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.