LabVIEW 7.0 visa and serial issue

[lost_rebel]

I get the following error when doing a Visa serial read. -1073807298. I just added LabVIEW 7.0 to this system (Compaq). Running the same source on my Toshiba laptop (which is also upgraded) yields no error. Any ideas?

[JRA]

This error code has a generic description because there are multiple causes for this error. One cause in particular may be that you are not using a proper resource name for your instrument. For instance GPIB0::5::INSTR would be a proper resource name for an instrument with primary address 5 connected to GPIB0. One thing to keep in mind is that your instrument may also have a secondary address. The proper resource name for an instrument with primary address 5 and secondary address 96 would be GPIB0::5::96::INSTR. This is the most common solution to the error. It's worth a try! Make sure the your VISA device is recognized inside MAX. Maybe with the upgrade the drivers got a bit confused.

[lost_rebel]

I can rule that out. Same source runs on a different computer, just fine! In addition, the software in question had been running fine in LabVIEW 6.1 for 4 months without problems both source and compiled, now non of them work.

[Ben]

Double check the version of VISA.

New upgrades do not always have the latest and greatest version.

Also check that the device shows up in MAX.

Check with Compaq (HP) about driver updates.

Ben

[lost_rebel]

All I can say is that LabVIEW 7.0 had worked previously on this machine, was uninstalled due to compatiblity problem with 6.1 and reinstalled when I got the normal upgrade disks. I am convinced that the VISA installer has screwed something up.
I will double check on the latest version of VISA to see if a new one released since LabVIEW7.0 released.
Comm port works fine in MAX and other non-ni apps. The interesting thing is that the data being returned by the read function is correct, but there is an error being generated.
I guess I can try to uninstall VISA and then reinstall it as a seperate component and see what Happens.

[Ben]

I think you hitting close to the mark with this approach.

I have to admitthat I am a little scared. Here is why. I have have very good success running multiple versions of LV on the same machine as long as they are allowed to install in distict folders.

NI-VISA, like NI-DAQ however are shared.

Let us know what you find out.

Ben

[lost_rebel]

Fully uninstalled every NI package on my machine and reinstalled. Still no joy. Fortunatly, I am getting a new machine on friday. Guess this will just remain a mystery

[stu22]

Hi, i have/had the exact problem with visa side. in the end i had to remove the error handlers so my program would work otherwise the i would get the same errors. I find rebuilding the vi in the latest version does help sometimes.

stu

[lost_rebel]

That would probably work...But I am not going to rebuild a functioning VI to address problems with one isolated machine...even though it is my primary development machine. It makes this statement easier to say when I know I am getting a new primary development machine tomorrow.

[lost_rebel]

OK after extensive troubleshooting, I have discovered 4 seperate issues.
Problem 1> My device switches Parity on the fly. This is not documented and took a long time to discover.
Problem 2> NI VISA has been changed to either fix a bug (or created one) where this (change of parity) now causes a problem with the system where VISA 2.60 (and earlier did not have a problem with this)
Problem 3> Seems that VISA autodetects the Parity?? and switches it because when checking the Parity at run time it was always switched to none and should have been even according to my setup.
Problem 4> Still outputs this error and I have no insight into the actual problem, So now that the parity is set correctly at the correct time, the error message is trapped and the r
est of the program works fine. I would love to send the VISA spy log to someone at NI in the visa group who maybe able to put me onto the actual source of this error. I have trapping an error due to programming defiancies.