turck IM33-11-HI/24VDC - Page 17

17
more@turck.com • www.turck.com • 2015/04
Decommissioning and withdrawal from service
© exida.com GmbH TURCK 04-07-14 R001 V2R0.doc; February 8, 2013
Stephan Aschenbrenner Page 3 of 4
Table 2: Summary for IM33-**(Ex)-Hi/24VDC – Failure rates
Fail-safe state = “fail high”
Failure Category
λ
λλ
λ
sd
λ
λλ
λ
su
λ
λλ
λ
dd
λ
λλ
λ
du
SFF DC
S
2
DC
D
²
λ
low
= λ
sd
λ
high
= λ
dd
233 FIT 315 FIT 73 FIT 44 FIT 93% 42% 62%
λ
low
= λ
dd
λ
high
= λ
sd
73 FIT 315 FIT 233 FIT 44 FIT 93% 18% 84%
Fail-safe state = “fail low”
Failure Category
λ
λλ
λ
sd
λ
λλ
λ
su
λ
λλ
λ
dd
λ
λλ
λ
du
SFF DC
S
² DC
D
²
λ
low
= λ
sd
λ
high
= λ
dd
239 FIT 315 FIT 67 FIT 44 FIT 93% 43% 60%
λ
low
= λ
dd
λ
high
= λ
sd
67 FIT 315 FIT 239 FIT 44 FIT 93% 17% 84%
Table 3: Summary for IM33-**(Ex)-Hi/24VDC – PFD
AVG
values
T[Proof] = 1 year T[Proof] = 5 years T[Proof] = 10 years
PFD
AVG
= 1,92E-04 PFD
AVG
= 9,60E-04 PFD
AVG
= 1,92E-03
Table 4: Summary for IM35-**Ex-Hi/24VDC – Failure rates
λ
λλ
λ
safe
λ
λλ
λ
dangerous
SFF
583 FIT 103 FIT 85%
Table 5: Summary for IM35-**Ex-Hi/24VDC – PFD
AVG
values
T[Proof] = 1 year T[Proof] = 5 years T[Proof] = 10 years
PFD
AVG
= 4,50E-04 PFD
AVG
= 2,25E-03 PFD
AVG
= 4,48E-03
The boxes marked in yellow ( ) mean that the calculated PFD
AVG
values are within the
allowed range for SIL 2 according to table 2 of IEC 61508-1 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 ( ) mean that the calculated PFD
AVG
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.
Because the Safe Failure Fraction (SFF) is above 60%, also the architectural constraints
requirements of table 2 of IEC 61508-2 for Type A subsystems with a Hardware Fault
Tolerance (HFT) of 0 are fulfilled.
2
DC means the diagnostic coverage (safe or dangerous) of the safety logic solver for the Isolating
Transducers IM33-**Ex-Hi/24VDC.
Safety manual