Bosche WTS - Page 40

User manual WTS Ver.1.16
Seite 40 von 52
10. KEYPAD LOCK (ACCESS PROTECTION TO THE INSTRUMENT)
The PC transmits: $aaKEYckckCR
Possible instrument responses:
- correct reception: &&aa!\ckckCR
- incorrect reception: &&aa?\ckckCR
11. KEYPAD UNLOCK
The PC transmits: $aaFREckckCR
Possible instrument responses:
- correct reception: &&aa!\ckckCR
- incorrect reception: &&aa?\ckckCR
12. DISPLAY AND KEYPAD LOCK
The PC transmits: $aaKDISckckCR
Possible instrument responses:
- correct reception: &&aa!\ckckCR
- incorrect reception: &&aa?\ckckCR
13. CHECK-SUM CALCULATION
The two ASCII control characters (ckck) are the representation of a hexadecimal digit in
ASCII characters. The check digit is calculated by performing the operation XOR (exclusive
or) 8-bit ASCII codes of the only part of the underlined string.
The procedure to calculate the check- sum is the following:
Consider only the string characters highlighted with underlining;
Calculate the EXCLUSIVE OR (XOR) of the ASCII codes for the characters;
Example:
character
decimal ASCII code
hexadecimal ASCII code
binary ASCII code
0
1
t
48
49
116
30
31
74
00110000
00110001
01110100
XOR =
117
75
01110101
- The result of the XOR operation expressed in hexadecimal notation is made up of 2
hexadecimal digits (numbers from 0 to 9 or letters from A to F). In this case the
hexadecimal code is 0x75.
- The check-sum inserted in the strings transmitted is made up of the 2 characters
which represent the result of the XOR operation in hexadecimal notation (in our
example the character “7” and the character “5”).