A safety instrumented function (SIF) in a safety instrumented system (SIS) contains a sensor, logic solver and final element. All must function properly in the event of a safety demand to take the process into a safe state in coordination with other SIFs. The final element consists of several parts including the isolation valve, actuator, […]
The safety valve within a safety instrumented function (SIF) must be tested regularly to help assure proper operation in the event of a safety demand. Operators usually perform an offline full stroke test during a scheduled shutdown because of the impact of this test on the process. But when a SIF (a.k.a. safety loop) requires […]
Emerson’s Sergio Diaz and Alexandre Peixoto presented Best Practices for a Cybersecure SIS at the 2019 Emerson Exchange conference. Sergio opened that the goal of this presentation is to provide practical information to maintain a more defendable security posture for safety instrumented systems (SISs). Like control systems, defense in depth is an important concept for […]
Author: Sergio Diaz As a product marketing manager for DeltaV safety instrumented systems (SIS), I have been asked a few times why the key switch on the CHARMs Smart Logic Solver (CSLS) does not control the lock state as is common with many safety controllers. The next question is, “Why does the user still need […]
Safety instrumented systems (SIS), which are designed to take the process to a safe state in trip conditions, come in several architectures with the basic process control system (BPCS). The SIS and BPCS can be totally separate, interfaced or integrated, yet separate. While the debate on which approach is best has been going on for […]
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