I am looking for Modbus slave over Serial.I have already mentioned I am using Arduino UNO board.If you have any working code with uno for trail purpose will be appreciable
Are you looking for Modbus over Serial or over Ethernet, I didn't see this mentioned anywhere. If you want a Modbus/TCP slave then I have included the Mudbus library. I have an Arduino Mega 2560 with all of it's pins mapped out with the exception of those required by the Ethernet shield. I have this sketch working with an industrial HMI for a home automation type system, it works quite well. Some of the pins have thermistors connected, I multiply by 10 so I can divide by 10 on the master and carry a decimal place