Can't Open A Serial Port For Reading?
Aug 10, 2009I am trying to open a GPS device on a serial port but no matter what I try I just keep getting an IOException. This is on a pocket PC BTW.
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I am trying to open a GPS device on a serial port but no matter what I try I just keep getting an IOException. This is on a pocket PC BTW.
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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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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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i am using serial communication to read from a plc.The plc will send a string :&H3A as a header byte then C(which is a variable that contains data)I want to read and mask out the header byte.I use the following code but cannot read anything.
Private Sub btnread_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnread.Click
Msg = SerialPort1.ReadExisting
count = Val(Mid(Msg, 1, 2))
Lblno.Text = count
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For starters I'm using VB 2008 express edition.I have code that writes a string out of a serial port.My issue is that the machine sends data back and I don't know how to catch it.This is my latest attempt at creating an array of characters to create a string later but doesn't work.[code]
View 2 RepliesI am having a little trouble receiving data via the serial port. I can send just fine. I am using Serial Port object.
Basically my data expected is in the form of: [0x43 0x35 0x64 0x35...] broken up into bytes. I tried using the SerialPort.Read() function but can't get it to work.
I have microcontroller interfaced with serial port of my computer. In my microcontroller I have 2000 sample data and my primary target is to read those data. Now I can read those data in hyper terminal, but when it comes to my application it doesnt show anything.
Private Sub sp1_DataReceived(ByVal sender As Object, ByVal e As System.IO.Ports.SerialDataReceivedEventArgs) Handles sp1.DataReceived
sp1.Open()
MsgBox(sp1.ReadExisting())
End Sub
this simple code block should show me the data.But it doesnt.data format coming Microcontroller is in this following formate :
nitialization successful !,1023
Starting sampling process... 1023,1023 1023,1023
0,2 1023,1023 1023,1023 1023,1023 212,686 1023,1023 1023,1023
1,5 1023,1023 1023,1023 1023,1023,659 213,689 1023,1023 1023,1023
now, I dont understand why it doesn't read anything :NB: SP1 has a baudrate of 19200,Databits 8 and no parity,COM1 port. I aisnt sure whether I will be needing a buffer or not
I do not have much experience with VB.What I need to do is to read a serialport as a hexadecimal string.I've done this with the MSCommlib, but now want to convert to system.io.ports.The equipment wich is connected to the serialport is a RFID card-reader, so the application haft to detect when it is receveing data, and then continue on.[code]
View 5 RepliesDoes reading the serial port empty the buffer?
View 2 RepliesAfter searching around I am still having issues with reading data from a serial port in VB.Net/VS2010. I know the Serial Port works, I can write to the port fine but when reading from it, nothing happens. I have only been programming for the last 3 weeks so am still trying to get my head around it all.
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I have a strange problem. We are upgrading a software that works perfectly in a 32-bits environment.Software have to connect to a serial port (or a virtual serial port) and read data and do wathever it has to do with it. Program uses the IO.Ports.SerialPort object.
Now, under Win7 64-bits, is works well when using "real" serial devices, with a DB-9 connector. But using USB device, with a virtual serial port (provided by the manufacturer), it doesn't work at all. I receive nothing on the DataReceive event. But it works fine on a Win7 32-bits.
Strangely, it also works on the 64-bits PC using a program like realTerm. When connected to the virtual serial port, data are received and it's fine. But from our software, it don't. I don't get anything from the serial port.
how to write a code for reading serial port using vb.net with the combination of c#.
Note : (Its just reading data from the swipe).
Private Sub receive_data(ByVal sender As System.Object, ByVal e As System.IO.Ports.SerialDataReceivedEventArgs) Handles SerialPort1.DataReceived
Dim aBuffer(255) As Byte
Do While SerialPort1.BytesToRead > 0
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Basically, what I am trying to do is everytime I receive data from the serial port, I turn that data into an array (aBuffer) and I then call another sub using that info.The problem I'm having is that everytime I receive data, the array only fills up to the first 8 bytes! This isn't a problem when I receive smaller packets of 6 bytes but anything else gets chopped off.
What is really frustrating is that it seems quite fickle. I've read somewhere that this happens because the computer is handling the bytes received faster than they are being put in the buffer?? Not really sure but if I put a couple of breakpoints during debug, sometimes the array fills up correctly... Note the maximum size of any one incoming message would be 255 bytes.
This is an amateur radio project. I have a TNC (modem) that receives a digital stream (AX.25) from my radio. The TNC decodes the AX.25 frames and translates them to KISS frames (the protocol used between the TNC and the PC, see documentation here: [URL] It sends the data as HEX values.
What I'm looking for on the serial stream is the beginning of a data frame marked by 0xC0 0x00 and ending with 0xC0. Should be easy. Using serialport.readbyte() I should get binary data that I can convert to hex and look for the beginning of a data frame and then convert the subsequent data to ascii, as it will be text from a chat session.
