Honeywell HC900 User Manual

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.

Honeywell HC900 Specifications

General

Series	HC900
Redundancy	Optional
Programming Language	Function Block Diagram, Ladder Logic, Structured Text
Inputs	Analog, Digital
Outputs	Analog, Digital, Relay
Display	Optional
Control	PID, Advanced Control
Power Supply	24V DC or 100-240V AC
Storage Temperature	-40°C to 85°C
Humidity	5% to 95% non-condensing
Communication Protocols	Modbus, Ethernet