Fuji Bikes 5000G11S/P11S RS-485 Modbus RTU Serial Communications, Transmission Specification

9-4 RS-485 Modbus RTU Serial Communications

The serial interface supports operation, configuration and monitoring of inverter functions through an EIA/RS-485 connection. The serial interface is based on Modbus RTU protocol. This protocol allows the inverter to function as an RTU slave on an industrial network.

9-4-1 Transmission Specification

Item	Specification
Physical level	EIA/RS-485
Transmission distance	1600 ft (500 m)
Number of nodes	32 total
Transmission speed	19200, 9600, 4800, 2400 [bits/s]
Transmission mode	Half duplex
Transmission protocol	Modbus RTU
Character code	Binary
Character length	8 bits
Error check	CRC

9-4-2 Connection

Connection method

Use shielded wire and connect to the control terminals (DX-, DX+ and SD). A termination resistor should be added between the data lines on the each end of the network. The value of the termination resistor depends on the characteristic impedance of the cable. A common value for termination resistors is 120 ohms.

Control terminals

Terminal	Terminal name	Function description
marking
DX+	RS-485 communication data (+)	Input/output terminals for RS-485
DX-	RS-485 communication data (–)	communication.
SD	Cable shield	Electrically floating

9-4-3 Serial Interface Configuration

Inverter function codes H30 to H39 are used to configure the serial interface parameters, such as device address, baud rate and error response.

9-4-4 Modbus RTU Functions

The following RTU functions are supported. The maximum number of consecutive parameters for function 03 and 16 messages is 16.

Code Description

03Read Holding Registers (16 registers maximum)

06Preset Single Register

16Preset Multiple Registers (16 registers maximum)

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