Omron MX2 Series - Endian Function

8 Communications Functions
8 - 29
Multi-function Compact Inverter 3G3MX2-EV2 User’s Manual (I666-E1)
8-7-5 Endian Function
In communications, endian refers to the byte order in single-word communications data to be
sent/received.
Generally, big endian (where the MSB-side byte is stored first) and little endian (where the LSB-side
byte is stored first) are used.
Special endian is a kind of big endian where the word order of double-word data is reversed. For
3G3MX2-EV2 Series Inverter, Modbus communication is configured in big endian.
The endian function can set endian only for data sent/received in communications (without changing
the address).
In the Modbus Mapping Endian Selection (P400), set the endian you want to use.
The Modbus Mapping Endian Selection (P400) setting is enabled independent of the Modbus Mapping
Function Selection (P200) setting.
Parameter No.
Function name
Data
Default data
Unit
P400
Modbus Mapping Endian
Selection
00: Big endian
01: Little endian
02: Special endian
00
−
⚫ Byte order of single-word data
• Relationship between single-word data bits and bytes
Bit
8 to 15
7 to 0
Byte
MSB byte
LSB byte
• Order of data during Modbus communication
Send/Receive byte
order
Big endian
Little endian
Special endian
1
MSB byte
LSB byte
MSB byte
2
LSB byte
MSB byte
LSB byte
⚫ Byte order of double-word data
• Relationship between double-word data bits and bytes
Bit
24 to 31
16 to 23
8 to 15
7 to 0
Byte
MSB byte
Data 1
Data 2
LSB byte
• Order of data during Modbus communication
Send/Receive byte
order
Big endian
Little endian
Special endian
1
MSB byte
LSB byte
Data 2
2
Data 1
Data 2
LSB byte
3
Data 2
Data 1
MSB byte
4
LSB byte
MSB byte
Data 1
8
8-7 Modbus Mapping Function
8-7-5 Endian Function