Omron CJ2 CPU UNIT - Example of Recommended RS-422 A;485 Wiring; Connections to the CPU Unit

Appendices
A-136
CJ2 CPU Unit Hardware User’s Manual
z Connections to the CPU Unit
• Always turn OFF the power supply to the PLC before connecting or disconnecting communica-
tions cables.
• Tighten the communications connector attachment screws to 0.4 N·m.
We recommend using the following wiring for RS-422A/485 to ensure transmission quality.
1 Use shielded twisted-pair cable for communications cables.
• Recommended RS-422A/485 Cable
2 Connect the shield on the communications cable to the FG terminal on the RS-422A/485 Option
Board. Also, ground the protective earth (GR) terminal on the CPU Unit to a resistance of 100 Ω
or less.
Precautions for Correct UsePrecautions for Correct Use
Connect the shield on the communications cable to the FG terminal on the RS-422A/485 Option
Board. Do not connect it on the other end of the cable. If you ground both ends, a difference in
ground potential may damage the equipment.
Example of Recommended RS-422A/485 Wiring
Model Manufacturer
CO-HC-ESV-3P × 7/0.2 Hirakawa Hewtech Corp.