VS 2010 - SerialPort Lagging - Serial Port Is Open And Waiting For Some Signals From The Dyno
Sep 9, 2010
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
[CODE]...
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Jan 16, 2010
Recently we have connected one bluetooth device which receive data from our serial device. The bluetooth device further transmite this data to a Windows Mobile which is bluetooth enable. Baud rate of whole system is 19200 with 7 data bit and 1 stop bit.When we send command to serial device through bluetooth device it is accepting the command and respond accordingly. but some of data byte of string is desplay as question mark (?).But in case we connect the serial device directly to PC, the string received is correct.[code]Response given by Serial Port is "?09?D03?A D?
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Jan 16, 2010
Recently we have connected one bluetooth device which receive data from our serial device. The bluetooth device further transmite this data to a Windows Mobile which is bluetooth enable. Baud rate of whole system is 19200 with 7 data bit and 1 stop bit.When we send command to serial device through bluetooth device it is accepting the command and respond accordingly. but some of data byte of string is desplay as question mark (?).[code]...
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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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Sep 1, 2010
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
[Code3]...
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".
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Aug 10, 2009
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.
[Code]...
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Feb 25, 2009
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>
[Code] .....
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Jul 20, 2010
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?
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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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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
[Code]...
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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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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.
I need to open and config the com port in one call that leaves it open and then in other call use the com port to talk the equipment in the machine without closing the com port untill it is required to close it.
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Dec 31, 2010
I'm trying to read data coming from a serial port. I simply want to ignore all other data besides the string "button_pushed". The device actually writes "button_pushed" to clean up the display when viewing the serial connection from console or similar. I can change this easily but I'd like to keep it if possible.
My code is as follows:
[Code]...
I'll get an IOException from readLine(). I tried using readExisting() which prevented the error but results in the block being executed twice (probably caused by the "") so the log reads "No data match" and "Data match" for one button push.I have a few questions. First, why does ReadLine cause an exception? I tried to negate that with is_closing but it still occurs. Second, will I run into problems using readExisting as it reads the entire buffer?
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Jul 18, 2011
I want to send hex values across the serial port. I know, I know, your thinking not this again. But what I need to do does not seem to be addressed, or I am some how missing it when I search around.
[Code]...
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Feb 22, 2012
I am using two computer to connect to each other via serial port, I have made a program in VB that allows me to read from the serial port then store whatever that character is to a variable. The only problem is I have to hit a button to read in from the serial port and pass the character to the variable. Is there any way to do this automatically?
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Apr 3, 2012
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
[code]....
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.
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Apr 23, 2010
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:
[Code].....
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Aug 31, 2011
I have a serial port hub with 4 ports. 2 of them work perfectly and the other 2 don't.I've found out that the 2 that don't work always have CTS, CD, and DSR on/true.The 2 ports "don't work" because they aren't able to receive a response.How can I turn off CTS, CD, and DSR holding? It seems that they are ReadOnly properties.I don't know if this will help, but I've recorded a log (recorded pin values every 1 second interval) for one port that worked and another that didn't.The one that didn't work:
RTS,CTS,DTR,DSR,CD,RI,TX Total,RX Total,TX CPS,RX CPS,Break,Overrun,Parity,Framing
0,1,0,1,1,0,9,0,4,0,0,0,0,0
0,1,0,1,1,0,9,0,0,0,0,0,0,0
[code]....
As you can see, the one that doesn't work has a value of 1 in CTS, DSR, and CD at all times. Also, the one that does work was able to receive the data, which is shown by the 14.
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Mar 18, 2011
I got an Arduino hooked up to the PC and would like to read the serial port of it. I read the serial port in Visual Basic with com.Readline, but it won't read everything. It looses around 2-3 lines that were sent over the serial port to the Visual Basic code. They get "lost".
[Code]....
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Mar 29, 2012
In my project I'm trying to send data to Serial port. I have added the serial port control to the form. Now if I try to send data to serial port using Serialport1.write method in a button click event, I'm able to send the data successfully to the serial port. Otherwise if I try to send the data using the same "Write" method from another thread other than the one in which the serial port component was created, I'm getting an exception saying serial port busy.
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May 30, 2012
i'm using serial port monitor 4.0. i need to know how to received the data and show in a textbox.
here is how my data look like in the serial port monitor:
40 03 04 05 00 00 00 80 05 04 01 00 00 00 11 00 @......�........
80 07 04 05 00 10 00 01 02 02 14 80 07 04 05 00 �..........�....
10 00 01 02 02 14 80 07 04 05 00 10 00 01 02 02 ......�.........
[Code].....
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Apr 25, 2012
how to convert received string to double.
I'm receiving string as 420.8 280.9 140.2 like this from serial port.. and transferred it into textbox..
I'm using following code to split string and to convert to double
Dim ReceivedText As String
ReceivedText = txtReceived.Text
Dim str_RY_1U, str_RY_1V, str_RY_1W As String
[Code]...
For calculating percentage RY_R is calculating fine.. But when it comes to RY_Y it showing error "string not in a correct format..."
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Jul 12, 2011
What baud rates are supported by the serial port object in VB 2010?
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May 1, 2011
I 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
[code]....
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Apr 16, 2012
I need to make a program that whatever user enters in bits, then corresponding Return-to-zero signal would generate.. how to generate signals.. so would it be possible to make it in VB.NET?
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Apr 11, 2012
I'm trying to make a rs232 serial data logging program, that accepts a 12 bit hex RFID tagID from an RFID module. My end objective is to save this RFID tagID into a database and assigned to a person for a personnel management system.I had to use button3 to add the value of the variable 'msg' into textbox1 because I was getting the following error "Cross-thread operation not valid: Control 'TextBox1' accessed from a thread other than the thread it was created on". It is a temporary workaround.When I do press button3, I get the incomplete hex number, instead of "4C00A2C82A0C", I get "A2C82A0C", and sometimes I get random digits like 1,A,C etc etc.
Public Sub OpenPort()
Try
If SerialPort1.IsOpen Then
SerialPort1.Close()
[code]....
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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.
[Code]...
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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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