RS-485 Communication Features
7.2 Communication System Configuration
In an RS-485 communication system, the PLC or computer is the master device and the
inverter is the slave device. When using a computer as the master, the RS-232 converter
must be integrated with the computer, so that it can communicate with the inverter through
the RS-232/RS-485 converter. Specifications and performance of converters may vary
depending on the manufacturer, but the basic functions are identical. Please refer to the
converter manufacturer’s user manual for details about features and specifications.
Connect the wires and configure the communication parameters on the inverter by referring
to the following illustration of the communication system configuration.
Communication Line Connection
Make sure that the inverter is turned off completely, and then connect the RS-485
communication line to the S+/S-/SG terminals of the terminal block. The maximum number
of inverters you can connect is 16. For communication lines, use shielded twisted pair (STP)
cables.
The maximum length of the communication line is 1,200 meters, but it is recommended to
use no more than 700 meters of communication line to ensure stable communication.
Please use a repeater to enhance the communication speed when using a communication
line longer than 1,200 meters or when using a large number of devices. A repeater is
effective when smooth communication is not available due to noise interference.
When wiring the communication line, make sure that the SG terminals on the PLC and inverter
are connected. SG terminals prevent communication errors due to electronic noise interference.
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