Page 5–16
DuRApulse GS4 AC Drive User Manual – 1st Ed, Rev A - 10/20/2017
Chapter 5: Serial Communications
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.
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
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
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