Rockwell Automation 8520-GUM 9/Series CNC Grinder Operation and Programming Manual Documentation Set - Manual (Page 359)

Chapter 11
Coordinate Control
11-43
The control stops grinding wheel travel during overtravel conditions.
Overtravel conditions can occur from 3 causes:
hardware overtravel ---- the axes reach a travel limit, usually set by a
limit switch or sensor mounted on the axis. Hardware overtravels are
always active.
software overtravel ---- commands cause the axis to pass a software
travel limit. Software overtravels are active only after the axis has been
homed provided the feature has been activated in AMP by your system
installer.
programmable zone overtravel ---- The wheel reached a travel limit
established by independent programmable areas. Programmable zones
are activated through programming the appropriate G code.
In all cases, the control issues an error message.
When an overtravel condition occurs, all axis motion is forced to a stop,
the control is placed in cycle stop and one of the following applicable error
messages appears:
If you see this error message: It means that:
“HARDWARE OVERTRAVEL (-) AXIS (X)” the specified axis has tripped either the + or -
hardware limit switch mounted on the machine
“SOFTWARE OVERTRAVEL (+) AXIS (X)” the specified axis has entered the overtravel area
defined by the software overtravel limits in either a
positive or negative direction
“VIOLATION OF ZONE (2) AXIS (X)” the wheel has reached the specified axis
overtravel area defined by either programmable
zone 2 or 3
When an overtravel of any type has taken place, axis feed in the same
direction as the feed causing the overtravel is not allowed. Only axis feed
in the reverse direction is possible.
How a hardware overtravel condition is reset depends on the E-STOP
circuit design and the way PAL was programmed by your system installer.
To reset a software or programmable zone overtravel condition:
1. Determine whether the control is in E-STOP. If it is not, go to step 4.
2. Eliminate any other possible conditions that can have caused
emergency stop, then make sure that it is safe to reset the emergency
stop condition.
11.8.5
Resetting Overtravels