to the workpiece datum,
they are referred to as absolute coordinates. Each position on a
workpiece is clearly defined by its absolute coordinates (see figure).