Emerson DeltaV S-series Traditional I/O I/O Card Redundancy

I/O Card Redundancy

Redundant I/O cards are available for critical applications.

The same card can be used in simplex or redundant

applications. When installed on a two-wide redundant terminal

block, the cards are recognized as a redundant pair by the

controller. The controller scans each card and determines which

card is acting as the active interface. When a fault is detected,

the system automatically switches to the standby I/O card.

DeltaV control modules reference simplex and redundant

I/O channels identically and there is no special configuration

required to take advantage of redundancy.

Switchover of a redundant I/O card is completed within

two scans of the I/O bus. Make-before-break contacts ensure

digital field instruments remain powered and the process

is undisturbed. Analog output signals are briefly driven by

both cards for <5 ms during switchover of the card.

Hardware alerts automatically report hardware integrity errors

for both the primary and secondary cards. Any event that

causes a switchover is also reported automatically through the

system hardware alerts and is logged in the Event Chronicle.

Events that can cause a switchover include:

„ Hardware failure within the active card.

„ Communications failure between the active card

and the controller.

„ Detection of a fault in the field wiring.

A switchover may also be initiated from the diagnostics explorer, and the health and status of both cards and their channels are

available in the diagnostics explorer.

The system automatically commissions a new standby card. In safe areas, failed cards can be replaced under power.

In hazardous areas, appropriate installation procedures must be followed.

Hardware Specifications