HEIDENHAIN TNC 640 (34059x-01) ISO programming - Manual (Page 306)

306 Programming: Miscellaneous Functions
9.4 Miscellaneous F
unctions f
o
r Cont
our
ing Beha
vior
Automatically retract tool from the contour at
an NC stop: M148
Standard behavior
At an NC stop the TNC stops all traverse movements. The tool stops
moving at the point of interruption.
Behavior with M148
The TNC retracts the tool by up to 2 mm in the direction of the tool axis
if, in the LIFTOFF column of the tool table, you set the parameter Y for
the active tool (see "Tool table: Standard tool data" on page 145).
LIFTOFF takes effect in the following situations:
„ An NC stop triggered by you
„ An NC stop triggered by the software, e.g. if an error occurred in the
drive system
„ When a power interruption occurs
Effect
M148 remains in effect until deactivated with M149.
M148 becomes effective at the start of block, M149 at the end of
block.
The M148 function must be enabled by the machine tool
builder. The machine tool builder defines in a machine
parameter the path that the TNC is to traverse for a
LIFTOFF
command.
Danger of collision!
Remember that, especially on curved surfaces, the
surface can be damaged during return to the contour.
Retract the tool before returning to the contour!
In the CfgLiftOff machine parameter, define the value by
which the tool is to be retracted. In the CfgLiftOff
machine parameter you can also switch the function off.