Question

我试图通过RS232通过modbus与PLC通信，但它只是说我的消息应包含至少6个字节的数据。首先，我很抱歉，我似乎总是在努力解决代码输入...，我使用相同的类进行TCP / IP modbus连接似乎工作得很好，现在我试图通过RTU RS232 我在编辑中添加了我的两个课程，提前感谢我希望有人可以帮助我。

namespace ConsoleApplication2
{
    class Program
    {
        public static ModBusDriver modbusDriver;

    static void Main(string[] args)
    {
        SerialPort port = new SerialPort("COM1");
        port.BaudRate = 38400;
        port.DataBits = 8;
        port.ReadTimeout = 600;
        port.WriteTimeout = 600;
        port.Parity = Parity.None;
        port.StopBits = StopBits.One;

        modbusDriver = new ModBusDriver(port);
        modbusDriver.connect(1);
        byte slaveAddress = 1;
        modbusDriver.WriteMultipleCoils(slaveAddress, 8193, new bool[6] { false, false, false, false, false, false });
        Console.WriteLine("done");
        Console.Read();
    }

Modbusdriver.cs

using Modbus.Device;
using System;
using System.IO.Ports;
using System.Net.Sockets;
using System.Threading;

namespace CoCoSModBusDriver
{

    // based on nmodbus4: 
    // -https://github.com/NModbus4/NModbus4
    class ModBusDriver
    {
        public int connected;
        private bool gotClient = false;
        public IModbusSerialMaster modbusConnector;
        public SerialPort serialPort;

        public ModBusDriver(SerialPort port)
        {
            serialPort = port;
            modbusConnector = ModbusSerialMaster.CreateRtu(port);
        }

        public void connect(int retries)
        {

            int retryCounter = 0;
            while (retryCounter < retries || retries == -1)
            {
                try
                {
                    serialPort.Open();
                }
                catch (Exception ex)
                {
                    retryCounter++;
                    Thread.Sleep(5000);
                }
            }
        }

        public void WriteMultipleCoils(byte slaveAdress, ushort startAdress, bool[] data)
        {
            try
            {
                modbusConnector.WriteMultipleCoils(slaveAdress, startAdress, data);
            }
            catch (Exception ex)
            {
                Console.WriteLine(ex);
            }
        }
    }
}

Answer 1

您缺少请求中的从属地址。从IModbus主接口：

    /// <summary>
    ///    Writes a sequence of coils.
    /// </summary>
    /// <param name="slaveAddress">Address of the device to write to.</param>
    /// <param name="startAddress">Address to begin writing values.</param>
    /// <param name="data">Values to write.</param>
    void WriteMultipleCoils(byte slaveAddress, ushort startAddress, bool[] data);

Answer 2

您应该使用ModbusSerialMaster类。在mesta自动化主页上有一个很好的例子。

nmodbus - 消息帧必须包含至少6个字节的数据

2 个答案: