KROHNE OPTISWITCH 3x00C NAMUR SIL EN - Manual (Page 9)

This function test is triggered by an interruption of the supply
cable for at least two seconds. Then a special warm-up
reaction of the current output is carried out which must be
recorded.
The test procedure is described in detail in the operating
instructions manual.
Simulation key:
Pushing the simulation key simulates line break between
sensor and processing unit.
Note:
This test can be carried out only if the vibrating element is
uncovered.
The function of connected instruments can be checked in the
"
max." and "min." modes with the "Simulation key". The test
procedure is described in detail in the operating instructions
manual.
Note:
For this test, take note of the condition of the vibrating element:
l
Mode "max.": Vibrating element "uncovered"
l
Mode "min.": Vibrating element "covered"
1 .7 Safety-related characteristics
The failure rates of the electronics, the mechanical parts of the
transmitter as well as the process fitting are determined by an
FMEDA according to IEC 61508. The calculations are based
on component failure rates according to SN 29500. All values
refer to an average ambient temperature during the operating
time of 40 °C (104 °F).
For a higher average temperature of 60 °C (140 °F), the failure
rates should be multiplied by a factor of 2.5. A similar factor
applies if frequent temperature fluctuations are expected.
The calculations are also based on the specifications stated in
chapter "Planning".
After 8 to 12 years, the failure rates of the electronic
components will increase, whereby the derived PFD and PFH
values will deteriorate (IEC 61508-2, 7.4.7.4, note 3).
Function test of con-
nected instruments
Basics
Service life
OPTISWITCH series 3000 • - NAMUR 9
Functional safety
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EN
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080414