Serial port connection

[Kosmachevskiy]

Hi!

I have some trouble with ModbusSerialMaster. I got a NPE during reading registers.

My code:

`

    SerialParameters parameters = new SerialParameters();

    parameters.setPortName("/dev/ttyUSB1");
    parameters.setBaudRate(9600);
    parameters.setDatabits(8);
    parameters.setStopbits(1);
    parameters.setParity("none");
    parameters.setEncoding("rtu");
    parameters.setEcho(false);

    ModbusSerialMaster master = new ModbusSerialMaster(parameters);

    master.connect();
    master.readMultipleRegisters(1, 0, 100);
    master.disconnect();

` And stack:

Exception in thread "main" java.lang.NullPointerException at com.ghgande.j2mod.modbus.net.SerialConnection.setComPortTimeouts(SerialConnection.java:221) at com.ghgande.j2mod.modbus.io.ModbusSerialTransport.setTimeout(ModbusSerialTransport.java:142) at com.ghgande.j2mod.modbus.io.ModbusSerialTransport.open(ModbusSerialTransport.java:131) at com.ghgande.j2mod.modbus.io.ModbusSerialTransport.writeMessage(ModbusSerialTransport.java:73) at com.ghgande.j2mod.modbus.io.ModbusSerialTransaction.execute(ModbusSerialTransaction.java:143) at com.ghgande.j2mod.modbus.facade.AbstractModbusMaster.readMultipleRegisters(AbstractModbusMaster.java:236)

Library version: 2.3.1

[Kosmachevskiy]

Sorry, it should be a message to other library.

[cevatbostancioglu]

Hi , you have to download modbus4j source and reference your project if you want to solve serial library problems in linux & windows. Then ,

• first you are using j2mod library. remove it.
• you can use fazecastj SerialComm, i tested yesterday both linux and windows are fine. i don't know how to behave at mac os;
• modbus4j source code is little bit different from jar. actually jar files are little bit old, they made a lot of nice stuff but if you use jar files , you can not access it.
• for rtu/ascii protocols, they made serialwrapper interface. so you can use whatever you want as a serial port library.

i am kind of busy right now , so i can't write too much. you have to figure out , it's easy.

import java.io.InputStream; import java.io.OutputStream; import java.io.File; import java.io.IOException;

import com.fazecast.jSerialComm.SerialPort;

public static SerialPort serialLocalPort;

serialLocalPort= SerialPort.getCommPort("/dev/tty0");

        serialLocalPort.setBaudRate(115200);
        serialLocalPort.setParity( 0);
        serialLocalPort.setNumDataBits(8);
        serialLocalPort.setNumStopBits(1);

        SerialPortWrapper spw = new SerialPortWrapper()
        {
            @Override
            public void open() throws Exception
            {
                // TODO Auto-generated method stub
                if (serialLocalPort.openPort())
                {

                }
            }

            @Override
            public int getStopBits()
            {
                return serialLocalPort.getNumStopBits();
            }

            @Override
            public int getParity()
            {
                return serialLocalPort.getParity();
            }

            @Override
            public OutputStream getOutputStream()
            {
                return serialLocalPort.getOutputStream();
            }

            @Override
            public InputStream getInputStream()
            {
                return serialLocalPort.getInputStream();
            }

            @Override
            public int getFlowControlOut()
            {
                return 0;
            }

            @Override
            public int getFlowControlIn()
            {
                return 0;
            }

            @Override
            public int getDataBits()
            {
                return serialLocalPort.getNumDataBits();
            }

            @Override
            public int getBaudRate()
            {
                return serialLocalPort.getBaudRate();
            }

            @Override
            public void close() throws Exception
            {
                if (serialLocalPort.closePort())
                {

                }
            }
        };

        master = factory.createRtuMaster(spw);
    }

[Kosmachevskiy]

@cevatbostancioglu Thanks a lot! I am going to use this library.

[Kosmachevskiy]

@cevatbostancioglu I tried to run your code - it is works. Thanks a lot!

[cevatbostancioglu]

your welcome.