Siemens SIMATIC PCS 7 Operating Manual page 22

Configuring S7F/FH hardware
6.1 Adapting CPU parameters (single F-system)
Example
The following example shows how you can switch between protection level "2" (MODE = 1)
and "3" (MODE = 12) of the CPU with a digital input signal (e.g. from a key switch) with SFC
109. When the system, or the safety program, starts up, protection level "3" is activated with
a signal "0" at the input. With a signal "1", this is reduced to protection level "2". At this
protection level, the CPU can be accessed and changes loaded into the CPU if the password
is known.
Note
The figure is available in its original size as appendix to the manual in the ZIP download of
the checklists.
22
Compendium Part B - Process Safety (V8.2)
Operating Manual, 07/2016, A5E35031794-AB