Each safety instrumented function (SIF) including its sensor, logic solver and final control element must be periodically tested to make sure it will perform as designed in the event of a safety demand. These “proof tests” help to uncover and failure conditions which may have developed since the last proof test or safety demand. A […]
Preventing overfill conditions in tanks and vessels is a job for safety instrumented systems across many industries. In a Flow Control article, A Systemic Approach to Storage Tank Overfill Protection, Emerson’s Lydia Miller and AnnCharlott Enberg describe the key components in a comprehensive tank management system to meet the safety requirements for the application. Lydia […]
One of the necessities in managing safety instrumented systems throughout the IEC 61511 safety lifecycle is to perform periodic proof tests on the components in a safety instrumented function to verify proper function. A short 2:44 YouTube video, How to Remotely Proof-Test the Rosemount 2140:SIS shows how this proof testing can be performed remotely for […]
A safety instrumented function (SIF) within a safety instrumented system (SIS) consists of a sensor, logic solver, and final element. As part of the IEC 61511 global safety standard, these elements within the SIF must be tested during the operational phase of the safety lifecycle. Of the 3 elements, the final control element, typically a […]
Author: Riyaz Ali Partial stroke test is one of the viable means to check mechanical integrity of Final Element of Safety Instrumented Function (SIF) loop. Generally, end users struggle on question of credit of PST for improvement in SIL (Safety Integrity Level). IEC 61508 and IEC 61511 define diagnostic coverage factors (DCF), but do not […]
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