Serial com port not displaying

[dakudiv]

we are having some prob in the system.Actually COM port is been read by the device manager but it is not getting selected in our front panel.

In other words in labview the COM port is not being read although computer is reading it.

I guess there is some prob is withthe software and i m not able to figure it out.

[JLS]

Hello,

That is a bit strange... a few years back I may have had even better intuition on this specific issue.

One suggestion that comes to mind (albeit very general) would be to force Windows to "reinstall" the device.  The goal being perhaps to get it out of some funky state where it currently isn't being detected.

The general procedure for that would be:

1. Shut down LabVIEW completely (for sanity)
2. Go to Device Manager
3. Right-click on the device and choose Uninstall
4. Choose the menu option to Scan for Hardware Changes (or similar verbiage depending on Windows version perhaps)
5. Launch LabVIEW again, open a VI, drop a VISA Resource Name control down on the front panel (or a corresponding constant on the block diagram).
6. Does your COM port populate there now?

That process should force Windows to find that hardware installed again, and resinstall the driver for it.  If for some reason it was in a strange state previously, this might help tidy things up.

I have assumed some things here, such as you have NI VISA installed and you're looking for the COM port using a VISA Resource Name control or contstant.  If any of those assumptions are incorrect, perhaps clarify the steps you're taking and we'll see if that leads to any new ideas.

There is also an NI VISA VI to "Find VISA Resources" - have a look in the VISA palette for that... running it and viewing the result/polled resourses may also shed some light.

Attacking from another angle, are you able to see/use the COM port via hyperterminal? 

Finally, if you're not able to solve the problem, perhaps provide some more details about your setup and installation.  For example, operating system, version of LabVIEW, version of NI VISA, perhaps some data from device manager about the COM port (ex. UART info), and results of anything you've tried so far.