Shihlin electric SDP Series, Manual

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LRC error check(ASCII mode)
The error check in ASCII mode is LRC (Longitudinal Redundancy Check). To calculate the LRC
value: add all the data from ADR to the last one, take the result by using 256 as the unit, and
the excess part is removed(for example, the result obtained after adding is 128H in hexadecimal,
then only 28H is taken), and then calculate complement of 2. The complement is LRC error
value.
For example: read 2 words (word) from the start address 0104h of the servo drive device
number 01h. 01H+03H+01H+04H+00H+02H = 0BH. The complement of 2 is F5H, thus LRC
is ’F’,’5’.
STX :
ADR
0
1
CMD
0
3
Start Data
Address
0
1
0
4
Data quantity
0
0
0
2
LRC error check
F
5
End1 0DH(CR)
End0 0AH(LF)
End1, End0(communication is completed)
Use “0Dh” which character is ’\r’
『
carriage return
』
and “0Ah” which character is ’\n’
『
new line
』
to denote the end of communication.