Closing serial port

Hi,
I'm doing a program with Netbeans 5.5 (JDK 1.6.0) for working with a serial port and I'm following an example from a tutorial (see on the web: http://java.sun.com/developer/Books/javaprogramming/cookbook/11.pdf).
The problems come when I call the last method of the PortChooser class: addWindowListener(new WindowCloser(this, true)); it doesn't find the constructor WindowCloser, I think that it is provoked by the parameters given to the constructor...
Can you help me?
Thank you!

Dennis is spot on. Hide the entire tool bar from the user. The abort is a hard exit - your ports and all of your controls don't have a chance against it. Attached is a jpeg, showing a common method I use to close the ports, and do some general "housekeeping" on Exit. (I assume you are using VISA).Message Edited by Broken Arrow on 06-27-2005 09:41 AM
Richard
Attachments:
loopEnd.jpg ‏73 KB

Similar Messages

Closing a serial port after executing a for loop of write and reads.

Hello,
Labview is opening and then closing each write to the port. I have tried to leave the close outside of the for loop, but labview wont allow it. What do I need to change to make all the writes and reads execute on 1 open and close of the serial port.?
Thanks.
Attachments:
Controller.vi ‏27 KB

J_es--
The program that you posted looks to be ok for the most part, you might consider putting an open after your configure (but that's trivial). The other thing that is a minor issue is the loop tunnel coming out of your for loop is currently being auto-indexed. This function is used to index data for each interation of the loop. You are using a static address (not an array) and so you don't need this. If you right-click and remove the auto-index the broken wire will go away. Other than that it should be ok.
I would suggest looking at one of the shipping examples that come with LabVIEW. "Basic Serial Read and Write" is essentially the same thing that you are doing and is tested here and might save you a bit of time. Anyway, take a look if you have a second. Best of luck with your application!
John H.
Applications Engineer
National Instruments
http://www.ni.com/support

In CVI !!!! How to dynamic change BaudRate of RS232 Serial COM Without closing the Port !!!

Dear all:
I want to change the buadrate of serial com without closing the serial com, but it failed when I use the function "SetCommConfig(m_hCom, &Com_cfg, Com_cfg_S) " to reset the buadrate ,baudrate is no change when use GetCommConfig to read back the value.
Appreciated all of your advice . TKS!
Code with WINAPI as beloow:
CreateFile(..) ;
GetCommState(..);
dcb.BaudRate= 1000000 ;
SetCommState(..);
//......do other things
//change baudrate to normal without closing port .
GetCommConfig(m_hCom, &Com_cfg, &Com_cfg_S);
Com_cfg.wVersion = 0X100;
Com_cfg.dwProviderSubType = 1;
Com_cfg.dcb.BaudRate =9600 ;
Com_cfg.dcb.StopBits =1 ;
SetCommConfig(m_hCom, &Com_cfg, Com_cfg_S);
GetCommConfig(m_hCom, &Com_cfg, &Com_cfg_S);
Solved!
Go to Solution.

This topic has been discussed some years ago: see here. Please note that even if I made that sample program which changes the baud rate without closing the port, I never used it in a real situation: you'll need to made your tests and check if this solution can satisfy your needs in the short and long term.
Proud to use LW/CVI from 3.1 on.
My contributions to the Developer Zone Community
If I have helped you, why not giving me a kudos?

