Sis Example - Emerson Rosemount 8800D Series Safety Manual

Proof tests
This procedure assumes that you are familiar with plant procedures. For details on how to
do any of the following steps, see the product reference manual.
Procedure
1.
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3.9

SIS example

The following figures illustrate the indicative benefits of using a combination of
comprehensive and partial proof tests to manage the level of risk associated with a
particular SIS Installation.
Figure 3-2
comprehensive and partial proof tests on the system's PFD.
Note
It is assumed that the sensor typically contributes ~30% to the systems SIL 2 PFD budget, with the
logic solver and actuator the remaining ~70%.
18
Take appropriate action to avoid a false trip by electronically bypassing the safety
Programmable Logic Controller (PLC).
Inspect flow meter for any leaks, visible damage or contamination.
Verify that the transmitter does not indicate alarms or warnings using HART host or
LCD.
Cycle power and use HART communications to retrieve any diagnostics and take
appropriate action.
Disable write protection (see
Using the Loop Test function, send a HART command to the transmitter to go to the
high alarm current output and verify that the analog current reaches that value.
• Loop Test can be found at Service Tools > Simulate > Analog Output > Loop Test.
• High alarm and low alarm levels can be found in the product reference manual.
This step tests for compliance voltage problems, such as low voltage on the loop
power supply, or increased wiring resistance.
Send a HART command to the transmitter to go to the low alarm current output and
verify that the analog current reaches that value.
This step tests for possible failures related to quiescent current.
Exit fixed current mode.
Perform a 3 to 5-point calibration check of the transmitter and flowmeter against a
reference standard.
Verify all safety-critical configuration parameters (see
Enable write-protection (see
Remove the bypass and otherwise restore normal operation.
Document the results of this proof test as part of your plant safety management
procedures.
Figure 3-1
through Figure 3-5 illustrate the benefit of implementing a combination of
Section 2.3).
Section 2.3).
shows a typical 1oo1 safety system configuration.
Rosemount
Section 2.2).
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8800D Safety Manual