Emerson FB3000 - Connecting a Serial Port to an RS-232 Device (3 SRSG4); 4-Port Communications Module

FB3000 RTU Instruction Manual
D301851X012
November 2023
Installation 41
Port
Pin
RS-232
4-wire RS-485
2-wire RS-485
13
RxD3
RxD3+
X
14
CTS3
RxD3-
X
15
GND3
GND3
GND3
COM4
16
TxD4
TxD4+
TxRxD4+
17
RTS4
TxD4-
TxRxD4-
18
RxD4
RxD4+
X
19
CTS4
RxD4-
X
20
GND4
GND4
GND4
X = N/C
Use FBxConnect software to choose the port usage for each of the four COM ports on the
4-port Communications module.
Note
Older standards refer to RS-485 (4-wire) as RS-422.
2.11.2 Connecting a serial port to an RS-232 Device (3SRSG4)
You can wire any of the four serial ports for communication with an RS-232 device.
When connecting a COM port to another device using RS-232, follow this configuration:
Figure 2-31. COMn Port Configured for RS-232
1
RS-232 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