BECKHOFF CX50x0 - Manual (Page 17)

Notes on the documentation
CX50x0 - Hardware Documentation 15
CF card
The Compact-Flash card (CF card) is a non-volatile memory.
Data to be retained in the event of a power failure should be saved on the CF card. The CF card operates like a hard
disk.
Note
Using CF cards
We strongly recommend that only CF cards supplied by Beckhoff Automation GmbH
should be used.
These are industrial CF cards with a higher number of write/read cycles and an extended
temperature range (+85 °C).
Proper operation can only be guaranteed with CF cards from Beckhoff Automation GmbH!