Rockwell Automation 8520-MUM 9/Series CNC Mill Operation and Programming Manual Documentation Set - Manual (Page 415)

Axis Motion
Chapter 14
14-39
The mirrored plane is fixed and cannot be moved from the selected axis.
This mirrored plane is the equivalent of programming a programmable
mirror image and using all zero values for the axis words.
The system installer may install a switch for each of the 4 available axes.
What axes are mirrored with what switches is dependant on the PAL
program in a particular system. It is also possible to mirror about more
than one axis using more than one manual mirror image switch at the same
time or one switch may control more than one axis. Refer to
documentation prepared by the system installer for details.
Important: It is possible to use programmable mirror image at the same
time as manual mirror image. When this is done, the programmable mirror
image is done first followed by the manual mirror image. The same axis
may be mirrored by programmable and manual mirror image at the same
time.
This feature is used to disable the axis position display and allow an axis to
be clamped into position. Typically an axis clamp is performed by the
execution of an M-code in a part program or by a switch of some type
controlled by the operator. The system installer determines how the axis
clamp feature is enabled in PAL. Refer to the system installer’s
documentation for details.
When an axis is clamped, the control will freeze the axis position displays
at their position. Any drift or movement generated by some external force
will not generate any corrective response from the axis servo. This will
prevent the servo from trying to move an axis back into position when it
has been mechanically clamped to not move.
Any movement of the axis when it is clamped will be added to the current
value of the following error and may be viewed on the screen displaying
following error. Refer to your integration manual for more information. If
the axis following error exceeds the allowable maximum following error
(set in AMP), an error will be generated, and the control will go into
E-STOP.
When the axis is unclamped, the control position display will be
reactivated and the servo will return the axis to the necessary position for
zero following error.
14.6
Axis Clamp