Ascii Mode - INVT Goodrive20-EU VFD Series Operation Manual

Goodrive20-EU series VFD
In ladder logic, CKSM calculated the CRC value according to the frame with the table inquiry.
The method is advanced with easy program and quick calculation speed. But the ROM space
the program occupied is huge. So use it with caution according to the program required space.

7.2.3 ASCII mode

Name
Communication protocol belongs to hexadecimal system. The meaning of message
character in ASCII: "0"..."9", "A"..."F", each hex is represented by the ASCII
message corresponds to the character.
Coding
Character
system
ASCII CODE
Character
ASCII CODE
Starting bit, 7/8 data bit, check bit and stop bit. The data formats are listed as
below:
11-bit character frame:
Starting
Data
bit
format
10-bit character frame:
Starting
bit
In ASCII mode, the frame header is ":" ("0*3A"), frame end is "CRLF" ("0*0D" "0*0A") by
default. In ASCII mode, all the data bytes, except for the frame header and frame end, are
transmitted in ASCII code mode, in which four high bit groups will be sent out first and then,
four low bit groups will be sent out. In ASCII mode, the data length is 8 bit. As for 'A' – 'F', its
capital letters is adopted for ASCII code. The data now adopts LRC checkout which covers
slave address to data information. The checksum equals to the complement of the character
sum of all the participated checkout data.
Standard structure of ASCII frame:
START
Address Hi
Address Lo
Function Hi
Function Lo
'0'
0x30
'8'
0x38
BIT1 BIT2 BIT3 BIT4 BIT5 BIT6 BIT7 BIT8
BIT1 BIT2 BIT3
ASCII data frame format
Starting character:
Slave
"0x3A"
address
8-bit address is formed by the combination of two ASCII codes
8-bit address is formed by the combination of two ASCII codes
Definition
'1' '2' '3'
0x31 0x32 0x33
'9' 'A' 'B'
0x39 0x41 0x42
BIT4 BIT5
Modbus message
Function
Checkout
Data
code
Communication address:
Function code:
119
Communication protocol
'4' '5'
0x34 0x35
'C' 'D'
0x43 0x44
Check
Check
BIT6 BIT7
Ending character:
"0*0D""0*0A"
':' (0x3A)
'6' '7'
0x36 0x37
'E' 'F'
0x45 0x46
Stop bit
bit
Stop bit
bit