USB-6009. Can't collect data when the device work for several hours

[BillBear]

Hello I am a user of USB-6009. I use it to acquire a signal(-8V ~ 8V, 50Hz) and I use the DAQ assistant to creat the task.. When the USB-6009 work for several hours, the devicet can't collect data suddenly and the indicator light of the device is off. The error out is DAQmx Create Channel (AI-Voltage-Basic).vi:2 Specified Device：Dev1 Task Name:_unnamedTask<0>. I want to know how to solve it. Regards Bill

[crossrulz]

Your problem is most likely that your computer is turning off the USB bus power.  This is a power-saving feature of Windows 7.  Go into the Device Manager and find the USB hub you are on.  In the properties is a Power Management tab.  Uncheck the "Allow the computer to turn off this device to save power".

[SnowMule]

Power management, exactly.  Turn it off on the root hubs, and any/all "USB Hubs" on the system. 

Annoying "feature" of windows.

[BillBear]

Thank you  for your answer.

However， after I Uncheck the "Allow the computer to turn off this device to save power", the device still can't collect data when work for several hours.

Do you know any  other possible causes?

[BillBear]

I I have turn off them as you suggest. But the problem is not resolved.

Do you know any  other possible causes?