Omron NX Series User Manual page 123

Additional Information
The CPU Unit has no ground terminals, thus no DIN Track Contact Plates.
Therefore, the grounding part of the CPU Unit will be grounded through the Power Supply Unit.
Grounding the CPU Rack
This section describes how to ground the ground terminals on the CPU Rack.
The protective ground terminals on the Power Supply Units, the functional ground terminals that are
provided on some Units, and the DIN Track are grounded.
Power Supply Unit
DIN Track
Ground
• GR terminal is a ground terminal to prevent electrical shock. Always ground the terminal.
• LG terminal is a noise-filtered neutral terminal to increase noise resistance, and it is effective in sup-
pressing power supply common noise. The internal circuit is shown in the following figure. Ground
the LG terminal alone or connect the LG terminal with the GR terminal.
Power supply
input terminal
• When you ground the LG terminal or connect the LG terminal with the GR terminal, it may cause to
enter noise into devices or equipments. In this case, do not ground the LG terminal or connect the
LG terminal with the GR terminal.
• Ground the GR and LD terminals with a ground resistance of less than 100 Ω using a 14-gauge wire
(minimum cross-sectional area of 2 mm
• The ground wire should not be more than 20 m long.
• When wiring an AC Power Supply Unit, if one power supply phase of the equipment is grounded,
always connect the grounded phase to the L2/N terminal.
NX-series CPU Unit Hardware User's Manual (W535)
Electrically connected to the DIN Track
through the DIN Track contact plate.
Ground terminal
Power Supply Unit
Power supply
input terminal side CPU Unit side
LG
2
GR
).
4 Installation and Wiring
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