Rockwell Automation 8520-GUM 9/Series CNC Grinder Operation and Programming Manual Documentation Set - Manual (Page 545)

Dresser/Wheel Radius Compensation
Chapter 15
15-57
Figure 15.50
Compensation Re-Initialized after a Manual or MDI Operation.
Manually jog axes (or any MDI
execution) and return to the
compensated path.
Compensation is re-initialized here. The control assumes that the current
position is a programmed position at the point of re-initialization.
Consequently, after the initialization, compensation is offset by twice the tool
radius.
Radius
Over Compensated Path
(after MDI/Manual Interrupt)
Original Compensated Path
(had no interruption occurred)
Programmed Path
Use the Jog Retract feature if you must jog the axes away from a
compensated path. Jog retract prevents the overcompensation from
occurring.
If you interrupt compensation with a manual or MDI operation and the
next programmed block is a circular block, the control generates an error
when it tries to re-initialize compensation. You can avoid this by using the
jog retract feature instead of manual or MDI when you need to interrupt
compensation.
We recommend that you use a G40 command to cancel the dresser/wheel
radius compensation before the execution of a return-to or a return-from
the machine home or the secondary machine home. This refers to the
operations performed when the control executes either the G28, G29, or
G30 commands as described in chapter 12.
If compensation is not canceled using a G40 command, the control
temporarily cancels compensation for the return-to machine home or
secondary machine home operations. This is done by using the move to
the intermediate point, as designated when the operation was performed, as
an exit move for compensation.
Important: You should always program an intermediate point for a
return-to home operation if dresser/wheel radius compensation is active. If
no intermediate point is specified, the control executes the move prior to
the return-to home operation as an exit move. This can cause undesired
overcutting of the part.
15.7.6
Moving To/From Machine
Home