전주 modbus 개발 ittang@naver.com
modbus RTU
Id / function code / data / crc
modbus over TCP (KG30X)
Id / function code / data / crc
modbus TCP/IP
transaction id (2byte) / protocol id (0x00 고정) / langth (2byte) / slave id (1byte)
----------------------------------------------------------------------------------MBAP Header
MBAP Header + function code (1byte) + nData (nByte)
