C#多线程访问PLC MXComponent

Question

开三个线程同时读取三菱PLC内变量数据。不知道问什么报错，用单线程就没有问题。第一个线程能通过，第二个就报错。

public partial class Form1 : Form
{
    public ACTETHERLib.ActQNUDECPUTCP plc1 = null;
    public ACTETHERLib.ActQNUDECPUTCP plc2 = null;
    public ACTETHERLib.ActQNUDECPUTCP plc3 = null;

    public Form1()
    {
        InitializeComponent();
    }

    private void Form1_Load(object sender, EventArgs e)
    {
        this.plc1 = new ACTETHERLib.ActQNUDECPUTCP();
        this.plc2 = new ACTETHERLib.ActQNUDECPUTCP();
        this.plc3 = new ACTETHERLib.ActQNUDECPUTCP();


        this.plc1.ActHostAddress ="192.168.1.21";
        this.plc1.ActHostAddress = "192.168.1.31";
        this.plc1.ActHostAddress = "192.168.1.41";

        int rtn1 = this.plc1.Open();
        int rtn2 = this.plc2.Open();
        int rtn3 = this.plc3.Open();

        if (rtn1 == 0)  MessageBox.Show("PLC1 Connect Succesful !");
        else MessageBox.Show("PLC1 Connect Fail,Please Check Comunication Setting!");
        if (rtn2 == 0) MessageBox.Show("PLC1 Connect Succesful !");
        else MessageBox.Show("PLC2 Connect Fail,Please Check Comunication Setting!");
        if (rtn3 == 0) MessageBox.Show("PLC1 Connect Succesful !");
        else MessageBox.Show("PLC2 Connect Fail,Please Check Comunication Setting!");

        Thread Read_PLC1_thread = new Thread(new ThreadStart(Read_PLC1));
        Thread Read_PLC2_thread = new Thread(new ThreadStart(Read_PLC2));
        Thread Read_PLC3_thread = new Thread(new ThreadStart(Read_PLC3));

        Read_PLC1_thread.Start();
        Read_PLC2_thread.Start();
        Read_PLC3_thread.Start();         

    }

    private void Read_PLC1()
    {
        int[] PLC1_D = new int[100];
        int rtn1 = this.plc1.ReadDeviceBlock("D1", 10, out PLC1_D[1]);
    }

    private void Read_PLC2()
      {
         int[] PLC2_D = new int[100];
         int rtn2 = this.plc2.ReadDeviceBlock("D1", 10, out PLC2_D[1]);          
      }

    private void Read_PLC3()
      {
         int[] PLC3_D = new int[100];
         int rtn3 = this.plc3.ReadDeviceBlock("D1", 10, out PLC3_D[1]);
      }


}

}

Answer 1

可能readdeviceblock这个函数不支持重入，你需要用lock代码块同步下。