using System;
using System.Collections.Generic;
using System.Text;
using System.IO.Ports;
using System.Threading;namespace SerialPort_Lib
{public class modbus{private SerialPort sp = new SerialPort();public string modbusStatus;#region Constructor / Deconstructorpublic modbus(){}~modbus(){}#endregion#region Open / Close Procedurespublic bool Open(string portName, int baudRate, int databits, Parity parity, StopBits stopBits){//Ensure port isn't already opened:if (!sp.IsOpen){//Assign desired settings to the serial port:sp.PortName = portName;sp.BaudRate = baudRate;sp.DataBits = databits;sp.Parity = parity;sp.StopBits = stopBits;//These timeouts are default and cannot be editted through the class at this point:sp.ReadTimeout = -1;sp.WriteTimeout = 10000;try{sp.Open();}catch (Exception err){modbusStatus = "Error opening " + portName + ": " + err.Message;return false;}modbusStatus = portName + " opened successfully";return true;}else{modbusStatus = portName + " already opened";return false;}}public bool Close(){//Ensure port is opened before attempting to close:if (sp.IsOpen){try{sp.Close();}catch (Exception err){modbusStatus = "Error closing " + sp.PortName + ": " + err.Message;return false;}modbusStatus = sp.PortName + " closed successfully";return true;}else{modbusStatus = sp.PortName + " is not open";return false;}}#endregion#region CRC Computationprivate void GetCRC(byte[] message, ref byte[] CRC){//Function expects a modbus message of any length as well as a 2 byte CRC array in which to //return the CRC values:ushort CRCFull = 0xFFFF;byte CRCHigh = 0xFF, CRCLow = 0xFF;char CRCLSB;for (int i = 0; i < (message.Length) - 2; i++){CRCFull = (ushort)(CRCFull ^ message[i]);for (int j = 0; j < 8; j++){CRCLSB = (char)(CRCFull & 0x0001);CRCFull = (ushort)((CRCFull >> 1) & 0x7FFF);if (CRCLSB == 1)CRCFull = (ushort)(CRCFull ^ 0xA001);}}CRC[1] = CRCHigh = (byte)((CRCFull >> 8) & 0xFF);CRC[0] = CRCLow = (byte)(CRCFull & 0xFF);}#endregion#region Build Messageprivate void BuildMessage(byte address, byte type, ushort start, ushort registers, ref byte[] message){//Array to receive CRC bytes:byte[] CRC = new byte[2];message[0] = address;message[1] = type;message[2] = (byte)(start >> 8);message[3] = (byte)start;message[4] = (byte)(registers >> 8);message[5] = (byte)registers;GetCRC(message, ref CRC);message[message.Length - 2] = CRC[0];message[message.Length - 1] = CRC[1];}#endregion#region Check Responseprivate bool CheckResponse(byte[] response){//Perform a basic CRC check:byte[] CRC = new byte[2];GetCRC(response, ref CRC);if (CRC[0] == response[response.Length - 2] && CRC[1] == response[response.Length - 1])return true;elsereturn false;}#endregion#region Get Responseprivate void GetResponse(ref byte[] response){//There is a bug in .Net 2.0 DataReceived Event that prevents people from using this//event as an interrupt to handle data (it doesn't fire all of the time).  Therefore//we have to use the ReadByte command for a fixed length as it's been shown to be reliable.for (int i = 0; i < response.Length; i++){response[i] = (byte)(sp.ReadByte());}}#endregion#region GetModbusData 获得接收数据public bool GetModbusData(ref byte[] values){//Ensure port is open:if (sp.IsOpen){// 等待线程进入 //Monitor.Enter(sp);//Clear in/out buffers://sp.DiscardOutBuffer();//sp.DiscardInBuffer();//Message is 1 addr + 1 type + N Data + 2 CRCtry{//GetResponse(ref readBuffer);//string str = readBuffer.ToString();int count = sp.BytesToRead;if (count > 0){byte[] readBuffer = new byte[count];GetResponse(ref readBuffer);//   readData = new byte[29];//   Array.Copy(readBuffer, readData, readData.Length);// CRC 验证if (CheckResponse(readBuffer)){//显示输入数据values = readBuffer;modbusStatus = "Write successful";sp.DiscardInBuffer();//values = System.Text.Encoding.ASCII.GetString(readData);return true;}else{modbusStatus = "CRC error";sp.DiscardInBuffer();return false;}}else return false;}catch (Exception err){modbusStatus = "Error in write event: " + err.Message;sp.DiscardInBuffer();return false;}//finally//{// 通知其它对象//Monitor.Pulse(sp);// 释放对象锁 //Monitor.Exit(sp);//}}else{modbusStatus = "Serial port not open";return false;}}#endregion#region SendModbusData 打包发送数据public bool SendModbusData(ref byte[] values){//Ensure port is open:if (sp.IsOpen){//Clear in/out buffers:sp.DiscardOutBuffer();sp.DiscardInBuffer();//Function 3 response buffer:byte[] response = new byte[values.Length + 2];Array.Copy(values, response, values.Length);//BuildMessage(address, (byte)3, start, registers, ref message);//打包带有 CRC 验证的modbus 数据包:byte[] CRC = new byte[2];GetCRC(response, ref CRC);response[response.Length - 2] = CRC[0];response[response.Length - 1] = CRC[1];values = response; //返回带有 CRC 验证的modbus 数据包//Send modbus message to Serial Port:try{sp.Write(response, 0, response.Length);//GetResponse(ref response);return true;}catch (Exception err){modbusStatus = "Error in read event: " + err.Message;return false;}//Evaluate message://if (CheckResponse(response))//{//    //Return requested register values://    for (int i = 0; i < (response.Length - 5) / 2; i++)//    {//        values[i] = response[2 * i + 3];//        values[i] <<= 8;//        values[i] += response[2 * i + 4];//    }//    modbusStatus = "Read successful";//    return true;//}//else//{//    modbusStatus = "CRC error";//    return false;//}}else{modbusStatus = "Serial port not open";return false;}}#endregion}
}

public partial class FormConfig : Form,IModbusData
{//业务处理类B_ModbusData ModbusDataBLL = new B_ModbusData();modbus mb = new modbus();//SerialPort sp = new SerialPort();System.Timers.Timer timer = new System.Timers.Timer();public FormConfig(){InitializeComponent();timer.Elapsed += new ElapsedEventHandler(timer_Elapsed);}#region Timer Elapsed 事件处理程序bool runEnd = true;void timer_Elapsed(object sender, ElapsedEventArgs e){if (runEnd == true){runEnd = false;PollFunction();runEnd = true;}}//定时器调用方法private void PollFunction(){byte[] values = null;try{mb.GetModbusData(ref values);//while (!mb.SendFc3(Convert.ToByte(txtSlaveID.Text), pollStart, pollLength, ref values)) ;}catch (Exception err){DoGUIStatus("Error in modbus read: " + err.Message);}if (values != null){//业务处理byte[] sendData = ModbusDataProcess(values);}}#endregion#region IModbusData 接口成员处理public byte[] ModbusDataProcess(byte[] _data){byte[] sendData = ModbusDataBLL.ModbusDataProcess(_data);// CRC验证，并打包发送数据。mb.SendModbusData(ref sendData);return sendData;}#endregion
}