Pepperl+Fuchs KFD2-SH-Ex1 - Page 15

Functional Safety KFD2-SH-Ex1(.T)(.OP), KHA6-SH-Ex1
Planning
2017-04
15
KFD2-SH-Ex1.T(.OP)
The characteristic safety values like PFD, PFH, SFF, HFT and T
1
are taken from
the FMEDA report and the assessment documentation created by the issuer.
Please note, PFD and T
1
are related to each other. The function of the devices
has to be checked within the proof test interval (T
1
).
The safety values MTTF
d
, DC
d
, Category and PL for the machinery directive are
taken from the assessment report and certificate.
Parameters acc. to IEC 61508 Characteristic values
Assessment type and
documentation
FMEDA, proven-in-use assessment, certificate
Device type A
Mode of operation Low Demand Mode or High Demand Mode
HFT 0
SIL 3 (proven-in-use) 2 (proven-in-use)
Safety function Output I is de-energized when
input in low state
Output II is de-energized when
input in low state

s
181 FIT 194 FIT

du
1.4 FIT 51.6 FIT

dd
38.4 FIT 38.4 FIT

no effect
1
1
"Annunciation failures" are not directly influencing the safety functions and are therefore added to the 

no effect
value.
195 FIT 130 FIT

total (safety function)
218 FIT 282 FIT
SFF 99.4 % 81 %
MTBF
2
2
acc. to SN29500. This value is calculated with the failure rates of the device components which are part of the
safety function of the device.
275 years 276 years
MTTF
d
2860 years –
DC
d
96.5 % (medium) –
B10
d
– –
Category (ISO 13849-1) 3 –
PL d –
PFH 1.38 x 10
-9
1/h 5.16 x 10
-8
1/h
PFD
avg
for T
1
= 1 year 6.04 x 10
-6
2.26 x 10
-4
PFD
avg
for T
1
= 2 years 1.21 x 10
-6
4.52 x 10
-4
PFD
avg
for T
1
= 5 years 3.02 x 10
-5
1.13 x 10
-3
Reaction time
3
3
Time between fault detection and fault reaction.
< 30 ms < 30 ms
Table 3.3