Consumer in Java to read and write PLC variables
This sample explains how to create an ADS-WebService-Consumer to read and write PLC-Variables via ADS-HTTP.
Unzip the sample 'WebServiceTestConsumer (Java)'.
Copy the files "TcAdsSOAP.java" and "Base64.java" to the folder of your Java-application and compile them.
Add the following line to the Java-file in which you want to use the ADS WebService:
TcAdsSOAP tcSoap = new TcAdsSOAP("http://192.168.0.2/TcAdsWebService/TcAdsWebService.dll");The address must be the URL of your TwinCAT ADS WebService-DLL-file.
reading PLC-variables
To read PLC-variables use the following method of the TcAdsSoap-object:
DataInputStream SOAPCall(String netId, int port, long group, long offset, int cblen)
- String netId: String indicating the AMS-Net-Id of the PLC
- int port: Port-number of the Runtime-System
- long indexGroup: IndexGroup of the variables to read
- long indexOffset: First byte to read
- int cblen: Number of bytes to read
- return value: DataInputStream with the read data, throws exception on failure
The 3 methods
short ReadInt(String netId, int port, long group, long offset)
boolean ReadBool(String netId, int port, long group, long offset)
String ReadString(String netId, int port, long group, long offset, int cblen)
convert the variables to their corresponding type.
Example:
boolean Bool1;
try
{
Bool1 = tcSoap.ReadBool("192.168.0.2.1.1", 801, 16416, 0)
}
catch (Exception e)
{
System.out.println("Error");
}
Write PLC-variables
boolean SOAPWrite(String netId, int port, long group, long offset, byte[] data)
- String netId: String indicating the AMS-Net-Id of the PLC
- int port: Port-number of the Runtime-System
- long indexGroup: IndexGroup of the variable
- long indexOffset: First byte to write to
- byte[] pData: Byte-array containing the data to write
- return value: "true" if successful, throws exception on failure
The 3 methods
boolean WriteBool(String netId, int port, long group, long offset, boolean data)
boolean WriteInt(String netId, int port, long group, long offset, int data)
boolean WriteString(String netId, int port, long group, long offset, String data)
convert the variables to a byte-arrays.
Example:
try
{
tcSoap.WriteBool("192.168.0.2.1.1", 801, 16416, true)
}
catch (Exception e)
{
System.out.println("Error");
}
PLC-program, IEC1131 daclaration of the variables:
PROGRAM MAIN
VAR
PlcVarBool AT %MX0.0 : BOOL := TRUE;
PlcVarInt AT %MW1 : INT := 1234;
PlcVarString AT %MD3 : STRING := 'Hello Automation';
END_VAR
The source-code:
public class AdSWebServiceSample
{
public static void main(String args[])
{
TcAdsSOAP tcSoap = new TcAdsSOAP("http://192.168.0.2/TcAdsWebService/TcAdsWebService.dll");
try
{
String netId = "192.168.0.2.1.1";
int port = 801;
int offset = 16416;
/* write bool */
boolean testBool = true;
if (tcSoap.WriteBool(netId,port,offset,0,testBool))
System.out.println("Boolean "+testBool+" Written");
/* write int */
int testInt = 1234;
if (tcSoap.WriteInt(netId,port,offset,1,testInt))
System.out.println("Integer "+testInt+" Written");
/* write string */
String testString = "Hello Automation";
if (tcSoap.WriteString(netId,port,offset,3,testString))
System.out.println("String "+testString+" Written");
/* read bool */
System.out.println(String.valueOf(tcSoap.ReadBool(netId,port,offset,0) ));
/* read int */
System.out.println(String.valueOf(tcSoap.ReadInt(netId,port,offset,1) ));
/* read string */
System.out.println(tcSoap.ReadString(netId,port,offset,3,81));
}
catch(Exception ex)
{
System.out.println(String.valueOf(ex));
}
}
}