Suitable Networks; Industrial Ethernet - Siemens SIMATIC S7-400H Manual

Resource requirements of fault-tolerant S7 connections
CPU 417-4H allows the operation of 64 fault-tolerant S7 connections. On the CP
each partial connection requires a connection resource.
7.2

Suitable Networks

The choice of physical transfer medium depends on the desired expansion, the
fault tolerance aimed at and the transmission rate. The following bus systems are
used for communications with fault-tolerant systems:
Industrial Ethernet (fiber-optic cable, triaxial or twisted pair copper cable)
PROFIBUS (fiber-optic cable or copper cable)
You will find further information on suitable networks in the manuals
" Communication with SIMATIC ", "Industrial Twisted Pair Networks" and
"PROFIBUS Networks ".
7.2.1

Industrial Ethernet

The industrial Ethernet is a communications network for cells in baseband
transmission technology complying with IEEE 802.3, with the CSMA/CD access
procedure.
An industrial Ethernet network can be configured as a redundant medium with
either electrical or optical components. A very wide range of electrical and optical
network components is available for the industrial Ethernet.
Electrical network
The electrical network can be configured as a classical bus structure having triaxial
cabling for the transmission medium.
An addition and an alternative to conventional bus cabling for connections to
terminals are electrical link modules (ELMs) or industrial twisted pairs (ITPs). With
them star networks complying with IEEE 802.3 can be configured.
Optical network
The optical industrial Ethernet network (transmission medium: fiber-optic cable)
can be configured as a line-type, ring or star network. The configuration is
accomplished for a transmission rate of 10 Mbps with optical link modules (OLMs)
and/or star hubs for the fast Ethernet of 100 Mbps with optical switching modules
(OSMs) and optical redundancy manager (ORM).
S7-400H Programmable Controller Fault-Tolerant Systems
A5E00068197-04
Communications
7-5