Rockwell Automation 1768-L45S Compact GuardLogix Controllers - Manual (Page 11)

Rockwell Automation Publication 1768-UM002C-EN-P - April 2012 11
Chapter
1
System Overview
Safety Application
Requirements The Compact GuardLogix controller system is certified for use in safety
applications up to and including Safety Integrity Level (SIL) 3 and Performance
Level (e) 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/PLe criteria.
For SIL 3 and PLe 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 Compact GuardLogix SIL 3, PLe safety system.
Compact GuardLogix-based SIL 3/PLe safety applications require the use of at
least one safety network number (SNN) and a safety task signature. Both affect
controller and I/O configuration and network communication.
Refer to the GuardLogix Controller Systems Safety Reference Manual,
publication
1756-RM093 , for details.
Safety Network Number
The safety network number (SNN) must be a unique number that identifies
safety subnets. Each safety subnet that the controller uses for safety
communication must have a unique SNN. Each CIP Safety device must also be
configured with the safety subnet’s SNN. The SNN can be assigned
automatically or manually.
Topic Page
Safety Application Requirements 11
Distinguishing Between Standard and Safety Components 12
Controller Data Flow Capabilities 13
Selecting System Hardware 14
Selecting Safety I/O Modules 14
Selecting Communication Networks 14
Programming Requirements 15