Grounding - Omron NX Series Hardware User Manual

5 Installation and Wiring
High-voltage power panel
Power lines
200 mm
Controller
Example: Separating Controller from Power Lines
l Other Precautions
• Digital I/O Units have both plus and minus commons, so pay attention to the polarity when wir-
ing.
5-5-6

Grounding

This section describes the earthing methods and precautions.
Considerations for Earthing Methods
Local potential fluctuations due to lightning or noise occurred by power devices will cause potential
fluctuations between ground terminals of devices. This potential fluctuation may result in device mal-
function or damage. To prevent this, it is necessary to suppress the occurrence of a difference in elec-
trical potential between ground terminals of devices. You need to consider the earthing methods to
achieve this objective.
The recommended earthing methods for each usage condition are given in the following table.
Specification of communications cables for
EtherCAT and EtherNet/IP
The cable shield connected to the connector
hood at both ends of the communications cable
Neither EtherCAT nor EtherNet/IP used
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.
5-64
Power
lines
Controller
200 mm
Equipotential
bonding sys-
Recommend-
ed
Recommend-
ed
Metal tubing
Ground to 100 Ω or less
Earthing methods
Star earthing
Connecting devi-
ces and noise
sources to sepa-
tem
rate earth elec-
trodes
Recommended
Recommended
NX-series NX502 CPU Unit Hardware User's Manual (W629)
Connecting devi-
ces and noise
Daisy chain
sources to a
common earth
electrode
Not recommend- Not recom-
ed mended
Not recommend- Not recom-
ed mended