Rockwell Automation 8520 9/Series CNC Lathe - Manual (Page 737)

Program Interrupt
Chapter 29
29-7
Type 2 Interrupts
The control returns the tool to the point in the program where it was when
the interrupt was performed by using type 2 interrupts. Normally the first
4 linear moves (G00 or G01) in the interrupt program are remembered.
This may be altered by programming a specific M-code.
If You Perform: As: Then: the Control
Remembers:
A non-linear (G02 or
G03) circular move
One of the first 4 blocks of the interrupt The moves up to that
block
A non-linear (G02 or
G03) circular move
The first block in the interrupt The start point of that
block
These remembered blocks are retraced after the M99 code is read by the
control in the interrupt program. This returns the cutting tool to the
location in the program where program execution was interrupted.
Figure 29.2
Type 2 Interrupt
Programmed Path
Path of Interrupt
Interrupt
occurs
This block is not
executed unless there
are no motion commands
in the interrupt
Return path
Motions due to
Delayed interrupt
M99 M99
Return path
Motions due to
Immediate Action
interrupt
Part program
path before
interrupt