Chapter 9 Installation and Wiring

9.2.3 Grounding

(1)This PLC has sufficient protection against noise, so it can be used without grounding except for special much noise. However, when grounding it should be done conforming to below items.

(2)Ground the PLC as independently as possible. Class 3 grounding should be used (grounding resistance 80or less).

(3)When independent grounding is impossible, use the joint grounding method as shown in the figure below (B).

PLC

Other device

PLC

Other device

PLC

Other device

Class 3 grounding

Class 3 grounding

 

 

(A)Independent grounding : Best

(B) Joint grounding : Good

(C) Joint grounding : Not allowed

(4) Use 2 (14AWG) or thicker grounding wire. Grounding point should be as near as possible to the PLC to minimize the distance of grounding cable.

9.2.4 Cable Specifications for wiring

The specifications for wiring is as follows:

 

Kinds of external connection

 

 

Cable Specifications ()

 

 

 

 

Minimum

 

 

Maximum

 

 

 

 

 

 

 

 

 

Digital Input

 

0.18 (AWG24)

 

 

1.5 (AWG16)

 

 

 

 

 

 

 

 

 

 

Digital Output

 

0.18 (AWG24)

 

 

2.0 (AWG14)

 

 

 

 

 

 

 

 

 

 

Analog Input / Output

 

0.18 (AWG24)

 

 

1.5 (AWG16)

 

 

 

 

 

 

 

 

 

 

Communication

 

0.18 (AWG24)

 

 

1.5 (AWG16)

 

 

 

 

 

 

 

 

 

 

Main power

 

1.5 (AWG16)

 

 

2.5 (AWG12)

 

 

 

 

 

 

 

 

 

 

Grounding

 

1.5 (AWG16)

 

 

2.5 (AWG12)

 

 

 

 

 

 

 

 

 

 

Be sure to use solderless terminal for power supply and I/O wiring.

Be sure to use M3 type as terminal screw.

Make sure that terminal screw is connected by 69 ㎏·㎝ torque..

Be sure to use fork shaped terminal screw as shown below.

cable solderness terminal (fork shaped)

less than 6.2mm

9-9

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LG Electronics 120S user manual Installation and Wiring Grounding, Cable Specifications for wiring