HELIX CTI-CRYOGENICS On-Board FastRegen Programming And Operation Instructions page 90

Appendix B - On-Board Module RS-232 Interface Protocol Format
B-4
Checksum of hex 40 data field:
Bits 76543210
Sum = 40 = 01000000
Bits 7 and 6
aligned for
X0R 00000001
X0R result 01000001
Mask D5,D0 00000001
Addend "0" 00110000
Final Chk 00110001
Slave sends replay of AP A2.01, meaning no error, pump version A2.01.
Flag
ASCII [$]
Hex [24]
Checksum of hex data field:
Bits 76543210
Sum of
41 01000001
50 01010000
20 00100000
41 01000001
32 00110010
2E 00101110
30 00110000
31 00110001
equals 10110011 or hex B3 modulo 256.
Bits 7 and 6
aligned for
X0R 00000010
X0R result 10110001 or B1
Mask D5,D0 00110001
Addend "0" 00110000
Final Chk 01100001
Hex 31, ASCII "1"
Data Field
[A] [P] [ ] [A]
[2] [.] [0] [1]
[41] [50] [20] [41]
[32] [2E] [30] [31] [61]
Hex 61, ASCII "a"
-
C TI CRYOGENICS
HELIX TECHNOLOGY CORPORATION
Checksum Terminator
[a] [CR]
[0D]
P/N 8040406