Appendix A Modbuscommunication protocol
ICON500
high performance vector control frequency inverter user
manual
- 104
-
≥
3.5Byte
1Byte
1Byte
N*Byte
2Byte
≥
3.5Byte
空
闲
目
标
站
CRC
校
验
和
空
闲
(
起始
)
地址
命令
码
数据
L
„„
H
(
结
束
)
PDU
RTU
报
文
Appendix A
Modbus communication protocol
ICON500 series of inverter provides RS485 communication on interface, and adopts MODBUS
communication protocol. User can carry out centralized monitoring through PC/PLC to get operating
requirements and user can set the running command, modify or read the function codes, the
workingstate or fault information of frequency inverter by Modbus communication protocol.In
addition ICON500can also be used as a host to broadcast with other ICON500 communication.
Protocl fomat
RS485 asynchronous half-duplex.
RS485 terminal default data format: 1-8-N-1 (1 start bit, 8 data bits, no parity, 1 stop bit), the default baud
rate: 9600bps. See parameter group set 30.
Message format
The ICON500 series inverter Modbus message includes the start sign, the RTU message, and the
end sign
。
The RTU message includes the address code, the PDU (Protocol Data Uint, the protocol data unit),
and the CRC check. PDU includes the function code and the data section.
RTU frame format
：
Frame start (START)
More than the 3.5 byte transmission time
Target station address
(ADR)
Communication address:1 to 247(0: broadcastaddress)
Command code
(CMD)
Command
code
Description
0x03
Read multiple registers of the AC drive
0x06
Write a single register to the AC drive.
0x10
Write Multiple registers to the AC drive.
0x08
Diagnostic command code
Number of function
code
Including the register address (2Byte), the number of registers n(2Byte)
and the register content (2nByte), etc.see A3 in detail
CRC CHK low level
It indicates the replying data or the data waiting to
write-in. CRC 16 check value,During the transmission, high bit is put in
frontand low bit is at the back.see detail in A.5 Chapter
CRC CHK high level
FRAME END
More than 3.5 byte transmission time
