Windows 7 hangs when trying to go to sleep withUSB-6210 attached.

[cbfsystems]

My computer with Windows 7 often hangs or crashes when trying to go into sleep mode when USB-6210 DAQ is plugged into the computer.  The first time that I try to put my computer into sleep mode after rebooting, everything seems to work fine, but after waking the computer and trying to sleep it a second time, the system hangs.  The monitor shuts off, but the power LED on the computer is still illuminated.  If I unplug the USB-6210 at this time, the computer goes to sleep immediately and can be woken later without any obvious trouble.  Occassionally, the computer just crashes when I try to sleep it with the USB-6210 attached (indicates that Windows did not shut down properly when I restart it).  I have several other USB devices such as hard drive, mouse, keyboard, USB-9162 with NI 9481 attached to the computer, but have isolated the problem to the USB-6210.  The problem does not happen if everything but the USB-6210 is connected and happens if the USB-6210 is the only thing connected.  This problem does not seem to happen on my Windows XP Pro machine. 

System configuration:

Laptop with Intel i5

Windows 7 Home Premium

NI-DAQmx 9.2.3

LabView 2010 32 bit (not running at the time)

USB selective suspend is enabled in the power settings

 Any suggestions about what could be the problem and/or the fix?

[Seth_B.]

Do you have anything connected to the USB-6210 when you try to put the computer to sleep?

[cbfsystems]

Some analog inputs of the 6210 are connected to some passive circuitry, which is connected to some of the digital outputs of the 6210.  When I disconnected the 6210 from the circuitry, the problem seemed to go away.  I then reconnected the circuitry, but the problem did not seem to return.

[Seth_B.]

Are any of the digital outputs sourcing current when you try to put the computer to sleep (e.g. driving a line high)?  It's possible that there is a continuous power draw from the USB bus that is higher than the USB spec allows in suspend mode.  I would recommend disconnecting your circuitry before putting the computer to sleep.

[Seth_B.]

EDIT: Double post for some reason.

[cbfsystems]

I don't believe that the digital outputs are sourcing much current when the computer tries to sleep.  The load on the digital outputs is around 6k ohms.  I have not explicitly set the outputs high and a multimeter indicates no voltage across the load (the outputs must default either low or tristate).