Huawei SmartModule1000A01 Quick Manual page 8

4.5 Connecting the RS485 Communications Cable
•
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.
Port
COM1, COM2, COM3
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.
Identifier
+
–
Description
RS485A, RS485 differential signal+
RS485B, RS485 differential signal–
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