[2008] Serial Port Received Bytes Is Zero?
Mar 12, 2009
In my serial port application, I have my code -
Private Sub SerialPort_DataReceived(ByVal sender As System.Object, ByVal e As System.IO.Ports.SerialDataReceivedEventArgs) Handles SerialPort.DataReceived
Dim cnt2 As Byte
[code]....
For some packets I sent, "Error Data Received" came up. I checked BytesReceived, it was 0. My question is: since SerialPort_DataReceived processes data received, data was supposed to be received. Why the number of bytes I read was zero? BTW, when is this event accessed? it is accessed when any number of bytes received or the whole packet received?
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Oct 6, 2011
the problem I am having is probably mainly because of I am very new at VB.net, anyway, the thing is, I am able to receive data from microcontroller successfully. The format of the data coming from the Microcontroller is shown below
0,2 1023,1023 1023,1023 1023,1023
1,5 1023,1023 1023,1023 1023,1023
2,8 1023,1023 1023,1023 1023,1023
[code].....
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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) _
[code].....
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Oct 25, 2009
I'm looking to write a few lines of code that listen to the COM port and count the number of words (as defined by the presence of a start bit) received during a set period of time.
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Nov 10, 2010
I am current using VS2008 to write a little app to transmit hex data via the serial port to the target device and receive back data from it and display that on a text box.
The problem i am facing is receiving "read" data "hex" back from the serial port and displaying it. I am able to send data to the target system without any problem. For example, if i send this command "&H10, &H0, &H1, &H7E, &HFF, &H49" The LEDs on the system blink 10 times and it works every time. If i send this command "&H10, &H0, &H0, &HFF, &HD" i should get 5E back and I use Realterm to verify the communication and it works great. When i use my VB app it fails, instead of getting back 5E.I get "&H35, &H45, &HD, &HA" on the buffer
Private Sub sendbutton_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles sendbutton.Click
Dim send_Buffer() As Byte = {&H10, &H0, &H0, &HFF, &HD}
[Code]...
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Oct 1, 2009
I am writing a program to read data from the serial port using the data received event. But, I realised that My data received event run more than 1 time when there is a data received at the com port and this actually makes my reading command reads the wrong data. The correct procedure is whenever I send a "+++" over to my device. It should responses with "OK."message.
Why the DataReceived Event will read more than 1 time?
Below is my coding for your reference.
Public Class ControlProgram
[code].....
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May 5, 2011
How do I send XML commands in vb to get data received over a serial Port?
I know the commands I'm just not sure how to send them.
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May 17, 2010
I don't know why this is. I am using VB 2008.net and I am trying to receive data on the serial port.
For some reason, the following event is not executing. Here is the
[Code]...
Just simple as of right now for debugging purposes. I have a breakpoint at getMe and it doesn't hit it at all. I know for sure that the serial port should be receiving data as I am using RealTerm to monitor serial port input data before I run my program.
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Oct 2, 2009
I am trying to write something through serial port to my device. Before that, I added the data received handler to read the data when the device response with some data. The problem now is how can i check the status of the data received event? I need to know when the data received event has started or has ended before I can proceed to do some other task like check if the result is successfully receive.
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Jun 4, 2010
I'm doing a project and want to do a graphical interface using V. Studio 2010. I want to use VB.NET as a programming language.
- Do I have to add any software to define VB.net?
- What is the function that reads the data from the serial port?
- If I want to receive more than one type of data, and I want to put/read them in separate text boxes, what is the function to filter the incoming data?
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Apr 26, 2012
I'm new to VB, I'm now want to know how to convert received string to double. I'm receiving string like this 420.8 280.9 140.2 from serial port.. and transferred it into textbox.. I'm using following code to split string and to convert to double
[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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Nov 2, 2011
I'm having trouble with parsing an XML data from serial port.Actually I need to parse it automatically after all data is received from serial port.I can display all the data in a richtextbox control and all data is received perfectly but my problem isit seems that serialdata.eof function seems like it's not firing.
here's some of my code:
Private Sub frmMain_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
'set serial port properties
With COMPort
.BaudRate = 19200
[code]....
what i need to know is how can i automatically parse the XML data from serial port after all data is received.
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Aug 30, 2010
I'm working with a device using the serial port and i am sending a command from the pc to the device like this:
1. I Change the parity to mark
2. then send a byte
3. then Change the parity to space (here is the problem)
4. Send a lot of bytes
but the device just ignores all the last bytes, im pretty sure its a timing problems, so a timeout occurred attempting to send a command, how can i change the parity without losing time?
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Mar 10, 2010
I'm using 2008 Express and I'm trying to send 1 byte of data on the serial port.
