Rockwell Automation Publication 5069-UM004A-EN-P - April 2019 209
Configure and Replace Safety Modules   Chapter 7
Replace a Module in a Logix 5000 System
Consider the following conditions before you replace a Compact 5000 I/O 
safety module in a Logix 5000™ system:
• If you rely on a portion of the CIP Safety system to maintain SIL 3 
behavior during module replacement and functional testing, you must 
use the Configure Only When No Safety Signature Exists feature. 
• If you rely on the entire routable CIP Safety control system to maintain 
SIL 3/PL (d or e) during the replacement and functional testing of a 
module, you can use the Configure Always feature. 
Replacement with `Configure Only When No Safety Signature Exists’ Enabled
When a module is replaced, the configuration is downloaded from the safety 
controller if the DeviceID of the new module matches the original. The 
DeviceID is updated whenever the SNN is set.
If the project is configured with Configure Only When No Safety Signature 
Exists enabled, follow the appropriate instructions in to replace a Compact 
5000 I/O safety module. 
After you complete the steps in a scenario correctly, the DeviceID matches the 
original. This match enables the safety controller to download the proper 
module configuration, and re-establish the safety connection.
Table 47 - Replace a Compact 5000 I/O Safety Module
Controller Safety Signature 
Exists
Replacement Module 
Condition
Action Required
No No SNN (Out-of-box) None. The module is ready for use.
Yes or No Same SNN as original safety task 
configuration
None. The module is ready for use.
Yes No SNN (Out-of-box) Complete the steps in 
Set the SNN Manually on page 206.
Yes Different SNN from original 
safety task configuration
No