Allen-Bradley 1734-IB8S, Installation & User Manual, Page: 18 / 156

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Rockwell Automation Publication 1734-UM013C-EN-P - August 2010
Chapter 1
POINT Guard I/O Overview
Safety Application
Requirements
The POINT Guard I/O system is certified for use in safety applications up to
and including Safety Integrity Level (SIL) 3 and Category (CAT) 4 in which the
de-energized state is the safe state. Safety application requirements include
evaluating probability of failure rates (PFD and PFH), system reaction time
settings, and functional verification tests that fulfill SIL 3 criteria.
For safety system requirements, including functional validation test intervals,
system reaction time, and PFD/PFH calculations, refer to the GuardLogix
Controller Systems Safety Reference Manual, publication
1756-RM093 . You
must read, understand, and fulfill these requirements prior to operating a
POINT Guard I/O system.
Safety Network Number
For information on the safety network number, refer to the GuardLogix
Controller Systems Safety Reference Manual, publication
1756-RM093 .
Safety Signature
Safety signatures are created by the safety controller. The safety signature consists
of an ID number, date, and time that uniquely identifies the safety portion of a
project. This includes all safety logic, data, and configuration. The POINT
Guard I/O modules use the safety signature to determine the project’s integrity
and to let you verify that the correct project is downloaded to the target
controller.
Creating, recording, and verifying the safety signature is a mandatory part of the
safety application development process.
Refer to the GuardLogix Controller Systems Safety Reference Manual,
publication
1756-RM093 , for details.