Honeywell HC900 - Failover

Redundant Operating Characteristics - Failover
158 HC900 Process Controller Installation and User Guide Revision 19
06/14
Figure 84 – 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.