Java ME 8 Permission check failed when opening a serial port

I have a larger Jave ME8.1 application that was going well until I tried to add one last piece, reading and writing data from a serial port. This was left to last because it is trivial, at least in most programming languages. The is IDE NetBeans 8.0.2 running on a Windows 7 PC. The platform is a Raspberry Pi B or B+ (I have tried both) with the most current Raspbian (12/24/2014 I believe). To simplify the process I created a new app with just the open and close code and this generates the same error I am experiencing in the larger application. The program is as follows:
package javamecomapp;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.util.logging.Level;
import java.util.logging.Logger;
import javax.microedition.io.CommConnection;
import javax.microedition.io.Connector;
import javax.microedition.midlet.MIDlet;
* @author ****
public class JavaMEcomApp extends MIDlet {
    static int BAUD_RATE = 38400;
    static String SERIAL_DEVICE = "ttyAMA0";
    static CommConnection commConnection = null;
    static OutputStream os = null;
    static InputStream is = null;
    static String connectorString;
    private int rtnValue = -1;
    @Override
    public void startApp() {
        java.lang.System.out.println("Opening comm port.");
        try {
            rtnValue = JavaMEcomApp.openComm();
        } catch (IOException ex) {
            Logger.getLogger(JavaMEcomApp.class.getName()).log(Level.SEVERE, null, ex);
    @Override
    public void destroyApp(boolean unconditional) {
        java.lang.System.out.println("Closing comm port.");
        try {
            rtnValue = JavaMEcomApp.closeComm();
        } catch (IOException ex) {
            Logger.getLogger(JavaMEcomApp.class.getName()).log(Level.SEVERE, null, ex);
        private static int openComm()throws IOException {
            java.lang.System.out.println("Opening comm port.");
            connectorString = "comm:" + SERIAL_DEVICE + ";baudrate=" + BAUD_RATE;
            commConnection = (CommConnection)Connector.open(connectorString);
            is = commConnection.openInputStream();
            os = commConnection.openOutputStream();
        return 0;
    private static int closeComm()throws IOException {
        java.lang.System.out.println("Closing comm port.");
            is.close();
            os.close();
            commConnection.close();
        return 0;
If I comment out the JavaMEcomApp.openComm and closeComm lines it runs fine. When they are included, the following error is dumped to the Raspberry Pi terminal:
Opening comm port.
Opening comm port.
[CRITICAL] [SECURITY] iso=2:Permission check failed: javax.microedition.io.CommProtocolPermission "comm:ttyAMA0;baudrate=38400" ""
TRACE: <at java.security.AccessControlException: >, startApp threw an Exception
java.security.AccessControlException:
- com/oracle/meep/security/AccessControllerInternal.checkPermission(), bci=118
- java/security/AccessController.checkPermission(), bci=1
- com/sun/midp/io/j2me/comm/Protocol.checkForPermission(), bci=16
- com/sun/midp/io/j2me/comm/Protocol.openPrim(), bci=31
- javax/microedition/io/Connector.open(), bci=77
- javax/microedition/io/Connector.open(), bci=6
- javax/microedition/io/Connector.open(), bci=3
- javamecomapp/JavaMEcomApp.openComm(), bci=46
- javamecomapp/JavaMEcomApp.startApp(), bci=9
- javax/microedition/midlet/MIDletTunnelImpl.callStartApp(), bci=1
- com/sun/midp/midlet/MIDletPeer.startApp(), bci=5
- com/sun/midp/midlet/MIDletStateHandler.startSuite(), bci=246
- com/sun/midp/main/AbstractMIDletSuiteLoader.startSuite(), bci=38
- com/sun/midp/main/CldcMIDletSuiteLoader.startSuite(), bci=5
- com/sun/midp/main/AbstractMIDletSuiteLoader.runMIDletSuite(), bci=130
- com/sun/midp/main/AppIsolateMIDletSuiteLoader.main(), bci=26
java.security.AccessControlException:
- com/oracle/meep/security/AccessControllerInternal.checkPermission(), bci=118
- java/security/AccessController.checkPermission(), bci=1
- com/sun/midp/io/j2me/comm/Protocol.checkForPermission(), bci=16
- com/sun/midp/io/j2me/comm/Protocol.openPrim(), bci=31
- javax/microedition/io/Connector.open(), bci=77
- javax/microedition/io/Connector.open(), bci=6
- javax/microedition/io/Connector.open(), bci=3
- javamecomapp/JavaMEcomApp.openComm(), bci=46
- javamecomapp/JavaMEcomApp.startApp(), bci=9
- javax/microedition/midlet/MIDletTunnelImpl.callStartApp(), bci=1
- com/sun/midp/midlet/MIDletPeer.startApp(), bci=5
- com/sun/midp/midlet/MIDletStateHandler.startSuite(), bci=246
- com/sun/midp/main/AbstractMIDletSuiteLoader.startSuite(), bci=38
- com/sun/midp/main/CldcMIDletSuiteLoader.startSuite(), bci=5
- com/sun/midp/main/AbstractMIDletSuiteLoader.runMIDletSuite(), bci=130
- com/sun/midp/main/AppIsolateMIDletSuiteLoader.main(), bci=26
Closing comm port.
Closing comm port.
TRACE: <at java.lang.NullPointerException>, destroyApp threw an Exception
java.lang.NullPointerException
- javamecomapp/JavaMEcomApp.closeComm(), bci=11
- javamecomapp/JavaMEcomApp.destroyApp(), bci=9
- javax/microedition/midlet/MIDletTunnelImpl.callDestroyApp(), bci=2
- com/sun/midp/midlet/MIDletPeer.destroyApp(), bci=6
- com/sun/midp/midlet/MIDletStateHandler.startSuite(), bci=376
- com/sun/midp/main/AbstractMIDletSuiteLoader.startSuite(), bci=38
- com/sun/midp/main/CldcMIDletSuiteLoader.startSuite(), bci=5
- com/sun/midp/main/AbstractMIDletSuiteLoader.runMIDletSuite(), bci=130
- com/sun/midp/main/AppIsolateMIDletSuiteLoader.main(), bci=26
java.lang.NullPointerException
- javamecomapp/JavaMEcomApp.closeComm(), bci=11
- javamecomapp/JavaMEcomApp.destroyApp(), bci=9
- javax/microedition/midlet/MIDletTunnelImpl.callDestroyApp(), bci=2
- com/sun/midp/midlet/MIDletPeer.destroyApp(), bci=6
- com/sun/midp/midlet/MIDletStateHandler.startSuite(), bci=376
- com/sun/midp/main/AbstractMIDletSuiteLoader.startSuite(), bci=38
- com/sun/midp/main/CldcMIDletSuiteLoader.startSuite(), bci=5
- com/sun/midp/main/AbstractMIDletSuiteLoader.runMIDletSuite(), bci=130
com/sun/midp/main/AppIsolateMIDletSuiteLoader.main(), bci=26
I have tried this with three different serial ports, /dev/ttyAMA0 (yes I did disable the OS from using it), an arduino board /dev/ttyACM0, and a USB to RS485 adaptor /dev/ttyUSB0. All of these ports could be connected and use normally with both a C program and terminal program in the Pi. The API Permissions were set in the project properties / Application Descriptor / API Permissions to jdk.dio.DeviceMgmtPermission "/dev/ttyAMA0". This of course was changed as I tested different devices.
I found a reference suggesting adding the line "authentication.provider = com.oracle.meep.security.NullAuthenticationProvider" to the end of the jwc_properties.ini file. This had no effect. I found references that during development in eclipse and NetBeans, the app is already elevated to the top level so this should not be an issue until deployment. This does not appear to be the case.
I am out of time and need a solution quickly. Any suggestions are welcome.

Terrence,
   Thank you for responding and confirming the issues I'm having with static addressing. As far as the example above, I do have the standard LEDs working correctly, however, the example I'm referring to above is from the JavaME samples using the GPIO Port for the LEDS, according to the Device I/O Preconfigured List you referenced:
GPIO Ports
The following GPIO ports are preconfigured.
Devicel ID
Device Name
Mapped
Configuration
8
LEDS
PTB22
PTE26
PTB21
direction = 1 (Output only)
initValue = 0
GPIOPins:
controllerNumber = 1
pinNumber = 22
mode = 4 (Push-pull mode)
controllerNumber = 4
pinNumber = 26
mode = 4 (Push-pull mode)
controllerNumber = 1
pinNumber = 21
mode = 4 (Push-pull mode)
So is the assumption that using GPIOPort for accessing the GPIO port for Device ID 8 as listed in the Device I/O Preconfigured list not supported?

