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

Sensor type Type A
Overflow protection
(max./A-operation)
Dry run protection
(min./B-operation)
SFF 89 % 89 %
PFD
avg
T
Proof
= 1 year
T
Proof
= 5 years
T
Proof
= 10 years
< 0.012 x 10 -2
< 0.06 x 10 -2
< 0.12 x 10 -2
< 0.013 x 10 -2
< 0.065 x 10 -2
< 0.13 x 10 -2
PFH < 0.027 x 10 -6 /h < 0.03 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.
1 5 10
T
Proof
PFD
avg
1
2
3
4
Fig. 1: Chronological sequence of PFD
avg
(figures see above charts)
1 PFD
avg = 0
2 PFD
avg
after 1 year
3 PFD
avg
after 5 years
4 PFD
avg
after 10 years
Multiple channel architecture
If the measuring system is used in a multiple channel architecture, the
safety-relevant characteristics of the selected structure of the meas.
chain must be calculated specifically for the selected application
according to the above failure rates.
A suitable Common Cause Factor must be taken into account.
Time-dependent proc-
ess of PFD
avg
Specific characteristics
OPTISWITCH series 5000 • - transistor (NPN/PNP) 9
1 Functional safety
32749
-
EN
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100128