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

From the perspective of the object to be protected, safety is indivisible. The causes
of hazards and therefore also the technical measures to avoid them can vary signi-
ficantly. 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 relevant standards. The requirements to achieve func-
tional safety are based on the following basic goals:
S Avoiding systematic faults,
S Controlling systematic faults,
S Controlling random faults or failures.
The level of the functional safety achieved is expressed using different terms in the
standards. In EN 61508, EN 62061, EN 61800--5--2: "Safety Integrity Level" (SIL)
and EN ISO 13849--1 "Performance Level" (PL).
1.2 Safety of machinery in Europe
The EU Directives that apply to the implementation of products are based on Arti-
cle 95 of the EU contract, which regulates the free exchange of goods. These are
based on a new global concept ("new approach", "global approach"):
S EC directives only specify general protection goals and define basic safety re-
quirements.
S Technical details can be defined by means of standards by Standards Associa-
tions that have the appropriate mandate from the commission of the European
Parliament and Council (CEN, CENELEC). These standards are harmonized in
line with a specific directive and listed in the official journal of the commission of
the European Parliament and Council. Legislation does not specify that certain
standards have to be complied with. When the harmonized standards are com-
plied with, then it can be assumed that all of the applicable safety requirements
and specifications of the directives involved are fulfilled.
In order to market or sell a product in the European Economic Area (EEA), this
product must fulfill the protective goals and requirements of all of the applicable EC
directives. For machines, in addition to the machinery directive, these can also inc-
lude e.g. the EMC directive, the noise protection directive, the guideline for explo-
sion protection, the low--voltage directive.
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