Rockwell Automation 8520-MUM 9/Series CNC Mill Operation and Programming Manual Documentation Set - Manual (Page 760)

Program Interrupt
Chapter 29
29-2
The format for these M codes is:
M96L__P__;
M97L__;
Where : Selects:
L the type of interrupt and the signal that will call the interrupt. L ranges from 0 - 3.
P the interrupt program. P is followed by a 5 digit non-decimal program name.
An error is generated if anything other than an N word, a P or L word, a
block delete /, or a comment character is programmed in the M96 or M97
block.
An interrupt M code M96 or M97 may also be programmed within a
interrupt program. If this is the case the interrupt does not become
enabled/disabled until the interrupt currently being executed is completed
and execution is returned to the main program.
Selecting the Type of Interrupt
Two types of interrupt programs may be enabled or disabled with these
M-codes. These two types are described in section 29.3 . You can use up
to 4 signals to PAL (switches) to call interrupt programs. The system
installer determines what switch corresponds to which type of interrupt in
PAL. Refer to documentation prepared by the system installer for details
on the types available and switches used to control them for a specific
machine application.
The M code determines which type and which switch signal is enabled or
disabled by programming an L-word with the M code. There are 4
L-words:
L0 Interrupt type 1 Switch 0 triggers this.
L1 Interrupt type 2 Switch 1 triggers this.
L2 Interrupt type 2 Switch 2 triggers this.
L3 Interrupt type 2 Switch 3 triggers this.
Program these L-words in each M96 or M97 block. Not programming the
L-word causes the control to assume an L-word of L0 has been
programmed. Refer to documentation prepared by the system installer for
the location and operation of the 4 switches.
If more than one L-word is programmed in a block, the right most L-word
is the one that is used for that block. Other L-words in that block are
ignored.