Single channel architecture (1oo1d), The chronological sequence of pfd – KROHNE OPTISWITCH 5xx0C NAMUR SIL EN User Manual
Page 9

Overflow protection
(max./A-operation)
Dry run protection
(min./B-operation)
λ
sd
9 FIT
9 FIT
λ
su
203 FIT
202 FIT
λ
dd
9 FIT
9 FIT
λ
du
43 FIT
45 FIT
MTBF = MTTF + MTTR
3.79 x 10
6
h
3.79 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
83 %
83 %
PFD
avg
T
Proof
=
1 year
T
Proof
=
5 years
T
Proof
=
10 years
<
0.019 x 10
-2
<
0.095 x 10
-2
<
0.189 x 10
-2
<
0.020 x 10
-2
<
0.097 x 10
-2
<
0.195 x 10
-2
PFH
<
0.043 x 10
-6
/h
<
0.045 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 • - NAMUR
9
1 Functional safety
32747
-
EN
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100128