Use As Acoustic Warning System Without Test Function - Pfannenberg DS5-SIL Instructions De Service

The acoustic warning system with diagnosis function is implemented as follows:
a) A measurement (input (1), logic (2) records a dangerous condition and activates the acoustic warning system
(output (3)
b) The diagnosis (4) monitors the function of the acoustic warning system and reports OK to a superior control
system (5)
c) If an OK message takes place, then the superior control system (5) introduces the safe condition via other
measures (6).
1
Recording
(Input)
Fig. 7 Warning system
The safety loop in one-channel architectures consists of position 1 – 6 as is shown in
In section 4.4.2.2 the sounder partial systems (output - position 3) and diagnosis channel (diagnosis - position 4) are
evaluated. It should be noted that the sum of all PFH or PFD values must correspond to the required safety integra-
tion level for the entire system.

4.4.2.1. Use as acoustic warning system without test function

The safety function (generating a warning signal) is realised via a one-channel system (1oo1 according to
IEC/EN61508) without taking account of the diagnosis function, as also described in section 4.2.
Low and high requirement rates (low and high demand mode) can be used in the system without automatic test func-
tion.
T-Proof Test
*
PFD mean
PFH
SFF
DC
MTTR
λ
, Sounder
DU
λ
, Sounder
S
λ
, Diagnosis
DU
λ
, Diagnosis
S
β (CCF)
λ
, Complete
DU
λ
, Complete
S
MTTFd
HFT
Category
SIL
Type
PL
The monitoring of the function of the sounder is used during the 'proof test'. The 'proof test' is described in section
4.10 of the operating instructions/safety manual.
* The PFD for deviating intervals of the proof test can be ascertained in this case by simply multiplying the value for 1 year
by the envisaged annual intervals between the tests. Ensure that the limit value for the entire safety chain is not exceeded.
44% of the SIL2 level is already used for a proof test interval of 4 years.
Datei/ file name:085501929j de-en-fr-it.docx
2
Evaluation
(Logic)
5
Superior
system
1 4
1,10E-03 4,40E-03
2,51E-07
96,8
0
48
243
79
77
7459
10
251
7610
>100
0
1
2 2
B
c c
page 25 / 68
3
Output
(Output)
Diagnosis
(Output)
Output
Fig. 7.
15
1,65E-02 1/ requirement
1
c
4
6
%
%
h
Fit
Fit
Fit
Fit
%
Fit
Fit
a
Drwg-no.: 30007-008-12j