I am using VB 2005 and need to trap a serial port timeout. I use a standard try/catch block, but if no characters arrive the code still hangs at the ReadByte call. Here is the code:
Try
SerialPort.ReadTimeout = 200
' read timeout of 200 mSecs
thisByte = SerialPort.ReadByte()
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I'm not sure if this is a VB.NET error or SQL Server. But I get the above error with following stack trace:
[SqlException (0x80131904): Timeout
expired. The timeout period elapsed
prior to completion of the operation
or the server is not responding.]
System.Data.SqlClient.SqlConnection.OnError(SqlException
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I am trying to read caller id from a internal modem. modem is caller id enable and it works in hyper terminal. but when i try from vb.net it only shows 'RING'. here is my full code
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Recently while trying to help someone with an issue using USB SerialPort's I discovered sometheing interesting when the ports Handshake was set to RequestToSend. My setup COMx <---> BreakOutBox <---> COMy COMx and COMy are on the same PC. The breakout box is used to create a null modem, pins 2 & 3 crossed, pin 20 to pin 6.When the handshake was set to RequestToSend every Write resulted in Carrier Detect and Ring being raised. Is this just my adapter or are all USB SerialPorts like this?Serial Port Random Microsoft® Community Contributor 2011
View 2 RepliesI have wrote this program (for PDA), to connect a PDA to the PC via RS232.It only works half way.
If I send anything from the pda to the pc, I receive data correctly.If I send anything from the pc, then the pda hangs up.Can anybody tell me what I'm doing wrong?
Also, how do I make sure the port on PDA is closed when quitting the application?
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I have written some code (VB.net) which simply runs a backup on all required servers and databases in a loop. The code works perfectly, except for the first backup which Timeout's after 30 seconds (even with my Connect Timeout=0).
Everything is written manually for the dataconnection, the connection opens and timeouts on SQLComm.ExecuteNonQuery()
dbConnStr= Data Source='Server';Initial Catalog='Database';Integrated Security=False;User ID=sa;Connect Timeout=0;User Instance=False
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I have written a page with an iFrame that basically cycles through a series of internal pages on our server displaying daily activity for our company. The problem I think is that it sporadically loses its session and redirects back to the login screen to keep losing its session which is the default behavior for anyone on our site trying to access a webpage without being logged in.
I have set the session timeout to 4hrs, the iframe cycles through 6 pages anywhere from 10 seconds to 5 minutes on each, and I have even set the META refresh on the page to refresh every 3 hours. I don't understand what else could possibly stop this page from staying active.
Setting timeout on a vb.net webservice.
View 2 RepliesLooking for serial port communication using ASP.NET 4.0. I have a cardwriter/reader from IDTECH which talks through a comport. Is there any way to accomplish with .net through the web.
I read things but most of the topics on speaking about .net 2.0 and I was not sure if they created something to handle this in .net 4.0
We have been debugging a problem with serial communications with an embedded device on 115200 baud, Even parity, 8 databits and 2 stopbits. The problem: a lot of extra 0x00 are sometimes received from the serialport.
1) We build a real basic sample program that only handles the data exchange. It was completely build according the serial-port-vb.doc from msdn. It was build in vb.net 2010. So this was the most basic setup possible on the PC side. This simple tool clearly shows the datareceived event spitting out extra bytes.
2) We used a scope to look at the hardware bits/levels. No problems / differences seen between good and bad messages. No extra bytes visible that the serialport event send to our programm.
3) We tapped the serial communication and received no wrong data on the tapping system but still on the .net tool. Again the serialport datareceived event gave us many extra 0x00 bytes.
So our only possible conclusion is that there is a problem in the serialport component from .net. My question: Are there any know issues? Can I get in contact with a microsoft engineer?
I want to send some data through a serialport (USB) permanently and got a problem once the USB interface crashes. Sometimes it just happens, but if I ask the PC "serialport2.isopen ()" I will get a TRUE, even though the USB cable was uplugged. How can I check if a connection is still available. CDHolding wasnt working either. I am using VB 2008 Express
View 7 Replieshow to use the SerialPort in Visual Basic Express?
I have this in the Serial Port Data Recieved event
Code:
SerialText = SerialText & SerialPort1.ReadChar
TextBox1.Text = SerialText
I get : Cross-thread operation not valid: Control 'TextBox1' accessed from a thread other than the thread it was created on. As soon as the event is triggered.
