Chapter 5: DURAPULSE MODBUS Communications
5–72
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.
RTU Mode:
Response Message
ADR 01H
CMD 03H
Starting data
address
21H
02H
Number of data
(Count by word)
00H
02H
CRC CHK Low
CRC CHK High
6FH
F7H
Command Message
STX ':'
ADR 1
ADR 0
'0'
'1'
CMD 1
CMD 0
'0'
'3'
Starting data
address
'0'
'4'
'0'
'1'
Number of data
(Count by word)
'0'
01H+03H+04H+01H+00H+01H=0AH;
the 2's complement negation of 0AH is F6H.
'0'
'0'
'1'
LRC CHK 1
LRC CHK 0
'F'
'6'
END 1
END 0
CR
LF
DURAPULSE AC Drive User Manual
1st Ed. Rev. D 05/2013
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