dolycon CT112 Series - Page 51

Solar Pump Inverter Chapter 7 Communication protocol
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RTU frame format
START
Interval time of 3.5 bytes
ADR Communication address: 1～247
CMD
03: read slave parameters; 06: write slave parameters
DATA (N-1)
Function parameter address, function parameter number,
function parameter value etc.
DATA (N-2)
……
DATA (0)
CRC CHK low bit
Detection value: CRC
CRC CHK high bit
END Interval time of 3.5 bytes
CMD (command instruction) and DATA
Command code: 03H, read N words (at most 16 words can be read)
For example: the baud rate 19200bps, even check (E, 8,1) for RTU, read continuous two
data from the inverter F06.19 with the slave address of 01.
Master command message
ADR 01H
CMD 03H
High bit of start address
06H (Function code group)
Low bit of start address 13H (Function code bit)
High bit of register number
00H
Low bit of register number 02H
Low bit of CRC CHK 35H
High bit of CRC CHK 46H
Slave response message
ADR 01H
CMD
03H
The number of bytes 04H
High bit of F06.19 data
00H
Low bit of F06.19 data 00H
High bit of F06.20 data 03H
Low bit of F06.20 data E8H
Low bit of CRC CHK
FAH
High bit of CRC CHK 8DH
Command code: 06H, write a word
For example: the baud rate 19200bps, even check (E, 8,1) for RTU, write 40.00Hz