I'd like to display the recieved info in a textbox and transmitt info as well, but I don't know how...
i am coding a tool which is able to connect GPS devices over the IO.Ports.SerialPort function in .NET..Everything works fine, but to list all available COM interfaces it looks like: [code] its impossible to connect to a device which is called COM3°. If i simply try to connect manually to COM3 it works perfect. [code]
View 3 RepliesI have an application that requires several threads, otherwise the main UI thread would end up frozen.i am after a little advice as i have not really don alot of threaded applications.
First Question;
I have a thread which handles data coming in from the serial port( this wil become much more complicated), is it safe to use a synclock on the serialport object : -
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Im using VB express 2008 (compiled with .NET 3.5) to write a program that communicates with a USB device. The USB device is a communication class device and thus will emulate the usual rs232 serial port once attached to the PC. The USB device sends a fixed number of bytes and i have set the threshold received byte property to this value. I have run the program and it seems to read the USB device "correctly" but when i debug the code, i realise that the datareceived event of the serial port gets fired on the eventtype = EOF. I am using the Read function to read the bytes from the serial port and the Newline property is set to "" (but i thought that this is irrelevant if im not using ReadLine). When the datareceived event fires with EOF, the Read function blocks until one byte arrives, reads it and calls the function that processes the data. I went through the forum and realised that the EOF eventtype is no longer supported, is this true? I dont think that getting this eventtype is logical anyways in my case.
View 5 RepliesI'm trying to enable a timer within a SerialPort.PinChanged even is reached but the timer tick even never starts. Has anyone ever tried this? I am using vb.net 2008 express so I dont know if that is the issue or not.
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I'm using the following to read a serial port. When run it displays the data correctly but stepping through the program I find that it loops through the serialdatarecieved event for each character of the port input rather than reading all of it. So _msg only equals one letter at a time. I'm trying to set a variable equal to the entire input stream but only get one character of it.The end goal is to capture all of the data available on the port when the event triggers so that this data can then be processed. I tried using the bytestoread function, which gets the correct number of bytes to read, and then looped through to read a byte at a time but that didn't seem to work as I expected either. It just kept reading the first byte.
Imports System.IO.Ports
Public Class CommTest
Dim WithEvents SerialPort As New SerialPort
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I am doing a sms project using VB .net to connect to my gsm modem via serialport. All the connection and everything was working great and I can send and receive sms. Then here come a problem, I need to send long sms more than 160 chars. I read and did some research and I know that I need to use the pdu and udh. I managed to understand slightly of the pdu packet but is still quite confuse on that part.
Anyone can briefly explain the exact way to do the concatented sms (long sms)?Another problem is how can I use vb to encode the data into pdu gsm 7bit data? Is there any built in functions or do i need to write them myself?
I am trying to access a printer via the serial port in VB Express 2008. I wrote a small prog with buttons on the form to exercise the escape codes in a Windows Vista 32 laptop with a USB to serial adapter. Only 3 codes worked, BEL, reset and a printer specific command. Also, when i try to receive data, it justs times out. So, I tried to move to a WinXP machine with real serial ports. The program now has an illegal argument exception and the message is to the effect that the name of the port for the property portName does not start with COM/com. Which is very puzzling because I did verify the portname and it is com1.Is this a known issue or am I doing something wrong? The form works on Vista but not in XP.
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I am writing a program which detects a development board I designed which communicates with an FTDI chip. Right now my program scans any COM ports and generates a list, which the user will then choose from and connect with that device. The problem is that I want to isolate that list to only the devices which I designed. The FTDI has a unique manufacturer and device ID, but I only know how to access this data 'the old fashioned way' (i.e. through device manager).
What I would like to know how to do is determine the VID and PID of a COM port from VB, so I can dynamically get rid of any devices which do not meet the proper requirements and thus my list will only show the correct devices.
I'm working on application which uses SerialPort Control to send/receive commands to/from microcontroller.
Here is the basic
CODE:
I maybe missing something because the reaction of microcontroller very accidential! I mean, sometime it works from the first click and sometime from the third... I must make a number of clicks until it reacts back!
