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The chronological sequence of pfd, Single channel architecture (1oo1d) – KROHNE OPTISWITCH 3x00C NAMUR SIL EN User Manual

Page 10

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Overflow protection

(max. operation)

Dry run protection

(min. operation)

λ

sd

12 FIT

36 FIT

λ

su

160 FIT

155 FIT

λ

dd

390 FIT

366 FIT

λ

du

47 FIT

52 FIT

DC

S

7 %

19 %

DC

D

89 %

88 %

MTBF = MTTF + MTTR

1.56 x 10

6

h

1.56 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

92 %

91 %

PFD

avg

T

Proof

=

1 year

T

Proof

=

5 years

T

Proof

=

10 years

<

0.021 x 10

-2

<

0.104 x 10

-2

<

0.207 x 10

-2

<

0.023 x 10

-2

<

0.114 x 10

-2

<

0.228 x 10

-2

PFH

<

0.047 x 10

-6

/h

<

0.052 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

10

OPTISWITCH series 3000 • - NAMUR

Functional safety

32742

-EN

-080414