Emerson DeltaV™ Controller Redundancy Product Description

Product Description

For critical process control applications where you can’t afford

interruptions, the DeltaV system offers controller redundancy.

The standby controller contains the same control strategies as

the active controller and the redundancy link transfers control

parameters to the standby controller to ensure it is ready to take

control if needed.

With redundancy enabled, each module will calculate the

required updates for the Standby controller when it executes.

These updates are transferred to the standby controller over

the redundancy link. These additional operations for controller

redundancy will typically reduce your CPU free time by

approximately 10%.

When a fault is detected, the standby controller can take over

without bumping the process control signals. The DeltaV Event

Chronicle stores a record of each switchover and the reason it

occurred (if the reason has been identified).

Replacing an existing standby controller is as simple as removing

the existing unit and installing a new controller. The active

controller will detect the standby and the system will automatically

commission and download the new hardware. A redundancy

license is required in addition to the redundant hardware. The

redundant controller appears in the Explorer window as a single

node, indicated by a redundant controller icon.

Switchover Detection

The redundant controllers continuously monitor themselves

and each other for conditions that require a switchover. Each

controller runs continuous self-test routines to determine their

ability to function. A hard failure of the active controller will trigger

an immediate switchover to the standby controller. The standby

controller also monitors the I/O bus traffic to detect if the active

controller stops functioning and failed to issue a switchover

command. This switchover requires a verification cycle, during

which time all output signals hold their values until the new active

controller begins executing control strategies.