Siemens ET 200pro Operating Instructions Manual page 68

Connection
4.1 General rules and regulations for operating the ET 200pro
24 V DC power supply
The following table identifies requirements you must observe for the 24 V DC supply.
With ...
buildings
24 V DC power supply cables, signal cables internal lightning
24 V DC power supply
Looping-through of the supply voltage
Protection against external electrical interference
The table below shows how you must protect your system against electrical interference or
faults.
With ...
all plants or systems in which the ET 200pro
is integrated
supply/signal/bus cables
signal and bus cables
See also
Commissioning ET 200pro (Page 155)
68
you must ensure ...
external lightning Install lightning protection
protection (e.g. lightning protection
elements).
protection
Safe (electrical) isolation of safety extra-low voltage
(SELV)
Voltage drop at looping-through
make sure that ...
the plant or system must be grounded observing EMC
in order to dissipate electromagnetic interferences.
the cable routing and installation is correct.
a cable/conductor break does not cause undefined
plant or system states.
Operating Instructions, 03/2013, A5E00335544-08
ET 200pro distributed I/O system