Rockwell Automation 8520-MUM 9/Series CNC Mill Operation and Programming Manual Documentation Set - Manual (Page 567)

Cutter Diameter Compensation
(G40, G41, G42)
Chapter 21
21-49
If compensation was not cancelled using a G40 command before returning
to machine or secondary home points, the control automatically
re-initializes cutter compensation for the return from machine or secondary
home points. This is done by using the move to the intermediate point,
designated when the operation is performed, as an entry move for
compensation.
Figure 21.46 gives an example of either a G28 or G30 block followed by a
G29 block.
Figure 21.46
Cutter Compensation During G28, G30, and G29 Blocks
Temporary cancel of
compensation here
at intermediate point
Reference point
Programmed
path
G41
N11 N12
N13
N13’
N14’
N15
N14
r r
r r
r r
r r
It is recommended that cutter compensation be cancelled using a G40
command before any modifications to the current work coordinate system
are made including any offsets or any change of the coordinate system
(G54-G59.3).
Important: Changes can only be made, to axes in the cutter compensation
plane, in the executing part program or using MDI. Changes to axes not in
the current cutter compensation plane can be made manually in the offset
tables (using the softkeys). Changes to work coordinate system offsets for
axes that are in the active cutter compensation plane can not be performed
manually in the offset tables.
21.6.7
Changing or Offsetting Work
Coordinate System