Safety Scanner for GuardPLC Controllers User Manual

Publication 1753-UM002A-EN-P - July 2005
Preface 3
Understanding Terminology
The following table defines acronyms used in this manual.
Acronym: Full Term: Definition:
1oo2 One Out of Two A safety architecture consisting of two channels connected in parallel, such
that either channel can perform the safety function.
CAN Controller Area Network The networking standard that defines the physical layer of DeviceNet.
COS Change of State A type of I/O data communication in which the interface module can send and
receive data with slave devices whenever a data change occurs in the
configured slave device.
EDS Electronic Data Sheet A vendor-supplied template that specifies how device configuration
information is displayed as well as what is an appropriate entry (value).
EPR Expected Packet Rate The rate at which packets are expected to be received by a device.
HSP High-Speed Safety Protocol A high-speed, high-integrity protocol designed to transfer both safety and
standard data between the GuardPLC controller and the DeviceNet Safety
Scanner for GuardPLC Controllers.
MAC ID Media Access Identifier The network address of a DeviceNet node.
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.
PC Personal Computer Computer used to interface with, and control, a controller-based system via
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.
Rx Receive —
SNN Safety Network Number A unique number that identifies a safety network, or safety sub-net, across all
networks in the safety system.
Tx Transmit —