Glossary
Safety Engineering in SIMATIC S7
Glossary-6
System Manual, 04/2006, A5E00109529-05
F-Control Blocks
S7 F/FH Systems: Block container of the
Failsafe Blocks F-library, which contains the -> F-
blocks that are automatically called/added during compiling of the -> safety program in order
to generate an executable safety program from the safety program programmed by the user.
F-CPU
An F-CPU is a central processing unit with fail-safe capability that is permitted for use in S7
Distributed Safety/S7 F/FH Systems. For S7 F/FH systems, the F-Runtime license allows the
central processing unit to be used as an F-CPU. That is, it can execute a safety program.
For S7 Distributed Safety, an F-Runtime license is not required. A -> standard user program
can also be run in the F-CPU.
F-Data Type
S7 F/FH Systems: A -> standard user program and -> safety program use different data
formats. Safety-related F-data types are used in the safety program.
F-DBs
S7 Distributed Safety: Optional fail-safe data blocks that can be read and written to within the
entire -> safety program.
F-Driver Block
The F-driver block is used for inputting/outputting AS values from/to the -> F-I/O. It forms the
software interface to the process, converts the physical values to process data (and vice-
versa), and also provides information about the availability of the hardware addressed.
In S7 F/FH Systems, -> safety-related communication takes place using inputs and outputs
of F-driver blocks. The user must position and interconnect special F-driver blocks in ->
continuous function charts (CFC) of the -> F-runtime group.
F-FBD
Programming language for -> safety programs in S7 Distributed Safety. The standard
FBD/LAD Editor in
STEP 7 is used for programming.
F-FBs
S7 Distributed Safety: Fail-safe function blocks (with instance DBs), in which the user
programs the -> safety program in -> F-FBD or -> F-LAD.
F-FCs
S7 Distributed Safety: Fail-safe FCs, in which the user programs the -> safety program in ->
F-FBD or -> F-LAD.
