Siemens S7-400 120/230 VAC Supply, VDC Supply, Protection Against External Electrical Effects

Assembling and Installing Systems

120/230 VAC Supply

The following table shows which points you must observe when connecting the S7-400 to a 120/230 VAC supply.

With ...	... You Must Ensure ...
buildings	that suitable external lightning protection measures are
	provided.
supply cables and signal	that suitable internal and external lightning protection
lines	measures are provided.
stationary equipment and	that a supply disconnector (switch) is installed in the
systems without all-pole	building.
disconnector
load power supplies and	that the set line voltage range corresponds to the local line
power supply modules	voltage.
all circuits of the S7-400	that fluctuations of line voltage from the rated value are
	within permissible tolerances (see Technical Data of the
	modules).
residual-current devices	that the RCD is suitable for the total discharge currents of
(RCDs)	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 ...	... You Must Ensure ...
buildings	that suitable external lightning protection measures are
	provided.
24 VDC supply cables and	that suitable internal and external lightning protection
signal lines	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 ...	... You Must Ensure ...
all plants and systems in	that the plant and all system sections are properly
which the S7-400 is	connected to protective ground to discharge
installed	electromagnetic interference.
connecting cables and	that all cables are correctly routed and connected.
signal lines
signal lines	that an open circuit in a signal line does not place the
	equipment in an undefined state.

Automation System S7-400	Hardware and Installation	A-3
A5E00850741-01