Rockwell Automation 1794 FLEX I/O System with ControlLogix for SIL2 - Manual (Page 5)

1 Publication 1794-RM001G-EN-P - December 2011
Chapter
1
SIL Policy
This chapter introduces you to the SIL policy and how the
ControlLogix/FLEX I/O system meets the requirements for SIL2
certification.
Introduction to SIL Certain catalog numbers (listed in Table 1.1 on page 1-5) of the FLEX I/O with
ControlLogix system are type-approved and certified for use in SIL2
applications, according to IEC 61508. SIL requirements are based on the
standards current at the time of certification.
These requirements consist of mean time between failures (MTBF),
probability of failure, failure rates, diagnostic coverage and safe failure
fractions that fulfill SIL2 criteria. The results make the ControlLogix/FLEX
I/O system suitable up to, and including, SIL2. When the
ControlLogix/FLEX I/O system is in the maintenance or programming
mode, the user is responsible for maintaining a safe state.
For support in creation of programs, the PADT (Programming and
Debugging Tool) is required. The PADT for ControlLogix/FLEX I/O is
RSLogix 5000, per IEC 61131-3, and this Safety Reference Manual.
The TUV Rheinland has approved the ControlLogix/FLEX I/O system for
use in up to and including SIL 2 safety related applications in which the
de-energized state is considered to be the safe state. All of the examples related
to I/O included in this manual are based on achieving de-energization as the
safe state for typical Emergency Shutdown (ESD) Systems.
For information about: See page:
Introduction to SIL 1-1
SIL2 Certification 1-2
Proof Tests 1-3
SIL2-Certified FLEX I/O System Components 1-5
Hardware Designs and Firmware Functions 1-8
Hardware Designs and Firmware Functions 1-8
Difference Between PFD and PFH 1-8
SIL Compliance Distribution and Weight 1-13
Response Times 1-13