Appendix 4 MODBUS Communication
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Appendix 4 MODBUS Communication
This series of inverter can perform serial transmission by using a programmable
controller (PLC) and MODBUS communication.
Composition of MODBUS Communication
MODBUS is composed of one master PLC and 1 to 31 (maximum) slave inverters. In
signal transmission between master and slave units, the master unit always starts
transmission and the slave units respond to it.
The master unit performs signal transmission with one slave unit at a time. Hence,
different address numbers must be assigned to each slave unit in advance and the master
unit specifies a number to perform signal transmission.
The slave receives the command from the master, performs the function and returns the
response to the master unit.
MODBUS Communication Specification
Interface RS-485
Start-stop synchronous Asynchronous, half-duplex Communication.
Communication parameters
Baud rate: 1200/2400/4800/9600/19200/38400 bps
Data length: 8 bit fixed.
Parity selection: EVEN / ODD / NONE
STOP bit: 1 bit fixed.
Communication protocol In accordance with MODBUS
Maximum number of units to
be connected
31
MODBUS Communication Terminals
To use MODBUS communication function, please connect Terminal 485+, Terminal
485- to PLC. If there is more than one inverter connected to PLC, the terminal resistance
should switch at ON position as the following. (The terminal resistance is only for
model of 35R5GB/37R5PB and above models)
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