Lock the Controller
ATTENTION:
Safety-locking alone does not satisfy SIL 2/PLd or SIL 3/PLe requirements.
The default state of the controller is safety-unlocked. We recommend that you safety-lock the controller to help protect safety control components from modification and help prevent the safety signature from being deleted accidentally. However, safety-locking the controller is not a requirement for SIL 2 or SIL 3.
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 signature.
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:
- Update the firmware without using the Redundancy System Update (RSU) process
- Online or offline programming or editing
- Forcing safety I/O
- Data manipulation of safety components except through routine logic
- Creating or editing safety Add-On Instructions
- Generating or deleting the safety signature
IMPORTANT:
If a safety signature exists and the controller is safety-locked, only projects with a matching safety signature can be downloaded to the controller.
You can place the safety application in a safety-locked state regardless of whether you are online, offline, or you have the original program source. However, no safety forces or pending safety edits can be present. Safety-locked or -unlocked status cannot be modified when the keyswitch is in the RUN position.
Safety-lock and safety-unlock actions are logged in the controller log. For more information on accessing the controller log, see the Logix 5000 Controllers Information and Status Programming Manual, publication 1756-PM015.
You can safety-lock and -unlock the controller from the Safety tab of the Controller Properties dialog box. In the Logix Designer application, you can also select Tools > Safety > Safety Lock/ Unlock.
Safety Lock/Unlock Button
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