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What is a safety component?
Art. 2 c) 2006/42/EC
• It guarantees a safety function
• It is marketed separately
• Its failure and/or malfunction
of the component endangers
safety of persons and it can be
replaced by standard
components for the
functioning of the machine.
The EC Machinery Directive
defines whether a component
is a safety component or not,
and this depends on how it is
marketed. The term safety
component generally does not
indicate the safety level or
reliability of a component. The
EC Machinery Directive does not
prescribe the use of safety
components. It only describes
the conformity assessment
procedure for components which
correspond to the definition for
safety components.
Manufacturers of safety
components must comply
with the conformity assessment
procedures to market the safety
components in the EEA. For the
user, it makes no difference
whether a safety function is
implemented via a purchased
safety component or an
internally developed and
internally evaluated safety-
related part of the controller to
EN ISO 13849-1.
What is the difference between
a safety component and
a safety-related part of
a controller (SRP/CS)?
• A safety component is
evaluated by the manufacturer
of the safety component for
its safety function.
• A safety-related part of
a controller (SRP/CS) is
developed by the
manufacturer of a machine,
and evaluated for its safety
level and function as part
of the manufacturing
of a machine.
Examples of safety components
• Light curtain
• EMERGENCY STOP relay
• Safety door switch
• EMERGENCY STOP command
device
• Safety relay
Do vales with switching position
sensing come under the
definition “Valve with failure
detection? And do they have to
be marketed as safety
components?
• No – switching position
sensing can be used to
implement failure detection,
but does not detect the failure
without further circuitry or the
evaluation via a PLC.
Safety component