C#实现三菱PLC通信

一、基于HslCommunication库的串口通信示例

using HslCommunication;
using HslCommunication.Profinet.Melsec;
using System;
using System.Threading.Tasks;

public class MelsecPLC
{
    private MelsecMcNet _plc;

    public async Task ConnectAsync(string ipAddress, int port = 5000)
    {
        _plc = new MelsecMcNet(ipAddress, port);
        var result = await _plc.ConnectServerAsync();
        if (!result.IsSuccess)
        {
            throw new Exception($"连接失败: {result.Message}");
        }
    }

    // 读取D寄存器（示例读取D0-D9）
    public ushort[] ReadDRegisters(int startAddress, int count)
    {
        var result = _plc.Read("D" + startAddress, count);
        return result.IsSuccess ? result.Content : new ushort[0];
    }

    // 写入单个D寄存器
    public bool WriteDRegister(int address, ushort value)
    {
        var result = _plc.Write("D" + address, value);
        return result.IsSuccess;
    }

    // 批量写入D寄存器
    public bool WriteDBlock(int startAddress, ushort[] values)
    {
        return _plc.Write("D" + startAddress, values) is OperateResult<byte[]> { IsSuccess: true };
    }
}

// 使用示例
var plc = new MelsecPLC();
await plc.ConnectAsync("192.168.1.100");
ushort[] data = plc.ReadDRegisters(0, 10);
plc.WriteDRegister(100, 1234);

---

二、基于AxActUtlTypeLib的TCP/IP通信示例

using System;
using System.Runtime.InteropServices;
using ActUtlTypeLib;

public class MelsecPLC
{
    private AxActUtlType _axActUtlType;

    public MelsecPLC()
    {
        _axActUtlType = new AxActUtlType();
        ((System.ComponentModel.ISupportInitialize)(_axActUtlType)).BeginInit();
        Controls.Add(_axActUtlType);
    }

    public int Connect(string ipAddress, int station = 0)
    {
        _axActUtlType.ActLogicalStationNumber = station;
        _axActUtlType.ActPassword = "";
        return _axActUtlType.Open();
    }

    public short[] ReadWords(string address, int count)
    {
        short[] buffer = new short[count];
        int result = _axActUtlType.ReadDeviceBlock2(address, count, out buffer[0]);
        return result == 0 ? buffer : new short[0];
    }

    public bool WriteWords(string address, short[] values)
    {
        return _axActUtlType.WriteDeviceBlock2(address, values.Length, ref values[0]) == 0;
    }
}

// 使用示例
var plc = new MelsecPLC();
int status = plc.Connect("192.168.1.100");
short[] data = plc.ReadWords("D0", 10);
plc.WriteWords("D100", new short[] { 100, 200 });

---

三、基于MC协议的TCP/IP通信示例

using System;
using System.Net.Sockets;
using System.Text;

public class McProtocolPLC
{
    private TcpClient _client;
    private NetworkStream _stream;

    public bool Connect(string ip, int port = 5000)
    {
        _client = new TcpClient();
        _client.Connect(ip, port);
        _stream = _client.GetStream();
        return _client.Connected;
    }

    // 构建读取帧（示例读取D0-D9）
    private byte[] BuildReadFrame(string device, int startAddr, int count)
    {
        byte[] header = { 0x50, 0x00, 0x00, 0x03, 0xFF, 0x03, 0x00, 0x00, 0x00, 0x00, 0x00 };
        byte[] cmd = { 0x01, 0x04 }; // 批量读取指令
        byte[] addr = BitConverter.GetBytes(startAddr);
        byte[] len = { (byte)(count & 0xFF), (byte)(count >> 8) };
        byte[] devCode = GetDeviceCode(device);

        using (MemoryStream ms = new MemoryStream())
        {
            ms.Write(header, 0, header.Length);
            ms.Write(cmd, 0, cmd.Length);
            ms.Write(addr, 0, addr.Length);
            ms.Write(len, 0, len.Length);
            ms.Write(devCode, 0, devCode.Length);
            return ms.ToArray();
        }
    }

    private byte[] GetDeviceCode(string device)
    {
        return device switch
        {
            "D" => new byte[] { 0xA8 },
            "M" => new byte[] { 0x90 },
            "X" => new byte[] { 0x9C },
            "Y" => new byte[] { 0x9D },
            _ => throw new ArgumentException("无效设备类型")
        };
    }

