63
Operation Manual
Safety I/O Terminals
SI4000 / SO4000
Document no.: 5.08009.05
A
PPENDIX
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BBREVIATIONS
CPU
Central Processing Unit
DC
Diagnostic Coverage
Diag
Diagnostic LED
DIN
Deutsches Institut für Normung
e.V.
EMC
Electromagnetic compatibility
EN
European standard
FSoE
Safety protocol „Safety over Ether-
CAT“
HFT
Hardware Failure Tolerance
I/O
Input/Output
I/O bus
Bus between b maXX safe PLC
and the modules right of the PLC
and/or power supply
LED
Light-emitting diode
MTTF
d
Mean Time To Failure
PFD
Probability of Failure on Demand
PFH
Probability of Failure per Hour
PLC
Process loop control, stored Pro-
gram Control, SPS
RAM
Random Access Memory
ROM
Read Only Memory
SFF
Safe Failure Fraction (Fraction of
failures which lead to safe status)
SIL
Safety Integrity Level
SW
Software