Chapter 5 Parameters_VFD-B Series 
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Revision 10/2005, BE13, SW V4.08 
3. Communication Protocol 
3.1 Communication Data Frame:
 
ASCII mode: 
STX   Start character ‘:’ (3AH)  
Address Hi 
Address Lo 
Communication address: 
8-bit address consists of 2 ASCII codes 
Function Hi 
Function Lo 
Command code: 
8-bit command consists of 2 ASCII codes 
DATA (n-1) 
to 
DATA 0 
Contents of data: 
Nx8-bit data consist of 2n ASCII codes 
n<=20, maximum of 40 ASCII codes 
LRC CHK Hi 
LRC CHK Lo 
LRC check sum: 
8-bit check sum consists of 2 ASCII codes 
END Hi 
END Lo 
End characters: 
END1= CR (0DH), END0= LF(0AH) 
 
RTU mode: 
START  A silent interval of more than 10 ms 
Address  Communication address: 8-bit address 
Function 
Command code: 8-bit command 
DATA (n-1) 
to 
DATA 0 
Contents of data: 
nÈ8-bit d  ata, n<=40 (20 x 16-bit data) 
CRC CHK Low 
CRC CHK High 
CRC check sum: 
16-bit check sum consists of 2 8-bit characters 
END  A silent interval of more than 10 ms 
3.2  Address (Communication Address) 
Valid communication addresses are in the range of 0 to 254. A communication address equal to 0, 
means broadcast to all AC drives (AMD). In this case, the AMD will not reply any message to the 
master device.  
00H: broadcast to all AC drives 
01H: AC drive of address 01 
0FH: AC drive of address 15 
10H: AC drive of address 16 
   : 
FEH: AC drive of address 254