Allen-Bradley 2711P Technical Data Manual page 13

Earth/Ground Connection for Isolated DC Terminals
PanelView Plus 700 to 1500 terminals with an isolated DC power supply have an
earth/ground terminal that you must connect to a low-impedance earth/ground.
IMPORTANT
The earth/ground connection is on the rear of the display module. The
earth/ground terminal wiring requires a minimum wire gauge.
Table 6 - Earth/Ground Wiring for Isolated DC Terminals
PE Symbol
The earth/ground terminal is typically connected to a system grounding bus. If
the grounding bus has tapped holes, the conductor from the functional earth
terminal must have a ground lug on the ground bus end. A bolt should pass
through a star washer, then through the ground conductor lug, then into the
ground bus.
Use the shortest, practical wire length to connect the earth/ground to a
low-impedance earth/ground. The ground wire must be either green or green
with a yellow stripe. Refer to local wiring codes and regulations for grounding
requirements.
Figure 5 - Earth/Ground Connection for 700 to 1500 Isolated DC Terminals
Ground Bus
Star Washer
Ground Lug
Bolt
Rockwell Automation Publication 2711P-TD001D-EN-P - February 2011
Wiring and Grounding Guidelines for PanelView Plus Terminals
The earth/ground connection to ground is mandatory. This connection is
required for noise immunity, reliability, and Electromagnetic Compliance
(EMC) with the European Union (EU) EMC directive for CE-mark
conformance and for safety by Underwriters Laboratory.
Wire Type
GND Cu 90 °C (194 °F)
Stranded or solid
ATTENTION: Damage or malfunction can occur when a voltage potential
exists between two separate ground points. Make sure the PanelView
Plus terminal does not serve as a conductive path between two ground
points at different potentials.
Earth/Ground to Ground Bus
Tapped Hole
Ground Bus
Wire Gauge
2
Copper 2.1...5.3 mm
(14...10 AWG)
To Grounding Electrode System
13
Terminal Screw Torque
1.13...1.36 N•m
(10...12 lb•in)
Enclosure Wall