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10� Functional Safety notes (for SIL 2 / PL d certified versions only)
Designated category and fail exclusions
The safety function of the transducer is the correct measure and transduction of the read pressure value, with
generation of a current output signal (4...20mA) within specification written in the datasheet and in the current
operating manual, for comparison with a fixed safety threshold - high threshold (comparison performed by
external downstream controller)
The designated category to which are limited the use of safety related parts is Category 2.
The SIL/PL parameters of the transducer are shown in the table below:
In the evaluation three different failures have been excluded:
•
Wearing/corrosion of the mechanical parts at the process front end [13849-2:2012 prospect A.4]
•
Break of the mechanical parts at the process front end [13849-2:2012 prospect A.4]
•
Plastic deformation due to excessive loads of the mechanical parts at the process front end [13849-2:2012
prospect A.4]
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Parameter
Architecture
HFT
Category
β, β
factors
D
λ
DD
Analog output
λ
DU
Analog output
DCavg
Analog output
SFF
Analog output
MTTFd
Analog output
PFH
Analog output
Systematic capability
SILCL (IEC/EN 62061)
SIL (IEC/EN 61508)
PL (EN ISO 13849)
Life time
Tab� 10�1�
Value
Measuring Unit
1oo1(D)
--
0
--
2
--
0,02
--
7,50E-07
1/h
1,13E-07
1/h
90
%
92,68
%
132
years
1,13E-07
1/h
2
--
2
--
d
--
20
years
80636B_MAN_HMF - HWF_05-2022_ENG
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