Omron NX-PA Series User Manual page 138

4 Installation and Wiring
Control panel
Precautions for Grounding
• To prevent electrical shock, do not connect devices to ground poles (or steel frames) with
non-equalized potential to which multiple devices are connected.
• Use a ground pole as close to the Controller as possible and keep the ground line as short as pos-
sible.
• If the same ground is used for both the signal lines and the enclosure, isolate the channel base (a
grounded metal plate inside a control panel) with an insulating material.
Refer to Isolating the CPU Rack from the Control Panel on page 4-38 for how to isolate the
NX-series Controllers.
Example: Insulating and Grounding an Enclosure
• If high-frequency equipment is present, then ground not only the high-frequency equipment but
also the panel itself in which the Controller is housed.
• As shown in the following diagram, when using shielded cable for I/O wiring, connect the shield
near the Controller to the enclosure ground terminal.
Follow the instructions in the Communications Unit manual for preparing shielded communica-
tions cable.
4 - 50
Other device NX-series CPU Units
Hub
Insulating material
Channel base
Controller
Input Output
Common Common
Shielded Cable Ground
A device that could be
NX-AUX01 a noise source
PLC
NX-series CPU Unit Hardware User's Manual (W535)