A little outside the scope of Opto gear, but interesting none the less.....
PAC Display, like all Windows programs, simply makes calls to the OS to do any reads and writes to any drives.
Its the OS that we need to take a look at.
You dont mention what version of Windows you are using, not sure how much that matters, but I did a bit of Google Foo on the topic and it seems that Win 7 has a timeout value that you can tweak for networked drives. This timer sets how long unused shared drives will hang in there before they are disconnected.
I also read that Win 7 will automatically try and reconnect them as soon as the drive is used again.
Sounds like in your case, the network goes down for more than a few minutes and it will not reconnect.
How do you get the drives to reconnect once the network comes up?
Do you reboot the PC, or run a batch job?
If a batch job will reconnect, then you could look at some batch job glue to test the network drive via ping, if its down, keep pinging, once its back up, reconnect the drive and then grab the date time stamp of the files on the local drive and the remote drive and send up the files that are missing.
Yes, it will be a pretty solid batch file, but I don't think its outside the realm of doable.
Do your IT guys have any thoughts on the matter?
They often have cool little utility programs for just this sort of thing in their back pocket (in the form of a USB drive).
I see why you are thinking of off loading it to the controller, but given you have a PC in the mix, I would focus my energy there and put it to work since it has the file and the network drive connectivity (When the network is up).