Abbreviations And Symbols - Eaton PKE series Handbuch

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Abbreviations and
symbols
34
Symbols used in this manual have the following meanings:
CLASS Tripping class
Central Processing Unit
CPU
Ex e Ignition protection type "Increased Safety"
FIT Failure in Time, number of dangerous failures
9
in 10 hours
HFT Hardware-Fault-Tolerance
MTTF Mean Time To Dangerous Failure
d
PL Performance Level
PTB Physikalisch-Technische Bundesanstalt.
German Federal Testing Laboratory:
Accredited certification authority for devices
operated in Ex e areas
SIL Safety Integrity Level
TSC Transport Safety Consult of the TÜV Rheinland
InterTraffic GmbH
10/15 MN03402004Z-DE/EN