LG Electronics 120S user manual Wire resistance ≤10 Ω

Chapter 7 Usage of Various Functions

9) Wiring

(1) Caution for wiring

•Make sure that external input signal of the mixture module of AC and analog I/O is not affected by induction noise or occurs from the AC through using another cable.

•Wire is adopted with consideration about peripheral temperature and electric current allowance. Thicker than Max. size of wire AWG22 (0.3 ㎟) is better.

•If wire is put near to high temp. radiated device or contacted with oil for a long time, it may cause of electric leakage so that it gets broken or miss-operation during wiring.

•Be sure to connect with care of polarity while connecting to external 24V DC power supply.

•In case of wiring with high voltage line or generation line, it makes induction failure so then it may cause of miss-operation and out of order.

(2)Wiring example

•Number of method of connection between Pt and RTD input module are three, that is, 2-wired type, 3-wired type and 4-w wired type.

•The resistance of the wires used to connect Pt to RTD input module should be 10 Ω or less per wire.

The same wire (in thickness, length, and kind, etc.) should be used for each channel.

Connection	Connection Example		Wire Conditions
Method
2-wired type
			wire resistance≤10Ω
			wire resistance≤10Ω
			wire resistance≤10Ω
3-wired type
		The difference between the resistance values
		of the wires	① and ② : 1Ω or less
		The difference between the resistance values
		of the wires	② and ③ : 1Ω or less
4-wired type
		The difference between the resistance values
		of the wires	③ and ① : 1Ω or less

Method of Connection between Pt and RTD Input Module

*1: RTD (Pt100 or JPt1000)

*:2: Shielded wire - The shields of the RTD and shields of wire should be connected to the FG of the RTD input module.

REMARK

The difference between the resistance values of the wires used should be 1 Ω or less, or the accuracy shown in 1) performance specification could not be satisfied.

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