ICP DAS USA tM-TH8 User Manual page 30

Checksum Calculation:
1. Calculate the ASCII code sum of all the characters in
the command/response string except for the carriage
return character (CR).
2. The checksum is equal to the sum masked by 0FFh.
Example:
Command string: $012(CR)
1. Sum of the string = "$"+"0"+"1"+"2" =
24h+30h+31h+32h = B7h
2. Therefore the checksum is B7h, and so
CHKSUM = "B7"
3. The command string with the checksum = $012B7(CR)
Response string: !01200600(CR)
1. Sum of the string =
"!"+"0"+"1"+"2"+"0"+"0"+"6"+"0"+"0" =
21h+30h+31h+32h+30h+30h+36h+30h+30h = 1AAh
2. Therefore the checksum is AAh, and so
CHKSUM = "AA"
3. The response string with the checksum
= !01200600AA(CR)
Note:
All characters should be in upper case.
30 tM-TH8 User Manual, Rev: A1.1 7MH-018-A11