Write to serial port asyncronously

I am trying to write a commands to a serial port but my problem is that the operation is tedious so it is freezing up my UI. What makes it more complicated is that I must call this procedure when the form loads I want to ask if anyone can provide an alternative
way to get the same or better result I was thinking of running it asynchronously but I don't know how to?
This is the code I am calling on load
If lblConnected.Text = "" Then
MsgBox("Please connect to port.", MsgBoxStyle.OkOnly, "Validation")
Exit Sub
End If
RichTextBox1.Text = ""
Try
With SerialPort1
rcvdata = ""
.Write("AT" & vbCrLf)
Threading.Thread.Sleep(1)
.Write("AT+CMGF=1" & vbCrLf)
Threading.Thread.Sleep(1)
.Write("AT+CPMS=""SM""" & vbCrLf)
Threading.Thread.Sleep(1)
.Write("AT+CMGL=""ALL""" & vbCrLf)
Threading.Thread.Sleep(1)
.Write("AT+CNUM" & vbCrLf)
Threading.Thread.Sleep(2000)
Dim lineoftext As String
Dim arytextfile() As String
Dim myString As String
lineoftext = rcvdata.ToString
arytextfile = Split(lineoftext, "Your number is", CompareMethod.Text)
myString = "Your number is"
lineoftext = lineoftext.Substring(lineoftext.IndexOf("Your number is"), 40)
lineoftext = lineoftext.Replace("Your number is", "")
lineoftext = lineoftext.Substring(0, 13)
txtDonglePhoneNumber.Text = LTrim(lineoftext)
End With
Catch ex As Exception
MsgBox(ex.Message)
End Try
I am trying to extract the phone number from this whole routine and it works but its freezing up my UI. How can I run from another thread.
If you think it you can achieve it

Imports System.IO.Ports
Imports System.Threading
Public Class Form1
Private comport As SerialPort
Private sending As Boolean
Private Sub Form1_Load(sender As System.Object, e As System.EventArgs) Handles MyBase.Load
sending = False
End Sub
Private Sub Button1_Click(sender As System.Object, e As System.EventArgs) Handles Button1.Click
comport = CreateComport(comport)
If sending = False AndAlso OpenComport(comport) = True Then
Dim t As Threading.Thread = New Threading.Thread(AddressOf SendData)
t.IsBackground = True
t.Start(comport)
End If
End Sub
Private Sub Button2_Click(sender As System.Object, e As System.EventArgs) Handles Button2.Click
CloseComport(comport)
End Sub
Private Function CreateComport(ByVal port As SerialPort) As SerialPort
If port Is Nothing Then
port = New SerialPort("COM4", 9600, Parity.None, 8, StopBits.One)
End If
Return port
End Function
Private Function OpenComport(ByVal port As SerialPort) As Boolean
Try
If (Not port Is Nothing) AndAlso (port.IsOpen = False) Then
port.Open()
End If
Return True
Catch ex As Exception
MessageBox.Show(String.Format("Exception :{0}", ex.ToString()))
Return False
End Try
End Function
Private Sub CloseComport(ByVal port As SerialPort)
Try
If (sending = False) AndAlso (Not port Is Nothing) AndAlso (port.IsOpen) Then
port.Close()
MessageBox.Show("Port closed")
End If
Catch ex As Exception
MessageBox.Show(String.Format("Exception :{0}", ex.ToString()))
End Try
End Sub
Private Sub SendData(ByVal port As Object)
Dim buffer(1023) As Byte
For i As Int32 = 0 To buffer.Length - 1
buffer(i) = i Mod 256
Next
sending = True
Try
DirectCast(port, SerialPort).Write(buffer, 0, buffer.Length)
Catch ex As Exception
CloseComport(DirectCast(port, SerialPort))
MessageBox.Show(String.Format("Exception :{0}", ex.ToString()))
Finally
sending = False
End Try
End Sub
End Class
在現實生活中，你和誰在一起的確很重要，甚至能改變你的成長軌跡，決定你的人生成敗。和什麼樣的人在一起，就會有什麼樣的人生。和勤奮的人在一起，你不會懶惰；和積極的人在一起，你不會消沈；與智者同行，你會不同凡響；與高人為伍，你能登上巔峰。

Problems with access to serial port using reentrant code

Hi,
I have a VI that send commands and receive answers from an instrument using
de serial port.
This VI runs perfectly when used alone.
However I'm trying run two instances of that VI simultaneously using
reentrant code and I'm facing some problems.
Sometimes everything is OK but sometimes, in the process of writing to
serial port the following error happen:
Error code 36.
Invalid refnum device.
What is this?
Does someone know how to prevent this?
Thanks in advance for any help.

"Paro, Paula [CMPS:2721:EXCH]" wrote:
>
> Hi,
>
> I have a VI that send commands and receive answers from an instrument using
> de serial port.
> This VI runs perfectly when used alone.
> However I'm trying run two instances of that VI simultaneously using
> reentrant code and I'm facing some problems.
> Sometimes everything is OK but sometimes, in the process of writing to
> serial port the following error happen:
> Error code 36.
> Invalid refnum device.
>
> What is this?
> Does someone know how to prevent this?
>
> Thanks in advance for any help.
You can't use reentrant vi's vith serial vi calls without supervising of
driver.
Use VISA instead and you have to control the VISA session opening and
closing. Another word is that the only one serial port sess
ion should be
opened at a time.
Reentrant vi's for serial port without checking serial port session is a
mistake of program algorithm. Change it in any convenient way.
Sergey Krasnishov
Automated Control Systems
National Instruments Alliance Member
Moscow, Russia
[email protected]
http://acs.levsha.ru

