Siemens SINUMERIK 840D sl Function Manual page 544

Supplementary conditions
3.2 Output behavior
3.2 Output behavior
Thread cutting
During active thread cutting G33, G34 and G35, the following output behavior is always
active for the spindle-specific auxiliary functions:
• M3 (spindle right)
• M4 (spindle left)
:
• Output duration one OB40 cycle (quick acknowledgment)
• Output during motion
The spindle-specific auxiliary function M5 (spindle stop) is always output at the end of the
block. The parts program block that contains M5 is always ended with exact stop, i.e. even
during active continuous path mode.
Synchronized actions
With output auxiliary functions from synchronized actions, the parameterized output behavior
is ignored except for the following parameters:
• Bit0: Output duration one OB1 cycle (normal acknowledgment)
• Bit1: Output duration one OB40 cycle (quick acknowledgment)
Auxiliary functions: M17 or M2 / M30 (end of subroutine)
In its own parts program block
If one of the auxiliary functions M17, M2 or M30 is programmed as the only auxiliary function
in a part program block and an axis is still in motion, the auxiliary function is not output to the
PLC until after the axis has stopped.
Overriding the parameterized output behavior
The parameterized output behavior of the auxiliary functions M17 or M2/M30 is overridden by
the output behavior that is determined in the following machine data:
MD20800 $MC_SPF_END_TO_VDI, Bit 0 (subprogram end / stop to PLC)
Bit Value
0
56
Meaning
0 The auxiliary functions M17 or M2/M30 (subprogram end) are not output to the PLC.
Continuous-path mode is not interrupted at the end of the subroutine
1 The auxiliary functions M17 or M2/M30 (subprogram end) are output to the PLC.
Basic logic functions: Auxiliary Function Output to PLC (H2)
Function Manual, 11/2006, 6FC5397-0BP10-2BA0