Conditions That Result In Switchover; Conditions That Do Not Result In A Switchover - Honeywell Experion C300 User Manual

Conditions that result in switchover

The Secondary controller must be in either the Synchronized state or Standby state for a
switchover to occur. The following conditions result in a switchover:
Switchover command (from Primary or Secondary Platform FB).
•
Both FTE links to Primary controller are lost.
•
Both IOL channels connected to Primary C300 I/O Link X are lost where:
•
X is the I/O Link number (i.e. equally applies to either I/O Link).
−
The IOLINK Type for this I/O Link has a value other than NONE
−
There is at least one configured IOM communicating on the I/O Link.
−
ATTENTION
Controller redundancy protects against all single faults and some dual faults.
The Primary C300 Dual IOL Cable Disconnect switchover trigger is a dual
fault that cannot be detected until after some control has been back-initialized
with failsafe data. Although this dual fault affects control, switchover provides
automatic recovery that doesn't require the operator to diagnose how to deal
with a primary that has a complete loss of IOM view
Loss of input power to Primary controller
•
Primary controller failure
•
Removing the powered Primary controller module from its IOTA
•
Starting with an unsynchronized redundant controller pair with both controllers
•
experiencing a dual-FTE cable disconnect, FTE reconnect to the secondary
controller results in initial-sync followed by immediate switchover.

Conditions that do not result in a switchover

These conditions do not result in a switchover:
Redundancy cable (private path) between Primary and Secondary controllers is lost.
•
Single or both FTE links to Secondary controller are lost.
•
Single or both IOL channels connected to Secondary C300 I/O LINK are lost.
•
Loss of input power to Secondary controller
•
R301.1
11/06
Experion C300 Controller User's Guide
Honeywell
Switchover
Conditions that result in switchover
199