Serial Communication speed is very low under WinXP but its good under WinMe

[Shady Yehia]

I'm Using LabVIEW 7.0 to creat an application that communicates with a (DATA Logger) via RS232. the program is working very well under windows ME, but under windows XP the speed is too slow. i'm using the visa read and writ VIs.

If the problem is un-solvable, please confirm that it is a problem with Windows XP.

[Dan_Mondrik]

I highly recommend you upgrade from NI-VISA 3.0 to 3.1 at www.ni.com/downloads

We definitely improved the performance of large Serial I/O reads. I know the performance of other areas improved as well. I don't think we saw much difference on XP, but it probably depends quite a bit on the specific computer.

Dan Mondrik
National Instruments

[Brian_Powell]

I agree with Dan's suggestion, but I have an additional question.

Are you reading large amounts of data, or small?

If large, then Dan's suggestion is sufficient.

If small, then I would follow Dan's suggestion, but also investigate configuring your Reads and Writes to do I/O synchronously. (There's a popup setting on the Read and Write nodes for this.)

By default LabVIEW does the I/O asynchronously, so that if it takes a long time to transfer, it doesn't tie up one of LabVIEW's execution threads. But for small transfers where you know the data's going to be available, the asynchronous setup can take a long time compared to dealing with the actual data transfer.

I hope this helps.

Brian