Siemens SIMATIC S7-400 Hardware And Installation Manual page 15

Components of an S7-400
The most important components of the S7-400 and their functions are given in the
following tables:
Components
Racks
(UR: Universal Rack)
(CR: Central Rack)
(ER: Expansion Rack)
Power Supply Modules
(PS = Power Supply)
Accessories:
Backup battery
CPUs
Central Processing Units (CPUs)
Memory cards
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
Interface modules
(IM = Interface Module)
Accessories:
Connecting cable
Terminator
Cable ducts
PROFIBUS-DP bus cables
S7-400 and M7-400 Programmable Controllers, Installation Manual
C79000-G7076-C424-01
www.gkbpx.com
Function
... provide the mechanical and
electrical connections between
the S7-400 modules.
... 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.
... execute the user program;
communicate via the multipoint
interface (MPI) with other CPUs
or with a programming device
(PG).
... store the user program and
parameters.
... match the different process
signal levels to the S7-400.
... form the interface between
PLC and process.
... interconnect the individual
racks of an S7-400.
...are used for routing cables and
as ventilation.
...connect CPUs to programming
devices.
Product Overview
Illustration
1-3