58 Rockwell Automation Publication 1756-RM093J-EN-P - April 2018
Chapter 6 Safety Application Development
9. Use the RSLogix 5000 Program Compare utility to perform these
comparisons:
• Compare all of the properties of the GuardLogix controller and CIP
Safety I/O modules.
• Compare all of the properties of the safety task, safety programs and
safety routines.
• Compare all of the logic in the safety routines.
Safety Validation
An independent, third-party review of the safety system may be required before
the system is approved for operation. An independent, third-party certification is
required for IEC 61508 SIL 3.
Lock the GuardLogix Controller
The GuardLogix controller system can be safety-locked to help protect safety
control components from modification. However, safety-locking the controller is
not a requirement for SIL 3 applications. The safety-lock feature applies only to
safety components, such as the safety task, safety programs, safety routines, safety
tags, safety Add-On Instructions, safety I/O, and safety task signature. However,
safety-locking alone does not satisfy SIL 3 requirements.
No aspect of safety can be modified while the controller is in the safety-locked
state. When the controller is safety-locked, the following actions are not
permitted in the safety task:
• Online or offline programming or editing
• Forcing safety I/O
• Data manipulation (except through routine logic or another GuardLogix
controller)
• Creating or editing safety Add-On Instructions
• Generating or deleting the safety task signature
• If a safety task signature exists, only projects with a matching safety task
signature can be downloaded to controller.
The default state of the controller is safety-unlocked. You may place the safety
application in a safety-locked state regardless of whether you are online or offline,
and regardless of whether you have the original source of the program. However,
no safety forces or pending safety edits may be present. Safety-locked or
-unlocked status cannot be modified when the keyswitch is in the RUN position.
To provide an additional layer of protection, separate passwords may be used for
safety-locking or -unlocking the controller. Passwords are optional.
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