HEIDENHAIN TNC 426 (280 476) - Manual (Page 219)

192 7 Programming: Miscellaneous functions
7.
5 Miscellaneous F
unctions f
or Rotary Ax
es
Behavior with M126
With M126, the TNC will move the axis on the shorter path of traverse
if you reduce display of a rotary axis to a value less than 360°.
Examples:
Effect
M126 becomes effective at the start of block.
To cancel M126, enter M127. At the end of program, M126 is
automatically canceled.
Reducing display of a rotary axis to a value less
than 360°: M94
Standard behavior
The TNC moves the tool from the current angular value to the
programmed angular value.
Example:
Behavior with M94
At the start of block, the TNC first reduces the current angular value to
a value less than 360° and then moves the tool to the programmed
value. If several rotary axes are active, M94 will reduce the display of
all rotary axes. As an alternative you can enter a rotary axis after M94.
The TNC then reduces the display only of this axis.
Example NC blocks
To reduce display of all active rotary axes:
To reduce display of the C axis only
To reduce display of all active rotary axes and then move the tool in
the C axis to the programmed value:
Effect
M94 is effective only in the block in which it is programmed.
M94 becomes effective at the start of block.
Actual position Nominal position Traverse
350° 10° +20°
10° 340° –30°
Current angular value: 538°
Programmed angular value: 180°
Actual distance of traverse: –358°
L M94
L M94 C
L C+180 FMAX M94