Rockwell Automation 8520-MUM 9/Series CNC Mill Operation and Programming Manual Documentation Set - Manual (Page 455)

Programming Feedrates
Chapter 18
18-7
Feedrate Override Switch
Feedrates programmed in any of the feedrate modes (G93/94/95) can be
overridden using the feedrate override switch on the MTB panel. The
feedrate override switch has a range of 0-150 percent of the active feedrate,
and can alter the active feedrate in 10 percent increments.
The feedrate override switch operates on the feedrate that is active. The
active feedrate may be less than the feedrate you programmed if:
the control has limited the feedrate to the maximum cutting feedrate that
is defined in AMP
or
the Acc/Dec feedrate clamping has limited the active feedrate to a value
that the axis can decelerate from in the current block. See the section on
Short Block Acc/Dec on page 18-22.
The control checks whether the feedrate resulting from the feedrate
override switch setting exceeds the maximum cutting feedrate set in AMP.
If it does, the feedrate is restricted to the AMP maximum.
An M49 (overrides disabled) causes the override amounts that are set by
the switches or buttons on the MTB panel to be ignored by the control.
With M49 active, the override switches or buttons for feedrate, rapid
feedrate, and spindle speed are all set to 100 percent. They can be enabled
by programming an M48 (overrides enabled).
Rapid Feedrate Override
Rapid feedrate override on the MTB panel is used to override the rapid
feedrate for G00 mode in four increments:
F1 -- percent value set in AMP by system installer
25%
50%
100%.
Important: Normally this override is not active for any dry run motions
unless otherwise specified in PAL.
Important: This override is also effective for jog moves that use the rapid
feedrate (jogging using the {TRVS} button chapter 4).
18.1.6
Feedrate Overrides