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5 resetting overtravels – Rockwell Automation 8520 9/Series CNC Lathe User Manual

Page 341

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Chapter 12

Overtravels and Programmable Zones

12-13

Tool motion stops during overtravel conditions that occur from 3 causes:

Cause:

Description:

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 the system installer.

Programmable zone

overtravel

The tool 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 stops, the control goes into cycle stop and

one of the these error messages appears.

Error Message:

Description:

HARDWARE OVERTRAVEL

(-) BY AXIS (X)

indicates that the specified axis has tripped either the + or -

hardware limit switch mounted on the machine.

SOFTWARE OVERTRAVEL

(+) BY AXIS (X)

indicates that 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) BY

AXIS (X)

indicates that a tool has reached the specified axis overtravel
area defined by either programmable zone 2 or 3.

When an overtravel of any type occurs, axes cannot move in the same

direction as the feed causing the overtravel. Only axis motion 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 may have caused an

emergency stop, then make sure that it is safe to reset the emergency

stop condition.

3.

Press the

button to reset the emergency stop

condition. If the E-Stop does not reset, it is a result of some cause

other than overtravel.

4.

Make sure it is safe to move the axis away from the overtravel limit.

5.

Use any of the jog features described on page 4-1 except homing, to

manually move the axis away from the limit.

END OF CHAPTER

12.5

Resetting Overtravels