Just to try it out and see the raw data coming from the port, I use teraterm or realterm and capture the data and it's a mix of junk (control frames and what not) and valid text. When I display the same data in a text box in VB I get data that look like this:
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Is there any other way to access a serial port using visual basic.net 2010? I followed the steps in this site, [URL] but I just got this output Open the serial port. Send the attention command to the modem. Wait for data to come back to the serial port... and stopped there. I can't get the Read the OK response data in the serial port. Close the serial port. And I was thinking, because it is very much easy to access serial port in vb6, so can I just use vb6 and then connect to visual basic.net? it is like a language inside a language.
View 3 RepliesCurrently, I am using a VB.NET to read data from serial port. when i open the serial port, the data is read and plotting the graphic at the same time
View 2 RepliesI am developing a Winforms application which read barcode from barcode scanner. It's an Human wedge scanner. This will work if I placed the cursor in any textbox or notepad. But i don't want like that. Reason is that it's cordless scanner. If some want to scan some thing in store they will move around, so there is possibility of screen saver coming or system gets locked if that happens the barcodes wont capture, but the user who is scanning the barcodes won't know this thing.
So i am reading the data using serial port communication and my scanner sending the data character by character, Not a whole string. so for that I wrote the following code. Thsi code will works if i am writing to any textbox. But it is not working if want to store it in any global string. Only first character is storing in the string. The below code is working perfectly fine. but if want to save the string in Global String variable instaed of textbox the only first character in the string is storing.
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Using 2008 VB.Net trying to do serial communications. I have a Scantron scanner I can send data to it, but I can not get read data back sent to my serial port. I have tried ReadLine, ReadByte, etc. but i'm not capturing anything, and I don't understand the DataReceived event. [Code]
View 15 RepliesI'm working on a project involving reading RFID tags, I've written the code and it reads the tags ok by using the recieved data handler and displaying the result in a listbox, the only problem is that the data displayed has a couple of unreadable characters at the start (I'm using ReadLine() command.)If I read the buffer byte by byte the data is all readable.How can I read and display the whole 16 Bytes in one go??
View 3 Repliesreading and writing data to a serial port. the settings for the port are correct (from manual of device):
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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?
View 2 RepliesI am using a VB.NET(VS2010) to read data from serial port. I have 8-bit data to collect through rs232. This data is represented numbers. What reading method should I use and how to convert it to double format?
View 3 RepliesI am having an issue with serial port timing when using it to read large flash content. If I slowly step through the code the program works as expected. If I let it runs by itself it only shows part of the result. The problem is not related to displaying the data on the form but mainly the "Serialport.BytesToRead".
Here is the code
Private Sub MemoryReport_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MemoryReport.Click
Me.BackgroundWorker1.RunWorkerAsync()
'Memory_Report()
'SerialPort.DiscardInBuffer()
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Public Class my_class Dim WithEvents COMPort As New System.IO.Ports.SerialPort
Public Sub FindReader()
Dim ports As String() = IO.Ports.SerialPort.GetPortNames()
Dim port As String
For Each port In ports
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When it runs, it shows a single COM port "COM1". I am assured that the device attached to it is a standard 8,n,1 and uses 9,600 baud. The exception is "Acess to the port 'COM1' is denied".
I wrote a program that uses the following class from that site: VB.NET Tutorials - Serial Port Communication In VB.Net. The problem is that I cannot open a virtual serial port, and the second is that I want to make the communication asynchronous.
This is the subroutine which reads from the port:
#Region "comPort_DataReceived"
''' <summary>
''' method that will be called when theres data waiting in the buffer
''' </summary>
''' <param name="sender"></param>
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In VB6 I had to always check if the port was open or not. But with VB.NET and the new Serial Port control I don't see any.If SerailPort1.Open then statements. In fact when I tried to use the code I got Expression does not produce a value.So does this mean that we no longer have to check to make sure the port closed?Is there a way to check if the port is open or not?
View 1 RepliesI have conquered the problem of the database however what i need is the serial port data sent to a database and outputted on screen however i keep getting cross thread errors ..
Imports System.Data.OleDb
Imports System
Imports System.ComponentModel
Imports System.Threading
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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
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
I have things set up so that the program is ready to start logging ,only when Recieving=true.This is controlled with Button1. So I click button1,Serial port is open and waiting for some signals from the Dyno.When 1 signal come it put a "1" in TextBox1 ,and for the second a "2" and so on. Thing is sometimes it starts right away, like I want it to,and sometimes it lags a fraction of a second, even though the Port is open.When it lags there are already 5 to 10 signals gone by before it starts logging 1,2,3,...and so on. Sometimes it don't start at all.Then I have to close and re-open the form and it works,but with lagging on the first "set"
"Textbox1 > 0 then" triggers a timer (not seen in this code)that samples Textbox1 once pre interval and writes the value to a listbox. On the upside as soon as a "1" is displayed in textbox1 the timer starts like it's supposed to.I noticed this behaviour before I added the timer and besides the timer has nothing to do with the signals coming from the SerialPort. I have my form setup so I can run "sets".Run one "set"...save...reset...run another "set" ...and compare.It's always the first "set" thats off.If I run multiple "sets" the first one is completely "whacked", and the rest are consistent.
Think this could be the SerialPort lagging,or code problems?
Public Class Form1
Dim resetValues As Boolean = False
Dim RPM As Double
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