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.

Some of the events that can cause a switchover are:

•Hardware failure within the active controller

•Communications failure between the active controller

and I/O

•Communications failure on both control network ports of the

active controller

•Removal of the active controller from the carrier

•User request initiated from Diagnostic Explorer

System Compatibility

M-series, S-series and SZ controllers are all supported on

DeltaV v12.3 and beyond. PK Controllers are supported on

DeltaV v14.3 and beyond. For detailed version compatibility

see the Prerequisites section below.

Redundant controller pairs must be of the same series. For

example, M-series and S-series controllers cannot be connected

together as a redundant pair.

Although an SX controller can operate as a standby controller to an

SQ active controller, it is recommended that both the active and

standby controllers be of the same hardware. The SQ may not have

sufficient memory or CPU capacity to accept the configuration that

runs in an SX controller. This applies for MX and MQ controllers as

well, only mix controller types as a temporary condition during a

hardware upgrade.

The MQ, MX, SQ, SX and PK Controllers are all capable of

redundancy. For more information on these controllers, refer to

the respective controller product data sheet.

SZ Controllers are also capable of redundancy. For more

information on this controller, refer to the DeltaV SIS Electronic

Marshalling or DeltaV SIS IS Electronic Marshalling product

data sheets.