Unable To Close Serial Port After USB / Serial Converter Disconnected
Mar 28, 2006
I have a stand alone VB.Net 2005 application that uses a serial port that generally stays open while the application runs on a Windows XP system. In trying to bullet-proof the UI, I ran into a problem when the USB to Serial Converter normally used to provide the serial port is disconnected while the serial port is open. In trying to handle the resulting error when accessing the port, I find I cannot close the port.
When trying to do so, the error message says something like "unable to close the port. You may not have sufficient permissions." Reconnecting the USB/Serial Converter does not reactivate the port.
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Aug 16, 2011
i am a absolute beginner and i want to use vb to receive data from micro controller through serial port using rs232 standards, i found this code to receive the data serially, can any one tell me where should i paste this code, so that the data received will be displayed in message box.Private Sub DataReceived(ByVal sender As System.Object, ByVal e As System.IO.Ports.SerialDataReceivedEventArgs) HandlesSerialPort1.DataReceived
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Oct 26, 2011
The link below has code to connect to a modem thru the serial port but it is for an earlier version of VB. when I convert the code, it does not fully convert and has 4 errors that prevent building the project. can someone tell me what needs to be changed or added?
[URL]
Note: the error: not CLS-Compliant
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Jul 8, 2008
I have a programme that accepts data from a serial port. If I close the port and then the form no problem. However if I try to close the form with out closing the port it appears to hang. I have tried closing the port in the forms close event but this did not solve the problem.The data recieved event is as below and UseData is the private sub which actually handles the data. Usedata contains the code line Dim InputText As String = SerialPort1.ReadLine
Private Sub SerialPort1_DataReceived(ByVal sender As System.Object, ByVal e As System.IO.Ports.SerialDataReceivedEventArgs) Handles SerialPort1.DataReceived
Me.Invoke(New myDelegate(AddressOf UseData), New Object() {})
End SubI am aware that this event runs on another thread and I have seen but cannot now find information about closing multiple active threads.or do I have to "uninvoke" the delegate
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Feb 22, 2009
I have the following code that listens to a serial port and writes the incoming data to a listview control (the serial data are a delimited string taht arrives once per second that I parse into separate listview subitems). I would like to be able to close/disconnect the serial port once a specific value in the incoming string is detected. For example, in this case one of the columns of data in the incoming string represents depth, I would like to close the serial port when the depth falls below a given number. I have tried the code below, but my program crashes on the SerialPort.CLose method.
dim m_strOBS() as string
Private Sub SerialPort_OBS_DataReceived(ByVal sender As Object, ByVal e As System.IO.Ports.SerialDataReceivedEventArgs) _
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May 4, 2011
I am writing a VB based program which will receive data from a Micrcontroller (programmed in C) via UART. The data that is transmitted from the Microntroller can be displayed on Hyperterminal when I set it up with the correct settings (Baud, Parity etc), so I know that Microcontroller end is working fine. The VB-based program however (written in Visual Studio 2010 Express), does not however receive any data and I always get the TimeOut exception (despite the fact that Microcontroller is sending data via UART, I have an onboard LED to indicate this). Here is the VB code, it is an adapted version from the MSDN library:
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Oct 1, 2009
There seems to be a lot of discussion around about handling exeptions when a USB serial port device gets unplugged. What I want to know is how can one re-attach to it once it is plugged back in. The problem is that if you unplug a USB serial port device the app doesn't know it has gone and remains convinced it is still open. I have to close the app completely before I can re-attach to the device. I need a way to force it to close/go away.
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Aug 18, 2009
I'm trying to write a bit of code to communicate with an RS232 coin mech.The problem i have is that the coin mech works fine when used with Putty or Hyperterm but i do not appear to be able to 'activate' the serial port with my code.[code...]
When i open the hypertem or putty session the coinmech's active light immediatly comes on and i am able to send and recieve data. When the port is opened with the code nothing happens.
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Nov 27, 2010
I'm mohammed from Oman ,I'm visual studio.net programmer How I can Read the Data From Barcode Weight scales By Serial port and TcpIp port
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Jul 25, 2011
I have a Windows form.in windows form have a combo box that give me a list of available port serial with it code (Dim ports As String() =SerialPort.GetPortNames())for example( Com1,Com8,Com15,...).but I want to give me fullname of serial port in device manager for example in dvice manager is these (Comunication Port(COM1) - Printer Port(LPT1) And USB Serial Port(COM8)).how to Get it?
