Siemens Sinumerik 840D sl Programming Manual page 123

Machine data
The response of the interrupt program function can be determined from the following
machine data:
MD10808 $MN_EXTERN_INTERRUPT_BITS_M96:
Bit 0 = 0
Interrupt program is not possible as M96/M97 are normal M functions.
Bit 0 = 1
Activation of an interrupt program with M96/M97 is allowed.
Bit 1 = 0
The part program is processed further with the end position of the block immediately after
the interruption block (REPOSL RME).
Bit 1 = 1
The part program is continued from the interruption position (REPOSL RMI).
Bit 2 = 0
The interrupt signal interrupts the current block immediately and starts the interrupt routine.
Bit 2 = 1
The interrupt routine is started only at the end of the block.
Bit 3 = 0
The execution cycle is interrupted immediately after an interrupt signal arrives.
Bit 3 = 1
The interrupt program is started only at the end of the execution cycle (evaluation in the shell
cycles).
Bit 3 is evaluated in the shell cycles,and the cycle sequence is adapted accordingly.
Bit 1 is evaluated in cover cycle CYCLE396.
If the interrupt program is not called via the cover cycle CYCLE396,
($MC_EXTERN_FUNCTION_MASK, Bit 10 = 1) must be evaluated with Bit 1. If Bit 1 =
TRUE, REPOSL RMI must be used for positioning on the interruption point, otherwise
REPOSL RME must be used for positioning on the block end position.
Example:
N100 M96 P1234
....
....
N300 M97
ISO Milling
Programming Manual, 06/09, 6FC5398-7BP10-1BA0
;Activate ASUB 1234spf. In the case of a rising edge of the
;1st rapid input, the program
;1234.spf is started
;Deactivation of ASUB
Additional functions
4.6 Measuring functions
123