When the display unit is offline, the CF Card connection feature cannot be used.
There is a limit to the frequency that data can be rewritten to the CF Card. 500 KB of data can be rewritten around 100,000 times. Backup to another media.
A.5 Transferring Data Between a CF Card and a USB Storage Device
If there is no action taken for five minutes after you start [CF Card connection], a warning message appears. If you do not take any action for another five minutes, the display unit is disconnected.