Emerson R2L0N1A1A PACSystems RXi2-LP IPC

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.