ADS in Java

Ads In Java

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• 依赖包
  TcJavaToAds.jar， 可以直接在TwinCAT的安装目录下找到，路径（我这里装在C盘）：C:\TwinCAT\AdsApi\AdsToJava，对应的DLL（adstojava.dll）也在这个目录下，DLL不用管，只要安装了TwinCAT XAE，TcJavaToAds.jar 使用时会自己按默认路径装载这个DLL，我们只需要在Java项目中加入TcJavaToAds.jar这个外部包就行。
• 示例
  Java中ADS通信的流程比C#中复杂些，底层机制都一样，只是C#封装的相对好一些，这里为了更清晰的说明使用方式，将分成几段进行描述；项目中，我们通常只对发布的变量进行读写，即使用了AT指定段地址和偏移地址的，此时group和offset可以直接从PLC中获取到，这里我们描述的更为通用的方式，通过变量名自动获取段地址和偏移地址，进而对变量进行读、写、监听；当然也可以通过变量名获取变量句柄，然后通过句柄对变量进行读写，但所提供的API中没有通过句柄进行变量监听的操作，要监听必须提供段地址和偏移地址。另外，这里读写监听示例主要针对单线程环境，如果需要在多线程环境下使用，需要使用相应的Ex结尾的API函数，函数名和参数均类似单线程的。
  • 建立Ads连接

  AmsAddr addr = new AmsAddr();
  AdsCallDllFunction.adsPortOpen();
  addr.setNetIdStringEx("*.*.*.*.*.*");
  addr.setPort(851);
  

  • 读取变量地址信息

  long err;
  String PLC_VAR = "MAIN.sTest";
  //JNIByteBuffer handleBuff = new JNIByteBuffer(16);
  JNIByteBuffer symbolInfoBuff = new JNIByteBuffer(BUFF_LENGTH_MAX); //BUFF_LENGTH_MAX:16
  JNIByteBuffer symbolBuff = new JNIByteBuffer(PLC_VAR.getBytes());
  err = AdsCallDllFunction.adsSyncReadWriteReq(addr, AdsCallDllFunction.ADSIGRP_SYM_INFOBYNAME, 0x0,
  			symbolInfoBuff.getUsedBytesCount(), symbolInfoBuff, symbolBuff.getUsedBytesCount(), symbolBuff);//err处理略	
  byte[] bArr = symbolInfoBuff.getByteArray();
  System.out.println(bArr.length);
  ByteBuffer wrapped = ByteBuffer.wrap(bArr);
  wrapped.order(ByteOrder.LITTLE_ENDIAN);
  int group = wrapped.getInt();
  System.out.println("group: "+group);
  int offset = wrapped.getInt();
  System.out.println("offset: "+offset);
  int len = wrapped.getInt();
  System.out.println("len: "+len);
  

  • 根据Group+Offset读取变量

    	JNIByteBuffer dataBuff = new JNIByteBuffer(BUFF_LENGTH_MAX);
    	err = AdsCallDllFunction.adsSyncReadReq(addr, group, offset, len, dataBuff);//err处理略	
    	ByteBuffer wrapped2 = ByteBuffer.wrap(dataBuff.getByteArray()); 
    	wrapped2.order(ByteOrder.LITTLE_ENDIAN);
    

    • 读取INT变量

      System.out.println("val: " + wrapped2.getShort());
      

    • 读取DINT变量

      wrapped2.getInt();
      

    • 读取LREAL变量

      wrapped2.getDouble();
      

    • 读取字符串

      new String(dataBuff.getByteArray());
      

    • 读取数组

      for(int i=0; i<len/2; i++) {
      	System.out.println("val: [" + i + "]: " + wrapped2.getShort());
      }
      

    • 读取结构体

      System.out.println(wrapped2.getShort());
      System.out.println(wrapped2.get());
      System.out.println(wrapped2.getDouble(8));
      

      其中，PLC中对应的结构体定义为：

      TYPE S_Test :
      STRUCT
      	i: INT;
      	b: BOOL;
      	q: LREAL;
      END_STRUCT
      END_TYPE
      

      注意结构体中变量的字节对齐问题
  • 根据Group+Offset写变量

    AdsCallDllFunction.adsSyncWriteReq(addr, group, offset, dataBuff.getUsedBytesCount(), dataBuff);
    

    • 写INT变量

      dataBuff.setByteArray(ByteBuffer.allocate(Short.SIZE/Byte.SIZE)
      .order(ByteOrder.LITTLE_ENDIAN).putShort((short) 99).array(), true);
      

    • 写DINT变量

      dataBuff.setByteArray(ByteBuffer.allocate(Integer.SIZE/Byte.SIZE)
      .order(ByteOrder.LITTLE_ENDIAN).putInt((short) 99).array(), true);
      

    • 写LREAL变量

      dataBuff.setByteArray(ByteBuffer.allocate(Double.SIZE/Byte.SIZE)
      .order(ByteOrder.LITTLE_ENDIAN).putDouble((short) 99).array(), true);
      

    • 写字符串

      dataBuff.setByteArray("Hi\0".getBytes(), true);
      

    • 写数组

      ByteBuffer buf = ByteBuffer.allocate(len).order(ByteOrder.LITTLE_ENDIAN);
      for(int i=1; i<=32; i++) {
      	buf.putShort((short) i);
      }
      dataBuff.setByteArray(buf.array(), true);
      

    • 写结构体

      ByteBuffer buf = ByteBuffer.allocate(len).order(ByteOrder.LITTLE_ENDIAN);
      buf.putShort((short)19);
      buf.put((byte)1);
      buf.putDouble(8, 9.99);
      dataBuff.setByteArray(buf.array(), true);
      

  • 事件触发读取变量

    • 注册变量监听

      JNILong notification = new JNILong();
      AdsNotificationAttrib attr = new AdsNotificationAttrib();
      attr.setCbLength(Short.SIZE / Byte.SIZE);
      attr.setNTransMode(AdsConstants.ADSTRANS_SERVERONCHA);
      attr.setDwChangeFilter(10000000); // 1 sec
      attr.setNMaxDelay(20000000);   // 2 sec
      
      AdsListener listener = new AdsListener();
      AdsCallbackObject callObject = new AdsCallbackObject();
      callObject.addListenerCallbackAdsState(listener);
      err = AdsCallDllFunction.adsSyncAddDeviceNotificationReq(
      	      addr,
      	      group, 
      	      offset, 
      	      attr,
      	      99,
      	      notification);
      
      

    • 监听器实现

      public class AdsListener implements CallbackListenerAdsState {
      	private final static long SPAN = 1929293939399L;
      
      	//回调函数
      	public void onEvent(AmsAddr addr, AdsNotificationHeader notification, long user) {
      		long dateInMillis = notification.getNTimeStamp();
      		Date notificationDate = new Date(dateInMillis / 10000 - SPAN);
      		System.out.println("Value: " + notification.getData());
      		System.out.println("Notification: " + notification.getHNotification());
      		System.out.println("Time: " + notificationDate.toString());
      		System.out.println("User: " + user);
      		System.out.println("ServerNetID: " + addr.getNetIdString() + "\n");
      	}
      }
      

    • 取消变量监听

      AdsCallDllFunction.adsSyncDelDeviceNotificationReq(addr, notification);