I-7000 Remote I/O 007

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Q.How to calculate the checksum ?

Ans: The steps to calculate the checksum are given as following:

1. step 1: checksum=0

2. step 2: for all command byte checksum = checksum + command byte

3. step 3: checksum=checksum&0xff

4. step 4 : convert checksum to ASCII high byte and ASCII low byte

for example,

command = $012[Enter]

checksum = $+0+1+2 = 0x24+0x30+0x31+0x32= 0xB7

checksum & 0xff = 0xB7

checksum ASCII high byte = ASCII B = 0x42

checksum ASCII low byte = ASCII 7 = 0x37

command with checksum = $012B7[Enter]

Written by David Chen 

Date:2002/12/24