Omron CJ1W-ID Series User Manual page 155

Grounding
Termi-
nal
name
LG Functional
Grounding
GR Protective
Grounding
• 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.
• The NJ-/CJ-series Controllers are designed to be mounted so that they are isolated (separated) from
the mounting surface to protect them from the effects of noise in the installation environment (e.g.,
the control panel).
• Do not share the Controller's ground with other equipment or ground the Controller to the metal struc-
ture of a building. Doing so may worsen operation. Whenever possible, use an independent ground
(with the ground pole separated by a minimum of 10 m from any other ground pole).
NJ-series CPU Unit Hardware User's Manual (W500)
LG (Noise-filter neutral terminal)
GR (Ground terminal)
Grounding
Symbol
type
Functional grounding is done to protect device and system func-
tions, including prevention of noise from external sources, or pre-
vention of noise from devices or equipment that could have
harmful effects on other devices or equipment.
Protective grounding is done to ensure safety. It is intended to pre-
vent electrical shock by grounding the electrical potential that is
generated by factors such as leakage, induction, or failure.
Power Supply Unit
Power supply
input terminal side CPU Unit side
LG
Function
GR
2
).
4 Installation and Wiring
4
4-31