Connecting The Power Supply To The Cfu - Siemens SIMATIC CFU Commissioning Manual

Connecting

7.3 Connecting the power supply to the CFU

Additional information
● You can find information about required tools in section "Tools and tightening torques
(Page 186)".
● You can find information about cables and wire end ferrules in section "Preparing cables
(Page 63)".
7.3 Connecting the power supply to the CFU
Introduction
The power supply of the CFU is fed via two 2-pole connection plugs that are capable of feed-
through wiring and are located on the front of the CFU.
You can find information on power consumption for the CFU version used in section "Technical
specifications (Page 147)".
Power supply unit
Safety extra-low voltage
Only use power supply units of type SELV/PELV with safe electrically isolated functional extra
low voltage (≤ 28.8 V DC).
For the CFU PA, the SELV/PELV power supply unit must also comply with at least one of the
following requirements:
● The power supply unit supplies safety extra low voltage (SELV) with power limitation
● The power supply unit for the device complies with NEC Class 2 of the National Electrical
NOTICE
Potentials
The freely configurable channels of the CFU are connected to the potentials of the power
supplies (not floating).
● CFU PA: In case of polarity reversal of the power supply, a short circuit is possible via the
● CFU DIQ: The power supply connections are protected against polarity reversal.
Observe section "Use in hazardous areas (Page 29)", if necessary.
56
WARNING
(Limited Power Source, LPS) in accordance with the following standards: IEC 60950-1 /
EN 60950-1 / VDE 0805-1.
Code (r) (ANSI / NFPA 70).
ground connections.
Commissioning Manual, 08/2019, A5E39252870-AD
SIMATIC CFU