C#写了一款上位机监控软件，基于MODBUS_RTU协议。 软件的基本结构：1.采用定时器（Timer控件）为时间片。2.串口采用serialPort1_DataReceived中断接收，并进行MODBUS格式判断。3.把正确接收的数据取出，转换为有特定的结构体中。4.数据通过时间片实时刷新。5.MODBUS协议（这里不介绍了，网上有很多的权威资料）。 　　串口接收问题这里采用的是MODBUS_RTU协议，是没有回车等明显的结束符的哈。所以在C#也不可以用serialPort1.ReadLine来读取。我用的是serialPort1.BytesToRead先读缓冲区中的数据个数，再通过个数据读数据。这样在用串口软件测试的时候确实很有用，再随之问题又出现了。下位机传上来的数据长度高出8个，就会分断接收。即接收到的两次的长度，第一次是8个，然后再接收到后面的。 原因是因为软件没有接收完一整帧数据后就进行了中断。解决方法：在中断中加入线程阻塞方法，然后再读取串口中的数据。　　发送读数据和发送写数据的结构 写了多个MODBUS协议的上位机后，总结了些经验，并将这部分程序封装在一个类中。使用时只需对其接口函数调用即可，有很强的移植性。在写软件时不用再在协议这部分花太多的时间。基本的使用方法在注释中。程序总体感觉 可能过于臃肿，希望各位大神批评指点。以下是源代码：/*   * MODBUS协议  *    *    * 介绍：  * 此modbus上位机 协议类 具有较强的通用性  * 本协议类最主要的思想是 把所有向下位机发送的指令 先存放在缓冲区中（命名为管道）  * 再将管道中的指令逐个发送出去。  * 管道遵守FIFO的模式。管道中所存放指令的个数 在全局变量中定义。  * 管道内主要分为两部分：1，定时循环发送指令。2，一次性发送指令。  * 定时循环发送指令:周期性间隔时间发送指令，一般针对“输入寄存器”或“输入线圈”等实时更新的变量。  * 这两部分的长度由用户所添加指令个数决定（所以自由性强）。  * 指令的最大发送次数，及管道中最大存放指令的个数在常量定义中 可进行设定。  *    * 使用说明：  * 1，首先对所定义的寄存器或线圈进行分组定义，并定义首地址。  * 2，在MBDataTable数组中添加寄存器或线圈所对应的地址。 注意 寄存器：ob = new UInt16()。线圈：ob = new byte()。  * 3，对所定义的地址 用属性进行定义 以方便在类外进行访问及了解所对应地址的含义。  * 4，GetAddressValueLength函数中 对使用说明的"第一步"分组 的元素个数进行指定。  * 5，在主程序中调用MBConfig进行协议初始化（初始化内容参考函数）。  * 6，在串口中断函数中调用MBDataReceive()。  * 7，定时器调用MBRefresh()。（10ms以下）  *    指令发送间隔时间等于实时器乘以10。 例：定时器5ms调用一次  指令发送间隔为50ms。  * 8，在主程序初始化中添加固定实时发送的指令操作 用MBAddRepeatCmd函数。  * 9，在主程序运行过程中 根据需要添加 单个的指令操作(非固定重复发送的指令)用MBAddCmd函数。  *    *    * 作者：王宏强  * 时间：2012.7.2   *    *    *    *    *    *   */    using System;  using System.Collections.Generic;  using System.ComponentModel;  using System.Data;  using System.Drawing;  using System.Text;  using System.Windows.Forms;  using System.IO.Ports;    namespace WindowsApplication1  {        public class Modbus      {          #region 所用结构体         /// <summary>          /// 地址对应表元素单元         /// </summary>          public struct OPTable{              public volatile int addr;              public volatile byte type;              public volatile object ob;          };          /// <summary>          /// 当前的指令         /// </summary>          public struct MBCmd          {              public volatile int addr;           //指令首地址             public volatile int stat;           //功能码             public volatile int len;            //所操作的寄存器或线圈的个数             public volatile int res;            //返回码的状态， 0：无返回，1：正确返回         };          /// <summary>          /// 当前操作的指令管道         /// </summary>          public struct MBSci          {              public volatile MBCmd[] cmd;             //指令结构体             public volatile int index;               //当前索引             public volatile int count;               //当前功能码执行的次数             public volatile int maxRepeatCount;      //最大发送次数             public volatile int rtCount;             //实时读取的指令各数(无限间隔时间读取)          };          #endregion            #region 常量定义         public const byte MB_READ_COILS = 0x01;             //读线圈寄存器         public const byte MB_READ_DISCRETE = 0x02;          //读离散输入寄存器         public const byte MB_READ_HOLD_REG = 0x03;          //读保持寄存器         public const byte MB_READ_INPUT_REG = 0x04;         //读输入寄存器         public const byte MB_WRITE_SINGLE_COIL = 0x05;      //写单个线圈         public const byte MB_WRITE_SINGLE_REG = 0x06;       //写单寄存器         public const byte MB_WRITE_MULTIPLE_COILS = 0x0f;   //写多线圈         public const byte MB_WRITE_MULTIPLE_REGS = 0x10;    //写多寄存器           private const int MB_MAX_LENGTH = 120;               //最大数据长度         private const int MB_SCI_MAX_COUNT = 15;             //指令管道最大存放的指令各数         private const int MB_MAX_REPEAT_COUNT = 3;           //指令最多发送次数         #endregion            #region 全局变量         private static volatile bool sciLock = false;                       //调度器锁 true:加锁  false:解锁         private static volatile byte[] buff = new byte[MB_MAX_LENGTH];      //接收缓冲器         private static volatile int buffLen = 0;          private static volatile byte[] rBuff = null;                  //正确接收缓冲器         private static volatile byte[] wBuff = null;                     //正确发送缓冲器         public static MBSci gMBSci = new MBSci() { cmd = new MBCmd[MB_SCI_MAX_COUNT], index = 0, maxRepeatCount = MB_MAX_REPEAT_COUNT, rtCount = 0, count = 0 };          private static SerialPort comm = null;          private static int mbRefreshTime = 0;          #endregion            #region MODBUS 地址对应表         //modbus寄存器和线圈分组 首地址定义         public const int D_DIO = 0x0000;          public const int D_BASE = 0x0014;          public const int D_RANGE = 0x0018;          public const int D_PWM = 0x001A;          public const int D_PID = 0x001E;            /// <summary>          /// 变量所对应的地址 在此位置         /// </summary>          public static volatile OPTable[] MBDataTable =           {              new OPTable(){addr = D_DIO,         type = MB_READ_INPUT_REG,      ob = new UInt16()},      //0              new OPTable(){addr = D_DIO + 1,     type = MB_READ_INPUT_REG,      ob = new UInt16()},              new OPTable(){addr = D_DIO + 2,     type = MB_READ_INPUT_REG,      ob = new UInt16()},              new OPTable(){addr = D_DIO + 3,     type = MB_READ_INPUT_REG,      ob = new UInt16()},              new OPTable(){addr = D_DIO + 4,     type = MB_READ_INPUT_REG,      ob = new Int16()},              new OPTable(){addr = D_DIO + 5,     type = MB_READ_INPUT_REG,      ob = new Int16()},                new OPTable(){addr = D_BASE,        type = MB_READ_HOLD_REG,      ob = new Int16()},        //6              new OPTable(){addr = D_BASE + 1,    type = MB_READ_HOLD_REG,      ob = new Int16()},              new OPTable(){addr = D_BASE + 2,    type = MB_READ_HOLD_REG,      ob = new Int16()},              new OPTable(){addr = D_BASE + 3,    type = MB_READ_HOLD_REG,      ob = new Int16()},                new OPTable(){addr = D_RANGE,       type = MB_READ_HOLD_REG,      ob = new Int16()},        //10              new OPTable(){addr = D_RANGE + 1,   type = MB_READ_HOLD_REG,      ob = new Int16()},                new OPTable(){addr = D_PWM,         type = MB_READ_HOLD_REG,      ob = new Int16()},        //12              new OPTable(){addr = D_PWM + 1,     type = MB_READ_HOLD_REG,      ob = new Int16()},              new OPTable(){addr = D_PWM + 2,     type = MB_READ_HOLD_REG,      ob = new Int16()},              new OPTable(){addr = D_PWM + 3,     type = MB_READ_HOLD_REG,      ob = new Int16()},                new OPTable(){addr = D_PID,         type = MB_READ_HOLD_REG,      ob = new UInt16()},        //16              new OPTable(){addr = D_PID + 1,     type = MB_READ_HOLD_REG,      ob = new UInt16()},              new OPTable(){addr = D_PID + 2,     type = MB_READ_HOLD_REG,      ob = new UInt16()},              new OPTable(){addr = D_PID + 3,     type = MB_READ_HOLD_REG,      ob = new UInt16()},              new OPTable(){addr = D_PID + 4,     type = MB_READ_HOLD_REG,      ob = new UInt16()},              new OPTable(){addr = D_PID + 5,     type = MB_READ_HOLD_REG,      ob = new UInt16()},            };          public static UInt16 gDioX { get { return Convert.ToUInt16(MBDataTable[0].ob); } set { MBDataTable[0].ob = value; } }          public static UInt16 gDioY { get { return Convert.ToUInt16(MBDataTable[1].ob); } set { MBDataTable[1].ob = value; } }          public static UInt16 gDioZ { get { return Convert.ToUInt16(MBDataTable[2].ob); } set { MBDataTable[2].ob = value; } }          public static UInt16 gDioD { get { return Convert.ToUInt16(MBDataTable[3].ob); } set { MBDataTable[3].ob = value; } }          public static Int16 gDioXx { get { return (Int16)Convert.ToInt32(MBDataTable[4].ob); } set { MBDataTable[4].ob = value; } }          public static Int16 gDioXy { get { return (Int16)Convert.ToInt32(MBDataTable[5].ob); } set { MBDataTable[5].ob = value; } }            public static Int16 gBaseF1 { get { return (Int16)Convert.ToInt32(MBDataTable[6].ob); } set { MBDataTable[6].ob = value; } }          public static Int16 gBaseF2 { get { return (Int16)Convert.ToInt32(MBDataTable[7].ob); } set { MBDataTable[7].ob = value; } }          public static Int16 gBaseF3 { get { return (Int16)Convert.ToInt32(MBDataTable[8].ob); } set { MBDataTable[8].ob = value; } }          public static Int16 gBaseF4 { get { return (Int16)Convert.ToInt32(MBDataTable[9].ob); } set { MBDataTable[9].ob = value; } }            public static Int16 gRangeMax { get { return (Int16)Convert.ToInt32(MBDataTable[10].ob); } set { MBDataTable[10].ob = value; } }          public static Int16 gRangeMin { get { return (Int16)Convert.ToInt32(MBDataTable[11].ob); } set { MBDataTable[11].ob = value; } }            public static Int16 gPwmF1 { get { return (Int16)Convert.ToInt32(MBDataTable[12].ob); } set { MBDataTable[12].ob = value; } }          public static Int16 gPwmF2 { get { return (Int16)Convert.ToInt32(MBDataTable[13].ob); } set { MBDataTable[13].ob = value; } }          public static Int16 gPwmF3 { get { return (Int16)Convert.ToInt32(MBDataTable[14].ob); } set { MBDataTable[14].ob = value; } }          public static Int16 gPwmF4 { get { return (Int16)Convert.ToInt32(MBDataTable[15].ob); } set { MBDataTable[15].ob = value; } }            public static float gP          {              get               {                  int tmp = (Convert.ToInt32(MBDataTable[16].ob) & 0xFFFF) | ((Convert.ToInt32(MBDataTable[17].ob) & 0xFFFF) << 16);                  byte[] arr = BitConverter.GetBytes(tmp);                  return BitConverter.ToSingle(arr, 0);               }              set              {                  byte[] val = BitConverter.GetBytes(value);                  MBDataTable[16].ob = BitConverter.ToUInt16(val, 0);                  MBDataTable[17].ob = BitConverter.ToUInt16(val, 2);              }          }          public static float gI          {              get               {                  int tmp = (Convert.ToInt32(MBDataTable[18].ob) & 0xFFFF) | ((Convert.ToInt32(MBDataTable[19].ob) & 0xFFFF) << 16);                  byte[] arr = BitConverter.GetBytes(tmp);                  return BitConverter.ToSingle(arr, 0);               }              set              {                  byte[] val = BitConverter.GetBytes(value);                  MBDataTable[18].ob = BitConverter.ToUInt16(val, 0);                  MBDataTable[19].ob = BitConverter.ToUInt16(val, 2);              }          }          public static float gD          {              get              {                  int tmp = (Convert.ToInt32(MBDataTable[20].ob) & 0xFFFF) | ((Convert.ToInt32(MBDataTable[21].ob) & 0xFFFF) << 16);                  byte[] arr = BitConverter.GetBytes(tmp);                  return BitConverter.ToSingle(arr, 0);               }              set              {                  byte[] val = BitConverter.GetBytes(value);                  MBDataTable[20].ob = BitConverter.ToUInt16(val, 0);                  MBDataTable[21].ob = BitConverter.ToUInt16(val, 2);              }          }            public static UInt16 gNode = 100;          public static UInt16 gBaud = 38400;          /// <summary>          /// 获取寄存器或线圈 分组后的成员各数         /// </summary>          /// <param name="addr">首地址</param>          /// <returns>成员各数</returns>          private static int GetAddressValueLength(int addr)          {              int res = 0;              switch (addr)              {                  case D_DIO: res = 6; break;                  case D_BASE: res = 4; break;                  case D_RANGE: res = 2; break;                  case D_PWM: res = 4; break;                  case D_PID: res = 6; break;                  default: break;              }              return res;          }          /// <summary>          /// 获取地址所对应的数据         /// </summary>          /// <param name="addr">地址</param>          /// <param name="type">类型</param>          /// <returns>获取到的数据</returns>          private static object GetAddressValue(int addr, byte type)          {              switch (type)       //功能码类型判断             {                  case MB_READ_COILS:                   case MB_READ_DISCRETE:                   case MB_READ_HOLD_REG:                   case MB_READ_INPUT_REG: break;                  case MB_WRITE_SINGLE_COIL:                  case MB_WRITE_MULTIPLE_COILS: type = MB_READ_DISCRETE; break;                  case MB_WRITE_SINGLE_REG:                  case MB_WRITE_MULTIPLE_REGS: type = MB_READ_HOLD_REG; break;                  default: return null;              }                for (int i = 0; i < MBDataTable.Length; i++)              {                  if (MBDataTable[i].addr == addr)                  {                      if (MBDataTable[i].type == type)                      {                          return MBDataTable[i].ob;                      }                  }              }              return null;          }          /// <summary>          /// 设置地址所对应的数据         /// </summary>          /// <param name="addr">地址</param>          /// <param name="type">类型</param>          /// <param name="data">数据</param>          /// <returns>是否成功</returns>          private static object SetAddressValue(int addr, byte type, object data)          {              for (int i = 0; i < MBDataTable.Length; i++)              {                  if (MBDataTable[i].addr == addr)                  {                      if (MBDataTable[i].type == type)                      {                          MBDataTable[i].ob = data;                          return true;                      }                  }              }              return null;          }          /// <summary>          /// 获取一连串数据         /// </summary>          /// <param name="addr">首地址</param>          /// <param name="type">功能码</param>          /// <param name="len">长度</param>          /// <returns>转换后的字节数组</returns>          private static byte[] GetAddressValues(int addr, byte type, int len)          {              byte[] arr = null;              object obj;              byte temp;              int temp2;                switch (type)              {                  case MB_WRITE_MULTIPLE_COILS:                       arr = new byte[(len % 8 == 0) ? (len / 8) : (len / 8 + 1)];                      for (int i = 0; i < arr.Length; i++)                      {                          for (int j = 0; j < 8; j++)                          {   //获取地址所对应的数据 并判断所读数据 是否被指定，有没被指定的数据 直接返回null                              obj = GetAddressValue(addr + i * 8 + j, MB_READ_COILS);                              if (obj == null)                                  return null;                              else                                  temp = Convert.ToByte(obj);                              arr[i] |=  (byte)((temp == 0? 0 : 1) << j);                           }                      }                      break;                  case MB_WRITE_MULTIPLE_REGS:                       arr = new byte[len * 2];                      for (int i = 0; i < len; i++)                      {                          obj = GetAddressValue(addr + i, MB_READ_HOLD_REG);                          if (obj == null)                              return null;                          else                              temp2 = Convert.ToInt32(obj);                          arr[i * 2] = (byte)(temp2 >> 8);                          arr[i * 2 + 1] = (byte)(temp2 & 0xFF);                      }                      break;                  default: break;              }              return arr;          }          #endregion            #region 校验         private static readonly byte[] aucCRCHi = {              0x00, 0xC1, 0x81, 0x40, 0x01, 0xC0, 0x80, 0x41, 0x01, 0xC0, 0x80, 0x41,              0x00, 0xC1, 0x81, 0x40, 0x01, 0xC0, 0x80, 0x41, 0x00, 0xC1, 0x81, 0x40,              0x00, 0xC1, 0x81, 0x40, 0x01, 0xC0, 0x80, 0x41, 0x01, 0xC0, 0x80, 0x41,              0x00, 0xC1, 0x81, 0x40, 0x00, 0xC1, 0x81, 0x40, 0x01, 0xC0, 0x80, 0x41,              0x00, 0xC1, 0x81, 0x40, 0x01, 0xC0, 0x80, 0x41, 0x01, 0xC0, 0x80, 0x41,              0x00, 0xC1, 0x81, 0x40, 0x01, 0xC0, 0x80, 0x41, 0x00, 0xC1, 0x81, 0x40,              0x00, 0xC1, 0x81, 0x40, 0x01, 0xC0, 0x80, 0x41, 0x00, 0xC1, 0x81, 0x40,              0x01, 0xC0, 0x80, 0x41, 0x01, 0xC0, 0x80, 0x41, 0x00, 0xC1, 0x81, 0x40,              0x00, 0xC1, 0x81, 0x40, 0x01, 0xC0, 0x80, 0x41, 0x01, 0xC0, 0x80, 0x41,              0x00, 0xC1, 0x81, 0x40, 0x01, 0xC0, 0x80, 0x41, 0x00, 0xC1, 0x81, 0x40,              0x00, 0xC1, 0x81, 0x40, 0x01, 0xC0, 0x80, 0x41, 0x01, 0xC0, 0x80, 0x41,              0x00, 0xC1, 0x81, 0x40, 0x00, 0xC1, 0x81, 0x40, 0x01, 0xC0, 0x80, 0x41,               0x00, 0xC1, 0x81, 0x40, 0x01, 0xC0, 0x80, 0x41, 0x01, 0xC0, 0x80, 0x41,              0x00, 0xC1, 0x81, 0x40, 0x00, 0xC1, 0x81, 0x40, 0x01, 0xC0, 0x80, 0x41,               0x01, 0xC0, 0x80, 0x41, 0x00, 0xC1, 0x81, 0x40, 0x01, 0xC0, 0x80, 0x41,              0x00, 0xC1, 0x81, 0x40, 0x00, 0xC1, 0x81, 0x40, 0x01, 0xC0, 0x80, 0x41,              0x00, 0xC1, 0x81, 0x40, 0x01, 0xC0, 0x80, 0x41, 0x01, 0xC0, 0x80, 0x41,               0x00, 0xC1, 0x81, 0x40, 0x01, 0xC0, 0x80, 0x41, 0x00, 0xC1, 0x81, 0x40,              0x00, 0xC1, 0x81, 0x40, 0x01, 0xC0, 0x80, 0x41, 0x01, 0xC0, 0x80, 0x41,              0x00, 0xC1, 0x81, 0x40, 0x00, 0xC1, 0x81, 0x40, 0x01, 0xC0, 0x80, 0x41,              0x00, 0xC1, 0x81, 0x40, 0x01, 0xC0, 0x80, 0x41, 0x01, 0xC0, 0x80, 0x41,              0x00, 0xC1, 0x81, 0x40          };          private static readonly byte[] aucCRCLo = {              0x00, 0xC0, 0xC1, 0x01, 0xC3, 0x03, 0x02, 0xC2, 0xC6, 0x06, 0x07, 0xC7,              0x05, 0xC5, 0xC4, 0x04, 0xCC, 0x0C, 0x0D, 0xCD, 0x0F, 0xCF, 0xCE, 0x0E,              0x0A, 0xCA, 0xCB, 0x0B, 0xC9, 0x09, 0x08, 0xC8, 0xD8, 0x18, 0x19, 0xD9,              0x1B, 0xDB, 0xDA, 0x1A, 0x1E, 0xDE, 0xDF, 0x1F, 0xDD, 0x1D, 0x1C, 0xDC,              0x14, 0xD4, 0xD5, 0x15, 0xD7, 0x17, 0x16, 0xD6, 0xD2, 0x12, 0x13, 0xD3,              0x11, 0xD1, 0xD0, 0x10, 0xF0, 0x30, 0x31, 0xF1, 0x33, 0xF3, 0xF2, 0x32,              