Need help in connecting Arduino with Dynamixel RX-64

AWOL:

I only obtain the data FFFFFF from the motor.

That suggest to me that you haven't fixed your code, and that you're reading -1 == "No serial data available" from your port.
Please post your code.

Hi AWOL,

I fixed the code already.

//___________________________________________________________________
//%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
// Initial condition
//___________________________________________________________________
//%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%

const int RTS = 4;   //1= transmit, 0 =receive
byte ping  =0x01;
byte READ  =0x02;
byte WRITE =0x03;
byte REG   =0x04;
byte ACTION=0x05;
byte RESET =0x06;
byte SYNC  =0x83;
byte BEGIN =0xff;
int incomingByte = 0;


//___________________________________________________________________
//%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
// Setup Function
//___________________________________________________________________
//%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
void setup () {
  pinMode(RTS, OUTPUT);
  Serial.begin(57600);
  Serial1.begin(57600);

}

// Main function
void loop() 
{
  byte notchecksum;
  byte motor_ID=0x01;
  byte length=0x02;
  digitalWrite(RTS,HIGH);
  delay (5);
  notchecksum=~(motor_ID + length + ping);
  Serial1.write(BEGIN);
  Serial1.write(BEGIN);
  Serial1.write(motor_ID);
  Serial1.write(length);
  Serial1.write(ping);
  Serial1.write(notchecksum);
  digitalWrite(RTS,LOW);
  // send data only when you receive data:
while (Serial1.available() == 0) 
{
     incomingByte = Serial1.read();
  }
  incomingByte = Serial1.read();
  Serial.print(Serial1.available(),HEX);
  delay(1000);
}//This is program to send data to servo

Now, is the serial monitor does not give any display. I suspect that it keep stuck inside the WHILE loop.
Now, I am wondering if my Dynamixel motor does not send any data or, My 485 breakout circuit does not send me any data.
Do you have any idea?

Thanks