Applies To:
  • CitectSCADA 5.xx, 6.00, 6.00 Service Pack A, 6.10
Summary:
I am using a USB to serial converter to connect to my devices. This works fine until a few days later when CitectSCADA loses communication to my devices. If I shutdown and restart the PC or unplug and reinsert the USB connection after the loss of communication, I am able to get communication back again.
 

Solution:
This is a Microsoft related issue and has been confirmed by them. Microsoft Windows will turn off the USB port to save power, thus a USB device may not be redetected after a power cycle. To fix the issue follow the link in Microsoft KB article 838989 (at http://support.microsoft.com/kb/838989/en-us at time of writing) and download the patch. 
 
Keywords:
USB, Devices  

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