DVP-ES2-EX2-SS2-SA2-SX2-Operation Manual

4. Communications
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−
−
7 data bits
1 stop bit
Even parity
− Baud rate: 9600
4.2 Communication Protocol ASCII mode
Communication Data Structure
9600 (Baud rate), 7 (data bits), Even (Parity), 1 (Start bit), 1 (Stop bit)
Field name Content Explanation
Start bit STX Start bit ‘:’ (3AH)
Communication ADR 1
address ADR 0
Address consists of 2 ASCII codes
Command code
Data
LRC checksum
Stop bit
CMD 1
CMD 0
DATA (0)
DATA (1)
……….
DATA (n-1)
LRC CHK 1
LRC CHK 0
END1
END0
Command code consists of 2 ASCII
codes
Data content consist of 2n ASCII codes,
n≤205
LRC checksum consists of 2 ASCII codes
Stop bit consists of 2 ASCII codes
END1 = CR (0DH),
END0 = LF (0AH)
Corresponding table for Hexadecimal value and ASCII codes
ASCII “0“ “1“ “2“ “3“ “4“ “5“ “6“ “7“
Hex 30H 31H 32H 33H 34H 35H 36H 37H
ASCII “8“ “9“ “A“ “B“ “C“ “D“ “E“ “F“
Hex 38H 39H 41H 42H 43H 44H 45H 46H
4.2.1 ADR (Communication Address)
Valid communication addresses are in the range of 0~254. Communication address equals to 0 means
broadcast to all PLCs. PLC will not respond to a broadcast message. PLC will reply a normal message
to the master device when communication address is not 0.
Example, ASCII codes for communication address 16 in Decimal. (16 in Decimal = 10 in Hex)
(ADR 1, ADR 0)=’1’,’0’’1’=31H, ‘0’ = 30H
4.2.2 CMD (Command code) and DATA
The content of access data depends on the command code.
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