Inovance MD280 Series - RTU Frame Format Details; CMD and DATA Structure

MD280/MD280N User Manual Appendix
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1
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RTU frame format
START 3.5-character time
ADDR Communication addr. : 0 to 247
CMD 03:Read slave parameters
06: Write slave parameters
DATA˄N-1˅
DATA˄N-2˅
……
DATA0
Function code parameter address, the
number of function code parameter,
Function code parameter,etc.
CRC CHK low order
CRC CHK high order
Detection Value: CAC value
END At least 3.5-character time
2
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CMD and DATA
Command code: 03H reads N words. (There are 12 characters can be read
at the most.)
For example:
The inverter start address F002 of the slave 01 continuously
reads two consecutive values.
ADDR 01H
CMD 03H
Byte number high order F0H
Byte number low order 02H
Register number high
order
00H
Register number low order 02H
CRC CHK low order
CRC CHK high order
CRC CHK values are to be calculated
Slave responding information
ADDR 01H
CMD 03H
Byte number 04H
Data F002H high order 00H
Data F002H low order 00H
Data F003H high order 00H
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