Siemens SIMATIC S5 Manual page 221

Fundamentals of COM 266
Function key menu:
If the IP is disconnected from the mains power, or if a power failure occurs, the
data in its RAM is lost, and must therefore be stored on EEPROMs before the IP is
actually put into operation in the plant. This applies to both machine data and
traversing (machining) programs. On IP start-up, this data is transferred to IP
RAM. The EEPROM has a maximum storage capacity of 8 Kbytes, only 7K of which
is available for traversing (machining) programs. The remaining capacity is
needed for machine data and housekeeping routines.
<F1> Press this key to transfer the data currently on the module to EEPROM.
This data may include machine data and/or programs.
<F2> Before the data stored on EEPROM can be used, it must be transferred
to the IP's RAM. The IP 266 normally makes this transfer automatically
in its restart routine. If you want to retransfer data from EEPROM to
RAM (because the data in RAM has been modified, for instance), you
can do so by pressing <F2>.
<F4> Press this key to start the transfer you defined in the data area of this
screen form.
<F7> This key is used as selector key for the following input fields:
"Device:"
"Drive:"
"Filename:"
<F8> This key terminates the "TRANSFER" function and returns you to the
"FUNCTION SELECT" menu.
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IP 266
EWA 4NEB 812 6057-02