    public ushort[] ReadData(string device, int startAddr, int count)
    {
        byte[] request = BuildReadFrame(device, startAddr, count);
        _stream.Write(request, 0, request.Length);

        byte[] response = new byte[1024];
        int bytesRead = _stream.Read(response, 0, response.Length);
        return ParseResponse(response, bytesRead);
    }

    private ushort[] ParseResponse(byte[] data, int length)
    {
        if (BitConverter.ToUInt16(data, 7) != 0x0000) // 检查结束码
            throw new Exception("PLC返回错误");

        int dataLength = (BitConverter.ToUInt16(data, 8) << 8) | data[9];
        ushort[] result = new ushort[dataLength / 2];
        for (int i = 0; i < result.Length; i++)
        {
            result[i] = (ushort)(data[10 + i * 2] | (data[11 + i * 2] << 8));
        }
        return result;
    }
}

// 使用示例
var plc = new McProtocolPLC();
plc.Connect("192.168.1.100");
ushort[] data = plc.ReadData("D", 0, 10);

---

四、核心功能实现要点

1. 地址转换规则

   • 位地址：Y7→ 37H→ ASCII码33 37
   • 字地址：D0→ 4000H→ ASCII码34 30 30 30

   public static string DecimalToWordAddress(int address)
   {
       return (address * 2 + 4096).ToString("X4");
   }

2. 数据校验机制

   private byte CalculateChecksum(byte[] data)
   {
       byte sum = 0;
       foreach (byte b in data)
       {
           sum += b;
       }
       return (byte)(sum % 256);
   }

3. 异常处理策略

   public async Task<OperateResult<byte[]>> SafeReadAsync(string address, int length)
   {
       try
       {
           return await ReadAsync(address, length);
       }
       catch (TimeoutException)
       {
           return OperateResult.Create<byte[]>(false, "通信超时");
       }
       catch (Exception ex)
       {
           return OperateResult.Create<byte[]>(false, ex.Message);
       }
   }

---

五、完整项目结构建议

PLC_Communication/
├── MelsecPLC/              # 核心通信类
│   ├── MelsecPLC.cs       # 主类
│   └── AddressConverter.cs # 地址转换工具
├── TestApp/               # 测试程序
│   ├── MainForm.cs        # 主界面
│   └── PLCConfigForm.cs   # 参数配置界面
└── Resources/             # 配置文件
    └── plc_params.json    # PLC参数存储

---

六、调试与优化建议

1. 串口调试工具

   使用Putty或SecureCRT验证基础通信，设置参数：

   波特率:9600 | 数据位:7 | 停止位:1 | 校验:偶校验

2. 性能监控

   public class PerformanceMetrics
   {
       public long MessagesSent { get; set; }
       public long MessagesReceived { get; set; }
       public double CPUUsage { get; set; }
       public double MemoryUsage { get; set; }
   }

3. 日志记录

   public static class Logger
   {
       public static void Log(string message)
       {
           File.AppendAllText("plc_log.txt", 
               $"{DateTime.Now:yyyy-MM-dd HH:mm:ss} - {message}{Environment.NewLine}");
       }
   }

---

七、扩展功能实现

1. 批量读写优化

   public ushort[] ReadWords(string startAddr, int count)
   {
       string cmd = $"{STX}30{StationNumber}0400{startAddr}{count:X2}{ETX}";
       var response = SendCommand(cmd);
       ushort[] result = new ushort[count];
       for(int i=0; i<count; i++)
       {
           result[i] = (ushort)(response[5+2*i] * 256 + response[6+2*i]);
       }
       return result;
   }

2. 自动重连机制

   public async Task AutoReconnectAsync()
   {
       while (!_isDisposed)
       {
           if (!_serialPort.IsOpen)
           {
               try
               {
                   _serialPort.Open();
                   Debug.WriteLine("自动重连成功");
               }
               catch (Exception ex)
               {
                   Debug.WriteLine($"重连失败: {ex.Message}");
                   await Task.Delay(5000);
               }
           }
           await Task.Delay(1000);
       }
   }

参考代码 三菱通讯字节写入 www.youwenfan.com/contentcso/112220.html

八、推荐开发工具

工具名称	用途	下载地址
GX Works3	PLC程序编写与调试	三菱电机官网
HslCommunication	高级PLC通信库	GitHub
Serial Port Monitor	串口数据监控	NirSoft官网