Logix Designer Application Capabilities and Redundancy State

Configure controller systems for redundant operation, which is the use of multiple similar devices, such that if one fails, the remaining device(s) take over the assigned functions, thus improving the devices' availability. When redundancy is enabled, certain software functions and capabilities are enabled and disabled based on the redundancy state.
The possible controller redundancy states are:
  • Synchronized Secondary
    A chassis that has a partner primary control chassis, and whose state and data information is synchronized with the primary control chassis. A synchronized secondary is capable of taking control of application programs with minimal impact to the assigned functions.
  • Synchronizing Secondary
    A chassis that has a partner primary control chassis, and is currently attempting to achieve synchronization. In this state of readiness, a secondary control chassis cannot assume the primary state.
  • Locked Secondary
    A chassis that presently has a partner primary control chassis and is in a state in which no application changes are allowed on either the primary or secondary controller.
  • Locking Secondary
    A chassis that presently has a partner primary control chassis and is in the process of locking the Redundancy System in preparation for entering the locked state.
  • Synchronizing Primary
    A chassis that has a partner secondary control chassis, and is currently attempting to achieve synchronization.
    This synchronization could be triggered as a result of a configuration action made within
    RSLinx Classic
    (for example, invoking the Initiate Synchronization command), the use of a MSG instruction, or an auto-synchronization attempt.
  • Locked Primary
    A chassis that has a partner secondary control chassis and is in a state in which no application changes are allowed on either the primary or secondary controllers.
  • Locking Primary
    A chassis that has a partner secondary control chassis and is in a state in which no application changes are allowed on either the primary or secondary controllers.
  • Disqualified Secondary
    A control chassis that may have had, or currently has, a partner primary control chassis, but is now incapable of performing a control function if the primary chassis fails
Refer to the table to determine the impact of the various redundancy states on these functions.
This function or capability is disabled
If the controller is in this redundancy state
Creating or deleting a component (for example, tag, routine)
Undetermined
Synchronized Secondary
Synchronizing Secondary
Locked Secondary
Locking Secondary
Synchronizing Primary
Locked Primary
Locking Primary
Editing or modifying component values
Undetermined
Synchronized Secondary
Synchronizing Secondary
Setting tag values
Undetermined
Synchronized Secondary
Synchronizing Secondary
Locked Secondary
Locking Secondary
Locked Primary
Locking Primary
Running or stopping trending
Undetermined
Synchronized Secondary
Synchronizing Secondary
Locked Secondary
Locking Secondary
Synchronizing Primary
Locked Primary
Locking Primary
Changing controller mode remotely
Undetermined
Synchronized Secondary
Synchronizing Secondary
Locked Secondary
Locking Secondary
Disqualified Secondary (with or without partner)
Changing or enabling force state (either by enabling, disabling, or removing all forces, or by modifying individual forces)
Undetermined
Synchronized Secondary
Synchronizing Secondary
Locked Secondary
Locking Secondary
Locked Primary
Locking Primary
Downloading
Undetermined
Synchronized Secondary
Synchronizing Secondary
Locked Secondary
Locking Secondary
Synchronizing Primary
Locked Primary
Locking Primary
Editing routine logic (including testing, untesting, assembling, and canceling edits, as well as accepting pending edits)
Undetermined
Synchronized Secondary
Synchronizing Secondary
Locked Secondary
Locking Secondary
Synchronizing Primary
Locked Primary
Locking Primary
Certain motion commands, such as the Start Motor/Encoder Test, Start Marker Test, and Start Tune commands
Undetermined
Synchronized Secondary
Synchronizing Secondary
Locked Secondary
Locking Secondary
Locked Primary
Locking Primary
Disqualified Secondary (with or without a partner)
Disabling nonvolatile memory
Undetermined
Synchronized Secondary
Synchronizing Secondary
Locked Secondary
Locking Secondary
Synchronized Primary
Synchronizing Primary
Locked Primary
Locking Primary
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