Sil Overfill And Underfill Protection (Fii-Sil) - Honeywell FlexLine SmartServo 954 Service Manual

COMMISSIONING

SIL overfill and underfill protection (FII-SIL)

7.3.12.1 Introduction
Part No.: 4417340 Revision 1
Field Interface Instrument - Safety Integrity Level (FII-SIL) is an optional
FlexConn board. The FII-SIL module provides overfill and underfill
protection functionality certified and suitable for use in Safety
Instrumented Systems at SIL 2 with systematic capability at SIL 3. It is
used with the 954 SmartServo FlexLine tank gauge system.
FII-SIL provides two relay contacts for signaling a safety shutdown or
safe state, and one 4-20 mA analog output both for monitoring the
product level and signaling a safe state. The presence of two relay
contacts provides configuration flexibility, such as separate signaling of
overfill and underfill conditions, or the capability of an overfill early
warning to allow corrective action before an overfill condition prompts a
safety shutdown.
The physical contacts of each relay are closed or energized during
normal operation. When a relay is in a safe state, the physical contacts
are open or de-energized. This allows loss of power to also signal a
safe state.
In compliance with NAMUR NE 43, the analog output signals a safe
state when the current at or above 21 mA, or is at or below 3.6 mA.
Service Manual
954 SmartServo FlexLine
213