
Rockwell Automation Publication 1756-UM013B-EN-P - October 2019
17
Digital Safety I/O Module Operation in a Control System
Chapter 1
Safety Application Requirements
Safety application requirements include evaluating the following:
• Probability of failure rates (PFD and PFH)
• System reaction time settings
• Functional verification tests that fulfill appropriate safety-level criteria
Creating, recording, and verifying the safety signature is also a required part of
the safety application development process. The safety controller creates the
safety signatures. The safety signature consists of an identification number, date,
and time that uniquely identifies the safety portion of a project. This number
includes all safety logic, data, and safety I/O configuration.
For safety system requirements, including information on the safety network
number (SNN), verifying the safety signature, functional verification test
intervals, system reaction time, and PFD/PFH calculations, see the
GuardLogix 5580 and Compact GuardLogix 5380 Controller Systems Safety
Reference Manual, publication
You must read, understand, and fulfill the requirements that are described in this
publication before you operate a safety system that uses 1756 ControlLogix
digital safety I/O modules.
Summary of Contents for 1756 Series
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