Observed Standards; Acronyms And Abbreviations - PR 9106B Manual

Safety Manual

1. Observed standards

Standard Description
Functional Safety of electrical / electronic / programmable
IEC 61508
electronic safety-related systems
IEC 61508- Part 2: Requirements for electrical / electronic / programmable
2:2000 electronic safety-related systems

2. acronyms and abbreviations

Acronym /
Abbreviation
Element
PFD
Failure on Demand
Probability of dan-
PFH gerous Failure per
SFF
SIF
SIL
9106 HART ® transparent repeater
Designation
Probability of
Hour
Safe Failure
Fraction
Safety Integrity
Function
Safety Integrity
Level
Version No. V1R0
Description
Term defined by IEC 61508 as "part of a
subsystem comprising a single component
or any group of components that performs
one or more element safety functions"
This is the likelihood of dangerous safety
function failures occurring on demand.
The term "Probability" is misleading, as IEC
61508 defines a Rate.
Safe Failure Fraction summarises the
fraction of failures which lead to a safe
state and the fraction of failures which will
be detected by diagnostic measures and
lead to a defined safety action.
Function that provides fault detection (to
ensure the necessary safety integrity for the
safety functions)
The international standard IEC 61508
specifies four discrete safety integrity levels
(SIL 1 to SIL 4). Each level corresponds to
a specific probability range regarding the
failure of a safety function.
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