0x36, 0xF6, 0xF7, 0x37, 0xF5, 0x35, 0x34, 0xF4, 0x3C, 0xFC, 0xFD, 0x3D,              0xFF, 0x3F, 0x3E, 0xFE, 0xFA, 0x3A, 0x3B, 0xFB, 0x39, 0xF9, 0xF8, 0x38,               0x28, 0xE8, 0xE9, 0x29, 0xEB, 0x2B, 0x2A, 0xEA, 0xEE, 0x2E, 0x2F, 0xEF,              0x2D, 0xED, 0xEC, 0x2C, 0xE4, 0x24, 0x25, 0xE5, 0x27, 0xE7, 0xE6, 0x26,              0x22, 0xE2, 0xE3, 0x23, 0xE1, 0x21, 0x20, 0xE0, 0xA0, 0x60, 0x61, 0xA1,              0x63, 0xA3, 0xA2, 0x62, 0x66, 0xA6, 0xA7, 0x67, 0xA5, 0x65, 0x64, 0xA4,              0x6C, 0xAC, 0xAD, 0x6D, 0xAF, 0x6F, 0x6E, 0xAE, 0xAA, 0x6A, 0x6B, 0xAB,               0x69, 0xA9, 0xA8, 0x68, 0x78, 0xB8, 0xB9, 0x79, 0xBB, 0x7B, 0x7A, 0xBA,              0xBE, 0x7E, 0x7F, 0xBF, 0x7D, 0xBD, 0xBC, 0x7C, 0xB4, 0x74, 0x75, 0xB5,              0x77, 0xB7, 0xB6, 0x76, 0x72, 0xB2, 0xB3, 0x73, 0xB1, 0x71, 0x70, 0xB0,              0x50, 0x90, 0x91, 0x51, 0x93, 0x53, 0x52, 0x92, 0x96, 0x56, 0x57, 0x97,              0x55, 0x95, 0x94, 0x54, 0x9C, 0x5C, 0x5D, 0x9D, 0x5F, 0x9F, 0x9E, 0x5E,              0x5A, 0x9A, 0x9B, 0x5B, 0x99, 0x59, 0x58, 0x98, 0x88, 0x48, 0x49, 0x89,              0x4B, 0x8B, 0x8A, 0x4A, 0x4E, 0x8E, 0x8F, 0x4F, 0x8D, 0x4D, 0x4C, 0x8C,              0x44, 0x84, 0x85, 0x45, 0x87, 0x47, 0x46, 0x86, 0x82, 0x42, 0x43, 0x83,              0x41, 0x81, 0x80, 0x40          };          /// <summary>          /// CRC效验         /// </summary>          /// <param name="pucFrame">效验数据</param>          /// <param name="usLen">数据长度</param>          /// <returns>效验结果</returns>          public static int Crc16(byte[] pucFrame, int usLen)          {              int i = 0;              byte ucCRCHi = 0xFF;              byte ucCRCLo = 0xFF;              UInt16 iIndex = 0x0000;                while (usLen-- > 0)              {                  iIndex = (UInt16)(ucCRCLo ^ pucFrame[i++]);                  ucCRCLo = (byte)(ucCRCHi ^ aucCRCHi[iIndex]);                  ucCRCHi = aucCRCLo[iIndex];              }              return (ucCRCHi << 8 | ucCRCLo);          }            #endregion            #region 发送指命操作         /// <summary>          /// 首部分数据 node:节点         /// </summary>          /// <param name="addr">寄存器地址</param>          /// <param name="len">数据长度，或单个数据</param>          /// <param name="stat"></param>          /// <returns></returns>          private static byte[] SendTrainHead(int node, int addr, int len, byte stat)          {              byte[] head = new byte[6];                head[0] = Convert.ToByte(node);              head[1] = stat;              head[2] = (byte)(addr >> 8);              head[3] = (byte)(addr & 0xFF);              head[4] = (byte)(len >> 8);              head[5] = (byte)(len & 0xFF);                return head;          }          /// <summary>          /// 计算数据长度 并在0x0f,0x10功能下 加载字节数         /// </summary>          /// <param name="arr"></param>          /// <param name="len"></param>          /// <param name="stat"></param>          /// <returns></returns>          private static byte[] SendTrainBytes(byte[] arr, ref int len, byte stat)          {              byte[] res;              switch (stat)              {                  default: len = 0; break;                    case MB_READ_COILS:                  case MB_READ_DISCRETE:                  case MB_READ_HOLD_REG:                  case MB_READ_INPUT_REG:                  case MB_WRITE_SINGLE_COIL:                  case MB_WRITE_SINGLE_REG:                      len = 0;                      break;                    case MB_WRITE_MULTIPLE_COILS:                      len = (len % 8 == 0) ? (len / 8) : (len / 8 + 1);                      res = new byte[arr.Length + 1];                      arr.CopyTo(res, 0);                      res[arr.Length] = (byte)(len);                      arr = res;                      break;                    case MB_WRITE_MULTIPLE_REGS:                      len *= 2;                      res = new byte[arr.Length + 1];                      arr.CopyTo(res, 0);                      res[arr.Length] = (byte)len;      //把字节写入数据最后位置                     arr = res;                      break;                }              return arr;          }          /// <summary>          /// 主控方式  发送指令模板         /// </summary>          /// <param name="node">节点</param>          /// <param name="data">数据</param>          /// <param name="addr">地址</param>          /// <param name="con">变量各数</param>          /// <param name="stat">功能码</param>          /// <returns></returns>          private static byte[] SendTrainCyclostyle(int node, byte[] data, int addr, int con, byte stat)          {              int crcVal = 0;              byte[] headData = http://www.mamicode.com/SendTrainHead(node, addr, con, stat);                   //写首部分数据             byte[] headDataLen = SendTrainBytes(headData, ref con, stat);       //计算数据的长度，有字节则写入。             