Write flag synchronously into the PLC

In this sample program, the value that the user has entered is written into flag double word 0:

Unpack the sample program 'Write flag synchronously into PLC': sample06.zip

• To execute the *.jar sample, the command 'java -classpath "Sample06.jar;[path to TcJavaToAds.jar] Main' must be executed in the console in the correct directory (example path: "C:TwinCAT\Ads Api\AdsToJava\*"). For this, java must be entered in the environment variables.

import de.beckhoff.jni.Convert;
import de.beckhoff.jni.JNIByteBuffer;
import de.beckhoff.jni.tcads.AdsCallDllFunction;
import de.beckhoff.jni.tcads.AmsAddr;

public class Main {
    public static void main(String[] args) {
    try{
        long err;
        AmsAddr addr = new AmsAddr();

        // Open communication        
        AdsCallDllFunction.adsPortOpen();
        err = AdsCallDllFunction.getLocalAddress(addr);
        addr.setPort(AdsCallDllFunction.AMSPORT_R0_PLC_RTS1);

        if (err != 0) {
        System.out.println("Error: Open communication: 0x"
            + Long.toHexString(err));
        } else {
        System.out.println("Success: Open communication!");
        }
        
        // Specify IndexGroup, IndexOffset and write PLCVar
        err = AdsCallDllFunction.adsSyncWriteReq(addr,
                    0x4020,     // Index Group
                    0x0,    // Index Offset
                    Integer.SIZE / Byte.SIZE,
                    new JNIByteBuffer(Convert.IntToByteArr(1024)));
        if(err!=0) { 
        System.out.println("Error: Write by adress: 0x" 
            + Long.toHexString(err)); 
        }

        // Close communication
        err = AdsCallDllFunction.adsPortClose();
        if(err!=0) { 
        System.out.println("Error: Close Communication: 0x" 
            + Long.toHexString(err)); 
        }

        System.out.println("Press enter to continue..");
        System.in.read();
    }
    catch (Exception ex){
        System.out.println(ex.getMessage());
    }
    }
}