Omron CP1H CPU Operation Manual page 741

Connections to Serial Communications Option Boards
Recommended RS-422A/485 Wiring Examples
Use the following wiring methods for RS-422A/485 to maintain transmission quality.
1. Always use shielded twisted-pair cables as communications cables.
Model
CO-HC-ESV-3Px7/0.2
2. Connect the shield of the communications cable to the FG terminal on the RS-422A/485 Option Board. At
the same time, ground the ground (GR) terminal of the CPU Unit to 100 Ω or less.
Note Always ground the shield only at the RS-422A/485 Option Board end. Grounding both ends of the shield
may damage the device due to the potential difference between the ground terminals.
Connection examples are shown below.
• 2-Wire Connections
CP1H CPU Unit
Option Board
Pin Signal
• 4-Wire Connections
CP1H CPU Unit
Option Board
Pin Signal
• Using a B500-AL001-E Link Adapter
CP1H CPU Unit
Option Board
RS-422
Pin
Signal
Manufacturer
Hirakawa Hewtech Corp.
Remote device
Signal
A (−)
B (+)
Shield
Remote device
Signal
Shield
B500-AL001-E
Pin
Signal Signal Pin
RS-422
interface
Signal
Pin
RS-422
Remote device
RS-422
Signal
Remote device
Signal
Appendix F
707