Siemens SIMATIC ET 200SP Manual page 30

Connection
4.1 Terminal assignment
Power supply units for AS-Interface
A connected power supply unit must have the following properties:
● Rated output voltage 30 V DC (AS-Interface Standard) or 24 V DC (AS-i Power24V)
● PELV/SELV (Protective/Safety Extra-Low Voltage) standard
● Residual ripple < 250 mVpp
● Limiting of output voltage to a maximum of 40 V in the event of a fault, including a second
fault.
The Siemens power supply units for AS-Interface meet these requirements. For additional
information, refer to the operating instructions of the power supply unit.
Use an AS-Interface power supply unit with integrated data decoupling or a combination of a
power supply unit that meets the above-indicated requirements and an AS-i data decoupling
unit.
In the following text, the expression "AS-i power supply unit" stands, unless described
otherwise, for an AS-Interface power supply unit with integrated data decoupling or a
combination of a power supply unit and an AS-i data decoupling unit.
When AS-i Power24V is used, there are limitations on the cable length (max. 50 m
AS-i cable) and usability of AS-i components and connected sensors/actuators due to the
reduced voltage.
Use a PELV / SELV power supply when operating the F-CM AS-i Safety ST module on
PROFIsafe.
Additional notes:
● AS-Interface System Manual
(http://support.automation.siemens.com/WW/view/en/26250840/0/en)
● FAQ "Compatibility for AS-i Power24V"
(http://support.automation.siemens.com/WW/view/en/20025980/133000)
30
Fail-safe Module F‑CM AS‑i Safety ST (3RK7136‑6SC00‑0BC1)
Manual, 03/2017, A5E03957059020A/RS-AB/002