Relay Output Noise Reduction Methods - Omron CP1E-E14SDR-A User Manual

5 Installation and Wiring
Reducing Electrical Noise for External Wiring
Take the following points into account when externally wiring I/O, power supply, and power lines.
• When multi-conductor signal cable is being used, do not combine I/O wires and other control wires in
the same cable.
• If wiring racks are parallel, allow at least 300 mm between them.
PLC I/O wiring
PLC power supply
General control
circuit wiring
Power lines
• If the I/O wiring and power cables must be placed in the same duct, they must be shielded from each
other using grounded steel sheet metal.
PLC power supply
General control
PLC I/O wiring circuit wiring
Ground to 100 Ω or less.
5-3-5

Relay Output Noise Reduction Methods

The CP1E PLCs conforms to the Common Emission Standards (EN61131-2) of the EMC Directives.
However, noise generated by relay output switching may not satisfy these Standards.
In such a case, a surge protector must be connected to the load side or other appropriate countermea-
sures must be provided outside the PLC. Countermeasures taken to satisfy the standards vary depend-
ing on the devices on the load side, wiring, configuration of machines, etc.
Following are examples of countermeasures for reducing the generated noise.
Countermeasures (Refer to EN 61131-2 for details.)
• Countermeasures are not required if the frequency of load switching for the whole system with the
PLC included is less than 5 times per minute.
• Countermeasures are required if the frequency of load switching for the whole system with the
PLC included is more than 5 times per minute.
5-22
Low-current
cables
300 mm min.
Control cables
300 mm min.
Power cables
Ground to 100 Ω or less.
Power lines
Steel metal
200 mm min.
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