Allen-Bradley GuardPLC 1753, Справочник по безопасности

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10 Publication 1753-RM002C-EN-P - September 2008
Preface
List of Abbreviations
The following table defines terms or abbreviations used in this
manual.
Term Definition
1oo2 One Out of Two Safety Architecture. Consists of 2 channels connected
in parallel, such that either channel can process the safety function.
Thus, a dangerous failure would have to occur in both channels before
a safety function failed on demand
2oo3 Two out of Three Safety Architecture. Consists of 3 channels
connected in parallel with a majority voting arrangement for the
output signals, such that the output state is not changed if only 1
channel gives a result that disagrees with the other 2 channels
CRC Cyclic Redundancy Check. A number derived from and stored or
transmitted with a block of data in order to detect corruption
EN European Norm. The official European Standard
EPROM Erasable Programmable Read-only Memory
HSP High-speed Safety Protocol
IEC International Electrotechnical Commission Standard
MAC ID Media Access Identifier. A node’s address on a network or subnet
Non-interacting Does not interfere or affect functions of the safety system
PES Programmable Electronic System
PFD Probability of Failure on Demand
PFH Probability of Failure per Hour
POU Program Organization Unit
PS Programming System
SIL Safety Integrity Level
SNN Safety Network Number
SRS System, Rack, Slot (This number is used as the System ID)
Standard Any object, task, tag, or program, that is not marked as being a safety
item
TÜV Technischer Überwachungs-Verein (Technical Inspection Association)
UNID Unique Node Identifier
WD Watchdog Time