Isolating Switching Amplifier Im1-***-R - turck IM1-12-R Handbuch

5.2 Isolating Switching Amplifier IM1-***-R

The FMEDA carried out on the Isolating Switching Amplifier IM1-***-R leads under the
assumptions described in sections 4.2.3 and 5 to the following failure rates:
λ
= 0,00E-00 1/h
sd
λ
= 1,72E-07 1/h
su
λ
= 0,00E-00 1/h
dd
λ
= 1,10E-07 1/h
du
λ
= 1,27E-07 1/h
no effect
λ
= 4,09E-07 1/h
total
λ
= 1,10E-08 1/h
not part
MTBF = MTTF + MTTR = 1 / (λ
Under the assumptions described in section 5 and the definitions given in section 4.1 the
following table shows the failure rates according to IEC 61508:
λ
safe
299 FIT
The PFD was calculated for three different proof test times using the Markov model as
AVG
described in Figure 3.
T[Proof] = 1 year
PFD = 4,80E-04
AVG
The boxes marked in yellow (
allowed range for SIL 2 according to table 2 of IEC 61508-1 and table 3.1 of ANSI/ISA–84.01–
1996 but do not fulfill the requirement to not claim more than 10% of this range, i.e. to be better
than or equal to 1,00E-03. The boxes marked in green (
values are within the allowed range for SIL 2 according to table 2 of IEC 61508-1 and table 3.1
of ANSI/ISA–84.01–1996 and do fulfill the requirement to not claim more than 10% of this
range, i.e. to be better than or equal to 1,00E-03. Figure 5 shows the time dependent curve of
PFD .
AVG
© exida.com GmbH
Stephan Aschenbrenner
more@turck.com • www.turck.com • 2015/04
Anhang – EXIDA-Report FMEDA Turck 04/07-14 R002
+ λ
) + 8 h = 272 years
total not part
λ
dangerous
110 FIT
T[Proof] = 5 years
PFD = 2,40E-03
AVG
) mean that the calculated PFD
73,15%
T[Proof] = 10 years
PFD
AVG
values are within the
AVG
) mean that the calculated PFD
TURCK 04-07-14 R002 V3R0.doc; February 21, 2014
SFF
= 4,79E-03
AVG
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