Emerson FB3000 - Connecting a Serial Port to an RS-485 (2-Wire) Device (3 SRSG4)

FB3000 RTU Instruction Manual
D301851X012
November 2023
Installation 43
2.11.4 Connecting a serial port to an RS-485 (2-wire) Device
(3SRSG4)
You can wire any of the four serial ports for communication with an RS-485 (2-wire)
device.
When connecting a COM port to another device using RS-485 (2-wire), follow this
configuration:
Figure 2-33. COMn Configured for RS-485 (2-wire)
1
RS-485 (2-wire) port on device
2
Connect cable shields to suitable Instrument Earth connection point
Notes
 For COM1, n=1, pin numbers as follows: a=1, b=2, c=3, d=4, e=5
 For COM2, n=
2, pin numbers as follows: a=6, b=7, c=8, d=9, e=10
 For COM3, n=3, pin numbers as follows: a=11, b=12, c=13, d=14, e=15
 For COM4, n=4, pin numbers as follows: a=16, b=17, c=18, d=19, e=20