C# MODBUS协议 上位机(转)

源：C# MODBUS协议 上位机

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 = ;               //最大数据长度
        private const int MB_SCI_MAX_COUNT = ;             //指令管道最大存放的指令各数
        private const int MB_MAX_REPEAT_COUNT = ;           //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 = ;
        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 = , maxRepeatCount = MB_MAX_REPEAT_COUNT, rtCount = , count =  };
        private static SerialPort comm = null;
        private static int mbRefreshTime = ;
        #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()},      //
            new OPTable(){addr = D_DIO + ,     type = MB_READ_INPUT_REG,      ob = new UInt16()},
            new OPTable(){addr = D_DIO + ,     type = MB_READ_INPUT_REG,      ob = new UInt16()},
            new OPTable(){addr = D_DIO + ,     type = MB_READ_INPUT_REG,      ob = new UInt16()},
            new OPTable(){addr = D_DIO + ,     type = MB_READ_INPUT_REG,      ob = new Int16()},
            new OPTable(){addr = D_DIO + ,     type = MB_READ_INPUT_REG,      ob = new Int16()},

            new OPTable(){addr = D_BASE,        type = MB_READ_HOLD_REG,      ob = new Int16()},        //
            new OPTable(){addr = D_BASE + ,    type = MB_READ_HOLD_REG,      ob = new Int16()},
            new OPTable(){addr = D_BASE + ,    type = MB_READ_HOLD_REG,      ob = new Int16()},
            new OPTable(){addr = D_BASE + ,    type = MB_READ_HOLD_REG,      ob = new Int16()},

            new OPTable(){addr = D_RANGE,       type = MB_READ_HOLD_REG,      ob = new Int16()},        //
            new OPTable(){addr = D_RANGE + ,   type = MB_READ_HOLD_REG,      ob = new Int16()},

            new OPTable(){addr = D_PWM,         type = MB_READ_HOLD_REG,      ob = new Int16()},        //
            new OPTable(){addr = D_PWM + ,     type = MB_READ_HOLD_REG,      ob = new Int16()},
            new OPTable(){addr = D_PWM + ,     type = MB_READ_HOLD_REG,      ob = new Int16()},
            new OPTable(){addr = D_PWM + ,     type = MB_READ_HOLD_REG,      ob = new Int16()},

            new OPTable(){addr = D_PID,         type = MB_READ_HOLD_REG,      ob = new UInt16()},        //
            new OPTable(){addr = D_PID + ,     type = MB_READ_HOLD_REG,      ob = new UInt16()},
            new OPTable(){addr = D_PID + ,     type = MB_READ_HOLD_REG,      ob = new UInt16()},
            new OPTable(){addr = D_PID + ,     type = MB_READ_HOLD_REG,      ob = new UInt16()},
            new OPTable(){addr = D_PID + ,     type = MB_READ_HOLD_REG,      ob = new UInt16()},
            new OPTable(){addr = D_PID + ,     type = MB_READ_HOLD_REG,      ob = new UInt16()},

        };
        public static UInt16 gDioX { get { return Convert.ToUInt16(MBDataTable[].ob); } set { MBDataTable[].ob = value; } }
        public static UInt16 gDioY { get { return Convert.ToUInt16(MBDataTable[].ob); } set { MBDataTable[].ob = value; } }
        public static UInt16 gDioZ { get { return Convert.ToUInt16(MBDataTable[].ob); } set { MBDataTable[].ob = value; } }
        public static UInt16 gDioD { get { return Convert.ToUInt16(MBDataTable[].ob); } set { MBDataTable[].ob = value; } }
        public static Int16 gDioXx { get { return (Int16)Convert.ToInt32(MBDataTable[].ob); } set { MBDataTable[].ob = value; } }
        public static Int16 gDioXy { get { return (Int16)Convert.ToInt32(MBDataTable[].ob); } set { MBDataTable[].ob = value; } }

        public static Int16 gBaseF1 { get { return (Int16)Convert.ToInt32(MBDataTable[].ob); } set { MBDataTable[].ob = value; } }
        public static Int16 gBaseF2 { get { return (Int16)Convert.ToInt32(MBDataTable[].ob); } set { MBDataTable[].ob = value; } }
        public static Int16 gBaseF3 { get { return (Int16)Convert.ToInt32(MBDataTable[].ob); } set { MBDataTable[].ob = value; } }
        public static Int16 gBaseF4 { get { return (Int16)Convert.ToInt32(MBDataTable[].ob); } set { MBDataTable[].ob = value; } }

