USB 6211 Isn't Recognised After Computer Restarts

[GrassNinja]

Hi,

I'm using three USB-6211s connected via a USB hub, which has its own power supply. These work fine until I restart the computer. When I log on I get messages saying the devices are not recognised and only one of the DAQs appears in MAX. If I physically unplug each DAQ from the hub and then plug it back in again, they show up in MAX and I can run my LabVIEW program.

Eventually the DAQ devices will be kept inside a closed control box so the user will not be able to unplug them. Can anyone help me figure out what's going wrong? I thought it might be the USB hub but I've made sure it is using its own power rather than drawing it from the computer's USB connection.

Thanks for your help,

Dan

[AAlZibdeh · Accepted solution]

Hi, 

In some cases USB devices are detected, but the OS has not completed its driver loading process, causing a race condition. You are able to recover only when you either power cycle the USB device or unplug and plug your device.

I would read the following article that explains how to force windows to remove and re detect a USB device

http://digital.ni.com/public.nsf/allkb/1D120A90884C25AF862573A700602459

Kind regards, 

Abdullah AL-Zibdeh 

Applications Engineering 

National Instruments

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[GrassNinja]

That seems to work, thanks very much!