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Missed bytes in VISA communication

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Hi,

 

I created two programs with labview which communicate together using virtual COM ports that are connected properly.

The first program sends a paquet containing an integer n to the second program which would return n paquets containing 9 bytes, between every two consecutive paquets there is a pause.

When I set the baudrate to 500 or 700 for both programs and for n=360 , they work properly and no byte is missed. 

The problem is when I change the baudrate to 1000 and higher , for both programs, and n is still equal to 360 , there are some seperated bytes missed ( between 0 and 3 bytes in general).

So what do you think the source of problem is ?

It can't be the buffer size because it's set to 64399599 ( no kidding , it is the maximum size allowed). Besides , I used the both programs for another purpose where the first one received from the second 1000 * 9 bytes for n times ( there are a period of pause between two consecutive times of sending of 9000 bytes).

 

On the other hand , I checked what the second program sends by looking at the return count output of the VISA write, and by trying to send these paquets to hyperTerminal. And there are no lost paquet ( even for a baudrate of 9600).

 

So I suppose the problem is in the read part.

 

If somebody would help me I would be very grateful.


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