Additional Rules And Regulations For Operation Of The S7-1500/Et 200Mp With Fail-Safe Modules; Safe Functional Extra-Low Voltage (Selv) For Fail-Safe Modules - Siemens SIMATIC S7-1500 System Manual

5.2 Additional rules and regulations for operation of the S7-1500/ET 200MP with fail-safe modules

5.2 Additional rules and regulations for operation of the
S7-1500/ET 200MP with fail-safe modules
5.2.1

Safe functional extra-low voltage (SELV) for fail-safe modules

The fail-safe modules must be operated with safe functional extra low voltage (SELV,
PELV).
You can find more information on safe functional extra-low voltage in the data sheets, for
example, of the applicable power supplies.
The fail-safe modules operate at a rated voltage of24 V DC. The tolerance range is
19.2 V DC to 28.8 V DC.
Within the overvoltage range from 32 V DC to 36 V DC, the F-modules react in a fail-safe
manner and the inputs and outputs are passivated. For overvoltages greater than 36 V DC,
the F-modules are permanently de-energized and can be damaged.
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, e.g., use
of a surge protection device.
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 a safe functional extra low
voltage (SELV, PELV). Refer to the relevant data sheets or contact the manufacturer.
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 safe functional extra-low
voltage 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
Automation system
System Manual, 09/2016, A5E03461182-AD
WA RNING
in the event of a fault.
m
WA RNING
= 36 V DC even in the event of a fault.
m
to be exceeded.
m
Wiring
65