Communication
14.2 Basics and terminology of fault-tolerant communication
S7-400H
232
System Manual, 03/2012, A5E00267695-11
Connection (S7 connection)
A connection represents the logical assignment of two communication peers for executing a
communication service. Every connection has two end points containing the information
required for addressing the communication peer as well as other attributes for establishing
the connection.
An S7 connection is the communication link between two standard CPUs or from a standard
CPU to a CPU in a fault-tolerant system.
In contrast to a fault-tolerant S7 connection, which contains at least two partial connections,
an S7 connection actually consists of just one connection. If that connection fails,
communication is terminated.
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Figure 14-5 Example of an S7 connection
Note
Generally speaking, "connection" in this manual means a "configured S7 connection". For
other types of connection, please refer to the
SIMATIC NET NCM S7 for PROFIBUS and
SIMATIC NET NCM S7 for Industrial Ethernet manuals.
Fault-tolerant S7 connections
The requirement for higher availability with communication components (for example CPs
and buses) means that redundant communication connections are necessary between the
systems involved.
Unlike an S7 connection, a fault-tolerant S7 connection consists of at least two underlying
subconnections. From the user program, configuration and connection diagnostics
perspective, the fault-tolerant S7 connection with its underlying subconnections is
represented by exactly one ID (just like a standard S7 connection). Depending on the
configuration, it can consist of up to four subconnections, of which two are always
established (active) to maintain communication in the event of an error. The number of
subconnections depends on the possible alternative paths (see figure below) and is
determined automatically. Within an S7-H connection, only subconnections over CP or over
the integrated CPU interface are used in the configuration.
Содержание SIMATIC S7-400H
Страница 24: ...Preface 1 1 Preface S7 400H 24 System Manual 03 2012 A5E00267695 11 ...
Страница 46: ...Getting Started 4 5 Special layout features of SIMATIC Manager S7 400H 46 System Manual 03 2012 A5E00267695 11 ...
Страница 120: ...Memory concept 10 1 Overview of the memory concept of S7 400H CPUs S7 400H 120 System Manual 03 2012 A5E00267695 11 ...
Страница 258: ...Communication 14 8 General issues regarding communication S7 400H 258 System Manual 03 2012 A5E00267695 11 ...
Страница 354: ...Synchronization modules 18 3 Selecting fiber optic cables S7 400H 354 System Manual 03 2012 A5E00267695 11 ...
Страница 434: ...Technical data 20 6 Runtimes of the FCs and FBs for redundant I Os S7 400H 434 System Manual 03 2012 A5E00267695 11 ...
Страница 460: ...Function modules and communication processors supported by the S7 400H S7 400H 460 System Manual 03 2012 A5E00267695 11 ...