Serial ports can not be opened by VISA

[Zador]

I am using StarTech.com 4-port USB to RS232 adapter (p/n ICUSB2324X) under Win XP, LabVIEW 7.1, NI VISA 4.5. 

The following problem occurs when a PC is freshly rebooted: VISA Find Resource returns resource names for all serial ports in the system; however, VISA Open returns error code -1073807343 [VISA:  (Hex 0xBFFF0011) Insufficient location information or the device or resource is not present in the system.], when called with a resource name corresponding to one of the aforementioned 4 expansion ports.

Then, as soon as I open MAX (v4.5) and expand "Serial and Parallel" in the configuration tree, VISA can work with those 4 ports without any problem. But only until the system is rebooted, after which it is back to square one.

I have never had this problem with other COM ports, whether on-board or expansion (PCI, USB, or IP). Obviously, MAX is somehow able to properly resolve and configure these ports. I would like to do whatever MAX is doing programmatically or, at least, figure out a way to save the configuration so that I don't have to run MAX after every system reboot.

Any insight is appreciated! 

[Justin_E]

Hello,

What happens if you try and reference one of your computer's COM ports? If you open up Device Manager, are there any issues in there? Have you tried accessing these ports through Hyperterminal, and if so what is the result there? Thanks,

[Zador]

Justin, the other COM ports on the same PC do not have this problem and are working just fine. I happen to have 2 of them on a PCI card. The 4 port on the USB adapter are properly registered in Windows device manager and work fine with hyperterminal. It's only NI VISA that seems to have a problem with them.

This USB adapter does have some advanced feature compared to the ones I used before. One of them is COM port retention, meaning that the COM port numbers will not change no matter which USB port the device is plugged into. I wonder if this is somehow involved in the problem I am having. Here's a link to the product page: http://www.startech.com/item-features/ICUSB2324X-Professional-4-Port-USB-to-RS-232-Serial-Adapter.as...

Thanks!

[Justin_E]

Hey Zador,

One thing I'd recommend trying is repairing the NI-VISA driver, in case anything has become corrupt on your machine. You can do this through Control Panel->Add/Remove Programs->National Instruments Software . After doing this, reboot your machine and open up visaconf.ini (found on XP at C:\Documents and Settings\All Users\Application Data\National Instruments\NIvisa). Take a look at the bottom of that ini file to see if your COM ports show up there. I'm thinking they should show up since VISA Find Resource returns the COM ports, but go ahead and check just to be sure. 

Another question I have is this : If you place a VISA Resource control on the front panel of a VI and select the drop-down arrow, can you see your COM ports?  Again, I'm fairly sure you should be able to do this, but please confirm it for me.

[JÞB]

Plug and play with com port retention and LabVIEW 7.1 interface to VISA.... Whoa  It brings to mind the time my youngest tried to make a call on a rotory phone.  

Frankly, I'm not sure this one has ANY solution without changing hardware or upgrading LabVIEW.

[jorges]

Hello all..

I has the same problem, to solve unistall the program of StarTech and install only the drivers (leave that Windows detec the new device, when ask for driver select manually, if the controller is a 4 port, you will need do it 4 times).

Aparently the Startech program is not compatible with Labview, if install the drivers manually it works..

[swanseauser]

I have a similar problem with the Startech USB to Serial adapter. I am using LabView 2011 with latest drivers on Windows 7 64 bit. My labview code seems to hang up sometimes while trying to access the serial ports on the Startech adapter. This also sometimes crashes my continuous voltage output code. 

Any suggestions are appreciated.

Thanks!

[jorges]

I has a problem a few weeks ago, I need make the same process that I mentioned plus add a hotfix from Microsoft.

http://support.microsoft.com/kb/969238

Also install lasted NI-MAX version plus drivers..

Hope it help...   🙂