Honeywell C300 User Manual

218
Series 8 C300 Controller User's Guide
Honeywell
R500
April 2017
8. C300 Redundancy operation
8.6. Switchover
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:
 Execution of a Switchover command (from Primary or Secondary Platform FB).
 Loss of both FTE links to Primary controller.
 Loss of both IOL channels connected to Primary C300 I/O Link X,
where:
 X is the I/O Link number (that is, 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 does not 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
 Removal of the powered Primary controller module from its IOTA
 In the case of an unsynchronized redundant controller pair with both controllers
experiencing a dual-FTE cable disconnect. The 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:
 Loss of redundancy cable (private path) between Primary and Secondary controllers.
 Loss of one or both FTE links to Secondary controller.
 Loss of one or both IOL channels connected to Secondary C300 I/O LINK.
 Loss of input power to Secondary controller.

Honeywell C300 Specifications

General

Brand	Honeywell
Model	C300
Category	Controller
Language	English