Omron NT631C manual TKVVBS4P-03

Connecting to the Host’s RS-232C Port				Section 5-1
	Name	Model	Maker	Remarks
	Cable	TKVVBS4P-03	Tachii Electric Wire
			Co., Ltd.
	Crimp ter-	1.25-N3A	Japan Solderless	Recommended cable size:
	minals	(fork type)	Terminal MFG	AWG22 to 18
		Y1.25-3.5L (fork	Molex Inc.	(0.3 to 0.75 mm2)
		type)

The terminal screws of the NT631/NT631C are M3.5 specification. When wir- ing, use crimp terminals for M3.5 use. Tighten terminal screws with a tighten- ing torque of 0.8 N⋅m.

Note Always use crimp terminals for wiring.

Examples of applicable terminals

Fork type

7 mm max.

Round type

7 mm max.

5-1-5 Setting the Terminal Resistance for RS-422A/485 Communications

The serial port B connector of the NT631/NT631C has a terminal resistance setting terminal (TRM).

In RS-422A/485 communications, a terminal resistor must be set at the device at the end of the communications cable, but not at any other device.

The NT631/NT631C has a built-in terminal resistor, and whether or not the terminal resistance is applied is set by shorting or opening the terminal resis- tance setting terminals (TRM). The terminal resistance is 120 Ω.

When carrying out RS-422A/485 communications using serial port B, short between TRM and RDA terminals at the NT631/NT631C at the end of the RS- 422A/485 cable. Leave these terminals open at NT631/NT631C PTs other than the one at the end of the cable.

When not using RS-422A/485 communications, the terminal resistance set- ting is ineffective.

Short-circuit tool

RDA

TRM

RDB

SDA

TRM-RDA terminals	Function
Shorted	Terminal resistance is applied.

Short only at the NT631/NT631C connected to the end of an

RS-422A/485 cable.

Open Terminal resistance is not applied.

Leave the terminals open when connecting an NT631/ NT631C anywhere other than at the end of the RS-422A/485 cable.

Note Before connecting or disconnecting cables between devices, make sure that the power supply to all of the connected devices (NT631/NT631C, PLC, etc.) is OFF.

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