Section 2: Functional Specification - Emerson EL-O-Matic F Series Safety Manual

SIL Safety Manual
DOC.SILM.EF.EN Rev. 1

Section 2: Functional Specification

The safety function for El-O-Matic F-Series pneumatic actuator is defined as follows:
Double-Acting Scenario:
Single-Acting Scenario:
The El-O-Matic brand Actuator Selection Procedure provides functional definition with
specifics on input variables and performance.
In any case, the choice of the safety function to be implemented is responsibility of the
system integrator.
Functional Specification
a. When an unsafe condition is detected in a plant by a process sensor, the
controller, via actuator control system, drives the Actuator to close the
shut-down valve, depressurizing (if under pressure) the Opening side of
the actuator and pressurizing the Closing side of the actuator.
b. When an unsafe condition is detected in a plant by a process sensor, the
controller, via actuator control system drives the Actuator to open the
blow-down valve, depressurizing (if under pressure ) the Closing side
of the pneumatic actuator and pressurizing the Opening side of the
pneumatic actuator.
a. When an unsafe condition is detected in a plant by a process sensor, the
controller, via actuator control system drives the Actuator to rotate with
sufficient torque to move a valve to its fail-safe state when hold-position
air pressure is released.
Section 2: Functional Specification
September 2018
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