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Chapter 9: Communication protocol
the structure description of this frame as follows:
RTU host machine command information
START
ADDR
CMD
High bit of start address
Low bit of start address
High bit of data number
Low bit of data number
CRC CHK Iow bit
CRC CHK high bit
END
T1-T2-T3-T4 (transmission time of
3.5 bytes)
01H
03H
00H
04H
00H
02H
85H
CAH
T1-T2-T3-T4 (transmission time of
3.5 bytes)
RTU slave machine response information
START
ADDR
CMD
Byte number
T1-T2-T3-T4 (transmission time of
3.5 bytes)
01H
03H
04H
High bit of data address 0004H
Low bit of data address 0004H
High bit of data address 0005H
00H
00H
00H
Low bit of data address 0005H
CRC CHK Iow bit
CRC CHK high bit
00H
43H
07H
END
T1-T2-T3-T4 (transmission time of
3.5 bytes)
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