Siemens SIMATIC ET 200AL System Manual page 143

Limits of the higher-level safety circuit
The ET 200AL standard modules do not fulfill any safety functions. Safety functions are
performed by the safety relay to bring the system into a safe state.
Adjust the operation inspection interval of the safety relay with relay output according to the
safety class.
Take the following measures if energy that is not provided by the higher-level safety circuit is
used to control the safety function.
Cover critical errors in the safety function that are not detected by the higher-level safety
circuit (e.g. 3SK1) with suitable safety measures. The "diagnostics" must be performed
indirectly via the controlled process.
Specifications for safety-relevant process data:
• Functionally safe
• Read via fail-safe inputs (e.g. F-DI)
• Fail-safe processing unit (e.g. F-CPU) for issuing commands
• Output through fail-safe outputs (e.g. F-DQ) to control the safety function
Requirements on the power supply
Operation requires a SELV/PELV power supply to limit overvoltages to L+ and M (24 V). This
measure prevents possible errors from the power supply side at the same time.
Select the power supply according to the requirements of the respective operating
instructions for the shutdown device and for the ET 200AL system.
You can find more information on safe SELV/PELV in the data sheets of the power supplies
used.
FAQ
Read the latest information on safety-related shutdown in the FAQ
(https://support.industry.siemens.com/cs/us/en/view/39198632).
In this FAQ, you can find the SIMATIC standard modules that are suitable for safety-related
shutdown.
Request German Technical Inspectorate report (Report no. SN89858T)
You can request copies of the German Technical Inspectorate report at the following address:
SIEMENS AG
Digital Industries
DI FA TI COS TT
P.O. Box 1963
D-92209 Amberg, Germany
Distributed I/O system
System Manual, 12/2023, A5E31861578-AL
Safety-related shutdown of ET200AL standard modules
143