Omron NX1P2 Series Hardware User Manual page 235

Additional Information
• In a country or region where the earthing method is regulated, you must comply with the reg-
ulations. Refer to the applicable local and national ordinances of the place where you install
the system, or other international laws and regulations.
• For details on wiring EtherCAT or EtherNet/IP, refer to the NJ/NX-series CPU Unit Built-in
EtherCAT Port User's Manual (Cat. No. W505) or the NJ/NX-series CPU Unit Built-in
EtherNet/IP Port User's Manual (Cat. No. W506).
• Ethernet switches are used with the EtherNet/IP. For information on the environmental resist-
ance of the Ethernet switch to use, the grounding between Ethernet switches, or the specifi-
cations of cables, ask the Ethernet switch manufacturer.
Each of these earthing methods is given below.
l Equipotential Bonding System
Equipotential bonding is an earthing method in which steel frames and building structures, metal
ducts and pipes, and metal structures in floors are connected together and make connections to
the earth trunk line to achieve a uniform potential everywhere across the entire building. We recom-
mend this earthing method.
The following figure shows an example of an equipotential bonding system.
Connect the main earthing terminal and building structures together with equipotential bonding con-
ductors and embed the mesh ground line in each floor.
Connect the ground line of each control panel to the equipotential bonding system.
Earth trunk line
Control panel
Equipotential bonding conductor
Building structure
l Star Earthing
If the earthing method used for the building is not equipotential bonding or the earthing system is
unknown, choose (a) from among the earthing methods given below.
a. Connecting devices and noise sources to separate earth electrodes
This is an earthing method to separately ground an earth electrode of the device that is con-
nected with a communications cable or other devices and an earth electrode of a high-power
NX-series NX1P2 CPU Unit Hardware User's Manual (W578)
Power device
Information device
Control panel Control panel
Hub
Metal structure in floor
Earth electrode
Metal duct and pipe
Noise source
Main earthing terminal
5 Installation and Wiring
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