Siemens SIMATIC ET 200AL System Manual page 43

5.2 What are fail-safe automation systems and fail-safe modules?
Fail-safe automation systems
Fail-safe automation systems are mainly used in applications where failure could have
consequences for the safety of people and/or the environment. Fail-safe systems are
therefore intended to reduce hazards or failures that could cause physical damage. Their
purpose is to ensure a tolerable level of risk.
F-systems are used to control processes and provide a safe operating state when faults are
detected. Fault detection is ensured by a very high level of diagnostic coverage. When a fault
is detected, appropriate actions are initiated to bring the affected application to a safe state.
F-systems offer improved fault detection and fault localization through detailed diagnostics
and diagnostic messages. This is the most important difference between fail-safe systems and
standard systems. The use of fail-safe systems should be considered for applications where
hazards are inherent and can cause physical damage.
Safety Integrated
Safety Integrated is the integrated safety concept for automation and drive technology from
Siemens.
Proven technologies and systems from automation technology are used for safety systems.
Safety Integrated includes the complete safety sequence, ranging from sensor, actuator and
fail-safe modules right through to the controller, including safety-related communication via
standard fieldbuses. Drives and controllers handle safety tasks in addition to their actual
functions.
Fail-safe modules
The key difference between fail-safe modules (F-modules) and standard modules is that they
have an internal two-channel design. This means the two integrated processors monitor each
other, automatically test the input and output circuits, and switch the fail-safe module to a
safe state in the event of a fault.
The F-CPU communicates with a fail-safe module via the safety-related PROFIsafe bus profile.
Possible uses of ET 200AL with fail-safe modules
The use of ET 200AL with fail-safe modules makes it possible to replace conventional
mounting technology in safety technology with PLC components. This also includes the
replacement of switchgear for EMERGENCY STOP, safety door monitoring, ambidextrous
operation, etc.
Fail-safe modules for ET 200AL are supported together with the STEP 7 Safety Advanced V17
or higher option package.
F-modules for ET 200AL can be used either with an ET 200AL PROFINET interface module
(IM), a direct ET connection to an ET 200SP F-CPU or a direct ET connection to an ET 200SP IM
(mixed configuration).
Distributed I/O system
System Manual, 12/2023, A5E31861578-AL
5.2 What are fail-safe automation systems and fail-safe modules?
System overview
43