0 bytes at serial port after Visa Write

Hi,
I'm having problems communicating with a Pollux box controlling a stepper motor (both from Micos). The Pollux box has an RS232/485 connection to the computer.
I have tried adaptations of LV's Basic Serial Read and Write example. Even for the basic example there has never been any bytes at the serial port after the write.
I have attached some sample code for LV 10.0.1(64bit) and the OS is Windows Server Enterprise 2008.
The Visa drivers have just been installed.
After some research I have added a 'Set I/O buffer size' as advised by http://digital.ni.com/public.nsf/allkb/60DDFED7EFEFE7188625705700750821?OpenDocument
The time-out is set to 10s, I have a wait of 1s before read and 0.5s between each write (the characters are written individually incase that was the problem).
The write command getaxisno_ should reply with the default axis no which is 1. However, there is never any reply.
The termination character for Venus2 is a space for transmitting commands and ASCII CR LF at the end of received data.
I'm not sure what else could be wrong. According to MAX the device is working properly. Although, when I try to open a Visa test panel in MAX the program crashes. I'm not sure if this is a related problem.
I'd be really grateful for any advice, have been trying to fix this for a few days now.
Thanks in advance!
Ciara
Attachments:
Getaxisno test.vi ‏18 KB

Thanks, I'll search those now.
When I click the test panel button, the Max window disappears and the program is closed. Next time I open it an Unexpected Error box opens with a message saying there was an unexpected error and I should search Info Code MAXKnownException.
'The exception occurred in the NIMax process in the function (Unknown).'
I have searched this and the info advised me to send a report with log files etc to NI which I have done. Just waiting on the reply.
I copied the Visa resource name from MAX and the termination character is the same as what a previous owner of the equipment used in Visual Basic.

The "VISA Configure Serial Port" VI will only run at 9600 Baud

I have written a Serial Port monitor "RS232 RW.vi" that works for the most part. The problem is that it will not respond to alternate port configuration settings.... For instance: the default RS232 Serial port configuration is:
(COM1,9600 baud,8 data bits,1 Stop bit, None no parity)
As a test, I am using a Null Modem Cable to connect From my LabView Com1 port to another PC running RealTerm Serial Port Monitor.. Using my newly designed "RS232 RW.vi" With port settings of (COM1,9600 baud,8 data bits,1 Stop bit, None no parity), I can send and receive data back and forth all day long no problems....
However, if I configure the "RS232 RW.vi" port to any other configuration, such as (COM1,2400 baud ,7 data bits,1 stop bit, Odd parity).. It will not take the expected chances and continues to operate @ 9600 baud etc.
I then changed the "RS232 RW.vi" default settings to (2400,7,1,Odd)
it still refuses to deviate from (COM1, 9600,8,1,None...)
I also went into the Win XP Device Manager on the LabView system and manually configured Com1 to 2400,7,1,Odd
and still,.... the "RS232 RW.vi" will only operate @ 9600,8,1,None
Can anyone else test drive my VI and see if they have the same problem of not being able to see new changes in the Port configuration settings ..other than (COM1, 9600,8,1,None...).... ?
FYI.. Unfortunately my LabView is running on Version 6.0 so you may need to up-convert the attached vi
Solved!
Go to Solution.
Attachments:
RS232 RW.vi ‏102 KB

Instead of just appreciating the comments, you need to implement them.
Having the VISA close inside the loop is definitely the problem. And Crossrulz is 100% correct about the problem being that the serial port gets reset to the default baud rate after closing the port. Here is the proof.
Note that while you may have set the port settings manually in device manager, those settings are revised by the VISA driver. If you look in Measurement and Automation Explorer under Devices and Interfaces >> Serial and Parallel, you'll see the default settings that the VISA driver uses. If you change the setting there, your program will work the way you want. But that is not the correct fix. The correct fix is to get the VISA close out of the while loop.
The port settings are established in this order.
1. By the Windows device drivers.
2. By the VISA driver as established in MAX. Since you are useing VISA, these settings will automatically override #1.
3. By the port settings you set programmatically in your LabVIEW program.
Attachments:
Example_VI.png ‏18 KB

Is it possible to communicate with two different devices using two seperate serial ports in the same labview program?

The two bits of the program will talk to each instrument successfully if the other part of the program is not running. i do not need them to communicte with both serial ports at the exact same time, just within the same program, one after the other. i am using labview 6. any ideas of what i could be doing wrong?

Hello,
If you are using the Legacy serial VIs, you should really switch to the VISA VIs. Also make sure you are opening a session to each of the com ports at the beginning of the program and closing each at the end of the program. Problems can arise if your try to open a session to a port that already has a session open. Also you should update LabVIEW to 6.0.2
If you are still having problems post the error code and error message you are getting.
Ray K
NI Applications Engineer

Executable does not release serial port after being stopped

Greetings:
I have created an executable that communicates through a serial port. However, if I stop the executable (not close it), the executable still has control over the COM port. This causes issues if I need to jump on Hyperterminal to send a couple quick queries to my system. In order to send the queries, I have to actually close the executable in order to release the COM port. It's problematic because I then have to start the executable back up, go through another configuration query, etc. and there are parameters from the previous run I would prefer to not lose.
Is there a way to force a LabView executable into releasing it's hold on a COM port after it's stopped, without closing the executable completely? If it makes a difference, I'm using LV 7.1 on a WinXP machine. Thanks for any help!

Gumby_Dammit wrote:
I changed the settings to have the stop button visible in the menu bar along with the start button. This is because the user has to select their COM port before continuing.
Raven has already said it but I'll say it a different way. No user should ever interact with the front panel unless the VI is running. And when it is running the user should never have access to the abort button in the toolbar. When you open Internet Explorer do you first need to click the run button? No it runs when you run it. Write your program so it is always running, and doesn't have an abort so if the user closes the program you can run the proper clean up like closing COM ports.
Unofficial Forum Rules and Guidelines - Hooovahh - LabVIEW Overlord
If 10 out of 10 experts in any field say something is bad, you should probably take their opinion seriously.

