Windmill Data Acquisition Software Logo

Windmill Software Ltd
Data Acquisition Intelligence
Call now: +44 (0)161 833 2782


What to do if Windows drops your USB connection?

A Windmill customer was having problems with his data acquisition hardware suddenly stopping, seemingly at random.

The cause of the problem was the USB connection. Under Windows 7, occasionally the USB connection drops. USB has no mechanism for recovery when this happens. The only thing you can do is unplug the cable and then plug it back in again, which re-initialises the Windows USB drivers.

For long-term monitoring and control this is obviously not ideal. In these cases we would recommend connecting devices to the PC using Ethernet rather than USB. Unlike USB, Ethernet can self-correct after an error. Our Ethernet data acquisition devices are listed at http://www.windmillsoft.com/daqshop/ethernet.html.

If you are already using USB hardware under Windows 7, and don't want to swap to using Ethernet, try these remedies.

  1. Disable "Allow the computer to turn off this device to save power" in USB Root Hub.
  2. Disable Selective Suspend settings in Advanced Power Options.

1. Prevent the Computer from Turning off USB Devices

  1. Open Windows Control Panel.
  2. Go to: Hardware and Sound, Device Manager.
  3. Expand the Universal Serial Bus controllers entry.
  4. Right-click the USB Root Hub and choose Properties.
  5. A dialogue box appears: click its Power Management tab.
  6. Un-check the "Allow the computer to turn off this device to save power" box.

2. Disable Selective Suspend Settings in Advanced Power Options

  1. Open Windows Control Panel.
  2. Go to: Hardware and Sound, Power Options.
  3. Select "Change plan settings" for your selected power plan.
  4. Select "Change advanced power settings".
  5. Find the entry "USB settings" and under this the "USB selective suspend setting" USB Power Settings in Control Panel
  6. Click "Enabled" and change it to "Disabled".

Hope this helps - any questions fill in one of the comments boxes below or e-mail us.


Comments

<

by Jill Studholme