Topic is about serial coomunication

Respected members 
 i have scs 32 serco controller and i am talking serially to it , my code is
it is not working , it doesnot show any error but also servo is not rotating plz help me
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.IO.Ports;


using System.Threading;


namespace cConsoleAppMonitorServoCompletion
{
    class Program
    {
        static SerialPort _serialPort;


        static void Main(string[] args)
        {
            try
            {
                _serialPort = new SerialPort();
                _serialPort.PortName = "COM1";
                _serialPort.Open();
                _serialPort.Write("#27 P1600 S750\r");
                Console.WriteLine("#27 P1500 S750\r");
                string output;
                output = "";
                //Example: "Q " 
                //This will return a "." if the previous move is complete, or a "+" if it is still in progress. 
                while (!(output == ".")) //loop until you get back a period 
                {
                    _serialPort.Write("Q  \r");
                    output = _serialPort.ReadExisting();
                    Console.WriteLine(output);
                    Thread.Sleep(10);
                }
                _serialPort.Close();
            }
            catch (TimeoutException) { }
        }
    }
}