byte[] res = new byte[headDataLen.Length + con + 2];                headDataLen.CopyTo(res, 0);                if ((stat == MB_WRITE_MULTIPLE_REGS) || (stat == MB_WRITE_MULTIPLE_COILS))                  Array.Copy(data, 0, res, headDataLen.Length, con);                   //把数据复制到数据中               crcVal = Crc16(res, res.Length - 2);              res[res.Length - 2] = (byte)(crcVal & 0xFF);              res[res.Length - 1] = (byte)(crcVal >> 8);                return res;          }          /// <summary>          /// 封装发送数据帧         /// </summary>          /// <param name="node">从机地址</param>          /// <param name="cmd">指令信息</param>          /// <returns></returns>          private static byte[] SendPduPack(int node, MBCmd cmd)          {              byte[] res = null;              switch (cmd.stat)              {                  case MB_READ_COILS:                   case MB_READ_DISCRETE:                  case MB_READ_HOLD_REG:                  case MB_READ_INPUT_REG:                  case MB_WRITE_SINGLE_COIL:                  case MB_WRITE_SINGLE_REG:                      res = SendTrainCyclostyle(node, null, cmd.addr, cmd.len, (byte)cmd.stat); break;                    case MB_WRITE_MULTIPLE_COILS:                  case MB_WRITE_MULTIPLE_REGS:                      byte[] data = http://www.mamicode.com/GetAddressValues(cmd.addr, (byte)cmd.stat, cmd.len);                      res = SendTrainCyclostyle(node, data, cmd.addr, cmd.len, (byte)cmd.stat); break;              }              return res;          }          #endregion            #region 回传数据操作         /// <summary>          /// 存储回传的线圈         /// </summary>          /// <param name="data">回传的数组</param>          /// <param name="addr">首地址</param>          /// <returns>存储是否正确</returns>          private static bool ReadDiscrete(byte[] data, int addr)          {              bool res = true;              int len = data[2];                if (len != (data.Length - 5))  //数据长度不正确 直接退出                 return false;                for (int i = 0; i < len; i++)              {                  for (int j = 0; j < 8; j++)                  {                      if (SetAddressValue(addr + i * 8 + j, data[1], data[i + 3] & (0x01 << j)) == null)                      {                          return false;                      }                  }              }              return res;          }          /// <summary>          /// 读回传的寄存器         /// </summary>          /// <param name="data">回传的数组</param>          /// <param name="addr">首地址</param>          /// <returns>存储是否正确</returns>          private static bool ReadReg(byte[] data, int addr)          {              bool res = true;              int len = data[2];                if (len != (data.Length - 5))  //数据长度不正确 直接退出                 return false;                for (int i = 0; i < len; i += 2)              {                  if (SetAddressValue(addr + i / 2, data[1], (data[i + 3] << 8) | data[i + 4]) == null)                  {                      res = false;                      break;                  }              }              return res;          }          /// <summary>          /// 回传的数据处理         /// </summary>          /// <param name="buff">回传的整帧数据</param>          /// <param name="addr">当前所操作的首地址</param>          /// <returns></returns>          private static bool ReceiveDataProcess(byte[] buff, int addr)          {              if (buff == null)                  return false;              if (buff.Length < 5)    //回传的数据 地址+功能码+长度+2效验 = 5字节                 return false;                bool res = true;              switch (buff[1])              {                  case MB_READ_COILS: ReadDiscrete(buff, addr); break;                  case MB_READ_DISCRETE: ReadDiscrete(buff, addr); break;                  case MB_READ_HOLD_REG: ReadReg(buff, addr); break;                  case MB_READ_INPUT_REG: ReadReg(buff, addr); break;                  case MB_WRITE_SINGLE_COIL:                  case MB_WRITE_SINGLE_REG:                  case MB_WRITE_MULTIPLE_COILS:                  case MB_WRITE_MULTIPLE_REGS: break;                  