plcmodbus rtu代码

对于PLC与Modbus RTU通信的代码，可以使用C#语言编写。以下是一个示例代码：

using System;
using System.IO.Ports;

public class ModbusRTU
{
    private SerialPort serialPort;

    public ModbusRTU(string portName, int baudRate)
    {
        serialPort = new SerialPort(portName, baudRate);
        serialPort.DataBits = 8;
        serialPort.Parity = Parity.None;
        serialPort.StopBits = StopBits.One;
        serialPort.Open();
    }

    public void WriteSingleRegister(byte slaveAddress, ushort registerAddress, ushort value)
    {
        byte[] command = new byte[]
        {
            slaveAddress,
            0x06, // Function code for writing a single register
            (byte)(registerAddress >> 8), // High byte of the register address
            (byte)(registerAddress & 0xFF), // Low byte of the register address
            (byte)(value >> 8), // High byte of the value
            (byte)(value & 0xFF) // Low byte of the value
        };

        serialPort.Write(command, 0, command.Length);
    }

    public ushort ReadSingleRegister(byte slaveAddress, ushort registerAddress)
    {
        byte[] command = new byte[]
        {
            slaveAddress,            0x03, // Function code for reading a single register
            (byte)(registerAddress >> 8), // High byte of the register address
            (byte)(registerAddress & 0xFF), // Low byte of the register address
            0x00, // Number of registers to read (high byte)
            0x01 // Number of registers to read (low byte)
        };

        serialPort.Write(command, 0, command.Length);

        byte[] response = new byte[5];
        serialPort.Read(response, 0, response.Length);

        ushort value = (ushort)((response[3] << 8) + response[4]);
        return value;
    }
}

// 示例用法
ModbusRTU modbus = new ModbusRTU("COM1", 9600);
modbus.WriteSingleRegister(1, 0, 100);
ushort value = modbus.ReadSingleRegister(1, 0);
Console.WriteLine("Value: " + value);