Problem with USB RS485/4 & NI-SERIAL

[GregUcker]

I have an USB RS485/4 and NI-SERIAL s/w (v1.8) which, about two weeks ago was recognized by the Windows XP machine I'm developing on. I stepped away from the project and just came back but now the device is no longer recognized. I used Troubleshooting Wizard and it says no NI serial devices are attached. When the device is plugged in Windows says initially that a new device has been attached and is ready for use, but then comes back with a second pop-up window message that the device has malfunctioned and no driver is available. If I click on the latter message, XP recommends replacing the device if error repeats (it does). I've been through all the setup / help files, 'add hardware' control panels, and checked the event log for 'niser' errors (none). I have even uninstalled NI-SERIAL 1.8 and upgraded to 3.1, all to no avail. Power cycling the device and rebooting the computer have not solved the problem. I'm beginning to suspect a h/w failure in serial device. Any clues would be helpful.

Thanks in advance,
Greg

[Wayne.C]

Greg,

Sure sounds like a h/w failure of either the USB port or the USB-RS485 adapter.  Have you tried different USB ports on the PC?  You might also try installing it on another PC.

 I have several of the USB adapters in use  and I've never seen the driver get messed up or corrupted.

[GregUcker]

I've checked the computer's h/w and all seems to be functioning properly. I've also moved the serial device to other ports on the same computer and have gotten the same error. The fact that it was working 2 weeks ago and nothing to my knowledge changed on the computer seems to point to the device as the culprit.

I'm in the field currently and don't have access to an alternate computer w/ MAX installed but when I plugged it in it came back with the same 'device malfunction' error, as though some the preliminary negotiation didn't even work (the 'what are you stuff?'). I'd expect a driver not found error instead.

Thanks,
Greg

[Wayne.C]

Greg,

Adapter hardware it is.  I'd be real interested in the failure analysis from NI.

[GregUcker]

NI replaced the unit and the replacement worked out of the box.

Thanks,
Greg