6
4.3 Serial Communications Ports
These connectors provide access to the Modbus registers using RS232 or 2-wire RS485.
The port configuration is as follows:
Modbus RTU
9600 baud, 8 data bits, no parity, 1 stop bit
The RS485 interface can be used on a compatible serial communications network shared
by multiple RS485 devices. The ‘Base Slave Address’ must be set to prevent multiple units
using the same slave numbers.
It is recommended that screened twisted-pair cable is used.
RS485-A is the non-inverting signal and is also named RS485+
RS485-B is the inverting signal and is also named RS485-
Common should be connected to the cable screen.
Serial Comms
Port
Pin 5
Pin 3
Pin 2
To PC
Comm Port
9 PIN D-SUB FEMALE
Serial Comms
Port
RS485-B
RS485-A
RS485
network
Common
A
B
Fig. 2 RS232 Comms Lead Wiring Diagram
Fig. 3 RS485 Comms Lead Wiring
Diagram
