Allen-Bradley GuardPLC 1753, Safety Reference Manual

Page: 14 / 120

14 Publication 1753-RM002C-EN-P - September 2008
Chapter 1 Safety Concept for GuardPLC Controllers and GuardPLC I/O
Certification
Certificate No. 968/EZ164.00/04
TÜV Rheinland Group
TÜV Industrie Service GmbH
Automation, Software, and Informatinstechnologie
Safety restrictions can be found in this manual. See Safety
Requirements on
page 17 .
For a listing of TÜV certified product and software versions, refer to:
http://www.rockwellautomation.com/products/certification/safety/
Introduction to Safety
The Programmable Electronic System (PES) for the Allen-Bradley
GuardPLC system is safety-related, based on the 1oo2 microprocessor
structure for one central module. These controllers are safety-related
up to and including Safety Integrated Level (SIL) 3 according to IEC
61508 and category 3,4 according to EN 954-1.
Safety tests are based on the safety standards current at the time of
certification. These safety tests consist of test routines that are run
during the entire operating phase. The routines are guaranteed to the
highest degree of integrity for existing systems, making the PES
suitable for the Safety Machinery Application.
Safety State
The PES has been designed to the closed-circuit current principle,
which requires that systems be designed so that the normally closed
or on state of external sensors and actuators is the normal run
condition. The off or normally open state is the safe state. This means
that in the event of a fault or safety trip, all inputs and outputs revert
to the off (current-free/voltage-free) state.
Topic Page
Certification 14
Introduction to Safety 14
Safety Requirements 17
Safety Times 20