NORSTAT Safety Relays - Handbuch (Seite 15)

application guide safety relays from riese electronic page 15
3.2.2 Relationship between PL and SIL:
-6
Probability of dangerous failures per hour
PL
a
PL
b
PL
c
PL
d
PL
e
10
-4
10
-5
10
-6
10
-7
10
-8
PL according to
ISO 13849-1
SIL according to
IEC 62021
low risk
high risk
9000 900 90 9 0.9
no special
safety
requirements
SIL 1 SIL 2 SIL 3
Dangerous failures per year and 10 000 systems
3 *10
3.2.3 Relationship between the categories, DC, MTTF
d
and PL:
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