Ведомый Modbuspal и Jamod в качестве мастера tcp

Я использую симулятор Modbuspal в качестве ведомого и мастер-код Jamod tcp в качестве ведущего. Ниже приведен мой мастер-код Jamod tcp для чтения данных из регистров:

import java.net.InetAddress;
import net.wimpi.modbus.io.ModbusTCPTransaction;
import net.wimpi.modbus.msg.ReadInputDiscretesRequest;
import net.wimpi.modbus.msg.ReadInputDiscretesResponse;
import net.wimpi.modbus.net.TCPMasterConnection;

public class SlaveTest {

Logger LOG = LoggerFactory.getLogger(SlaveTest.class);

TCPMasterConnection connection;
ModbusTCPTransaction transaction = null; //the transaction
ReadInputDiscretesRequest request = null; //the request
ReadInputDiscretesResponse response = null; //the response


public void test() {

    connection = null; //the connection             
    InetAddress addr = null; //the slave's address
    int port = 502;
    int ref = 1, count = 1;

    try {
        addr = InetAddress.getByName("127.0.0.1");
        connection = new TCPMasterConnection(addr);
        connection.setPort(port);
        connection.connect();
        request = new ReadInputDiscretesRequest(ref, count);
        transaction = new ModbusTCPTransaction(connection);
        transaction.setRequest(request);
        transaction.execute();
        response = (ReadInputDiscretesResponse) transaction.getResponse();
        System.out.println("Digital Inputs Status=" + response.getDiscretes().toString());
        connection.close();
    } catch (Exception e) {
        e.printStackTrace();
    }
}

Ведомое устройство Modbuspal:

Когда я выполняю свой код, соединение устанавливается, но я получаю следующую ошибку:

net.wimpi.modbus.ModbusIOException: Executing transaction failed (tried 3 times)
at         net.wimpi.modbus.io.ModbusTCPTransaction.execute(ModbusTCPTransaction.java:197)
at modbus.slave.SlaveTest.test(SlaveTest.java:49)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:498)
at org.apache.camel.component.bean.MethodInfo.invoke(MethodInfo.java:408)
at org.apache.camel.component.bean.MethodInfo$1.doProceed(MethodInfo.java:279)
at org.apache.camel.component.bean.MethodInfo$1.proceed(MethodInfo.java:252)
at org.apache.camel.component.bean.BeanProcessor.process(BeanProcessor.java:177)
at org.apache.camel.util.AsyncProcessorHelper.process(AsyncProcessorHelper.java:109)
at org.apache.camel.component.bean.BeanProcessor.process(BeanProcessor.java:68)
at org.apache.camel.component.bean.BeanProducer.process(BeanProducer.java:38)
at org.apache.camel.processor.SendProcessor.process(SendProcessor.java:141)
at org.apache.camel.management.InstrumentationProcessor.process(InstrumentationProcessor.java:77)
at org.apache.camel.processor.RedeliveryErrorHandler.process(RedeliveryErrorHandler.java:460)
at org.apache.camel.processor.CamelInternalProcessor.process(CamelInternalProcessor.java:190)
at org.apache.camel.processor.CamelInternalProcessor.process(CamelInternalProcessor.java:190)
at org.apache.camel.component.timer.TimerConsumer.sendTimerExchange(TimerConsumer.java:165)
at org.apache.camel.component.timer.TimerConsumer$1.run(TimerConsumer.java:73)
at java.util.TimerThread.mainLoop(Timer.java:555)
at java.util.TimerThread.run(Timer.java:505)

Ошибка возникает в строке "transaction.execute();". Пожалуйста помоги.

Заранее спасибо.