Siemens SINUMERIK 840D sl Function Manual page 747

Call of the replacement subroutine at block start or block end
The call time during programmed gear stage change with M41 to M45 and during spindle
positioning with M19 depends on the output response of this auxiliary function to the PLC. In
case of output of
• before or during the movement, the call takes place at block start
• afterthe movement, the call takes place at block end.
The call always takes place at block start during automatic gear step change with M40 and
during spindle positioning with SPOS, SPOSA.
Call at block start
If the replacement subroutine is called at block start, then the part program line that led to
the calling of the subroutine is processed after the subroutine is processed. The parts to be
replaced from the replacement subroutine are not processed any more.
Call at block end
During call at block end, the part program line that lead to the calling of the subroutine is
called first. The parts to be replaced in the replacement subroutine are processed. The
subroutine is called finally.
Read activation time of the replacement subroutine
The $P_SUB_STAT system variables can be used to define the time (block start / block end)
when the replacement operation is executed.
Restrictions
Only one of the possible spindle-related replacements can be executed in a part program
line. Multiple replacements lead to the termination of the part program processing. In this
case, the language constructs that are to be replaced must be divided among several part
program lines.
Moreover, the general conditions of replacement subroutines are applicable; refer to Chapter
"Properties of Replacement Subroutines".
Basic logic functions: Mode group, channel, program operation, reset response (K1)
Function Manual, 11/2006, 6FC5397-0BP10-2BA0
2.11 Subroutine call through NC language replacement
Detailed description
189