Chapter 9 Installation and Wiring

(7) As a measure against very large surge(e.g. due to lightening),connect a surge absorber as shown below.

 

PLC

E1

E2

 

Surge absorber for lightening

 

(8)Use a insulating transformer or noise filter for protection against noise.

(9)Twist every input power supply wires as closely as possible. Do not allow the transformer or noise filter across the duct.

Remark

1)Ground the surge absorber(E1) and the PLC(E2) separately from each other.

2)Select a surge absorber making allowances for power voltage rises.

9.2.2 Input and Output Devices Wiring

(1)Applicable size of wire to the terminal block connector is 0.18 to 2 . However, it is recommended to use wire of 0.5 for convenience.

(2)Separate the input and output lines.

(3)I/O signal wires must be at least 100 (3.94 in) away from high voltage and large current circuit wires.

(4)When the I/O signal wires cannot be separated from the main circuit wires and power wires, ground on the PLC side with batch- shielded cables. Under some conditions it may be preferable to ground on the other side.

PLC

Input

Shielded cable

RA

DC

(5)If wiring has been done with of piping, ground the piping.

(6)Separate the 24VDC I/O cables from the 110VAC and 220VAC cables.

(7)If wiring over 200m or longer distance, trouble can be caused by leakage currents due to line capacity. Refer to the section ’11.4 Troubleshooting Examples.’

9-8

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LG Electronics 120S user manual Input and Output Devices Wiring