This is the CMOS memory card for the Extended Controller. This memory card must be used in an Extended Controller where UAC is implememted.

There have been reports of the single relay on this card failing to switch when needed, resulting in a failed switch to the reserve controller during primary controller failure (CRM PD02 Z99 (D)). To address this potential weakness, WPC installs a new relay on every CMOS memory card that we supply.

For non-UAC systems, this CMOS memory (with 9V battery) can be used instead of the original core backup memory, 30750732-001.

This card is used to copy and maintain controller configuration data, such as ranges, configuration words, and tuning constants. In the event of a failure in a primary controller on a UAC system, current controller data is transferred from the CMOS card to the Reserve Controller during failover.

A switch on the front of the card allows lock-out of automatic data updating. In the ‘normal’ switch setting, the memory on this card is updated. In the ‘disable’ position, data is not updated and the UAC system will not replace the controller in the event of a failure.

This card has two LEDs, one of which blinks each time data is updated, the other of which indicates power is applied to the card.