I am trying to send and receive data using the SerialPort component. I am sending data to an Texas Instruments MSP430 which simply echos the sent character. I wanted my VB solution to read characters from a file, send a single character, and wait until the echoed character is received before sending another.
I have been fairly successful thus far but I have run into a little catch. When I attempt to send large files (323505+ characters) my MSP430 just hangs there and will not receive any more characters. My VB app return to VS '08 with timeout errors (timeout set to 1 minute).
I wanted to post my VB code here to see if the problem is from my VB app. I will be posting this problem on the IT usergroup to sort out anything on the MCU end. Here is the pastbin of the data write and the data receive subs:[URl]..
I'm using one form to make contact with the serial port with the next
Imports System.IO.Ports
Imports Microsoft
Public Class Menu
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output.gif?I've just upgraded to Visual Studio 2008 and have been given a project and getting gps string from a radio via the serial port. I used a program called "SerialWatcher" and it monitors the data coming in from the radio. It works perfectly. When I tell it the port and settings, click Open, I get consistent output. Here is an example of the data that I got:
<NUL><STX>$PKLDS,124043,A,3337.8562,N,08418.8077,W,000.0,146.5,091109,,00,101,2190,80,00,*1C<CR><LF><ETX><STX>$PKLDS,124104,A,3357.1421,N,08403.0604,W,000.0,000.0,091109,3.0,W00,101,3003,80,00,*61<CR><LF><ETX><STX>$PKLDS,124128,A,3354.1213,N,08414.3434,W,000.1,274.3,091109,4.9,W00,101,2576,80,00,*64<CR><LF><ETX>
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The little icon symbol before the dollar sign is actually two symbols which I think are the <stx> and <etx>. I'm including a screenshot to show what they actually look like. From the output my program created all I would need is actually the last line. I can't really check for "length" because some data received by the radio will be half that length (or more than half). But there should always be a start and end (regardless of what is in the middle) I would think.
I have to increase timeout period.Following is my code.
Private Function GetConnectionInstance() As SqlConnection
Dim objConn As SqlConnection
Dim strConnection As String
strConnection = ConfigurationSettings.AppSettings("conn")
[code]....
What code i have to add in above to increase timeout period.
In this situation, my application can connect to the MSSQL server in one of two ways; via a direct TCP/IP connection (WAN) (IP's filtered using RRAS in 2003 Server) or via a VPN connection. The application will first try to open the connection using the WAN connection string and if it can't, then it tries using the VPN connection string. My issue is, I set the connection timeout to 5 seconds for the first attempt but it's taking way longer than that to return an exception. The order in which I attempt to open the connection doesn't really matter. I have looked at the ConnectionTimeout property after changing the connection string and it does indeed show 5 seconds. It appears that the connection timeout value is being ignored.
View 6 RepliesWe got a legacy vb.net applicaction that was working for years. But all of a sudden it stops working yesterday and gives sql server timeout.
Most part of application gives time out error , one part for example is below code :
CODE:
It was working and now gives time out in command3.ExecuteNonQuery()
Some information : There isnt anything that has been changed on network and the app uses local database. The main issue is that even in development environment it donest work anymore
I am facing error with recaptha, timeout.
I have specify all keys and just valid() calpcha function on code behind.
It waits for while and time out.
More over, When doing page.Isvalid() with capcha, it is alway false, what should be the reason?
<recaptcha:RecaptchaControl ID="recaptcha" Theme="white" runat="server" PublicKey="6LdwMMgSAAAAALdraGklD-N1Jfr5Fuxq6gyaJMy7"
PrivateKey="6LdwMMgSAAAAAKV6hOjAHdFURCUZ6oS_NmxF8iaD" />
recaptcha.Validate();
am using vb.net 2008 and sql server 2008. I have a search form and when i search at times, I have "Connection Timeout Expired" error.I dispose and close the connection after establishment, but i still get it. tried setting MyConObj.ConnectionTimeout = 0 and it also gives me "Property ConnectionTimeout is ReadOnly.
View 1 RepliesI am looking for the VB.NET code of a very handy little *.bas file I used to use in Visual Basic 6. The file was called timeout.bas and it was the greatest module ever to me. I want to switch to start using VB.NET finally but this single file is holding me back. Trying to use .NET without it is like crippling me. [code]
View 3 Replies