Assembling and Installing Systems

A-3

AutomationSystem S7-400 Hardwareand Installation
A5E00850741-01
120/230 VACSupply

The following table shows which points you must observe when connecting the

S7-400 to a 120/230 VACsupply.

With... ... YouMust Ensure ...
buildings that suitable external lightning protection measures are
provided.
supply cables and signal
lines
that suitable internal and external lightning protection
measures are provided.
stationary equipment and
systems without all-pole
disconnector
that a supply disconnector (switch) is installed int he
building.
load power supplies and
power supply modules
that the set line voltage range corresponds to the local line
voltage.
all circuits of the S7-400 that fluctuations of line voltage from the rated value are
within permissible tolerances (see TechnicalData of the
modules).
residual-current devices
(RCDs)
that the RCD is suitable for the total discharge currents of
the power supply module.
24 VDC Supply

The following table shows the points you must observe when connecting the

S7-400 to a 24 VDC supply.

With... ... YouMust Ensure ...
buildings that suitable external lightning protection measures are
provided.
24 VDC supply cables and
signal lines
that suitable internal and external lightning protection
measures are provided.
24 V supply that the supply voltage produced is an isolated extra-low
voltage.
load power supplies that only isolated load current power supplies are used.
Protection Against External Electrical Effects

The following table shows what you must observe for protection against external

electrical effects.

With... ... YouMust Ensure ...
all plantsand systems in
which the S7-400 is
installed
that the plant and all system sections are properly
connected to protective groundto discharge
electromagnetic interference.
connecting cables and
signal lines
that all cables are correctly routed and connected.
signal lines that an open circuit in a signal line does not place the
equipment in an undefined state.