Finder message: serial port in use by another application

After giving a print command, I had a power outage with my application open. The computer tells me I
cannot print my document because the serial port is in use by another application. I have opened and closed each application to no avail. The printer has nothing in the cache. I suspect the power outage
left me in limbo with the original command, but I don't know how to get out of it to print the document.
Just so you know, I am not a computer wiz kid. I don't understand how or why anything works. I can,
however follow instructions. Can anyone one help?

Have you tried a Shut Down & Restart? This will close all applications.
Haven't booted into OS 9 for a long time, but try moving Appletalk to remote under Control Panels.
 Cheers, Tom

How to detect serial port

CommPortIdentifier portId;
          Enumeration en = CommPortIdentifier.getPortIdentifiers();
          Vector v=new Vector();
          while (en.hasMoreElements())
               portId = (CommPortIdentifier) en.nextElement();
               if (portId.getPortType() == CommPortIdentifier.PORT_SERIAL)
                         v.addElement(portId.getName());
          }

refer this URL
http://www.java2s.com/Code/Java/Development-Class/ReadfromaSerialportnotifyingwhendataarrives.htm
     * Project                     :
     * Class                     : GUIFrame.java
     * Purpose                    :
     * Date_Created               :
     * @ Version 1.0
import javax.swing.JFrame;
// import javax.swing.JPanel;
import javax.swing.JMenuItem;
import javax.swing.JMenu;
import javax.swing.JMenuBar;
import java.awt.event.*;
import javax.comm.*;
import java.awt.*;
import javax.swing.*;
// import javax.swing.border.TitledBorder;
public class GUIFrame extends JFrame implements ActionListener
     JButton connectPort;
     JComboBox combo;
     //JButton baudRate;
     //JComboBox baudRateCombo;
     public JTextArea textArea;
     JButton sendData;
     public SerialConnection serialConnection;
     public GUIFrame()
          setLayout(null);
          setTitle("First Frame");
          serialConnection = new SerialConnection();
          setJMenuBar(createMenuBar());
          combo = new JComboBox();
          combo.setBounds(50, 50, 80, 25);
          listPort();
          combo.addActionListener(this);
          connectPort = new JButton("Connect");
          connectPort.setBounds(150, 50, 100, 25);
          connectPort.addActionListener(this);
          sendData = new JButton("Send Data");
          sendData.setBounds(150, 150, 100, 25);
          sendData.addActionListener(this);
          textArea = new JTextArea();
          textArea.setBounds(300, 300, 400, 300);
          textArea.setFont(new Font("sansserif",0,18));
          add(connectPort);
          add(combo);
          add(sendData);
          add(textArea);;
          setSize(400, 300);
          setVisible(true);
          addWindowListener(new MainWindowAdapter());
     public static void main(String arg[])
          System.out.println("Hi");
          new GUIFrame();
     public JMenuBar createMenuBar()
          JMenuBar menuBar = new JMenuBar();
          JMenu fileMenu = new JMenu("File");
          JMenuItem connectMenuItem = new JMenuItem("Connect");
          connectMenuItem.addActionListener(new ActionListener()
               public void actionPerformed(ActionEvent ae){
                    try{
                         if(serialConnection.portName == null){
                              serialConnection.portName = combo.getSelectedItem().toString();
                         serialConnection.openConnection();
                    catch(Exception ex)
          JMenuItem disconnectMenuItem = new JMenuItem("Disconnect");
          disconnectMenuItem.addActionListener(new ActionListener()
               public void actionPerformed(ActionEvent ae){
                    try{
                         serialConnection.closeConnection();
                    catch(Exception ex)
          fileMenu.add(connectMenuItem);
          fileMenu.add(disconnectMenuItem);
          menuBar.add(fileMenu);
          return menuBar;
     public void listPort()
          CommPortIdentifier portId;
          java.util.Enumeration enumeration = CommPortIdentifier.getPortIdentifiers();
          while(enumeration.hasMoreElements())
               portId = (CommPortIdentifier)enumeration.nextElement();
               if(portId.getPortType() == CommPortIdentifier.PORT_SERIAL)
                    if(!portId.isCurrentlyOwned())
                         combo.addItem(portId.getName());
     public void actionPerformed(ActionEvent ae)
          if(ae.getSource() == connectPort)
               System.out.println("Connect is clicked");
               try
                    if(serialConnection.portName == null)
                         serialConnection.portName = combo.getSelectedItem().toString();
                    serialConnection.openConnection();
               catch(Exception ex)
          if(ae.getSource() == combo)
               System.out.print("Port Name = " + combo.getSelectedItem().toString());
               serialConnection.portName = combo.getSelectedItem().toString();
          if(ae.getSource() == sendData)
               byte b[] = new byte[5];
               b[0] = (byte)0xaa;
               b[1] = (byte)0xbb;
               b[2] = (byte)0xcc;
               b[3] = (byte)0xdd;
               b[4] = (byte)0xee;
               try
                    serialConnection.getOutputStream().write(b);
                    display(b);
               catch(Exception ex)
     public class MainWindowAdapter extends WindowAdapter
          public void windowClosing(WindowEvent win)
               dispose();
               System.exit(0);
     public void display(byte[] b)
          for(int i=0; i< b.length; i++)
               textArea.append(Integer.toHexString (b[i] & 0xff) + " ");
          textArea.append("\n");
     * Project                     :
     * Class                     : SerialConnection.java
     * Purpose                    :
     * Date_Created               :
     * @ Version 1.0
import javax.comm.*;
import java.io.*;
public class SerialConnection
     private OutputStream os;
     private InputStream is;
     private CommPortIdentifier portId;
     public SerialPort sPort;
     private boolean open;
     public String portName;
     SerialConnection serialConnection;
     public SerialConnection()
          serialConnection=this;
          PortHandler portHandler = new PortHandler(serialConnection);
          portHandler.init(serialConnection);
     public void setOutputStream(OutputStream os)
          this.os=os;
     public OutputStream getOutputStream()
          return os;
     public void setInputStream(InputStream is)
          this.is=is;
     public InputStream getInputStream()
          return is;
     * A Method to open the SerialConnection
public void openConnection() throws Exception
          try
               portId = CommPortIdentifier.getPortIdentifier(portName);
          catch (javax.comm.NoSuchPortException e)
               System.out.println("noPort : "+e);
          try
               sPort = (SerialPort)portId.open("port", 3000);
               open = true;
          catch (javax.comm.PortInUseException e)
               throw new Exception();
          try
               setOutputStream(sPort.getOutputStream());
               setInputStream(sPort.getInputStream());
               System.out.println("IO stream is opened");
          catch (java.io.IOException e)
               sPort.close();
     *A Method to Close the port and clean up associated elements.
     public void closeConnection()
          // If port is already closed just return.
          if (!open)
               return;
          if (sPort != null)
               try
                    this.os.close();
                    this.is.close();
                    System.out.println("IO stream is opened - CloseConnection");
               catch (java.io.IOException e)
                    System.err.println(e);
               sPort.close();
               System.out.println("Port is closed");
          System.out.println("Flag Open - 1 : " + open );
          open = false;
          System.out.println("Flag Open - 2 : " + open);
     * Send a one second break signal.
     public void sendBreak()
          sPort.sendBreak(1000);
