7
Connecting the RS485 Communications Cable
4.5
Port
Identifier
Description
COM1, COM2, COM3
+
RS485A, RS485 differential
–
RS485B, RS485 differential signal
–
• It is recommended that the RS485 communication distance be less than or equal to 1000 m.
• The SmartModule can connect to RS485 communications devices, such as a solar inverter, an
environmental monitoring instrument (EMI), and a power meter over the COM port.
• Ensure that the RS485+ and RS485– terminals are respectively connected to the COM+ and
COM
– ports on the SmartModule.
Cascading Connection
• You are advised to connect fewer than 30 devices to each RS485 route.
• The baud rate, communications protocol, and parity mode of all devices on the RS485
cascading link must be the same as those of the COM ports on the SmartModule.
