Rockwell Automation 1756-SPESMNRMXT GuardLogix Controllers User Manual - Manuel (Page 15)

Rockwell Automation Publication 1756-UM020I-EN-P - August 2012 15
Chapter
1
System Overview
Safety Application
Requirements The 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 GuardLogix SIL 3, PLe safety system.
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 15
Distinguishing Between Standard and Safety Components 16
Controller Data Flow Capabilities 17
Selecting System Hardware 18
Selecting Safety I/O Modules 20
Selecting Communication Networks 20
Programming Requirements 21