     * Reports the open status of the port.
     * @return true if port is open, false if port is closed.
     public boolean isOpen()
          return open;
     * A Method to add the event listener to the SerialPort
     public void addEventListener(java.util.EventListener listener)throws Exception
          System.out.println("Is not in opened state");
          if(isOpen())
               System.out.println("Is in opened state");
               try
                    sPort.addEventListener((javax.comm.SerialPortEventListener)listener);
               catch (java.util.TooManyListenersException e)
                    sPort.close();
               // Set notifyOnDataAvailable to true to allow event driven input.
               sPort.notifyOnDataAvailable(true);
               // Set notifyOnBreakInterrup to allow event driven break handling.
               sPort.notifyOnBreakInterrupt(true);
               // Set receive timeout to allow breaking out of polling loop during
               // input handling.
               try
               sPort.enableReceiveTimeout(50);
               //sPort.enableReceiveTimeout(-1);
               catch (javax.comm.UnsupportedCommOperationException e)
                    e.printStackTrace();
               // Add ownership listener to allow ownership event handling.
               portId.addPortOwnershipListener((javax.comm.CommPortOwnershipListener)listener);
     import javax.comm.*;
     public class PortHandler implements SerialPortEventListener,CommPortOwnershipListener{
          public SerialConnection serialConnection;
          public PortHandler(SerialConnection serialConnection)
               this.serialConnection=serialConnection;
               try{
                    serialConnection.addEventListener((SerialPortEventListener)this);
                    System.out.println("New Port Handler is called");
               catch(Exception e)
                    System.out.println("Exception PortHandler(); " +e);
                    e.printStackTrace();
               // Add this object as an event listener for the serial port.
               System.out.println("PortHandler is initialised...");
          public SerialConnection getConnection(){
               return serialConnection;
          public void setSerialConnection(SerialConnection serialConnection){
               this.serialConnection = serialConnection;
          public void init(SerialConnection serialConnection){
               setSerialConnection(serialConnection);
          public void serialEvent(SerialPortEvent e){
               System.out.println("Event Initialised");
               //Determine type of event.
               switch (e.getEventType())
                    case SerialPortEvent.DATA_AVAILABLE:
                         try{
                              readData();
                         catch(java.io.IOException e1)
                              System.out.println("IO Excep "+e1.getMessage());
                              e1.printStackTrace();
                         catch(Exception e1)
                              System.out.println("Exception from Serial Event "+e1.getMessage());
                              e1.printStackTrace();
                    break;
                    case SerialPortEvent.BI:
                    break;
          public void readData() throws java.io.IOException
               byte b[]=new byte[8500];
               int i=0,selectOption=0;
               int newData=0;
               int doubleLength=0;
               int length=0;
               // String mid="",strLen="";
               while (newData != -1)
                    try
                         System.out.println("getInputStream().available() : " + serialConnection.getInputStream().available());
                         newData = serialConnection.getInputStream().read();
                         System.out.println("newData\t"+newData);
                         if (newData == -1)
                              System.out.println("\n End of the File\n");
                              break;
                         if(i==0){
                              b=(byte)newData;
                              System.out.print("\n MSg ID \t= " + Integer.toString(newData&0xff,16)+"\n----------------------------");
                              if(b[0] == (byte)0x00)
                                   i=-1;
                                   i++;
                                   continue;
                              i++;
                              //System.out.println("Method is called - selectOption : " + selectOption);
                              continue;
                         if(i==1)
                              b[i]=(byte)newData;
                              System.out.print("\n Length =\t"+Integer.toString(newData&0xff,16)+"\n----------------------------");
                              length=newData;
                              if(length == 0)
                                   i=0;
                                   continue;
                              i++;
                              continue;
                         b[i]=(byte)newData;
                         if((b[0] == (byte)0x07) && (i == 2) || (b[0] == (byte)0xaf) && (i == 2) || (b[0] == (byte)0xec) && (i == 2)
                              || (b[0] == (byte)0x5c) && (i == 2) || (b[0] == (byte)0xbe) && (i == 2) )
                              String string = String.valueOf((byte)b[0]);
                              String strLen = Integer.toString(b[2]&0xff,16) + Integer.toString(b[1]&0xff,16);
                              System.out.println("\n\nLength String = " + strLen + "\n\n");
                              java.math.BigInteger bi=new java.math.BigInteger(strLen,16);
                              strLen = bi.toString();
                              doubleLength = Integer.parseInt(strLen);
                              System.out.println("\nLength int = " + doubleLength + "\n");
                              //System.out.println("Method is called");
                         i++;
                         // Added by Siva on Jan 06
                         switch(selectOption)
                              case 0:
                                   if(i>length+1)
                                        try
                                             b[i]=(byte)newData;
                                             System.out.print("\nThe Last Byte =\t"+Integer.toString(newData&0xff,16)+"\n----------------------------");
                                             System.out.print("\n"+i+" i Value =\t"+Integer.toString(newData&0xff,16));
                                             System.out.println("\n----------------------- FINISHED------------------------------");
                                             // service(b);
                                             System.out.println("\n----------------------- After Service------------------------------");
                                             i=-1;
                                             i++;
                                             continue;
                                        }catch (Exception e)
                                             System.out.println("Exception in calling service 0:"+e.getMessage());
                                             e.printStackTrace();
                                             b[i]=(byte)newData;
                                   System.out.print("\nMSg ID \t= "+Integer.toString(newData&0xff,16)+"\n----------------------------");
                                   break;
               }catch (java.io.IOException ex)     {
                    System.err.println("Abstarct Port handler Exception\t"+ex);
               catch(Exception e1)
                    System.out.println("Exception from Read Data "+e1.getMessage());
                    e1.printStackTrace();
               System.out.println("-----------------------------");
          public void ownershipChange(int type){
               if (type == CommPortOwnershipListener.PORT_OWNERSHIP_REQUESTED){
          public void destroy()
               try{
                    serialConnection.closeConnection();
               }catch(Exception e){
                    System.out.println("Exception 2:"+e);
                    e.printStackTrace();
          public void finalize(){
               destroy();

