Omron NJ501-1400 User Manual page 173

Wire Layout for the Power Supply System
Observe the following points when wiring the power supply system.
• Separate the Controller power supply from the I/O device power supply and install a noise filter near
the Controller power supply feed section.
• Use an isolating transformer to significantly reduce noise between the Controller and the ground.
Install the isolating transformer between the Controller power supply and the noise filter, and do not
ground the secondary coil of the transformer.
• Keep the wiring between the transformer and the Controller as short as possible, twist the wires well,
and keep the wiring separate from high-voltage and power lines.
Wiring External I/O Signal Lines
Observe the following points when wiring external I/O signal lines.
• To absorb reverse electromotive force when an inductive load is connected to an output signal, con-
nect a surge suppressor near the inductive load in an AC circuit, or connect a diode near the induc-
tive load in a DC circuit.
Inductive
load
Connect a diode in a DC circuit.
Input Signal Noise Countermeasures
• Never bundle output signal lines with high-voltage or power lines, and do not route them in close
proximity or parallel to such lines. If output signal lines must be routed in close proximity to such
lines, place them in separate ducts or conduits and be sure to ground the ducts or conduits.
I/O cables
Power lines
Suspended ducts
• If the signal lines and power lines cannot be routed in separate ducts, use shielded cable. Connect
the shield to the ground terminal at the Controller, and leave it unconnected at the input device.
NJ-series CPU Unit Hardware User's Manual (W500)
Power supply for general operations circuits
Noise
filter
Power Supply System Diagram
Controller
Diode
DC Input
Unit
Connect a surge suppressor in an AC circuit.
I/O cables Power lines
I/O cables
Floor ducts
I/O Cable Arrangement
4 Installation and Wiring
Power circuits
Power supply for Controller input circuits
Power supply for Controller output circuits
Power supply for Controller
Outlet (for peripheral devices)
Inductive
load
Controller
Output
Unit
Output Signal Noise Countermeasures
Power lines
Conduit
Inductive
load
Controller
Output
Unit
Connect a diode in a DC circuit.
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