Keba Kemro KeTop T10, Руководство по проектированию устройства

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The state of the art is defined as the state of development of advanced pro-
cedures, equipment or operating methods, that makes the practical applica-
bility of the measure appear assured overall in respect of the targeted goals
(e.g. the goals of protection of work, protection of the environment, safety of
third parties and operating efficiency: namely to achieve a generally high level
overall in relation to the aspects under consideration).
The state of the art can develop further irrespective of the Standards.
17.5 "Recognition of Conformity by means of Harmonised Stand-
ards"
The European Directives mainly contain general requirements for the safety
of products; however they do not contain details of how to carry them out.
The European Standards Institutes are responsible for this. They provide im-
plementation proposals for real safety problems or specific product classes.
Standards that are assumed to meet and correctly interpret the requirements
of the Directives are known as “Harmonised Standards”. Most of the available
Standards, however, are not harmonised.
By applying and implementing harmonised Standards, a manufacturer can
claim conformity for the respective product. However, the Standards, in con-
trast to the Directives, are not legally binding. This means that the manufacturer
may also take into consideration other solutions that are not described in the
Standards; but these solutions must attain at least the same safety level as the
relevant Standards and satisfy the requirements of the appropriate Directives.
17.6 Selection of Performance Level and Safety Categories in ac-
cordance with EN ISO 13849-1
The Machinery Directive demands that a fault in control circuit logic, or inter-
ference or damage thereto, shall not lead to a hazardous situation.
This general approach is substantiated in EN ISO 13849-1 "Safety of machi-
nery - Safety related parts of control systems", which defines Performance
Levels (PL a to e) for control parts that are relevant to safety. The PL depends
on the safety category, the MTTF
d
-value and the degree of coverage of diag-
nosis (DC
avg
) of the corresponding safety circuit.
As in the preceding standard EN 954-1, the safety category describes the
structure of the safety function. The Performance Level (PL), which describes
the conditional probability of failure and the defect discernability of the safety
function, has been added.
The selection of the PL has to be done by the manufacturer of a machine
depending on the real risk potential. The risk potential will be be determined
from a hazard and risk analysis. In case of hazards that can cause irrevisible
injury or death usually a Performance Level not less than PL d is required.
Appendix: Machinery Safety KeTop T10
© KEBA 2014
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