1 Observed standards
2 Acronyms and abbreviations
3 Purpose of the product
Conversion and scaling of temperature (Pt, Ni and TC) and current signals from hazardous area.
The device can be mounted in the safe area and in zone 2 / div. 2 and receive signals from zone
0, 1, 2, 20, 21 and 22 / Class I/II/III, Div. 1, Gr. A-G.
Error events, including cable breakage, are monitored and signalled via the individual status
relay and/or a collective electronic signal via the power rail.
The 9113 has been designed, developed and certified for use in SIL 2 applications according
to the requirements of IEC 61508.
Acronym /
Abbreviation
Designation Description
Element
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”
PFD
Probability of Failure
on Demand
This is the likelihood of dangerous safety function
failures occurring on demand.
PFH
Probability of danger-
ous Failure per Hour
The term “Probability” is misleading, as IEC
61508 defines a Rate.
SFF Safe Failure Fraction
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.
SIF
Safety Integrity
Function
Function that provides fault detection (to ensure the
necessary safety integrity for the safety functions)
SIL Safety Integrity Level
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.
Standard Description
IEC 61508
Functional Safety of electrical / electronic / programmable electronic
safety-related systems
IEC 61508-
2:2000
Part 2: Requirements for electrical / electronic / programmable electronic
safety-related systems
IEC 61508-
3:1998
Part 3: Software requirements
IEC 61326-3-
1:2008
Immunity requirements for safety-related systems
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