Functional Safety; Safety Of Machinery In Europe - Siemens SINUMERIK 840D sl Function Manual

Regulations and Standards

1.2 Safety of machinery in Europe

1.1.2

Functional safety

Safety, from the perspective of the object to be protected, cannot be split–up.
The causes of hazards and therefore also the technical measures to avoid them
can vary significantly. This is the reason that a differentiation is made between
different types of safety – e.g. by specifying the cause of possible hazards.
"Functional safety" is involved if safety depends on the correct function.
In order to achieve the functional safety of a machine or plant, it is necessary that
the safety–related parts of the protection and control devices function correctly.
And not only this, when faults develop, they must behave so that either the plant
remains in a safe state or it is brought into a safe state.
In this case, it is necessary to use specially qualified technology that fulfills the re-
quirements described in the associated Standards. The requirements to achieve
functional safety are based on the following basic goals:
S Avoiding systematic faults
S Controlling systematic faults
S Controlling random faults or failures
The measure for the achieved functional safety is the probability of dangerous
failures, the fault tolerance and the quality that should be guaranteed by minimizing
systematic faults. This is expressed in the Standards using different terms. In
EN 61508, EN 62061, EN 61800–5–2: "Safety Integrity Level" (SIL) and EN ISO
13849–1 "Categories" and "Performance Level" (PL).
1.2 Safety of machinery in Europe
The EC Directives, that apply to the implementation of products, based on Article
95 of the EU contract, that regulates the free exchange of goods. These are based
on a new global concept ("new approach", "global approach"):
S EC Directives only specify generally valid safety goals and define basic safety
requirements.
S Technical details can be defined in Standards by Standards Associations that
have an appropriate mandate from the European Parliament and the Council
(CEN, CENELEC). These Standards are harmonized under a specific Directive
and are listed in the Official Journal of the Commission of the European Parlia-
ment and the Council. Legislation does not specify that certain standards have
to be complied with. When the harmonized Standards are complied with, then it
can be assumed that all of the applicable safety requirements and specifica-
tions of the Directives involved are fulfilled.
The EC Directives are equal. This means that if several Directives apply for a spe-
cific piece of equipment or device, then the requirements of all of the relevant Di-
rectives apply (e.g. for a machine with electrical equipment, then the Machinery
Directive and the Low–Voltage Directive apply).
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SINUMERIK 840D sl/SINAMICS S120 SINUMERIK Safety Integrated (FBSI sl) – 05.2008 Edition
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