Rockwell Automation 8520 9/Series CNC Lathe - Manual (Page 432)

Programming Feedrates
Chapter 18
18-6
Rapid feedrate drives all active axes at a speed which creates a linear
move. The control determines which axis must travel the furthest and
drives that axis at its maximum feedrate assigned in AMP. Use rapid
feedrate to position the tool to a specified point at a high speed. It is called
during the execution of a G00 code followed by an axis motion command
and in many of the canned cycles for positioning.
After the execution of a rapid move the control restores the previously
commanded feedrate.
You can drive axes at their maximum allowable speeds during the jogging
operations by holding down the button while executing a jog
move. (For details on jogging an axis see chapter 4).
Use rapid feedrate to position axes to a specified point at a high speed. It
is called by executing a G00 followed by an axis motion command. It also
is called automatically for some of the motions made by the fixed cycles.
See the fixed cycle specifications.
When you command more than one axis to move at rapid feedrate, they are
driven together to produce a linear move. The control drives one of the
axes at its rapid feedrate and reduces the feedrate of the others as required
to make certain that all axes start and stop at the same time.
Switch
You can override feedrates programmed in any of the feedrate modes
(G93/94/95) using the switch on the MTB panel.
The switch has a range of 0-150% of the
programmed feedrate, and it can alter the programmed feedrate in 10
percent increments.
The control checks whether the feedrate resulting from the
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 on the MTB panel to be ignored by the control. With M49
active, the override switches for feedrate, rapid feedrate, and spindle speed
are all set to 100%. They can be enabled by programming an M48
(overrides enabled). See chapter 10 for details.
The feedrate override switch overrides the current axis feedrate. This may
or may not be the currently programmed feedrate. In cases where Acc/Dec
or the feedrate clamp features have overridden the programmed feedrate,
the feedrate override switch adjusts the new Acc/Dec or clamped feedrate.
18.1.4
Rapid Feedrate
18.1.5
Feedrate Overrides