_______________________________________________________________________________________________________________________________
European Safety Systems Ltd.
Impress House, Mansell Road, Acton, London W3 7QH [email protected] Tel: +44 (0)208 743 8880
www.e2s.com Fax: +44 (0)208 740 4200
Document No. D191-00-601-IS Issue 1 20-03-2020 Sheet 14 of 8
SIL Specific Unit Mounting Requirements
The beacon should be mounted no closer that 2m from a
beacon or light source of similar candela output. This is to
ensure false light activation does not occur when the unit is
monitoring the light pulse duration and flash failure.
17)
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 (i.e. hardware fault tolerance of 0) at
SIL 2
The product was assessed against failure modes:
Failure respond to an input by lighting a beacon
Spurious light output despite no input
Integrity
in
respect
of
failure
to
release
SIL
2
Total
Failure
rate
0.37
pmh
“hazardous”
failure
rate
(revealed)
0.297
pmh
“hazardous”
failure
rate
(unrevealed)
0.003
pmh
“safe”
failure
rate
(revealed)
0.006
pmh
“safe”
failure
rate
(unrevealed)
0
Diagnostic
Coverage
99%
System
type
B
Hardware
Fault
Tolerance
0
Safe
Failure
Fraction
>99%
PFD
(hazardous
failure)
3.8
x
10
‐
5
Proof
Test
Interval
Up
to
1
year
The SIL 2 units life is dependent on the cumulative running
hour of the unit. The maximum running duration is 2,500 hours.
18)
Synchronised Operation
All D1xB2 SIL2 beacons that are connected to the same
supply line will have a synchronised flash rate at one flash
every second.
19)
End of Line Monitoring
On the D1xB2 SIL2 beacons, DC reverse line monitoring can
be used if required. All DC beacons 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 system the customer selected
EOL resistor is kept to a value of 2.2k
Ω
however variation is
allowed as required by the SIL systems PLC parameters. See
section 16.2 and 21.
Values of current draw are given for the 2.2k
Ω
resistor if used
as set up in section 14.
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.
20)
SIL 2 Hard Reset
If required to hard system reset the unit, firstly, the unit will
need to be opened, to carry out this operation see section 7.
Warning
: - Ensure that an explosive atmosphere is not
present during reset operation.
Power down the unit completely for a minimum of 30 seconds.
Move the hard reset header pin (Jumper J7) to reset position
shown. Then power the unit for a minimum of 5 seconds.
Power down the unit for 30 seconds and then move the header
pin back to the Normal Position.
The unit has been reset. Close the unit as noted in section 7.
If the hard reset does not correct the fault the unit or power
supply integrity will need further investigation.
