We can help you meet SIL level 1, 2 & 3
requirement with our products. The
instruments that we manufacture are based on analogue techniques, no software, and
no microprocessors. The Amelec is a component part in a safety loop. The
standard (IEC61508-2:2001 page 23, 24 and annex C) details the permitted
failures rates of the components in the loop necessary to meet the requirements
of a particular SIL level for a given safety loop. The instruments from Amelec
are type A components, namely.
The failure modes of all constituent components are well
defined.
The behaviour of the subsystem under fault conditions can be
completely determined;
There is sufficient dependable failure data from field
experience to show that the claimed rates of failure for detected and
undetected dangerous failures are met.
We would supply information on our product to
support the safety case for the loop'(s). The numbers would be generated for the
particular fault conditions that you are looking /monitoring for. Following are
two typical examples.
Example 1:
Model ADT132X
Trip Amplifier with two set points, Input: 4-20mA, Set point 1: High, Set point
2:Low and primary supply of 24Vdc. Both relays configured to de-energise on
Alarm/Trip/Input open circuit/Loss of power.
Reliability data:
Parts count failure rate:
1.731 per million hours
MTBF: 65.94 years
FMEA failure rate:
0.578 per million hours
MTBF: 197.4 years
Diagnostic cover:
54.87%
Safe failure Fraction: 84.92%
PFD (Per year): 5.73E-04* (See note below)
SIL level:
1, 2 & 3* (See note below)
*Above data for
the ADT132X is generated based on one calibration check per year and the mean
time to repair a unit is eight hours. A PFD value of 5.73E-04 gives
a risk reduction of approximately 1700,
in accordance with IEC61508 the instrument when correctly installed can be used in a SIL
1, 2 or 3 loop.
Example 2:
Model ADM220X RTD
Resistance input signal conditioner, Input: 0-100C BS1904 three wire RTD,
Output: 4-20mA Isolated and primary supply of 115Vac. Output drives down scale
(<3.5mA) on input open circuit and loss of power.
*Above data for
the ADM220X is generated based on one calibration check per year and the mean
time to repair a unit is eight hours. A PFD value of
5.38E-04
gives
a
risk reduction of approximately 1855, in accordance with IEC61508 the instrument when correctly installed can be used in a SIL
1, 2 or 3 loop.
Above examples
represent just two typical applications, we can provide reliability data for
most of our product range. We have over 30 years of experience in the field of Signal
Conditioning / Process Control Instrumentation, with this we are confident we
can assist with meeting your SIL requirement with our products.
For printer friendly or download a file click on the
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For more information, please
contact our technical sales staff at the factory in Milton Keynes.
Post:
Cochran Close
Crownhill
Milton Keynes
Bucks
MK8 OAJ
