Omron CQM1H-SCB41 Recommended RS-232C Wiring Examples, Pin Function Factory Setting

Installation			Section 2-3
	Pin		Function	Factory
				setting
	1	Not used. Always set this pin to ON.		ON
	2	Built-in terminating resistance setting		ON
		ON:	Connects terminating resistance.
		OFF:	Disconnects terminating resistance.
	3	2/4-wire setting		OFF
		2-wire: Set both pins to ON.
	4			OFF
		4-wire: Set both pins to OFF.
	5	Transmission mode (See note)		ON
		Constant transmission: Set both pins to OFF.
		Transmission performed when CTS signal in RS-232C
	6	interface is at high level: Set pin 5 to OFF and pin 6 to ON.		OFF
		Transmission performed when CTS signal in RS-232C
		interface is at low level: Set pin 5 to ON and pin 6 to OFF.

Note When connecting to a CQM1H-series CPU Unit, turn OFF pin 5 and turn ON pin 6.

2-3-5 Recommended RS-232C Wiring Examples

It is recommended that RS-232C cables be connected as described below, es- pecially when the Serial Communications Board is used in an environment where it is likely to be subject to electrical noise.

1, 2, 3... 1. Always use shielded twisted-pair cables as communications cables.

Model	Manufacturer
UL2464 AWG28x5P IFS-RVV-SB (UL-approved)	Fujikura Ltd.
AWG28x5P IFVV-SB (not UL-approved)
UL2464-SB (MA) 5Px28AWG (7/0.127) (UL-approved)	Hitachi Cable,
CO-MA-VV-SB 5Px28AWG (7/0.127) (not UL-approved)	Ltd.

2.Combine signal wires and SG (signal ground) wires in a twisted-pair cable. At the same time, bundle the SG wires to the connectors on the Serial Com- munications Board and the remote device.

3.Connect the shield of the communications cable to the Hood (FG) terminal of the RS-232C connector on the Serial Communications Board. At the

same time, ground the ground (GR) terminal of the Power Supply Unit to 100 Ω or less.

4.A connection example is shown below.

Example: Twisted-pair Cable Connecting SD-SG, RD-SG, RTS-SG, and CTS-SG Terminals

Serial

Communications

Board

Pin	Signal
	SD
	RD
	RTS
	CTS
	SG
Hood	FG	Shield
	FG

Remote device

Signal

RD

SD

CTS

RTS

SG

FG

Actual Wiring Example

SG signal wires

Twist the braided shield to make it thinner and connect to Pin No. 1 (FG). Cover this section with heat-shrink tube to avoid contact with other sections.

Bundle the SG wires.

Aluminum foil

XM2S-0911-E

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