Rockwell Automation 1794 FLEX I/O System with ControlLogix for SIL2 - Manual (Page 4)

Publication 1794-RM001G-EN-P - December 2011
Preface 2
MTBF Mean Time
Between Failures Average time between failure occurrences.
MTTR Mean Time to
Restoration Average time needed to restore normal operation
after a failure has occurred.
PADT Programming and
Debugging Tool RSLogix 5000 software used to program and
debug a SIL2-certified FLEX I/O with ControlLogix
application.
PC Personal
Computer Computer used to interface with, and control, a
ControlLogix system via RSLogix 5000
programming software.
PFD Probability of
Failure on
Demand The average probability of a system to fail to
perform its design function on demand.
PFH Probability of
Failure per Hour The probability of a system to have a dangerous
failure occur per hour.
1oo1 One out of one A 1oo1 (one out of one) architecture consists of a
single channel where any dangerous failure leads
to a failure of the safety function.
1oo2 One out of two A 1oo2 (one out of two) architecture consists of
two channels connected in parallel such that
either channel can process the safety function.
Table Preface.2 List of Acronyms Used Throughout the Safety Application Manual
Acronym: Full Term: Definition: