Fault Classifications - Honeywell Experion PKS User Manual

13.2 Fault Classifications

Faults have been classified into a number of categories according to the severity of the failure. The PGM
behavior when a failure is detected is determined by type of fault and whether the PGM is non-redundant, or is
one of a redundant controller pair.
The following table identifies these fault classifications and describes PGM behavior in response to the fault
type.
Fault Classification
Hard Failure
Severe Failure
Soft Failure
Installation/Startup Failure
Communication Failure
13 PROFIBUS GATEWAY MODULE (PGM) TROUBLESHOOTING
Characteristics
Failure detected by hardware; operation cannot continue. If the fault does not
prevent software processing the problem, the affected node will be rebooted
under software control into the FAIL State.
• If failure occurs on a primary module, it triggers a switchover to the
synchronized secondary module.
• If failure occurs on a secondary module, it results in loss of
synchronization and reduced availability until the problem is resolved.
• If failure occurs on a non-redundant module, it results in loss of control
and loss of view.
Failure detected by software; operation cannot continue. The affected node
will be rebooted under software control into the FAIL State.
• Severe failure on a synchronized primary module triggers a switchover to
the secondary module.
• Severe failure on a secondary module causes a loss-of-synchronization
(and reduced availability until fault is corrected).
• Severe failure on a non-redundant module causes a loss-of-control and
loss-of-view.
Failure detected by software; operation continues with full control and full
view. Soft failures are alarmed to the operator. FTE will be monitored by the
FTE System Management Tool.
• If failure occurs on a primary module, it does not trigger a switchover to
the synchronized secondary module.
• If failure occurs on a secondary module, it does not result in loss of
synchronization.
• If failure occurs on a non-redundant module, it does not result in loss of
control and loss of view.
Detected by software. Module may not become operational.
• This failure does not apply to the synchronized primary module, since
installation and startup must be successful to reach synchronized primary
state.
• If failure occurs on a secondary module, it results in the inability to
complete the initial synchronization and to view the node on the network.
• If failure occurs on a non-redundant module, it results in an inability to
commence control and to view the module on the network.
Communication errors between peer modules and/or I/O devices, including
Fault Tolerant Ethernet Bridge (FTEB), do not cause any module state
change.
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