Appendices – KEYENCE BL-700 Series User Manual
Page 153
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Appendices
Appendices
Checksum calculation method
Calculate the checksum (CC) in the above example.
Convert each character into the ASCII code as shown below, and express the
result as 8-bit binary numbers.
Calculate the “Exclusive-OR” of the binary numbers of each bit.
Convert the calculated hexadecimal number into an ASCII code in two digits. The
result obtained is the checksum.
Therefore, the checksum for the above example is “cc =70 (37h 30h).
Example
•
Exclusive OR calculation formula
Calculate the numbers of each bit, referring to the following formula:
0 + 0 = 0
0 + 1 = 1
1 + 0 = 1
1 + 1 = 0
* + : Operator of Exclusive OR
•
Conversion from hexadecimal number into binary number
To convert ASCII codes into binary numbers, refer to the following table.
A
➔ 41h ➔ 0100 0001
B
➔ 42h ➔ 0100 0010
C
➔ 43h ➔ 0100 0011
1
➔ 31h ➔ 0011 0001
2
➔ 32h ➔ 0011 0010
3
➔ 33h ➔ 0011 0011
+
0111
0000
70h
* Based on the “Exclusive OR” logic,
when an odd number of “1”s are
present, the calculation result is “1”,
and when an even number of “1”s
are present, the calculation result is
“0”.
Header ERROR
CC
Delimiter
Header KEYENCE
100 %
:
Delimiter
CC=74
CC=58
CC
Tips
Hexadecimal number
0
1
2
3
4
5
6
7
Binary number
0000 0001
0010
0011 0100
0101 0110
0111
Hexadecimal number
8
9
A
B
C
D
E
F
Binary number
1000 1001
1010
1011 1100
1101 1110
1111
Heade
ABC123
CC
Delimiter
ASCII code
Bit