Perform Proof Test For Sis Applications - Emerson Rosemount 5408 Reference Manual

Reference Manual
00809-0100-4408
8.8

Perform proof test for SIS applications

8.8.1 Overview
The Rosemount 5408:SIS Level Transmitter must be tested at regular intervals to reveal
faults which are undetected by automatic diagnostics. It is the user's responsibility to
choose the type of testing and the frequency of these tests.
Results from periodic proof-tests shall be recorded and periodically reviewed. If an error is
found in the safety functionality, the transmitter shall be put out of operation and the
process shall be kept in a safe state by other measures.
Note
For a valid result, always perform the proof-test on the product that will be stored in the
tank while the device is in operation.
The following proof-tests are suggested:
• (A) 1-point level and analog output verification (see
output
• (B) 2-point level and analog output verification (see
output
• (C) Analog output verification (see
• (D) Level deviation monitoring (see
Table 8-2
Table 8-2: Suggested Proof-tests
Proof- Type
test #
A Comprehensive
B
C Partial
D
(1) With the assumption that the BPCS level sensor is used as independent measurement.
Proof-test interval
The time intervals for proof-testing are defined by the SIL verification calculation (subject
to the PFD
appropriate proof-test interval for the specific safety function based on equipment's
reliability and required risk reduction for the specific SIF.
The proof-tests must be performed more frequently than or as frequently as specified in
the SIL verification calculation, in order to maintain the required safety integrity of the
overall SIF.
Rosemount 5408 and 5408:SIS Level Transmitters
verification)
verification)
can be used as a guidance for selecting the appropriate proof-test.
Proof-test Remaining
coverage dangerous,
(%) of DU undetected
failures
73% 21 FIT
84% 13 FIT
33% 53 FIT
61% 31 FIT
). The SIL verification calculation is an analytical method to calculate an
AVG
Safety Instrumented Systems (SIS) requirements
Perform 1-point level and analog
Perfom 2-point level and analog
Perform analog output
Perform level deviation
Test coverage
Output Measurement
circuitry electronics
Y Y
Y Y
Y N
N Y
February 2020
verification)
monitoring)
Can be
performed
Antenna
remotely
(1)
Y Y
(1)
Y Y
N Y
N Y
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