Omron SYSDRIVE MX2 SERIES, User Manual

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8 Communications Functions
Multi-function Compact Inverter 3G3MX2-V1 User’s Manual (I585-E1)
8
-7 Mo
dbu
s Map
p
ing
Fu
nct
ion
8
8-7
-5 Endian Fu
nction
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-V1 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.
z Byte order of single-word data
• Relationship between single-word data bits and bytes
• Order of data during Modbus communication
z Byte order of double-word data
• Relationship between double-word data bits and bytes
• Order of data during Modbus communication
8-7-5 Endian Function
Parameter No. Function name Data Default data Unit
P400
Modbus Mapping Endian
Selection
00: Big endian
00
−
01: Little endian
02: Special endian
Bit 8 to 15 7 to 0
Byte MSB byte LSB byte
Send/Receive byte
order
Big endian Little endian Special endian
1 MSB byte LSB byte MSB byte
2 LSB byte MSB byte LSB byte
Bit 24 to 31 16 to 23 8 to 15 7 to 0
Byte MSB byte Data 1 Data 2 LSB byte
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