Rockwell Automation 8520-MUM 9/Series CNC Mill Operation and Programming Manual Documentation Set - Manual (Page 456)

Programming Feedrates
Chapter 18
18-8
Feedrate Override Switch Disable
An M49 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
percent. They can be enabled by programming an M48 (overrides
enabled).
Feedhold
The system installer may have written PAL to allow the activation of a
feedhold state through the use of a button or switch. When activated the
control will decelerate and hold the current feedrate for all axes to zero
until the feedhold state is deactivated. For details on using feedhold refer
to documentation provided by the system installer.
The system installer can set the allowed maximum cutting feedrate for
each axis individually in AMP. If a feedrate is programmed that would
cause an individual axis to exceed its limit, the control automatically
reduces the feedrate for the tool to keep the limiting axis at its maximum
cutting feedrate. This function is called feedrate clamping.
Figure 18.6
Feedrate Clamp
X
Y
F
F
YMAX
F
p
F
xMAX
: maximum X axis feedrate
F
YMAX
: maximum Y axis feedrate
F
p
: programmed feedrate
F : actual feedrate
F
XMAX
The programmed feedrate, F
p
in Figure 18.6, would cause the X axis
feedrate to exceed its maximum feedrate, F
x
max. consequently, the control
uses F as the actual feedrate.
18.1.7
Feedrate Limits (Clamp)