        public static Int16 gRangeMax { get { return (Int16)Convert.ToInt32(MBDataTable[].ob); } set { MBDataTable[].ob = value; } }
        public static Int16 gRangeMin { get { return (Int16)Convert.ToInt32(MBDataTable[].ob); } set { MBDataTable[].ob = value; } }

        public static Int16 gPwmF1 { get { return (Int16)Convert.ToInt32(MBDataTable[].ob); } set { MBDataTable[].ob = value; } }
        public static Int16 gPwmF2 { get { return (Int16)Convert.ToInt32(MBDataTable[].ob); } set { MBDataTable[].ob = value; } }
        public static Int16 gPwmF3 { get { return (Int16)Convert.ToInt32(MBDataTable[].ob); } set { MBDataTable[].ob = value; } }
        public static Int16 gPwmF4 { get { return (Int16)Convert.ToInt32(MBDataTable[].ob); } set { MBDataTable[].ob = value; } }

        public static float gP
        {
            get
            {
                int tmp = (Convert.ToInt32(MBDataTable[].ob) & 0xFFFF) | ((Convert.ToInt32(MBDataTable[].ob) & 0xFFFF) << );
                byte[] arr = BitConverter.GetBytes(tmp);
                return BitConverter.ToSingle(arr, );
            }
            set
            {
                byte[] val = BitConverter.GetBytes(value);
                MBDataTable[].ob = BitConverter.ToUInt16(val, );
                MBDataTable[].ob = BitConverter.ToUInt16(val, );
            }
        }
        public static float gI
        {
            get
            {
                int tmp = (Convert.ToInt32(MBDataTable[].ob) & 0xFFFF) | ((Convert.ToInt32(MBDataTable[].ob) & 0xFFFF) << );
                byte[] arr = BitConverter.GetBytes(tmp);
                return BitConverter.ToSingle(arr, );
            }
            set
            {
                byte[] val = BitConverter.GetBytes(value);
                MBDataTable[].ob = BitConverter.ToUInt16(val, );
                MBDataTable[].ob = BitConverter.ToUInt16(val, );
            }
        }
        public static float gD
        {
            get
            {
                int tmp = (Convert.ToInt32(MBDataTable[].ob) & 0xFFFF) | ((Convert.ToInt32(MBDataTable[].ob) & 0xFFFF) << );
                byte[] arr = BitConverter.GetBytes(tmp);
                return BitConverter.ToSingle(arr, );
            }
            set
            {
                byte[] val = BitConverter.GetBytes(value);
                MBDataTable[].ob = BitConverter.ToUInt16(val, );
                MBDataTable[].ob = BitConverter.ToUInt16(val, );
            }
        }

        public static UInt16 gNode = ;
        public static UInt16 gBaud = ;
        /// <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 = ;
            switch (addr)
            {
                case D_DIO: res = ; break;
                case D_BASE: res = ; break;
                case D_RANGE: res = ; break;
                case D_PWM: res = ; break;
                case D_PID: res = ; 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 = ; 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 = ; 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 %  == ) ? (len / ) : (len /  + )];
                    for (int i = ; i < arr.Length; i++)
                    {
                        for (int j = ; j < ; 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 *  + j, MB_READ_COILS);
                            if (obj == null)
                                return null;
                            else
                                temp = Convert.ToByte(obj);
                            arr[i] |=  (byte)((temp == ?  : ) << j);
                        }
                    }
                    break;
                case MB_WRITE_MULTIPLE_REGS:
                    arr = new byte[len * ];
                    for (int i = ; i < len; i++)
                    {
                        obj = GetAddressValue(addr + i, MB_READ_HOLD_REG);
                        if (obj == null)
                            return null;
                        else
                            temp2 = Convert.ToInt32(obj);
                        arr[i * ] = (byte)(temp2 >> );
                        arr[i *  + ] = (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 = ;
            byte ucCRCHi = 0xFF;
            byte ucCRCLo = 0xFF;
            UInt16 iIndex = 0x0000;

