Allen-Bradley GuardLogix 5570, User Manual

Page: 13 / 172

Rockwell Automation Publication 1756-UM022D-EN-P - May 2017 13
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 Claim Limit (SIL CL)
3 and Performance Level (e) where the de-energized state is the safe state.
Safety application requirements include probability of failure rates evaluation,
such as:
• Probability of failure on demand (PFD)
• Probability of failure per hour (PFH)
• System reaction-time settings
• Functional-verification tests that fulfill SIL 3/PLe criteria
GuardLogix-based SIL 3/PLe safety applications require at least one safety
network number (SNN) and a safety task signature be used. 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 and Compact GuardLogix 5370 Controller Systems Safety
Reference Manual, publication
1756-RM099 . You must read, understand, and
fulfill these requirements before you operate a GuardLogix SIL 3, PLe safety
system.
Topic Page
Safety Application Requirements 13
Distinguish between Standard and Safety Components 14
Controller Data-flow Capabilities 15
Select System Hardware 16
Select Safety I/O Device 17
Select Communication Networks 18
Programming Requirements 19