Configure serial port.vi 未找到

我现在用的是LabView 8.20 中文版，但是里面的对串口进行初始化的模块configure serial port 不能用，在程序框图里面显示是灰色图标（见图1），双击它，弹出“未找到VI”，并且附带的所有串口范例里面都是这样，运行弹出图二的错误列表！我下载了NI-Visa 4.1 安装后也不行，请问这是怎么回事？如何解决？期盼回复！谢谢
Attachments:
14.JPG ‏33 KB
21.JPG ‏42 KB

Instead of just appreciating the comments, you need to implement them.
Having the VISA close inside the loop is definitely the problem. And Crossrulz is 100% correct about the problem being that the serial port gets reset to the default baud rate after closing the port. Here is the proof.
Note that while you may have set the port settings manually in device manager, those settings are revised by the VISA driver. If you look in Measurement and Automation Explorer under Devices and Interfaces >> Serial and Parallel, you'll see the default settings that the VISA driver uses. If you change the setting there, your program will work the way you want. But that is not the correct fix. The correct fix is to get the VISA close out of the while loop.
The port settings are established in this order.
1. By the Windows device drivers.
2. By the VISA driver as established in MAX. Since you are useing VISA, these settings will automatically override #1.
3. By the port settings you set programmatically in your LabVIEW program.
Attachments:
Example_VI.png ‏18 KB

Java Serial Port Question !

Hello,
I am writing characters such as "open\r", "close\r" to the serial port of a PC from the Java program. This PC is connected to robot controller through the serial port.
Suppose, I am writing open\r to the serial port. After writing open\r, the controller immediately echos "open" back to the serial port, which my Java program can read & print. Then, approximately after 1 second, when the robot actually executes the open (Open Gripper) command, the controller sends "Done.>" this response. I want to monitor & read this response "Done.>" because I want to check controller's response ("Done.>") before sending next command.
1. Is it MUST to listen & read data at port at the time the data comes? Does the data gets lost if we don't read the data at the time it comes? For example, if data comes at 10000 millisecs, then is it MUST to start reading at 10000 or 10001? Would that data get lost if we start reading after say 3 seconds i.e. at 13000?
2. If some data ("Done") comes at the serial port from controller and the Java program does not read that and if suppose more data (".>")comes at the serial port after 1/2 second, then does the previous data("Done") gets erased?
3. My problem is --> the java program that I have written, can sometimes read & print controller's response --> "Done.>" and other times it does not find "Done.>"....That means the data --> "Done.>" is getting lost somewhere or Java program is not able to read it..The controller always sends "Done.>" when it excecutes "open" command.
Thank You !
Mayur
Below is the code I am using...
import java.io.*;
import java.util.*;
import javax.comm.*;
public class WriteReadEdit implements SerialPortEventListener {
CommPortIdentifier portId;
Enumeration portList;
OutputStream outputStream;
InputStream inputStream;
SerialPort serialPort;
public static void main(String[] args) {
          String command1 = "open\r";
          String command2 = "close\r";
          boolean EndCharacterQMark = false;
          WriteReadEdit readObject = new WriteReadEdit();
               readObject.Write(command1);
               try {
                    EndCharacterQMark = readObject.waitUntilDataComes();
                    System.out.println("EndCharacterQMark is: " + EndCharacterQMark);
               }     catch (IOException e) {}
                    if(EndCharacterQMark) {
                         EndCharacterQMark = false;
                         readObject.Write(command2);
                         try {
                              EndCharacterQMark = readObject.waitUntilDataComes();
                              System.out.println("EndCharacterQMark is: " + EndCharacterQMark);
                         }     catch (IOException e) {}
                    readObject.closePort();
synchronized boolean waitUntilDataComes() throws IOException {
     String total="";
     boolean EndCharQMark = false;
     StringBuffer inputBuffer = new StringBuffer();
     int newData = 0;
     while(true) {
                    if(!dataAvailable()) {
                         try {
                              wait();
                         }catch (InterruptedException e) {}
               try {
                    while (newData != -1) {
                         newData = inputStream.read();
                         inputBuffer.append((char)newData);
               }          catch (IOException ex) {
                         System.err.println(ex);
                    String dataAtPort = inputBuffer.toString();
                    for(int i = 0; i < dataAtPort.length(); i++) {
                              if(dataAtPort.indexOf("?")>1 || dataAtPort.indexOf(">")>1 ) {
                              EndCharQMark = true;
                              return EndCharQMark;
boolean dataAvailable() throws IOException {
     return inputStream.available() > 0;
          void Write(String commandToSend) {
          String command = commandToSend;
          try {
                    outputStream.write(command.getBytes());
                    System.out.println("\nSuccessfully Written: " + command);
          } catch (IOException e) {System.out.println("IO Exception Occured: " + e);
void closePort() {
     serialPort.close();
     System.out.println("Port closed successfully.");
// Constructor()
public WriteReadEdit() {
          portList = CommPortIdentifier.getPortIdentifiers();
          while (portList.hasMoreElements()) {
          portId = (CommPortIdentifier) portList.nextElement();
                    if (portId.getPortType() == CommPortIdentifier.PORT_SERIAL) {
          if (portId.getName().equals("COM1")) {
          try {
          serialPort = (SerialPort) portId.open("writereadobjectApp", 2000);
               System.out.println("Opened the port for writing: " + portId.getName());
          } catch (PortInUseException e) {
          try {
               serialPort.setSerialPortParams(9600,
          SerialPort.DATABITS_8,
          SerialPort.STOPBITS_1,
          SerialPort.PARITY_NONE);
          } catch (UnsupportedCommOperationException e) {
                                        System.out.println("UnsupportedCommOperationException, Could not set the port: " + e);
                                   try {
                                        outputStream = serialPort.getOutputStream();
                                        inputStream = serialPort.getInputStream();
                                   } catch (IOException e) {
                                   try {
                                        serialPort.addEventListener(this);
                                   } catch (TooManyListenersException e) {}
                                   serialPort.notifyOnDataAvailable(true);
synchronized public void serialEvent(SerialPortEvent event) {
     switch(event.getEventType()) {
     case SerialPortEvent.OUTPUT_BUFFER_EMPTY:
     case SerialPortEvent.DATA_AVAILABLE:
     notifyAll();
     break;

