Emerson FB1100 - Connecting to COM2 and COM3

FB1100 Flow Computer Instruction Manual
D301752X012
November 2023
Installation 41
When connecting COM1 to another device using RS-485 (2-wire), use a cable with
configurations as shown in Figure 2-27:
Figure 2-27. Connecting a Device to COM1 Using RS-485 (2-wire)
1
RS-485 (2-wire) port (COM1) on FB device
2
RS-485 (2-wire) port on external device
Regardless of the interface standard (RS-232, RS-485 [2-wire] or RS485 [4-wire]), you must
use FBxConnect to configure the port for proper usage.
2.13.2 Connecting to COM2 and COM3
COM2 and COM3 operate identically. Each can be configured for either RS-232 or RS-485
(2-wire) communication.
When connecting COM2 or COM3 to an RS-232 port on another device (a PC or another
controller/flow computer) use a cable with configurations as shown in Figure 2-28.
Note
Neither COM2 nor COM3 has its own GND terminal. Use either GND terminal on the COM1
terminal block.