Look's like the Library doesn't want to work.

[envyvan]

Hi there,
Great job.!
I also want to use your code to build up my own control pad, But my arduino IDE alway's show up the message like this:
This report would have more information with
"Show verbose output during compilation"
enabled in File > Preferences.
Arduino: 1.0.6 (Windows NT (unknown)), Board: "Arduino Uno"
In file included from Lamp.ino:8:
ModbusSerial.h:17: error: expected class-name before '{' token
ModbusSerial.h:21: error: 'u_int' does not name a type
ModbusSerial.h:31: error: 'u_int' has not been declared
Lamp.ino: In function 'void setup()':
Lamp:27: error: 'class ModbusSerial' has no member named 'addCoil'
Lamp.ino: In function 'void loop()':
Lamp:35: error: 'class ModbusSerial' has no member named 'Coil'

seems like the library has some issue?