Rockwell Automation 8520 9/Series CNC Integration Maintenance Manual Documentation Set - Manual (Page 340)

Section 6
Emergency STOP Design
6-4
Important: You may need to add a pilot relay if your E-Stop has one of
these characteristics:
the E-Stop string is very long
devices on the string cause a such a large line drop in the string that the
E-Stop relay will not latch.
In these cases, the control may:
not come out of E-Stop
enter E-Stop at different times during operation when the E-Stop string
voltage varies slightly
If your application requires a separate E-Stop pilot relay, you must provide
an external power supply to power the E-Stop string. The contactors of this
pilot relay are used to break the controls 12V E-Stop string. A typical
layout for this E-Stop string is shown in Figure 6.3.
ATTENTION: E-Stop wiring with a pilot relay requires circuit
continuity for normal operation (a customer’s E-Stop string
should be a normally closed circuit). Loss of power to the
external power supply should constitute an E-Stop condition.
Failing to do this may cause injury to personnel or damage to
the machine tool.
ATTENTION: Contact ratings on the control are DC only.
Figure 6.3
Typical Customer E-Stop String with Pilot Relay
MACHINE
DRIVES ENCLOSURE
Motor thermal switches
may be connected
directly
Extreme overtravel
switches
Drive System Ready,
(DROK TB1 on 1394)
(internally Connected on 9/440)
Remote
E-Stop
button
4
5
Customer Supplied
External Power Supply
for E-Stop String
6
Pilot Relay
11250-I
E-Stop connector (TB1)
on Motherboard for 9/260 or 9/290 and on the
processor board for the 9/230
CR