Change Detection on Redundant Controllers
The Change Detection feature on the controller generates the following unique values to
identify changes:
- Audit value—Use to identify if a change to a monitored event occurs.
- Tracked state value—Use to identify if a change to a tracked routine, Add-On Instruction, I/O module, or constant tag occurs.
After commissioning the system, record the preceding values and store them in a secure
location. For more information about change detection, see the ControlLogix 5590
Controllers User Manual, publication 1756-UM900.
To identify changes to safety applications, the controller uses the safety signatures
that are described in Logix SIS
Security Considerations.
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