Installing The Central Rack (Cr) And Expansion Rack (Er) - Siemens SIMATIC S7-400 Installation Manual

Installing the S7-400
2.2 Installing the Central Rack (CR) and Expansion Rack
(ER)
Function of the Racks
The racks of the S7-400 system form the basic framework which accepts the
individual modules. The modules exchange data and signals and are powered via
the backplane bus. The racks are designed for wall mounting, for mounting on rails,
and for installation in frames and cabinets.
Racks in the S7-400 System
No. of
Rack
Slots
UR1 18
UR2 9
ER1 18
ER2 9
CR2 CR2 18 18
CR3 4
UR2-H 2*9
2-6
Available Application
Buses
I/O bus
Communication Communication
bus
Restricted I/O Restricted I/O
bus
I/O bus,
Segmented Segmented
segmented segmented
Communication
bus, continuous
I/O bus
CR in standard
Communication
bus
Subdivided CR or
I/O bus,
ER for compact in-
segmented
stallation of a fault--
Communication
tolerant system
bus, segmented
CR
Rack for all module types in the S7-400. Rack for all module types in the S7 400
or or
ER
Racks for signal modules (SMs), receive
IMs, and all power supply modules.
The I/O bus has the following restric-
tions:
•
Interrupts from modules have no
effect because no interrupt lines
exist.
•
Modules are not supplied with 24 V, Modules are not supplied with 24 V,
ERs ERs
i.e. modules requiring 24 V cannot
be used (see technical data of the
modules).
•
Modules are neither backed up by
the battery in the power supply
module nor by the voltage applied
externally to the CPU or receive IM
(EXT.BATT. socket).
Rack for all module types in the S7-400
except receive IMs. p
The I/O bus is subdivided into 2 I/O bus
CR
segments of 10 and 8 slots respectively.
Racks for all S7-400 module types ex-
cept receive IMs. CPUs 41x-H only in
systems
stand-alone operation.
Rack for all S7-400 modules except
send IMs.
The I/O bus and communication bus are
divided into 2 bus segments, each with 9
slots.
Automation System S7-400 Hardware and Installation
Characteristics
A5E00850741-01