KROHNE OPTISWITCH 3x00C Transistor SIL EN - Manual (Page 9)

For a higher average temperature of 60 °C (140 °F), the failure
rates should be multiplied by a factor of 2.5. A similar factor
applies if frequent temperature fluctuations are expected.
The calculations are also based on the specifications stated in
chapter "Planning".
After 8 to 12 years, the failure rates of the electronic
components will increase, whereby the derived PFD and PFH
values will deteriorate (IEC 61508-2, 7.4.7.4, note 3).
Overflow protection
(max. operation)
Dry run protection
(min. operation)
λ
sd
0 FIT 0 FIT
λ
su
487 FIT 466 FIT
λ
dd
124 FIT 135 FIT
λ
du
30 FIT 40 FIT
DC
S
0 % 0 %
DC
D
81 % 77 %
MTBF = MTTF + MTTR 1.52 x 10 6
h 1.52 x 10 6
h
Diagnosis test period < 100 sek.
Single channel architecture (1oo1D)
SIL SIL 2
HFT 0
Sensor type Type B
Overflow protection
(max. operation)
Dry run protection
(min. operation)
SFF 95 % 94 %
PFD
avg
T
Proof
= 1 year
T
Proof
= 5 years
T
Proof
= 10 years
< 0.013 x 10 -2
< 0.066 x 10 -2
< 0.131 x 10 -2
< 0.018 x 10 -2
< 0.088 x 10 -2
< 0.177 x 10 -2
PFH < 0.03 x 10 -6 /h < 0.04 x 10 -6 /h
Service life
Failure rates
Fault reaction time
Specific characteristics
OPTISWITCH series 3000 • - transistor (NPN/PNP) 9
Functional safety
32744
-
EN
-
080414