Safety Integrated function
8.1 Standards and regulations
SINAMICS V90, SIMOTICS S-1FL6
Operating Instructions, 04/2019, A5E36037884-007
299
For electromechanical devices, a manufacturer specifies a failure rate λ with reference to the
number of operating cycles. The failure rate per unit time and the lifetime must be
determined using the switching frequency for the particular application.
Parameters for the sub-system, which comprises sub-system elements, that must be defined
during the design phase:
● T2: Diagnostic test interval
● β: Susceptibility to common cause failure
● DC: Diagnostic coverage
The PFHD value of the safety-related controller is determined by adding the individual PFHD
values for subsystems.
The user has the following options when setting up a safety-related controller:
● Use devices and sub-systems that already comply with EN ISO 13849-1, IEC/EN 61508,
or IEC/EN 62061. The standard provides information specifying how qualified devices
can be integrated when safety functions are implemented.
● Develop own subsystems:
– Programmable, electronic systems and complex systems: Application of EN 61508 or
EN 61800-5-2.
– Simple devices and subsystems: Application of EN 62061.
EN 62061 does not include information about non-electric systems. The standard provides
detailed information on implementing safety-related electrical, electronic, and programmable
electronic control systems. EN ISO 13849-1 must be applied for non-electric systems.
Note
Function examples
Details of simple sub
-
systems that have been implemented and integrated are now available
as "functional examp
les".
Note
EN 62061 and machinery directive
IEC 62061 has been ratified as EN 62061 in Europe and harmonized as part of the
Machinery Directive.
Series of standards EN 61508 (VDE 0803)
This series of standards describes the current state of the art.
EN 61508 is not harmonized in line with any EU directives, which means that an automatic
presumption of conformity for fulfilling the protective requirements of a directive is not implied.
The manufacturer of a safety-related product, however, can also use EN 61508 to fulfill basic
requirements of European directives in accordance with the latest conceptual design, for
example, in the following cases:
● If no harmonized standard exists for the application in question. In this case, the
manufacturer can use EN 61508, although no presumption of conformity exists here.
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