Instrument Control (GPIB, Serial, VISA, IVI)

Showing results for 
Search instead for 
Did you mean: 

USB 232/4 stops communicating



I have a test system using 2 USB 232/4 modules to communicate with up to 8 devices under test (DUTs). At least once a day, we'll loose communication to 4 devices, which are all connected to one of the two USB 232/4 modules. We end up resetting the PC to get things working again. We are running LV 8.2 and TestStand 3.5. I have a second identical test system running the same software, but my RS232 interface uses 2 "old" NI PCI 4-port cards. This system never experiences any communication failures like the failures we see on the USB 232/4 system. So I can rule out that the software (VIs and test sequence) are the cause of the problem, since they are identical on both systems.


I am aware of some MS Windows USB driver issues where the driver will shut down the USB port if there are too many errors/timeouts occurring on this port. I did notice that NI has their own driver for this card (saw this through Windows Device Manager). But I wonder if the NI driver might have "inherited" the Windows USB driver bug.


I was wondering if anyone has run into similar problems and come across a fix?


Thank you in advance for your time and response.


Thank you,


0 Kudos
Message 1 of 2

Or has windows powered down the bus.

Check if that can happen. Sometimes nasty to find. 

greetings from the Netherlands
0 Kudos
Message 2 of 2