1. Usually there are buffers in the serial port controller. Apart from that, as long as the port is open, any data recieved will be added at the end of the InputStream of the comport so nothing will be lost.
2. Nope, see above. But there might just be some kind of limit there.
3. Download portmon http://www.sysinternals.com/ntw2k/freeware/portmon.shtml or any other prog that is able to monitor what's happening on you're serial port. This allows you to see if the response is really send by the robot.
You're code seem to me to be more complex then it needs to be. Check out javax.comm.CommPort.enableRecieveTimeout(int). Setting a timeout will cause the the read function to return when the timeout is passed or data is recieved. A timeout of of say 4sec whould make sure that when a reply is send, it is recieved and it's stops reading when it gets no reply.
In that case you could do with a sendMsg function wich dus not return until the correct response is recieved, or the timeout passed.
You migth consider putting all the communicatoin with the com port in a different Thread so the rest of the program runs on when that thread is listening to the port...
Hope this helps you a bit...

Occasional freeze when reading serial port

I've a labview application which is a gui for a remote device via RS422. The host computer is a quad core running XP SP3. Initially I was developing with labview 7.1.1. At random intervals (anywhere between 10 minutes and 5 hours observed), labview will freeze. Using a port monitor during this freeze, I'm able to observe repeating calls for IOCTL_SERIAL_GET_COMM_STATUS followed by IRP_MJ_READ. VISA is configured for 0.5s timeout. The serial card is a MOXA, CP-114EL (4port RS422). During the freeze, Labview cannot be closed. Sometimes it will try by displaying the "Resetting..." text but it never completes. A hard reset is then required. After the freeze, processor usage is 25% (on average, 1 processor working full time for labview, but bouncing between cores). Before the freeze, its less than 2%.
At first I investigated the serial card driver via emails with MOXA. After running a terminal emulation program and a loopback connector they gave me for several days without their program freezing, they're confident the problem isn't with their card or driver. During discussions with them, I installed the evaluation of LabVIEW 2009. The program still freezes except now I have less access to the VI (I used to be able to switch to the block diagram and via the highlighter tool observe it stuck in the read operation. In either version though, the above mentioned port monitor output is the same.
My instinct is that the source of the problem is in the multi-core application, some kind of timeout race condition. My VI is fairly simple in summary, write a command (read temps, read status, write new params, etc) and wait for reply timing out if there's a problem. Repeat. Serial port is configured for 115kbps and transfers are in binary. Before the freeze, the communication works well.
I appreciate any suggestions. I've looked around the net and this forum and didn't find anything similar. Long time reader, first time poster. I've a lot of experience in labview but can't solve this - the random interval doesn't help. I think I'll start logging all serial transfers and see if anything always occurs before the freezing.

This morning I updated the labview drivers to the most recent online (I hadn't done that yet when I installed LV2009, download was large). It was something I planned to try if the LV2009 change alone did not resolve things. The update also did not solve the serial freezing problem.
I've attached two captures from NI Spy, one during normal operation and one of the last capture (up to the arrow). I did a brief probing of a different VI that isn't a part of this afterward. You can see the Read request of Com 2 for 266 bytes. In the before image, red lines are timeouts. So this read request is hung up waiting for bytes and never timing out. That's at least my interpretation.
I appreciate your and tbob's suggestions. I've a new serial card (Brainboxes PX-310 card) to try coming soon, not that I don't want to solve this, I just can't spend too much time on it. If it still gets hung up on the new card, I'll look into the motherboard PCIe port, maybe a failing transaction. I would've went with the NI card but I need electrical isolation and 8 ports is excessive.
Attachments:
NI Spy - before freeze.JPG ‏104 KB
NI Spy - after freeze.JPG ‏108 KB

Closing serial port

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