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Aug 2, 2011
If I uninstall the COM1 and reboot, it works. If I shut down (power off) and restart, I get the message below. If I uninstall then click on Scan for Hardware Changes,The given port name does not start with COM/com or does not resolve to a valid serial port. Parameter name:portName
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Jun 3, 2012
I am trying to buld a DLL in VB.NET 2010 that will be use to control a vending machine.Whin a call into the DLL to a function to open and setup the comport the first time its opens it just fine, but if a call into the DLL again it does not know that the port is open even if it is still open. I can check with another program and is shows the port is open and if I try to call into the DLL again to open the port I get an error that the port is already open. Any idea how to set this up so it will work
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Dec 30, 2009
i'm creating a windows form to send/receive data to/from serial port.At first : i send the data as string to the serial port .Second: i tried to read the string again for test the successfull transmission , but i recieved empty string
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Oct 21, 2011
I can find documentation (preferably with code samples) that will guide me through all the steps to activate and read from a serial port?
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Oct 31, 2010
For my application a need to set a breakstate on/off of 25ms.In Xp this runs fine when I set breakstate=true and wait for 25ms and then breakstate= false and wait 25ms.In CE6.0 when I set breakstate = true, it only throws a puls.It is even not possible to keep breakstate on.
how to solve this or is there an alternative to simulate a breakstate?
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Jan 15, 2011
can we communicate to Serial port COM1 through Microsoft Robotic Studio?We are developing wireless robot which will take data from serial por
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Mar 8, 2010
For many years, I have sent data between 2 computers using serial ports."Here is the data", "Thank you for that data!" type stuff.Where do I get more information for doing the same thing with 2 computers that are networked together? Assume a local ethernet connection.I have experimented with serial-ethernet modems and that works well but I don't want any more hardware.Is there a good thread here I should read?I want 2 VB programs running and I want to exchange data periodically.
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Apr 23, 2006
I know things have changed in VB2005.net and i have Express and i want to controll the serial port. I have a program from VB6 that i understand and i tried to convert it but i get alot of errors and i have know idead what they mean. As you can tell i haven't been programming very long.
If someone can point me in the right direction for programming the serial port in VB2005 .net i would appreciate it or tell me what differences there may be.
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Nov 9, 2009
I am developing a UI for an embedded device that I have designed and built. The device uses an FT232 chip which, when connected via USB is automatically assigned one of the COM ports. I was wondering if there is a way to set up a loop which would automatically detect which COM port the device has been assigned. I could then add some handshaking to verify that the port is correct.
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Feb 16, 2009
I have a little code for get the serial port available in the system.
For Each pn As String In IO.Ports.SerialPort.GetPortNames
Debug.WriteLine("NAME : " + pn.ToString)
Next
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So, The PORT1 and PORT5 its ok (because this are real serial port, with a real RS232 interface), but PORT4, I don't know.
How I can do for get only true serial ports ?
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Jan 30, 2011
I am facing problem reading data from Serial port. Actually I am connecting with the hardware device called Crimp Force Analyzer. It gives the data on hyperterminal and I have to read that data from my <acronym title="Visual Basic">vb</acronym>.net program. The data is somewhat like this:
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Oct 29, 2009
I'm looking for a program that would read and import data from my serial port and then graph it. I don't mind buying it if it's not a free program.
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Oct 27, 2009
i am new to VB.net and i am writeing a program to read a serial port and if there is any thing in the buffer i want to read the data and put it in a string then clear the buffer
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Jun 22, 2010
Ive got a big problem.I need to read data from the serial portIve used serialport from the toolbox , but dont know how to use it.I used to do it on a Amiga like this
open serial("serial.device".0.2400.0) rem(open port)
repeat GW.w=readserial(0)
if gw>29 and gw<128
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Jan 21, 2009
I am trying to interface with a Sylvac Gage over the Serial Port, but I can not get read any information sent by the gage.I am using the IO.Ports.SerialPort Object (called serialPort), and I can successfully write to the device. I can tell it to turn off by: serialPort.Write("off" & vbCrLf)But I can't seem to get any information back from the Gauge when I ask it to send information serialPort.Write("?" & vbCrLf)
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Sep 21, 2011
I am trying to listen to the COM3 port and display the output in the TextBox.If I understood correctly I will have to implement this by using eventhandlers, delegates.I tried following these articles:
[URL]
And this is the code I came up with...Unfortunately it doesn't display anything. App just starts display "True" and no data is being displayed.I am monitoring Arduino platform which I know is sending data constantly.
Imports System.IO.Ports
Imports System.Text
Public Class ArduinoSerial
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Jun 9, 2011
how to open all serial port in vb.net? i know how to open by getportname..but how to open all??can we do it?
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Aug 31, 2011
how difficult is it to print to a serial port?or will windows "find" the printer?
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Feb 22, 2008
I am working on barcode reading software. Runs ok, but reads at the most 8 characters at a time. How can I get it to read the entire barcode rather than in pieces?
Here is a snippet of my code
Imports System.Data.SqlClient
Imports System.IO.Ports
Public Class Form1
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Aug 5, 2009
I don't really quite understand how the receiving works but could anyone please help me on how does the receive sms works when using serial port and AT-commands? Here is how I use my code:
Imports System.Windows.Forms.Form
Imports System.Text.Encoding
Imports System.Threading
Imports System.IO.Ports
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