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.