CommRead data with unknown length

[Christof Kluß]

Hi

there are many good tutorial for communication with the serial port via
VBA like http://www.thescarms.com/vbasic/commio.aspx or
http://dev.emcelettronica.com/serial-port-communication-excel-vba
All of them seems to use something like

CommRead(intPortID, strData, lngSize)

But my device sends data with unknown length. Is there a way to
implement an wrapper for CommRead that bypass the lngsize, so that i can
read the whole string sended?

thx
Christof

 

[Christof Kluß]

Hi Bruce

Am 20-09-2012 20:10, schrieb Bruce Bowler:

On Thu, 20 Sep 2012 17:13:42 +0200, Christof Kluß wrote:
How does the device terminate what ever it is it sends? If that's known,
you should be able to read a character at a time, concatenating them
together, until you get the "end of data" indicator...

I only know that the output comes in lines that end with "CRLF", but it
is not set how many lines. Perhaps I can read until long time nothing
comes (after a CRLF)? Do you have an idea how to do this?

Probably, like you said, I have to read one character at time, but how
do I know, if I am out of time?

Do
lngStatus = CommRead(intPortID, strData, 1)
buffer = buffer & strData
...
Loop Until outoftime

Christof

 

[Christof Kluß]

Is there a way to implement a SerialPort.ReadExisting in VBA?

For NET there is

http://msdn.microsoft.com/library/system.io.ports.serialport.readexisting.aspx

Am 20-09-2012 20:37, schrieb Christof Kluß: