8-9
8-1-3 RS-485 Communication Protocol and Format
When using the RS-485 Modbus communication interface, each set of drivers must set its driver ID in
advance in parameter
Cn036
. The Supervisory Control Unit can then perform communication control on
the individual Drivers based on the ID.
Communication method utilizes Modbus network communication and can use the following two
protocols: ASCII (American Standard Code for information interchange) mode and RTU (Remote
Terminal Unit) mode. The required mode can be set using parameter
Cn038.0
.
Code Meaning
ASCII Mode
Each byte data consists of two ASCII bits.
For example, a 1-byte data 26H is represented by ASCII Code '26' and includes ASCII Code of '2' <32H>
and ASCII Code of “6” <36H>.
Number 0 ~ 9 and alphabet A ~ F represented by ASCII codes are listed in the following table:
Character
Symbol
‘0’ ‘1’ ‘2’ ‘3’ ‘4’ ‘5’ ‘6’ ‘7’
Corresponding
ASCII Code
30H 31H 32H 33H 34H 35H 36H 37H
Character
Symbol
‘8’ ‘9’ ‘A’ ‘B’ ‘C’ ‘D’ ‘E’ ‘F’
Corresponding
ASCII Code
38H 39H 41H 42H 43H 44H 45H 46H
RTU Mode
Every byte data consists of 2 4-bit hexadecimal bits.
For example: a 1-byte data 26H.
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