MODBUS Protocol 86
Appendix II: MODBUS Protocol Specification
1. Communication setting
F4.00＝X1XX, select MODBUS RTU protocol；
Note: X represents that the bit is arbitrary number.
2. Communication function
Complete communication between upper machine and inverter, including sending
operation command to inverter, setting running frequency, rewriting function
code parameter, reading running status of inverter, monitoring parameter, fault
message and function code parameter.
3. Protocol format
MODBUS RTU format
ADU
＞3.5
character
transmission
interval
Slave
machine
address
Function
code
CRC
Data
check
＞3.5 character
transmission
interval
PDU
1.1 Interpretation of protocol format
1. Slave address
0 is broadcast address and the slave address can be set as 1-30.
2. PDU part
(1) Function code 03: Read functional parameters, running status, monitoring
parameter and fault message of multiple inverters,and 6 inverter parameters with
continuous address at most in one time.
Sent by main machine:
PDU PART
03
Data length(Byte) 1
Register initial address
High
Low
1
1
Number of registers
High
Low
1
1
Slave machine response:
PDU PART
03
Number of reading
(2*Number of registers)
Data length(Byte) 1
1
bytes
Reading content
2*Number of registers
E550 Series Universal Low-Power Inverter
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