Additional Rules And Regulations For Operation; Safety Extra-Low-Voltage (Selv, Pelv) For Failsafe Modules - Siemens SIMATIC S7-1500 System Manual

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6.2 Additional rules and regulations for operation

6.2 Additional rules and regulations for operation
6.2.1

Safety extra-low-voltage (SELV, PELV) for failsafe modules

Please note the following if you use distributed I/O (for example ET200SP) with failsafe
modules:
The failsafe components/modules must be operated with safety extra-low voltage (SELV,
PELV).
You can find more information on safety extra-low voltage (SELV, PELV) in the data sheets
of the applicable power supplies, for example.
The failsafe modules operate with the 24 V DC rated voltage. The tolerance range is
19.2 V DC to 28.8 V DC.
The failsafe motor starters operate with the 24 V DC rated voltage. The tolerance range is
20.4 V DC to 28.8 V DC.
Within the overvoltage range of 32 V DC to 36 V DC, the F-modules react in a failsafe
manner and the inputs and outputs are passivated. For overvoltages greater than 36 V DC,
the F-modules are permanently de-energized.
Use a power supply unit that does not exceed U
For more on this, refer to the information in the data sheet on overvoltage protection in the
case of an internal error, or implement appropriate measures to limit the voltage, for
example use of an overvoltage protector.
All system components that can supply electrical energy in any form whatsoever must fulfill
this condition.
Each additional circuit (24 V DC) used in the system must have safety extra-low voltage
(SELV, PELV). Refer to the relevant data sheets or contact the manufacturer.
Please also note that sensors and actuators with an external power supply can also be
connected to F-modules. Make sure that power is supplied to these components from
safety extra-low voltage (SELV, PELV) as well. The process signal of a 24 V DC digital
module may not exceed a fault voltage U
Even when a fault occurs, the permissible potential difference between the supply of the
interface module (bus voltage) and the load voltage must not be exceeded.
An external direct electrical connection is one way to meet this requirement. This also
prevents potential differences from causing voltage additions at the individual voltage
sources, which could cause the fault voltage U
74
WARNING
WARNING
= 36 V DC even in the event of a fault.
m
even in the event of a fault.
m
to be exceeded.
m
System Manual, 11/2019, A5E46600094-AA
SIMATIC Drive Controller