VCIOM-05044
Page 16 of 75
DIgITal EPIC-2 TEChnICal Manual
InstallatIon and operatIng InstructIons
5.3.7 general requirements
The following general requirements for the
DEPIC-2 ESD must comply with the following:
• The system response time shall be less than
the process safety time. The DEPIC-2 ESD
switches to its fail safe state in less than
100ms. Response time is actuator dependent.
• The end user must add the DEPIC-2 ESD
response time to actuator/valve response
to obtain overall response time.
• all SIS components, including the DEPIC-2
ESD, must be operational before process
start-up.
• In order to use the PST as an automatic
diagnostic tool the PST shall be scheduled
(using auto-PST) to run at least once per
month or ten times within the expected
hazard demand interval, whichever comes
first. Detailed failure rate data is specified in
the FMEDa report available from the factory.
• In order to use the SOVT as an automatic
diagnostic tool the SOVT shall be scheduled
(using auto-SOVT) to run at least once per
week or twenty times within the expected
hazard demand interval, whichever comes
first. Detailed failure rate data is specified in
the FMEDa report available from the factory.
• Personnel performing maintenance and
testing on the DEPIC-2 ESD has to be
qualified to do so.
• Results from the FST, PST, and SOVT proof
tests shall be recorded and periodically
reviewed.
• The useful life of the DEPIC-2 ESD is
discussed in the Failure Modes, Effects and
Diagnostic analysis (FMEDa) Report for the
DEPIC-2 ESD.
5.4.4 signatures
If enabled, signatures of FST and PST may
be collected for analysis. The signatures are
graphical representations of the FST and PST
and can be used for trending information.
5.4.5 Proof test
You can automatically or manually run a proof
test (any of above tests). The objective of proof
testing is to detect failures within a DEPIC-2
and ESD valve that are not detected normal
operation of the system.Of main concern are
undetected failures that prevent the safety
instrumented function from performing its
intended function.
Proof testing frequency or proof test interval,
has to be determined in reliability calculations
for the safety instrumented functions to which
DEPIC-2 ESD is applied. The proof tests must
be performed either more frequent or as
frequently as specified in the PFD
avg
calculation
in order to maintain the required safety integrity
of the safety instrumented function.
The following proof test is recommended as a
guideline to increase the safety and reliability of
the operation. Report any detected failures that
compromise functional safety to the factory.
5.4 dIagNOsTICs
The DEPIC-2 provides several types of
diagnostic information from proof testing:
• Full-Stroke Testing (FST) diagnostics.
• Partial-Stroke Testing (PST) diagnostics.
• Solenoid Operated Valve Test (SOVT)
diagnostics.
• Signatures on FST and PST if enabled.
5.4.1 fsT
You can configure and run FST manually at
any. For more information on FST refer to
“Full-Stroke Testing” section in this document.
5.4.2 PsT
You can configure and run PST manually at
any time or set it up to be automated and run
periodically. For more information on PST
refer to “Partial-Stroke Testing” section in
this document.
5.4.3 sOVT
You can configure and run SOVT manually at
any time or set it up to be automated and run
periodically. For more information on SOVT
refer to “Solenoid Operated Valve Testing”
section in this document.
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