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9-2. Basic procedure of communication
9-2-1. Text format at the time of sending and receiving
①
Character received before STX is not received.
②
Always add CR(0DH), LF(0AH) as end code. (For both sending and receiving).
9-2-2. Check sum
This device adds check sum data as BCC (Block Check Code).
Check sum means, seeing each text data as binary and sending low order 8 bits of that total sum as
hexadecimal character.
①
Target range of BCC
②
BCC (Check sum)
The low order 8 bit data of the pure binary total sum of target range data is split into high and low order
4 bits and are converted to characters (30 to 39, 41 to 46H) 0 to F, and is kept in high order and low order
sequence. (2 characters)
③
When adding parity to BCC, the parity of BCC itself is considered.
④
BCC is not added in positive and negative response.
⑤
Nor it is added to ENQ, ACK, EOT.
⑥
BCC is added and checked for both sending and receiving.
31
32
2C 30
03
32 43
(2)
(C)
When the data to be sent and received is changed due to noise etc, by comparing with that value
calculated on the receiving side, that occurrence might be detected.
STX TEXT ETX BCC L BCC H CR LF
STX TEXT ETX BCC CR LF
STX TEXT ETX BCC L BCC H CR LF
STX 1 2 , 0 ETX BCC L BCC H CR LF