default: res = false; break;              }              return res;          }          #endregion            #region 收发调度         /// <summary>          /// 添加重复操作指令         /// </summary>          /// <param name="sci">待发送的指命管道</param>          /// <param name="addr">所添加指令的首地址</param>          /// <param name="len">所添加指令的寄存器或线圈个数</param>          /// <param name="stat">所添加指令的功能码</param>          private static void SciAddRepeatCmd(ref MBSci sci, int addr, int len, int stat)          {              if (sci.rtCount >= MB_SCI_MAX_COUNT - 1)  //超出指令管道最大长度 直接退出                 return;              if (len == 0)                               //地址的数据长度为空 直接退出                 return;                sci.cmd[sci.rtCount].addr = addr;              sci.cmd[sci.rtCount].len = len;              sci.cmd[sci.rtCount].stat = stat;              sci.cmd[sci.rtCount].res = 0;              sci.rtCount++;          }          /// <summary>          /// 添加一次性操作指令         /// </summary>          /// <param name="sci">待发送的指命管道</param>          /// <param name="addr">所添加指令的首地址</param>          /// <param name="len">所添加指令的寄存器或线圈个数</param>          /// <param name="stat">所添加指令的功能码</param>          private static void SciAddCmd(ref MBSci sci, int addr, int len, int stat)          {              if (len == 0)                               //地址的数据长度为空 直接退出                 return;                for (int i = sci.rtCount; i < MB_SCI_MAX_COUNT; i++)              {                  if (sci.cmd[i].addr == -1)      //把指令载入到空的管道指令上                 {                      sci.cmd[i].addr = addr;                      sci.cmd[i].len = len;                      sci.cmd[i].stat = stat;                      sci.cmd[i].res = 0;                      break;                  }              }          }          /// <summary>          /// 清空重复读取指令集         /// </summary>          /// <param name="sci">待发送的指命管道</param>          private static void SciClearRepeatCmd(ref MBSci sci)          {              sci.rtCount = 0;          }          /// <summary>          /// 清空一次性读取指令集         /// </summary>          /// <param name="sci">待发送的指命管道</param>          private static void SciClearCmd(ref MBSci sci)          {              for (int i = sci.rtCount; i < MB_SCI_MAX_COUNT; i++)              {                  sci.cmd[i].addr = -1;                  sci.cmd[i].len = 0;                  sci.cmd[i].res = 0;              }          }          /// <summary>          /// 跳到下一个操作指令         /// </summary>          /// <param name="sci">待发送的指命管道</param>          private static void SciJumbNext(ref MBSci sci)          {              if (sci.index >= sci.rtCount)           //非实时读取地址会被清除             {                  sci.cmd[sci.index].addr = -1;                  sci.cmd[sci.index].len = 0;                  sci.cmd[sci.index].stat = 0;              }                do{                  sci.index++;                  if (sci.index >= MB_SCI_MAX_COUNT)    //超出指令最大范围                 {                      sci.index = 0;                      if (sci.rtCount == 0)               //如果固定实时读取 为空 直接跳出                         break;                  }                } while (sci.cmd[sci.index].addr == -1);              sci.cmd[sci.index].res = 0;             //本次返回状态清零         }          /// <summary>          /// 发送指令调度锁定         /// </summary>          public static void SciSchedulingLock()          {              sciLock = true;          }          /// <summary>          /// 发送指令调度解锁         /// </summary>          public static void SciSchedulingUnlock()          {              sciLock = false;          }          /// <summary>          /// 待发送的指令管道调度         /// </summary>          /// <param name="sci">待发送的指命管道</param>          /// <param name="rBuf">收到正确的回传数据</param>          /// <param name="wBuf">准备发送的指令数据</param>          private static void SciScheduling(ref MBSci sci, ref byte[] rBuf, ref byte[] wBuf)          {              if (sciLock)   //如果被加锁 直接退出                  return;                if ((sci.cmd[sci.index].res != 0) || (sci.count >= sci.maxRepeatCount))              {                  sci.count = 0;       //发送次数清零                 if (sci.cmd[sci.index].res != 0)    //如果收到了正常返回                 {                      ReceiveDataProcess(rBuf, sci.cmd[sci.index].addr);     //保存数据                     rBuf = null;        //清空当前接收缓冲区的内容， 以防下次重复读取                 }                  else                  {                      //参数操作失败                 }                    SciJumbNext(ref sci);              }              wBuf = SendPduPack((int)gNode, sci.cmd[sci.index]);     //发送指令操作             sci.count++;                            //发送次数加1          }          /// <summary>          /// 快速刷新 处理接收到的数据   建议:10ms以下         /// </summary>          /// <returns>所正确回传数据的功能码, null:回传不正确</returns>          private static int MBQuickRefresh()          {              int res = -1;              if (rBuff != null)              {                  SciSchedulingLock();                  if (ReceiveDataProcess(rBuff, gMBSci.cmd[gMBSci.index].addr) == true)                  {                      gMBSci.cmd[gMBSci.index].res = 1;   //标记 所接收到的数据正确                     res = gMBSci.cmd[gMBSci.index].stat;                  }                  rBuff = null;                  SciSchedulingUnlock();              }              return res;          }          /// <summary>          /// 调度间隔时间刷新        建议:50ms以上         /// </summary>          /// <returns>封装好的协议帧</returns>          private static void MBSchedRefresh()          {              SciScheduling(ref gMBSci, ref rBuff, ref wBuff);              if (wBuff != null)                  comm.Write(wBuff, 0, wBuff.Length);          }            #endregion            #region 接口函数         /// <summary>          /// 清空存放一次性的指令空间         /// </summary>          public static void MBClearCmd()          {              SciClearCmd(ref gMBSci);          }          /// <summary>          /// 添加固定刷新（重复） 操作指令         /// </summary>          /// <param name="addr">地址</param>          /// <param name="stat">功能码</param>          public static void MBAddRepeatCmd(int addr, byte stat)          {              for (int i = 0; i < GetAddressValueLength(addr); i++ )                  if (GetAddressValue(addr, stat) == null)        //如果所添加的指令没有在MODBUS对应表中定义 直接退出                     return;              SciAddRepeatCmd(ref gMBSci, addr, GetAddressValueLength(addr), stat);          }          /// <summary>          /// 添加一次性 操作指令         /// </summary>          /// <param name="addr"></param>          /// <param name="stat"></param>          public static void MBAddCmd(int addr, byte stat)          {              for (int i = 0; i < GetAddressValueLength(addr); i++)                  if (GetAddressValue(addr, stat) == null)        //如果所添加的指令没有在MODBUS对应表中定义 直接退出                     return;              SciAddCmd(ref gMBSci, addr, GetAddressValueLength(addr), stat);          }          /// <summary>          /// 串口参数配置         /// </summary>          /// <param name="commx">所用到的串口</param>          /// <param name="node"></param>          /// <param name="baud"></param>          public static void MBConfig(SerialPort commx, UInt16 node, UInt16 baud)          {              gBaud = baud;              gNode = node;              comm = commx;              SciClearRepeatCmd(ref gMBSci);              SciClearCmd(ref gMBSci);          }          /// <summary>          /// 读取串口中接收到的数据         /// </summary>          /// <param name="comm">所用到的串口</param>          public static void MBDataReceive()          {              if (comm == null)                       //如果串口没有被初始化直接退出                 return;              SciSchedulingLock();              System.Threading.Thread.Sleep(20);      //等待缓冲器满               buffLen = comm.BytesToRead;          //获取缓冲区字节长度             if (buffLen > MB_MAX_LENGTH)            //如果长度超出范围 直接退出             {                  SciSchedulingUnlock();                  return;              }              comm.Read(buff, 0, buffLen);            //读取数据             if (gMBSci.cmd[gMBSci.index].stat == buff[1])              {                  if (Crc16(buff, buffLen) == 0)                  {                      rBuff = new byte[buffLen];                      Array.Copy(buff, rBuff, buffLen);                  }              }              SciSchedulingUnlock();          }          /// <summary>          /// MODBUS的实时刷新任务，在定时器在实时调用此函数         /// 指令发送间隔时间等于实时器乘以10。 例：定时器5ms调用一次  指令发送间隔为50ms。         /// </summary>          /// <returns>返回当前功能读取指令回传 的功能码</returns>          public static int MBRefresh()          {              if (sciLock)   //如果被加锁 直接退出                  return 0;                mbRefreshTime++;              if (mbRefreshTime > 10)              {                  mbRefreshTime = 0;                  MBSchedRefresh();              }              return MBQuickRefresh();          }          #endregion          }    }