Rockwell Automation 57C422B 2 Axis Servo Module - Manual (Page 34)

4-6 2-Axis Servo Module M/N 57C422B
If you intend to use the feedback marker during the home
sequence, you should enable the feedback encoder marker
pulse. Refer to section 4.35 for more information on the
“home axis” command in register 66.
To prevent your machine from moving beyond specified
physical limits, use the enable overtravel L/S bit. You can
define the condition to be true when the limit switch is closed
(normally open) or open (normally closed). If an overtravel
limit switch is tripped during operation, the control will be
turned off and, if programmed, the drive will coast to a stop.
The machine will then have to be moved off the overtravel
limit switch before the control can be re-enabled. In critical
applications, hardwire the overtravel L/S into the emergency
stop circuit so that the drive will be disabled regardless of the
state of the control.
The drive fault input is a simple means of shutting off the axis
control. This input can be either a fault signal from the drive
or an E-STOP push-button. You can define the asserted
sense of the input as either normally open or normally
closed. If the drive fault input is tripped, the axis control will
be disabled and, if programmed, the drive will coast to a
stop.
The software overtravel bit is a programmable way of limiting
machine travel. You can define the action that occurs when
the software overtravel limit is exceeded as either a decel to
stop or a coast to stop. If you have specified a decel to stop,
the drive will decelerate at the specified rate to zero speed
and regulate about that position. If you have specified a
coast stop, the drive control will be disabled and the drive will
coast to rest. When the drive has exceeded a software
overtravel limit, and if you have specified a "decel to stop,"
the drive can be commanded to move away from the
overtravel condition.
WARNING
RELIANCE STRONGLY RECOMMENDS THE USE OF AN
EXTERNAL, HARDWIRED EMERGENCY STOP CIRCUIT THAT
WILL DISABLE THE SYSTEM IN CASE OF IMPROPER
OPERATION. UNCONTROLLED MACHINE OPERATION MAY
RESULT IF THIS PROCEDURE IS NOT FOLLOWED. FAILURE
TO OBSERVE THIS PRECAUTION COULD RESULT IN BODILY
INJURY.