Product Overview
1-3
S7-400 and M7-400 Programmable Controllers Hardware and Installation
A5E00069481-04
Components of an S7-400
The most important components of the S7-400 and their functions are given in the
following tables:
Components
Function
Illustration
Racks
(UR: Universal Rack)
(CR: Central Rack)
(ER: Expansion Rack)
... provide the mechanical and
electrical connections between
the S7-400 modules.
Power Supply Modules
(PS = Power Supply)
Accessories:
Backup battery
... convert the line voltage
(120/230 VAC or 24 VDC) to the
5 VDC and 24 VDC operating
voltages required to power the
S7-400.
CPUs
Central Processing Units (CPUs)
... execute the user program;
communicate via the multipoint
interface (MPI) with other CPUs
or with a programming device
(PG).
Memory cards
... store the user program and
parameters.
IF 964-DP interface module
... used to connect distributed
I/Os via PROFIBUS-DP
Signal Modules
(SM = Signal Module)
(digital input modules, digital
output modules, analog input
modules, analog output modules)
Accessories:
Front connector with three
different terminal systems
... match the different process
signal levels to the S7-400.
... form the interface between
PLC and process.
Interface modules
(IM = Interface Module)
Accessories:
Connecting cable
Terminator
... interconnect the individual
racks of an S7-400.
Cable ducts
...are used for routing cables and
as ventilation.
PROFIBUS bus cables
...connect CPUs to programming
devices.
