Chk (Check Sum) - Delta VFD-L series User Manual

VFD-L Series
RTU mode:
Command message:
ADR
CMD
Data address
Data content
CRC CHK Low
CRC CHK High

3.4 CHK (check sum)

ASCII mode:
LRC (Longitudinal Redundancy Check) is calculated by summing up, module 256, the
values of the bytes from ADR1 to last data character then calculating the hexadecimal
representation of the 2's-complement negation of the sum.
For example, reading 1 word from address 0401H of the AC drive with address 01H
STX
ADR 1
ADR 0
CMD 1
CMD 0
Starting data
address
Number of data
LRC CHK 1
LRC CHK 0
END 1
END 0
RTU mode:
ADR
CMD
Starting address
Number of data
(count by word)
CRC CHK Low
CRC CHK High
01H
06H
01H
00H
17H
70H
86H
22H
':'
'0'
'1'
'0'
'3'
'0'
'4'
'0'
'1'
'0'
'0'
'0'
'1' 01H+03H+04H+01H+00H+01H=0AH, the
2's-complement negation of 0AH is F6H.
'F'
'6'
CR
LF
01H
03H
21H
02H
00H
02H
6FH
F7H
5-46
Response message:
ADR
CMD
Data address
Data content
CRC CHK Low
CRC CHK High
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01H
06H
01H
00H
17H
70H
86H
22H