User manual

13Publication 1756-RM093F-EN-P - January 2010 13

Chapter

Safety Integrity Level (SIL) Concept

Introduction

This chapter introduces you to the Safety Integrity Level (SIL) concept

and how the GuardLogix controller meets the requirements for SIL 3

certification.

SIL 3 Certification

1756 and 1768 GuardLogix controller systems are type-approved and

certified for use in safety applications up to and including SIL 3

according to IEC 61508 and IEC 62061, safety applications up to and

including Performance Level PLe (Category 4) according to

ISO 13849-1. SIL requirements are based on the standards current at

the time of certification.

In addition, the standard tasks within 1756 GuardLogix controllers can

be used either for standard applications or SIL 2 safety applications as

described in the Using ControlLogix in SIL 2 Applications Reference

Manual, publication 1756-RM001

. In either case, do not use SIL 2 or

standard tasks and variables to build up safety loops of a higher level.

The safety task is the only task certified for SIL 3 applications.

The standard task in 1768 Compact GuardLogix controllers may not be

used for SIL 2 safety applications.

RSLogix 5000 programming software is required to create programs

for 1756 and 1768 GuardLogix controllers.

Topic Page

SIL 3 Certification 13

Functional Verification Tests 14

GuardLogix Architecture for SIL 3 Applications 15

GuardLogix System Components 16

GuardLogix Certifications 18

GuardLogix PFD and PFH Specifications 19

Safety Integrity Level (SIL) Compliance Distribution and Weight 20

System Reaction Time 21

Safety Task Period and Safety Task Watchdog 21

Contact Information If Device Failure Occurs 22

IMPORTANT

When the GuardLogix controller is in the Run or Programming

mode and the application has not been validated by the user,

the user is responsible for maintaining safe conditions.