Fault classifications 
Hard/Severe Failures 
R301.1  Experion C300 Controller User's Guide  237 
11/06  Honeywell 
Fault Classification  Description 
Installation/Startup 
Failure 
Software detected failure.  Controller may not become operational.   
•  Installation/Startup failure on a non-redundant controller results in 
the inability to commence control or view the controller on the 
network.   
•  Installation/Startup failure on the backup controller results in the 
inability to complete initial synchronization or view the controller on 
the network.   
•  Installation/Startup failure does not apply to the synchronized 
primary controller, because installation & startup must be 
successful to reach a synchronized primary state.   
Communications 
Failure 
Communication errors between peer controllers, nodes and/or I/O 
devices - including FTEB, do not cause any controller state change. 
 
Hard/Severe Failures  
When a hard failure is detected, the following controller events occur depending on its 
redundancy status: 
•  Hard/Severe failure on a synchronized primary controller triggers a switchover to the 
backup controller.  The I/O modules associated with the controller force their outputs 
to safe values.  If capable, the failed controller reboots into the FAIL state and 
captures diagnostic data which may contain internal state events that occurred prior 
to a failure.   The Ctools utiltity can be used to retrieve the diagnostic data.   
•  Hard/Severe failure on a backup controller causes a loss-of-synchronization.  The 
Primary controller continues operation, but enters the ‘Not synchronized’ state.  If 
the redundant controller pair was not synchronized when the fault occurred, then the 
failed controller reboots into the FAIL state, if capable.  No further synchronization 
will occur and no switchover will occur.  
•  Hard/Severe failure on a non-redundant controller causes a loss-of-control and loss-
of-view.  The I/O modules associated with the controller force their outputs to safe 
values.  If capable, the failed controller reboots into the FAIL state and captures 
diagnostic data which may contain internal state events that occurred prior to a 
failure.  The CTools utility can be used to retrieve the diagnostic data.   
Alarm display and function block detail display 
Usually a hard or severe failure results in a communication failure.  Calling up the Alarm 
Detail Display in Station or the Controller Block Detail Display will indicate this failure.