Serialport1.write(123) Sends 3 bytes with the ascii codes representing 1 2 and 3.
I want to send 1 byte that contains 123.
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Jun 4, 2009
I have a timer control that sends data to a hardware every 3 seconds. I sent 6 bytes of data. In return I am expecting 8 bytes of data in DataReceived event. First time I send 6 bytes of date, in DataReceived event, I get the expected 8 bytes. Then in next 3 seconds, again the expected 8 bytes of data is received. But after that I find that DataReceived is fired 2 times: first time I get 6 bytes and then I get 2 bytes. After that I again get 8 bytes as expected. So in short, 2 times I get 8 bytes as expected and 6 bytes and 2 bytes and again 8 bytes. This pattern is repeating continuously. Why? Is there any reason why I cannot get all 8 bytes everytime? Note that the code is in vb.net 2008
Code in button btn_Start ()
'Set serial port parameters
x.PortName = "COM1"
[Code].....
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Jul 8, 2009
I'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??
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Feb 4, 2012
I just wanted to confirm my reading -- this is the number of bytes that is put in the buffer before the data received event is triggered, correct? And it's ONLY for that purpose?
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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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Nov 1, 2011
I'm successfully receiving bytes from an USB device using a HID USB .net library.Here is a sample of my code :
Dim ptr As IntPtr = USB.USB_Read()
Dim buff As Byte() = New Byte(USB.USB_ReadLength() - 1) {}
[code].....
My question is : how can I know wich button is pressed ? Meaning : I just want my program to store the button pressed and do an action when pressed.
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Nov 8, 2011
I receive the irc messages like this [code]...
This show the empty space where it auto-scrolls to when writing the received string to the console.
This shows the actual received message (a bit edited with time, etc ...)
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Apr 9, 2011
I am trying to make my own hyper terminal. I have used the serial port component and after setting all the configuration for the com port I press the button Enable ComPORT. The problem is that, when I press the enable com port button the program goes unstable untill the reception starts from the COM port. After the reception is start the program starts working fine.
[Code]...
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Jun 28, 2009
I am using Visual Basic express to create a serial interface to a multi-room audio controller. I have started by creating a form that can connect to the controller and I can receive data from the Controller and display Zone status, volume etc in corresponding texts box thaks to help from Stanav and Tassa in my previous thread.
My next problem is to do with receiving lots of data from the serial port and my application getting out of sync. This is mainly caused by turning the volum control as each time it is turned a little bit the controller sends out the new status of the Zone being effected
eg
****Turning Volume knob on Zone 1***
Status returned from Controller:
#Z01PWRON,SRC3,VOL05<CR>
[Code].....
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May 25, 2008
[Code]...
m really not sure in here because this code is for vb .net 2003.. are they the same?
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Oct 2, 2011
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
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Jul 20, 2011
This code was published a few years ago by stanav. I have it reading my Com1 db9 port but having some issues.i have tried adjusting some timeouts, but then, it may just sit there.Jarbled Text - I should be getting results like "SOHEM709US 17946US 1114 US62RST 123456789 201107141703 01 " etc., instead I am getting "3B?B?B?????99?F?F?3B?B?B?CAD?1? ? ?2?8?3?0? ?0?1?6"I/O Error - The I/O Operation has been aborted because of either a thread exit or an application request.
[Code]...
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Nov 18, 2009
All these days i used to program in Vb6.0. Now since from last 15 days I have been using Vb2008. In Vb6.0 I used MSCOMM for serial communications. Here in Vb2008 I found Serial port control equivalent to it. I somehow managed to learn how to send data using serial port control and set parameters like baudrate , stopbits , etc. But I' not getting how to get the received data. In VB 6.0 we used to use comEvReceive in OnComm event and used MSCOM1.Input to get the received data. But I'm not getting how to do the same in vb2008.
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Mar 11, 2010
I have written a sketch to an arduino board to send data to the serial port. How can I tell VB to only read from the serial port when data is sent to it? I have been using the timer.tick and tried to sink it with the delay I set in the arduino
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Aug 13, 2011
the program works fine but there is the possibility of a problem because this error message did pop up.I'm gathering my data bytes in an array --
dim rcvdata(19) as byte
serialport.read (rcvdata,0,20)
serialport.close
(Then decipher the array).But Should I go further with this? Could the error be related to my serialport.read?What if there were NOT 20 bytes read into the array?I think this may be it? I should poll the array for 20 bytes before proceeding?Yes? -- (It's a given and that's standard procedure).No? -- Don't worry, they're going to be there (the read will try again if it has to?) It won't proceed without the 20 bytes?
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