KROHNE OPTISWITCH 5xx0C 2wire SIL EN - Manual (Page 9)

Overflow protection
(max./A-operation)
Dry run protection
(min./B-operation)
λ
sd
35 FIT 141 FIT
λ
su
101 FIT 91 FIT
λ
dd
141 FIT 35 FIT
λ
du
25 FIT 35 FIT
MTBF = MTTF + MTTR 3.31 x 10 6
h 3.31 x 10 6
h
Fault reaction time < 1.5 sec.
Single channel architecture (1oo1D)
SIL SIL 2
HFT 0
Sensor type Type A
Overflow protection
(max./A-operation)
Dry run protection
(min./B-operation)
SFF 91 % 88 %
PFD
avg
T
Proof
= 1 year
T
Proof
= 5 years
T
Proof
= 10 years
< 0.011 x 10 -2
< 0.055 x 10 -2
< 0.11 x 10 -2
< 0.016 x 10 -2
< 0.078 x 10 -2
< 0.155 x 10 -2
PFH < 0.025 x 10 -6 /h < 0.035 x 10 -6 /h
The chronological sequence of PFD
avg
is nearly linear to the operating
time over a period up to 10 years. The above values apply only to the
T
Proof
interval after which a recurring function test must be carried out.
Failure rates
Fault reaction time
Specific characteristics
Time-dependent proc-
ess of PFD
avg
OPTISWITCH series 5000 • - two-wire 9
1 Functional safety
32750
-
EN
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100128