I have an application where I have been using LV8.6 & NI-Serial 3.6 along with either single USB-RS232 cables or USB-RS232/4 4 port systems at 115.2K baud fine for over a year and just recently upgrarded to LV2011 & NI-Serial 3.8.1. Since the upgrade I now periodically experience dropped data and yet get no error from my LabView app. I see this on multiple systems(XP & Vista) when using NI-USB hardware...when I remove the NI-USB hardware and use a native serial port on my XP machine the problem goes away(even with LV2011 & NI-serial 3.8.1). Other clue I have is that on VISTA machines I have that use internal PCI serial card (PCI-8430/8) I don't see the problem.
This is mysterious to me...scratching my head...any help would appreciated!
When you went from LV 8.6 to LV 2011, was there anything that changed in the program with the upconvert? As in, it sounds like the upconverting might have changed the VI's in some way. With a LabVIEW example or some other code, are you able to obtain data from your devices without loss?
Also, what other hardware would you happen to be using? When you say NI USB Hardware, so you mean the USB - 232 or something else?
Finally, have you used the NI I/O Trace? It would allow you to see more information about the communication
Thanks for the feedback!
It seems like something has changed in the way the buffer is handled in 2011, NI-serial, or Windows that has caused the issue to popup.
Once discovered I thought it would be a relatively simple fix to incerase the serial buffer size & flush the buffer but I have increased the buffer from the default 4K to 32K and still have problems...maybe IO trace will help me isolate the problem...I'm sure will end up being able to be solved in my code...but what is curious is why I am having to deal with it after update and not before.
Indeed, it is rather interesting that increasing the buffer size did not help and that the issue only appeared with 2011. Still, when you do take a look through IO trace, post what you learn such that we may isolate the error.
In addition, does this kinda problem pop up just with this piece of code or with any data acquisition with the same setup?
Upon further digging into this it seems like it may be more complicated...I have a support ticket covering this at NI...
Have you tried reinstalling the Serial drivers after your fresh install? During the install of the drivers it will repopulate the drivers in 2011 and should work for you.