KROHNE OPTISWITCH 3x00C Relay 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
586 FIT 565 FIT
λ
dd
124 FIT 135 FIT
λ
du
27 FIT 37 FIT
DC
S
0 % 0 %
DC
D
82 % 78 %
MTBF = MTTF + MTTR 1.33 x 10 6
h 1.33 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 96 % 95 %
PFD
avg
T
Proof
= 1 year
T
Proof
= 5 years
T
Proof
= 10 years
< 0.012 x 10 -2
< 0.059 x 10 -2
< 0.118 x 10 -2
< 0.016 x 10 -2
< 0.082 x 10 -2
< 0.164 x 10 -2
PFH < 0.027 x 10 -6 /h < 0.037 x 10 -6 /h
Service life
Failure rates
Fault reaction time
Specific characteristics
OPTISWITCH series 3000 • - Relay (DPDT) 9
Functional safety
32743
-
EN
-
080414