E2S BExS110D-SIL Instruction manual - page 14
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European Safety Systems Ltd. Impress House, Mansell Road, Acton, London W3 7QH sales@e-2-s.com Tel: +44 (0)208 743 8880
www.e-2-s.com Fax: +44 (0)208 740 4200
Document No. D197-00-601-IS Issue F 16-06-17 Sheet 14 of 19 (14)
17) SIL 2 Specific Unit Mounting
Requirements
The sounder should be mounted no closer that 5m from a
sounder source of similar SPL output. This is to ensure false
tone activation does not occur when the unit is monitoring the
tone pulse duration and tone failure.
18) SIL 2 Reliability Data
Reliability and Functional safety IEC/EN61508 which has
been assessed and is considered suitable for use in low
demand safety function:
•
Random Hardware Failures and Architectural constraints
(route 1
H
)
•
As an unvoted item (ie hardware fault tolerance of 0) at
SIL 2
The product was assessed against failure modes:
•
Failure respond to an input with a correct tone
•
Failure to respond to an input even with an
alternative tone
•
Spurious sound output despite no input
BExS110D-SIL (Correct tone needed)
Integrity in respect of failure to
release
SIL 2
Total Failure rate
0.304 pmh
“hazardous” failure rate (revealed)
0.233 pmh
“hazardous” failure rate (unrevealed)
0.017 pmh
“safe” failure rate (revealed)
0
“safe” failure rate (unrevealed)
0
Diagnostic Coverage
93%
System type
B
Hardware Fault Tolerance
0
Safe Failure Fraction
>93%
PFD (hazardous failure)
9.4 x 10
-5
Proof Test Interval
Up to 1 week
BExS110D-SIL (Total failure)
Integrity in respect of failure to
release
SIL 2
Total Failure rate
0.304 pmh
“hazardous” failure rate (revealed)
0.235 pmh
“hazardous” failure rate (unrevealed)
0.005 pmh
“safe” failure rate (revealed)
0.01
“safe” failure rate (unrevealed)
0
Diagnostic Coverage
98%
System type
B
Hardware Fault Tolerance
0
Safe Failure Fraction
>98%
PFD (hazardous failure)
2.0 x 10
-5
Proof Test Interval
Up to 1 week
19) Synchronised Operation
All BExS110D-SIL sounders that are connected to the same
supply line will be synchronised as tone as the same tone
pattern is selected.
20) End of Line Monitoring
On BExS110D-SIL DC units, DC reverse line monitoring can
be used if required. All DC sounders have a blocking diode
fitted in their supply input lines. An end of line monitoring
diode or an end of line monitoring resistor can be connected
across the +ve and
–ve terminals.
We suggest that with the SIL 2 system, the customer
selected EOL resistor is kept to a value of 2.2k
Ω however
variation is allowed as required by the SIL 2 systems PLC
parameters. See section 18.2 & 25.
Values of current draw are given for the 2.2k
Ω resistor if used
as set up in section 18.
If an alternative value end of line resistor is used it must have
a minimum resistance value of 3.3k
Ω and a minimum
wattage of 0.5 watts or a minimum resistance value of 500
Ω
and a minimum wattage of 2 watts.