Honeywell HC900 - Failover

Revision 6 HC900 Process & Safety Controller User and Installation Manual 169
21 April 2017
Figure 88 – Lead/Controller synchronization
Failover
Automatic Failover
 Triggered on any of the following conditions of the Lead Controller:
 Loss of communications with I/O Rack(s)
 Processor exception conditions
 Error conditions that occur in the following areas will not cause a failover:
 Loss of communications to a Host on a network
 Loss of communications to Modbus Slave devices
 Loss of communications to Operator Interface
 Loss of communications with a Peer controller
 During the transition from the Lead to the Reserve, analog and digital output status is maintained at the
I/O racks.