【C#】CS学习之Modbus通讯
摘要
本文详细描述了如何在在C#的Winform应用程序中使用NModbus库实现Modbus通讯,包括读取保持寄存器、以及相应的UI界面设计和事件处理。
前言
应用场景
Modbus 从站广泛应用于工业自动化领域:
1、传感器数据采集(如温度、压力等)
2、执行器控制(如电机、阀门等)
3、设备监控与故障诊断。
Modbus 从站(Slave)是 Modbus 通信协议中的响应设备,负责接收并执行来自主站(Master)的请求。
Modbus 从站是被动设备,它不能主动发起通信,只能响应主站的请求。从站的主要功能包括:
1、接收主站的指令(如读取数据或执行操作)。
2、执行相应的操作(如读取寄存器值或设置参数)。
3、返回响应数据或错误码给主站。
通信模式
Modbus 从站支持多种通信模式:
1、Modbus RTU/ASCII:通过串口(如 RS485)进行通信,从站监听串口链路并响应主站指令。
2、Modbus TCP:通过以太网进行通信,从站作为服务器监听 TCP 端口(默认 502 端口)并处理客户端请求。
寄存器类型
Modbus 从站通常管理四种类型的寄存器:
1、线圈(Coils):可读写的二进制状态(如开关状态)。
2、离散输入(Discrete Inputs):只读的二进制状态。
3、保持寄存器(Holding Registers):可读写的16位数据。
4、输入寄存器(Input Registers):只读的16位数据。
实现步骤
1、创建TcpListener并启动 侦听
2、创建Modbus从站数据存储
3、初始化数据
4、创建Modbus从站
5、创建Modbus TCP从站网络
6、添加从站到网络
7、异步侦听网络
运行结果
代码
Frm_ModbusService
public partial class Frm_ModbusService : Form{#region 字段//定时器Timer timer = null;ModbusService modbusService = null;#endregion#region 构造函数、初始化public Frm_ModbusService(){InitializeComponent();CenterToParent();CenterToScreen();}private void ModbusService_Load(object sender, EventArgs e){Initialize();}private void ModbusService_FormClosing(object sender, FormClosingEventArgs e){modbusService.Stop();}#endregion/// <summary>/// 初始化控件状态/// </summary>public void InitializeControlsState(){tbx_IPAddress.Text = modbusService.IpAddress.ToString();tbx_OpenPort.Text = modbusService.Port.ToString();tbx_StartAddress.Text = modbusService.StartAddress.ToString();tbx_SlaveID.Text = modbusService.SlaveId.ToString(); }/// <summary>/// 初始化/// </summary>public void Initialize(){modbusService = new ModbusService();modbusService.MessageUpdateHandler += OnUpdataMessage;InitializeControlsState();UpdataControlsState(modbusService.IsRunning);timer = new Timer();timer.Interval = 100;timer.Tick += Timer_Tick;dataGridView.Columns[0].Width = 100;dataGridView.Columns[1].Width = 100;dataGridView.Columns[0].DefaultCellStyle.Alignment = DataGridViewContentAlignment.MiddleCenter;dataGridView.Columns[1].DefaultCellStyle.Alignment = DataGridViewContentAlignment.MiddleCenter;dataGridView.RowHeadersVisible = false;//10行dataGridView.Rows.Add(new object[] { 0, 0});dataGridView.Rows.Add(new object[] { 1, 0 });dataGridView.Rows.Add(new object[] { 2, 0 });dataGridView.Rows.Add(new object[] { 3, 0 });dataGridView.Rows.Add(new object[] { 4, 0 });dataGridView.Rows.Add(new object[] { 5, 0 });dataGridView.Rows.Add(new object[] { 6, 0 });dataGridView.Rows.Add(new object[] { 7, 0 });dataGridView.Rows.Add(new object[] { 8, 0 });dataGridView.Rows.Add(new object[] { 9, 0 });}/// <summary>/// 定时器方法/// </summary>private void Timer_Tick(object sender, EventArgs e){var array = modbusService.DataStore.HoldingRegisters.ReadPoints(modbusService.StartAddress, 10);for (int i = 0; i < array.Length; i++){dataGridView.Rows[i].Cells[0].Value = (modbusService.StartAddress+ i);dataGridView.Rows[i].Cells[1].Value = array[i];}}/// <summary>/// 启动按钮/// </summary>private void btn_Start_Click(object sender, EventArgs e){try{if (!modbusService.IsRunning){modbusService.Start();timer.Start();UpdataControlsState(modbusService.IsRunning);}else{modbusService.Stop();timer.Stop();UpdataControlsState(modbusService.IsRunning);UpdataMessage("Modbus服务停止");}}catch (Exception ex){modbusService.Stop();timer.Stop();UpdataControlsState(modbusService.IsRunning);UpdataMessage($"Modbus服务异常停止:{ex.Message}");}}/// <summary>/// 更新消息/// </summary>private void UpdataMessage(string message){tbx_Output.BeginInvoke(new Action(() =>{if (tbx_Output.Lines.Length>100){tbx_Output.Clear();}tbx_Output.AppendText($"{DateTime.Now.ToString()}】{message}\r\n");}));}/// <summary>/// 更新消息/// </summary>private void OnUpdataMessage(object sender, string message){UpdataMessage(message);}/// <summary>/// 更新控件状态/// </summary>private void UpdataControlsState(bool isRunning){if (isRunning){tbx_IPAddress.Enabled = false;tbx_OpenPort.Enabled = false;tbx_SlaveID.Enabled = false;btn_Start.Text = "关闭";}else{tbx_IPAddress.Enabled = true;tbx_OpenPort.Enabled = true;tbx_SlaveID.Enabled = true;btn_Start.Text = "启动";}}#region 参数变更/// <summary>/// IP地址变更/// </summary>private void tbxIPAddress_TextChanged(object sender, EventArgs e){if (IPAddress.TryParse(tbx_IPAddress.Text,out IPAddress result)){modbusService.IpAddress = result;}else{tbx_IPAddress.Text = modbusService.IpAddress.ToString();}}/// <summary>/// 端口变更/// </summary>private void tbxOpenPort_TextChanged(object sender, EventArgs e){if (ushort.TryParse(tbx_OpenPort.Text, out ushort result)){modbusService.Port = result;}else{tbx_OpenPort.Text = modbusService.Port.ToString();}}/// <summary>/// 起始地址变更/// </summary>private void tbx_StartAddress_TextChanged(object sender, EventArgs e){if (ushort.TryParse(tbx_StartAddress.Text, out ushort result)){modbusService.StartAddress = result;}else{tbx_StartAddress.Text = modbusService.StartAddress.ToString();}}/// <summary>/// 站ID变更/// </summary>private void tbx_SlaveID_TextChanged(object sender, EventArgs e){if (byte.TryParse(tbx_SlaveID.Text, out byte result)){modbusService.SlaveId = result;}else{tbx_SlaveID.Text = modbusService.SlaveId.ToString();}}#endregion}
}
ModbusService
public class ModbusService
{#region 字段、属性public event EventHandler<string> MessageUpdateHandler;private IPAddress ipAddress = IPAddress.Parse("127.0.0.1");private int port = 502; //端口private byte slaveId = 1; // 从站地址private ushort startAddress = 0; //起始地址private bool isRunning = false; //运行状态private TcpListener tcpListener = null; //创建Modbus服务器private DefaultSlaveDataStore dataStore = null; //默认从站数据存储private ModbusFactory factory = null; //Bodbus工厂private IModbusSlave slave = null; //modbus从站IModbusTcpSlaveNetwork slaveNetwork = null; //ModbusTcp从站网络public IPAddress IpAddress { get => ipAddress; set => ipAddress = value; }public int Port { get => port; set => port = value; }public byte SlaveId { get => slaveId; set => slaveId = value; }public ushort StartAddress { get => startAddress; set => startAddress = value; }public bool IsRunning { get => isRunning; set => isRunning = value; }public TcpListener TcpListener { get => tcpListener; set => tcpListener = value; }public DefaultSlaveDataStore DataStore { get => dataStore; set => dataStore = value; }public ModbusFactory Factory { get => factory; set => factory = value; }public IModbusSlave Slave { get => slave; set => slave = value; }public IModbusTcpSlaveNetwork SlaveNetwork { get => slaveNetwork; set => slaveNetwork = value; }#endregionpublic ModbusService() {}/// <summary>/// 初始化从站数据存储/// </summary>private void InitializeDataStore(DefaultSlaveDataStore dataStore){// 初始化保持寄存器dataStore.HoldingRegisters.WritePoints(0, new ushort[] { 0 });// 初始化输入寄存器dataStore.InputRegisters.WritePoints(0, new ushort[] { 0 });// 初始化线圈dataStore.CoilDiscretes.WritePoints(0, new bool[] { false });// 初始化离散输入dataStore.CoilInputs.WritePoints(0, new bool[] { false });}/// <summary>/// 启动按钮/// </summary>public void Start(){try{if (!IsRunning){// 创建TcpListener并启动TcpListener = new TcpListener(IpAddress, Port);//启动侦听TcpListener.Start();// 创建Modbus从站数据存储DataStore = new DefaultSlaveDataStore();// 初始化数据InitializeDataStore(DataStore);// 创建Modbus从站Factory = new ModbusFactory();Slave = Factory.CreateSlave(1, DataStore);// 创建Modbus TCP从站网络SlaveNetwork = Factory.CreateSlaveNetwork(TcpListener);// 添加从站到网络SlaveNetwork.AddSlave(Slave);//异步侦听网络SlaveNetwork.ListenAsync();IsRunning = true;OnUpdataMessage("Modbus服务启动");}}catch (Exception ex){Stop();OnUpdataMessage($"Modbus服务异常停止:{ex.Message}");}}public void Stop(){TcpListener?.Stop();SlaveNetwork?.Dispose();DataStore = null;Factory = null;Slave = null;IsRunning = false;}/// <summary>/// 消息更新/// </summary>private void OnUpdataMessage(string message){MessageUpdateHandler?.Invoke(this,message);}
}
结语
总结来说,Modbus 从站是 Modbus 网络中的关键组成部分,负责响应主站指令并执行相应操作。广泛应用于工业自动化和设备控制。