App works in 95,98 and serial comm is balky in XP, rest of app is OK

[AnalyzerIII]

Application works great in 3.1,95,98 but serial communication is balky in XP otherwise works great. There are data delay indications and pauses in the display. Tried some of the newer serial drivers from the web site without success.

[Chris_Rake]

What serial hardware are you using?

[AnalyzerIII]

Standard rs232 serial port on the pc and our equipment which communicates at 19200 fixed (none 8 and 1a)

[Chris_Rake]

There are some differences between the built-in serial drivers on win9x and win2k/xp, but we usually don't see these difference at 19.2k.

There may be other things at work - are you using the same version of LabVIEW and/or NI-VISA?

[AnalyzerIII]

Same verion and install disks. The labview software application has a routine to monitor communication. Normally the pc polls the device about 1x per second to update display information. We get a data delay indicator after 2-3 seconds if the equipment has not responded. Talking to the equipment with hyperterminal has no delays. Again does not happen with 3.1, 95 or 98.

[Chris_Rake]

Are you seeing an unexpected delay (and thus false indication on equipment response)? How do you poll - write then read with timeout? Are you using VISA or the traditional vi's (what version of LabVIEW?)

[AnalyzerIII]

Yes at times, not sure of the exact version vintage 1995-7. Programmers long gone. Our customers are seeing the same problems and all want to upgrade to XP from 98. We poll the equipment then wait for the response, ususally immediate. No noticeable delays in older op sys just in xp.

[Chris_Rake]

OK - Let me talk to a few folks and see if we have some ideas.

[AnalyzerIII]

Just a further note... I have also tried rolling back XP to win 95 and 98 with no difference. Also changed the buffer settings for the com port with no difference however, max was a little better. Also, fixed memory and irq in bios vs auto settings with no luck.

[AnalyzerIII]

The original code is on some zip disk we are not able to read. However the verion is appears to be Labview 4.0