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Rockwell Automation Publication 1734-UM013C-EN-P - August 2010
Chapter 8
Considerations When Replacing POINT Guard I/O Modules
Replacing an I/O Module
When Using a GuardLogix
Controller
Follow the appropriate steps to replace an I/O module when using a GuardLogix
controller.
I/O Replacement with ‘Configure Only When No Safety Signature
Exists’ Enabled
From the Controller Properties dialog box, choose ‘Configure Only When No
Safety Signature Exists’.
If a safety signature exists, clicking Set downloads the correct SNN from the
correct GuardLogix project to the replacement module. The only exception
would be when the SNN is already the same as the replacement module, in which
case no action is required.
IMPORTANT
When your GuardLogix controller is used in a SIL 3 application,
you must choose ‘Configure Only When No Safety Signature
Exists’. Because you must have a safety signature in SIL 3
applications, this option verifies that the SNN of the
replacement I/O module matches that of the GuardLogix
controller before a connection is made.