Rockwell Automation 8520-GUM 9/Series CNC Grinder Operation and Programming Manual Documentation Set - Manual (Page 712)

In-process Dresser
Chapter 21
21-6
When the in-process dresser is deactivated, the control will remove any
offsets that have been generated by the in-process dresser. This can cause
the wheel to lose contact with the part since the wheel diameter has
changed and the offset compensating for this change has been canceled.
To solve this problem the in-process dresser has been designed to modify
select length and radius offsets in the offset tables that correspond to
specific offset numbers. These offsets are automatically updated to reflect
the new wheel diameter when the in-process dresser is deactivated.
Length offsets 01, 02, 03, and 04
Wheel length offset 01 to 04 are the length offsets that the in-process
dresser modifies when deactivated. When the in-process dresser is
deactivated, the control replaces the value of the length offset with the
“Vertical dressing axis” for each of these 4 length offsets. The “Vertical
dressing axis” is configured in AMP by the system installer. The
control replaces this length offset with a value equal to one-half the
current wheel diameter. Make sure you are calling one of these length
offsets with the correct T word to properly maintain a length offset.
Radius offset 33
Radius offset 33 is the radius offset that the in-process dresser modifies
when canceled. When the in-process dresser is deactivated the control
replaces the value of radius offset 33 with one-half the value of the
current wheel diameter. Radius offset number 33 cannot be modified
and does not appear on the radius offset table screen. This radius offset
number is reserved exclusively for the in-process dresser.
Length offsets other than 01 -- 04 or radius offsets other than 33 can be
used; however, it is the programmer’s responsibility (or system installer’s
PAL program responsibility) to make sure that these offsets get updated
when the in-process dresser is deactivated.
Keep in mind you should only have either the length offset or the radius
offset active. If both are active you will be compensating for the change in
wheel diameter twice as shown in Figure 21.3.
21.1.2
Maintaining Dresser Offsets