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.