Safety-related characteristic quantities for subsystem elements (devices):
● λ:
Failure rate
● B10 value: For elements that are subject to wear
● T1:
Lifetime
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 PFH
D
value of the safety-related controller is determined by adding the individual PFH
D
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 IEC 61508 or
IEC 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. DIN 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 examples".
Note
EN 62061 and machinery directive
IEC 62061 has been ratified as EN 62061 in Europe and harmonized as part of the Machinery
Directive.
Appendix
A.4 Standards and specifications
Safety Integrated - SINAMICS G110M, G120, G120C, G120D and SIMATIC ET 200pro FC-2
Function Manual, 01/2017, FW V4.7 SP6, A5E34261271B AD 427
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