            while (usLen-- > )
            {
                iIndex = (UInt16)(ucCRCLo ^ pucFrame[i++]);
                ucCRCLo = (byte)(ucCRCHi ^ aucCRCHi[iIndex]);
                ucCRCHi = aucCRCLo[iIndex];
            }
            return (ucCRCHi <<  | 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[];

            head[] = Convert.ToByte(node);
            head[] = stat;
            head[] = (byte)(addr >> );
            head[] = (byte)(addr & 0xFF);
            head[] = (byte)(len >> );
            head[] = (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 = ; 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 = ;
                    break;

                case MB_WRITE_MULTIPLE_COILS:
                    len = (len %  == ) ? (len / ) : (len /  + );
                    res = new byte[arr.Length + ];
                    arr.CopyTo(res, );
                    res[arr.Length] = (byte)(len);
                    arr = res;
                    break;

                case MB_WRITE_MULTIPLE_REGS:
                    len *= ;
                    res = new byte[arr.Length + ];
                    arr.CopyTo(res, );
                    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 = ;
            byte[] headData = 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 + ];

            headDataLen.CopyTo(res, );

            if ((stat == MB_WRITE_MULTIPLE_REGS) || (stat == MB_WRITE_MULTIPLE_COILS))
                Array.Copy(data, , res, headDataLen.Length, con);                   //把数据复制到数据中

            crcVal = Crc16(res, res.Length - );
            res[res.Length - ] = (byte)(crcVal & 0xFF);
            res[res.Length - ] = (byte)(crcVal >> );

            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 = 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[];

            if (len != (data.Length - ))  //数据长度不正确 直接退出
                return false;

            for (int i = ; i < len; i++)
            {
                for (int j = ; j < ; j++)
                {
                    if (SetAddressValue(addr + i *  + j, data[], data[i + ] & (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[];

            if (len != (data.Length - ))  //数据长度不正确 直接退出
                return false;

            for (int i = ; i < len; i += )
            {
                if (SetAddressValue(addr + i / , data[], (data[i + ] << ) | data[i + ]) == 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 < )    //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[])
            {
                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 - )  //超出指令管道最大长度 直接退出
                return;
            if (len == )                               //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 = ;
            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 == )                               //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 == -)      //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 = ;
                    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 = ;
        }
        /// <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 = -;
                sci.cmd[i].len = ;
                sci.cmd[i].res = ;
            }
        }
        /// <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 = -;
                sci.cmd[sci.index].len = ;
                sci.cmd[sci.index].stat = ;
            }

            do{
                sci.index++;
                if (sci.index >= MB_SCI_MAX_COUNT)    //超出指令最大范围
                {
                    sci.index = ;
                    if (sci.rtCount == )               //如果固定实时读取 为空 直接跳出
                        break;
                }

            } while (sci.cmd[sci.index].addr == -);
            sci.cmd[sci.index].res = ;             //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 != ) || (sci.count >= sci.maxRepeatCount))
            {
                sci.count = ;       //发送次数清零
                if (sci.cmd[sci.index].res != )    //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 = -;
            if (rBuff != null)
            {
                SciSchedulingLock();
                if (ReceiveDataProcess(rBuff, gMBSci.cmd[gMBSci.index].addr) == true)
                {
                    gMBSci.cmd[gMBSci.index].res = ;   //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, , 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 = ; 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 = ; 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();      //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, , buffLen);            //读取数据
            if (gMBSci.cmd[gMBSci.index].stat == buff[])
            {
                if (Crc16(buff, buffLen) == )
                {
                    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 ;

            mbRefreshTime++;
            if (mbRefreshTime > )
            {
                mbRefreshTime = ;
                MBSchedRefresh();
            }
            return MBQuickRefresh();
        }
        #endregion

    }

}

下面是自己开发的一个小控制软件及原代码：

原文件上传到我的网盘中：

http://115.com/file/dp4vm8c7#CopterSoftware.rar

提示：这个小软件用了第三方插件Developer Express v2011。确认安装此插件方能正常打开。

下面这个小工具是用modbus发送 大块数据的样例：

http://pan.baidu.com/share/link?shareid=157523&uk=118334538

日志 BUG修改：

1，如下图增加 ，修正在无重复指令时，单次指令的次数的正确性。

if (sci.cmd[0].addr == -1)                 return;