Siemens ST PCS 7 manual Safety-related automation systems, 10/24

© Siemens AG 2008

Automation systems

Safety-related automation systems

■Overview

Safety-related automation systems are used for critical applica- tions where a fault could endanger life or result in damage to the plant or the environment. These F/FH systems frequently re- ferred to as "fail-safe automation systems" detect both faults in the process and their own internal faults in association with the safety-related F modules of the ET 200 distributed I/O systems or fail-safe transmitters connected directly via the fieldbus. They automatically transfer the plant to a safe state in the event of a fault.

■Design

In general, two design versions are differentiated across all ar- chitectural levels of a system based on Safety Integrated for Process Automation:

•Single-channel, non-redundant design

•Redundant, fault-tolerant design

These two design versions are highly variable and offer a wide scope for design with regard to different customer requirements. Standard (basic process control) and safety-related functions can be combined flexibly, not only in the area of distributed I/O.

Even at the controller level, they can be combined in one system or separated. In addition, there are numerous possibilities aris- ing from the use of flexible modular redundancy.

At the individual architectural levels (controller, fieldbus, distrib- uted I/O) the configuration alternatives shown in the figure are available depending on the distributed I/O used (ET 200M and ET 200S remote I/O stations or PROFIBUS PA devices accord- ing to Profile 3.0).

Single-channel, non-redundant configuration

10

Distributed I/O and

direct fieldbus interfacing

AS 412F/

AS 414F/

AS 417F

ET 200M

F-modules

ET 200M

Flexible Modular Redundancy

Redundant, high-availabilityat module or device level and fault-tolerant configuration

Distributed I/O	Direct fieldbus interfacing
AS 412FH/	AS 412FH/
AS 414FH/	AS 414FH/
AS 417FH	AS 417FH
	DP/PA Link
ET 200M	PROFIBUS PA
F-modules

DP	F- and standard modules
PROFIBUS
	ET 200M
	Standard modules
	ET 200S
	F- and
	standard
	modules

DP/PA Link

PROFIBUS PA

PROFIBUS DP

ET 200M

F- and standard modules

ET 200M

Standard modules

ET 200M

Module or channel redundancy over several separate stations

F- and standard modules

PROFIBUS DP

DP/PA Link

with redundant DP/PA couplers

Active field	PROFIBUS PA
splitter

DP/PA Link

with redundant

DP/PA couplers

Active field distributors

ET 200S

Y-Link

PROFIBUS PA

Design versions for safety-related systems

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Siemens ST PCS 7 · Update November 2008