Rockwell Automation 1756-L7x GuardLogix 5570 Controllers - Manual (Page 11)

Rockwell Automation Publication 1756-UM022A-EN-P - November 2012 11
Chapter
1
System Overview
Safety Application
Requirements The GuardLogix 5570 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.
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.
For SIL 3 and PLe safety system requirements, including functional validation
test intervals, system reaction time, and PFD/PFH calculations, refer to the
GuardLogix 5570 Controller Systems Safety Reference Manual, publication
1756-RM099 . You must read, understand, and fulfill these requirements prior to
operating a GuardLogix SIL 3, PLe safety system.
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.
For information on assigning the SNN, see Managing the Safety Network
Number (SNN) on page 43 .
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 15
Selecting Communication Networks 16
Programming Requirements 16