Connection to PLC with Java

package de.siemens.simaticnet.itcp.example;

import java.applet.*;

import java.awt.*;

import java.awt.event.*;

import java.beans.*;

import de.siemens.simaticnet.itcp.api.*;

import de.siemens.simaticnet.itcp.gui.*;

/**

* @author ITCP Team

*/

public class Example1Net4x extends Applet implements PropertyChangeListener, ActionListener {

private CLTextOut cLTextOut1 = null;

private CLTimer cLTimer1 = null;

private S7CP s7CP1 = null;

private S7Device s7Device1 = null;

private S7Variable s7Variable1 = null;

private boolean isInit = false;

// flag to indicate whether or not init was done

/**

* Initializes the applet.

*

* @see #start

* @see #stop

* @see #destroy

*/

public void init() {

super.init();

setName("VariantA");

setLayout(null);

setSize(426, 240);

s7CP1 = new S7CP();

s7CP1.setHostString(new HostString ("192.168.1.23"));

s7Device1 = new S7Device();

s7Device1.setSlot(3);

s7Variable1 = new S7Variable();

s7Variable1.setS7Anypointer(new S7Anypointer((int)2, (int)1, (int)131,

(int)0, (int)10, (int)0));

s7Variable1.setVariableName("s7Variable1");

cLTimer1 = new CLTimer();

cLTimer1.setDelay(2000);

cLTextOut1 = new CLTextOut();

cLTextOut1.setName("cLTextOut1");

cLTextOut1.setBounds(0, 0, 200, 45);

cLTextOut1.setOutFieldSize(100);

cLTextOut1.setLabel("Value:");

cLTextOut1.setUnit("");

add(cLTextOut1, cLTextOut1.getName());

/* init connections */

s7CP1.addPropertyChangeListener(this);

s7Device1.addPropertyChangeListener(this);

cLTimer1.addActionListener(this);

s7Variable1.addPropertyChangeListener(this);

// initialization is valid

isInit = true;

}

/**

* Is called to start the applet. This method never needs be called directly.

* It is called when the applet document is accessed.

* @see #init

* @see #stop

* @see #destroy

*/

public void start() {

super.start();

// Is an init call necessary?

if (!isInit)

init();

// applet was stopped earlier, so call init again

}

/**

* Is called to stop the applet.

* Is called when the applet document is no longer

* displayed. Is always called before destroy()

* is called. This method must never be called directly.

* @see #init

* @see #start

* @see #destroy

*/

public void stop() {

super.stop();

// remove all components from this container

removeAll();

// destroy all used resources here

cLTextOut1 = null;

cLTimer1 = null;

s7CP1 = null;

s7Device1 = null;

s7Variable1 = null;

// remember that initialization was not done

isInit = false;

// terminate the api mechanisms, finalize objects

// and run the Garbage Collector

S7Api.terminate();

}

/**

* Cleans up whatever resources are being held. If the applet is active

* it is stopped.

*

* @see #init

* @see #start

* @see #stop

*/

public void destroy() {

super.destroy();

// clean up now in stop method !

}

/**

* Method to handle events for the PropertyChangeListener interface.

* @param evt PropertyChangeEvent

*/

public void propertyChange(PropertyChangeEvent pce) {

if (pce.getSource() == s7CP1)

s7Device1.propertyChange(pce);

if (pce.getSource() == s7Device1)

s7Variable1.propertyChange(pce);

if (pce.getSource() == s7Variable1)

cLTextOut1.propertyChange(pce);

}

/**

* Method to handle events for the ActionListener interface.

* @param e java.awt.event.ActionEvent

*/

public void actionPerformed(ActionEvent ae) {

if (ae.getSource() == cLTimer1)

s7Variable1.processGet();

}

}