visa error

[sng99]

The SW package had been deployed all over the world for years. It is very difficult to make such a structural change at this time. All deployments were created with this computer. I can continue to develop SW and create application and deploy them but just can’t test them with this computer. I have to move them to another computer to test them.

As for the port tree problem, I was able to get it back. The reason was after installing/uninstalling VISA, the COM port was disabled in BIOS. I enabled it, rebooted but it the port tree still wouldn't show until I inserted a USB to Serial converter (Note: My PC doesn't have a physical COM port). But as soon as the converter is removed, the tree disappears.

[RavensFan]

Well that makes sense.  Of course if you don't have any serial ports it is not going to show up in Windows, and not going to show up in a VISA control.

Installing and uninstalling VISA is not going to enable or disable a COM port in the BIOS.  That is a completely different problem that happens long before any drivers are involved.

[sng99]

But before all these happened, I could always see COM 1 even though there was no real COM port

[Dennis_Knutson]

I don't believe your problem has anything to do with LabVIEW or NI-VISA. VISA does not affect the bios and its certainly not required for your application so just remove it unless you are going to change your code to use it. You said you installed Visual Studio. That is much more likely to affect ActiveX and Microsoft components. You should review/post to ms and vs boards.

[sng99]

I have got some progress.

For some reasons, I had to uninstalled ALL National Instruments software including Test Stand. Following is what I did:

1. Uninstall Visual Studio 2010, Labview 2011, Test Stand 2010 and VISA441.
2. Unregister MSCOMM32.OCX
3. Reboot PC
4. Re-Install Test Stand 2010, Labview 2011, VISA441
5. Re-Register MSCOMM32.OCX
6. Reboot PC

Now I can run the debug.vi without problem. However, port tree in Device Manager is still missing when the USB to Serial converter is removed. Also, Visual Studio is still not installed. Not sure what will happen when I put it back.

[RavensFan]

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@sng99 wrote:

However, port tree in Device Manager is still missing when the USB to Serial converter is removed.

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And I believe, based on my experience, that is normal Windows behavior.