Failover - Honeywell HC900 User And Installation Manual

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.
Revision 6
21 April 2017
Figure 88 – Lead/Controller synchronization
HC900 Process & Safety Controller User and Installation Manual 169