Question

我正在尝试用Java编写代码，用于简单的SCADA / HMI，通过Modbus TCP将我的计算机连接到PLC。我写了代码在我的PLC上打开/关闭5个线圈，但应用程序工作非常慢 - 当我按下按钮两次（这是开启/关闭线圈的条件）PLC需要4-6秒才能完成命令。但我希望它能够迅速发挥作用。

在代码中，我编写了主类，我建立了连接，以及线程类，我在其中为每个线圈执行ModBusTCPTransaction。我将线程类称为“守护进程”并在主类中启动它。但也许这不是应该做的事情的方法 - 也许任何人都可以写下通常tese类型的SCADA / HMI系统是如何完成/工作的，只用2/3句子...我甚至需要一个deamon线程类......？

这是我的代码

import java.net.*;
import java.io.*;
import net.wimpi.modbus.*;
import net.wimpi.modbus.msg.*;
import net.wimpi.modbus.io.*;
import net.wimpi.modbus.net.*;
import net.wimpi.modbus.util.*;
import java.awt.Color;
import java.awt.FlowLayout;
import javax.swing.*;
import java.awt.*;
import java.awt.event.*;
import java.awt.Graphics;

// 1. daemon class
class NitCoil extends Thread {

    private WriteCoilRequest coil_req = null;
    private ModbusTCPTransaction trans = null;
    private int i;

    NitCoil(String s , int i) {
        super(s);
        this.i = i;
    }

    public void run(){
        try {
        while(true) {
            coil_req = new WriteCoilRequest(i, ModbusTest.coil_con[i]);
            trans = new ModbusTCPTransaction(ModbusTest.con);
            trans.setRequest(coil_req);
            trans.execute();
            this.sleep((int)(Math.random()*100));
        }
        } catch (Exception ex) {
            ex.printStackTrace();
    }
    }

}
//2. main class
public class ModbusTest {

    public static TCPMasterConnection con = null;
    public static boolean[] coil_con = {false,false,false,false,false};
    public static void main(String[] args) {

      try {

          /* Variables for storing the parameters */
          InetAddress addr = null; //the slave's address
          int port = Modbus.DEFAULT_PORT;
          int repeat = 1; //a loop for repeating the transaction

          //3. Setup the parameters
          if (args.length < 1) {
              System.exit(1);
          } else {
              try {
                  String astr = "192.168.0.25:502"; 
                  int idx = astr.indexOf(':');
                  {
                      port = Integer.parseInt(astr.substring(idx+1));
                      astr = astr.substring(0,idx);
                  }
                  addr = InetAddress.getByName(astr);
                  if (args.length == 1) {
                      repeat = Integer.parseInt(args[0]);
                  }
              } catch (Exception ex) {
                  ex.printStackTrace();
                  System.exit(1);
              }
          }

          //4. Open the connection
          con = new TCPMasterConnection(addr);
          con.setPort(port);
          con.connect();

          //5. defining frame, panel, button
          JFrame frame = new JFrame("JFrame Example");
          JPanel panel = new JPanel();
          panel.setLayout(new FlowLayout());
          JLabel label = new JLabel("This is a label!");

          //6. creating 5 buttons             
          JButton[] button = new JButton[5];

          for (int j = 0; j < 5; j++){
               final int temp = j;
               button[j] = new JButton(String.valueOf(j));

          //7. button
          button[j].setText("Switch ON light "+j);

          button[j].addActionListener(new ActionListener() {

            public void actionPerformed(ActionEvent e) {
                 if (coil_con[temp] == true) 
                     coil_con[temp] = false; 
                    else
                     coil_con[temp] = true;
            }
            });
          };
          panel.add(label);
          panel.add(button[0]);
          panel.add(button[1]);
          panel.add(button[2]);
          panel.add(button[3]);
          panel.add(button[4]);

          //8. call of demon
          NitCoil n1 = new NitCoil("daemon1", 0);
          n1.setDaemon(true);
          n1.start();
          NitCoil n2 = new NitCoil("daemon2", 1);
          n2.setDaemon(true);
          n2.start();
          NitCoil n3 = new NitCoil("daemon3", 2);
          n3.setDaemon(true);
          n3.start();
          NitCoil n4 = new NitCoil("daemon4", 3);
          n4.setDaemon(true);
          n4.start();
          NitCoil n5 = new NitCoil("daemon5", 4);
          n5.setDaemon(true);
          n5.start();


          //9. Close the connection
          JButton buttonClose = new JButton();
          buttonClose.setText("disconnect");

          buttonClose.addActionListener(new ActionListener() {

            public void actionPerformed(ActionEvent e) {
                 ModbusTest.con.close();
            }
            }); 
          panel.add(buttonClose);  
          panel.setBackground(Color.green);

          frame.add(panel);
          frame.setSize(300, 300);
          frame.setLocationRelativeTo(null);
          frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
          frame.setVisible(true);

      } catch (Exception ex) {
        ex.printStackTrace();
      }

    }  

}

Answer 1

你看过Wireshark看看响应时间是什么样的吗？也许该设备响应缓慢。

此外，您目前的设置方式是，您一直在连续写入所有五个线圈，这可能并不理想。

由于你的线圈地址是连续的，你也可以使用WriteMultipleCoils函数（0x0F）在一个请求中写入所有五个线圈。

java Modbus TCP SCADA / HMI工作很慢

1 个答案: