HEIDENHAIN TNC 640 (34059x-02) - Manual (Page 249)

Processing DXF Files (Software Option) 7.1
7
TNC 640 | User's Manual
HEIDENHAIN Conversational Programming | 5/2013
249
Defining the datum
The datum of the drawing for the DXF file is not always located
in a manner that lets you use it directly as a reference point for
the workpiece. Therefore, the TNC has a function with which you
can shift the drawing datum to a suitable location by clicking an
element.
You can define a reference point at the following locations:
At the beginning, end or center of a straight line
At the beginning or end of a circular arc
At the transition between quadrants or at the center of a
complete circle
At the intersection between:
A straight line and a straight line, even if the intersection is
actually on the extension of one of the lines
Straight line – circular arc
Straight line – full circle
Circle – circle (regardless of whether a circular arc or a full
circle)
You must use the touchpad on the TNC keyboard or a
mouse attached via the USB port in order to specify a
reference point.
You can also change the reference point once you
have already selected the contour. The TNC does not
calculate the actual contour data until you save the
selected contour in a contour program.