En Iec 62061 - Siemens SINUMERIK 840D sl Function Manual

Regulations and Standards
1.2 Safety of machinery in Europe
S MTTF
d
S DC: Diagnostics Coverage
diagnostic coverage
S CCF: Common cause failure
The Standard describes the calculation of the Performance Level (PL) for safety-
related parts of controls on the basis of designated architectures. For deviations
from this, EN ISO 13849–1 refers to IEC 61508.
When combining several safety-related parts to form a complete system, the Stan-
dard explains how to determine the resulting PL.
Note
prEN ISO 13849–1 (rev) is available as Draft. Until it is ratified, which is scheduled
for the end of 2005, EN 954–1 still applies for a transition period that is scheduled
for three years: 1996.
1.2.5

EN IEC 62061

EN IEC 62061 is a sector-specific standard below IEC 61508. It describes the im-
plementation of safety-related electrical control systems of machines and takes
into account the complete lifecycle - from the conceptual phase to de-commission-
ing. Safety functions are considered from both quantitative and qualitative stand-
points as basis.
In so doing, the Standard consequentially applies a top-down technique in imple-
menting complex control systems – known as functional decomposition. Starting
from the safety functions resulting from the risk analysis, a sub-division is made
into sub-safety functions and these sub-safety functions are then assigned to real
devices/equipment, subsystems and subsystem elements. Both the hardware as
well as the software is taken into consideration. EN IEC 62061 also describes the
requirements placed on implementing application programs.
A safety-related control system comprises various subsystems. The subsystems
are described from a safety-related perspective using the characteristic quantities
(SIL claim limit and PFH
Safety-related characteristic quantities for subsystems:
S SIL CL: SIL claim limit
S PFH
:
D
1-22
SINUMERIK 840D sl/SINAMICS S120 SINUMERIK Safety Integrated (FBSI sl) – 03.2006 Edition
: Meantime time up to a dangerous failure
meantime to dangerous failure
).
D
SIL claim limit
Probability of dangerous failures per hour
© Siemens AG, 2006. All rights reserved
03.06