User's Manual

QTI Page 13 of 15 Revision: C
Form #: 30Z0266 Effective Date: 5 October 2012
Example Checksum
Line to send is “#ACHR 597<CR>”
Convert characters to ASCII values:
# (35) + A (65) + C (67) + H (72) + R (82) + <sp> (32) + 5 (53) + 9 (57) + 7 (55)
NOTE: <CR> is not included in calculation.
Sum: 35+65+67+72+82+32+53+57+55 = 518T (206h)
1’s Complement is bit inversion: = [10 0000 0110]  [01 1111 1001] = 1F9h
2’s complement is adding 1 to the 1’s complement: 1F9 + 1 = 1FAh
Drop anything higher than the lowest 8 bits: [1 1111 1010]  [1111 1010] = FAh
The result is FAh, so send line as “#ACHR 597FA<CR>”
Note: Adding the checksum will result in zero for the low byte. (206h + FAh = 300h)