Re: SerialPort.WriteTimout

Portmon (sysinternals) is a free serial port monitoring tool

http://technet.microsoft.com/en-gb/sysinternals/bb896644.aspx


-----Original Message-----
From: Discussion forum for developers using Windows Forms to build apps and controls [mailto:[email protected]] On Behalf Of Don Clark
Sent: 09 January 2008 17:23
To: [email protected]
Subject: Re: [DOTNET-WINFORMS] SerialPort.WriteTimout

Peter - One other thing to look for.

Is all of the data that you're transmitting to the port data that the device
can accept? Perhaps you're unknowingly sending a control string to the
device and causing it to stop receiving data. If the device stops accepting
data you'll get a timeout exception.

A couple of things that I've done to figure this out in the past.

1) Set the timeout to infinite to see if the device can accept all of the
data.
2) Use a serial port spy to see what data is being transmitted between the
serial port and the device. I use a program named Advanced Serial Port
Monitor (about $60) and it has saved me many times.

Don





-----Original Message-----
From: Discussion forum for developers using Windows Forms to build apps and
controls [mailto:[email protected]] On Behalf Of Peter
Osucha
Sent: Tuesday, January 08, 2008 7:28 PM
To: [email protected]
Subject: Re: [DOTNET-WINFORMS] SerialPort.WriteTimout

Thanks, Don.  I have a very small test c# (2.0) app that opens a serial
port, sets the baud rate and a few other items, and then writes a stream of
50 chars.  Doesn't seem to present a problem.  I have a much larger, more
complicated c# app that also writes to a serial port with similar port
settings and less characters and I keep getting a write timeout error.  So
it doesn't seem to be the hardware.  I am looking for other places I might
have screwed up (and yes, I do know the port is open! :-)).

Peter

-----Original Message-----
From: Discussion forum for developers using Windows Forms to build apps and
controls [mailto:[email protected]] On Behalf Of Don Clark
Sent: Tuesday, January 08, 2008 5:31 PM
To: [email protected]
Subject: Re: [DOTNET-WINFORMS] SerialPort.WriteTimout

It's not always just the length of the data and the baud rate. I've seen
write timeouts happen when using virtual serial port controls even though
given the baud rate and the length of the data there was ample time to
complete the operation. The most recent drivers for the siLabs 210x USB to
Serial chips seem to be especially slow. With a write timeout of 400ms I was
sometimes unable to write 2 characters to my device at 38400 baud.

If the write operation isn't completed during the timeout period a
timeoutexception will be thrown.

Don



-----Original Message-----
From: Discussion forum for developers using Windows Forms to build apps and
controls [mailto:[email protected]] On Behalf Of Peter
Osucha
Sent: Tuesday, January 08, 2008 1:58 PM
To: [email protected]
Subject: [DOTNET-WINFORMS] SerialPort.WriteTimout

I have been searching for info on what actually will cause a WriteTimeout
error to happen on a serialport object in net 2.0.  There are lots of
articles that talk about a Write operation not being able to complete in the
time allotted.  However, besides having a series of bytes to be written that
when taking into the account the baud rate cannot complete in the allotted
time, I can't think of another reason for this error to occur - nor can I
find reference to when it will occur.

Any ideas or places you could point me, please?

Sincerely,
Peter