HEIDENHAIN TNC 426, User Manual

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188 7 Programming: Miscellaneous functions
7.
4 Miscellaneous F
unctions f
o
r Cont
our
ing Beha
vior
Retraction from the contour in the tool-axis
direction: M140
Standard behavior
In the program run modes, the TNC moves the tool as defined in the
part program.
Behavior with M104
With M140 MB (move back) you can enter a path in the direction of
the tool axis for departure from the contour.
Input
If you enter M140 in a positioning block, the TNC continues the dialog
and asks for the desired path of tool departure from the contour. Enter
the requested path that the tool should follow when departing the
contour, or press the MAX soft key to move to the limit of the traverse
range.
Effect
M140 is effective only in the block in which it is programmed.
M140 becomes effective at the start of the block.
Example NC blocks
Block 250: Retract the tool 50 mm from the contour.
Block 251: Move the tool to the limit of the traverse range.
250 L X+0 Y+38.5 F125 M140 MB 50
251 L X+0 Y+38.5 F125 M140 MB MAX
M140 is also effective if the tilted-working-plane function,
M114 or M128 is active. On machines with tilting heads,
the TNC then moves the tool in the tilted coordinate
system.
With the FN18: SYSREAD ID230 NR6 function you can find
the distance from the current position to the limit of the
traverse range in the positive tool axis.
With M140 MB MAX you can only retract in positive direction.