IAI America REXT - Manual (Page 294)

Part 2 Startup Chapter
(5) RS485SIO
Using the 2-wire method, connnect the Gateway R unit (RG W-SIO) to the RS-422A/485 port on the serial communication
unit (SCU) of the PLC, as shown below.
Gateway R unit PLC-SCU
RS--422A/485 connector
Cable connector (supplied)
(D-sub 9-pin male connector as
viewed from the soldered side)
MC1.5/4-ST-3.5 (manufactured by
Phoenix Contact)
Use a shielded twisted pair cable (AWG28-16) for the communication cable.
Gateway R unit
Shield
Shell
Caution
1. The polarities of the communication lines may be the other way around depending on the SCU of PLC.
SA (+) on Gateway R SDB (+) on SCU, SB (-) on Gateway R SDA (-) on SCU.,
2. Connect the shield to ground only on the PLC-SCUU end.
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