External Power Supply - Siemens SIMATIC NET CP 5711 Operating Instructions Manual

Hardware installation

3.3 External power supply

3.3 External power supply
Safety extra low voltage
The equipment is designed for operation with a directly connectable safety extra low
voltage (SELV) from a limited power source (LPS). (This does not apply to 100 V...240 V
devices).
The power supply therefore needs to meet at least one of the following conditions:
• Only safety extra low voltage (SELV) with limited power source (LPS) complying with IEC
• The power supply unit for the device must meet NEC Class 2 according to the National
There is an additional requirement if devices are operated with a redundant power
supply:
If the equipment is connected to a redundant power supply (two separate power supplies),
both must meet these requirements.
Note
Overvoltage protection
If the communications processor is supplied over long 24 V power supply lines or networks,
measures are necessary to prevent coupling of strong electromagnetic pulses on the supply
lines. Such coupling can result, for example, due to lightning or switching of large inductive
loads.
One of the tests used to attest the immunity of the communications processor to
electromagnetic interference is the "surge immunity test" according to EN 61000-4-5. This
test requires overvoltage protection for the power supply line. A suitable device is, for
example, the Dehn Blitzductor BVT AD 24V type no. 918 402 or a comparable protective
element.
Manufacturer;
DEHN+SÖHNE GmbH+Co.KG, Hans Dehn Str. 1, Postfach 1640, D-92306 Neumarkt, Germany
Conditions for the external power supply
The CP 5711 can also be operated with an external power supply with 24 VDC. You require
this external power in the following situations:
• The CP 5711 is operated on an external hub without its own power supply.
• The USB interface on the PC is a low-power interface that supplies only 100 mA.
• The end termination must be activated on the PROFIBUS connector if the CP 5711 is
located at the end of the cable. If you want this termination to be active even when no
USB cable is connected, an external power supply is necessary.
22
WARNING
60950-1 / EN 60950-1 / VDE 0805-1 or IEC 62368-1 / EN 62368-1 / VDE 62368-1 may be
connected to the power supply terminals.
Electrical Code (r) (ANSI / NFPA 70).
Operating Instructions, 12/2021, C79000-G8976-C283-08
CP 5711