ABB SACO16D1-AA Digital Annunciator Unit

external secured power source. The unit com

municates with higher-level data acquisition and control systems over

the SPA bus.

Self-supervision

The annunciator incorporates a sophisticated self-supervision system

which increases the availability of the device and the reliability of the system.

The self-supervision system continuously monitors the hardware and the soft

ware of the unit. The system also supervises the operation of the auxiliary

supply module and the level of the electronics' voltages generated by the

module. If a permanent fault is detected, the fault indicator on the front

panel is lit, the output relay of the self-supervision system operates and

the outputs are blocked.

Auxiliary supply voltage

The auxiliary supply of the relay is obtained from an internal plug-in type

power supply module. Two auxiliary power module types are available:

type SPGU 240A1 for the supply voltage range 80…265 V ac/dc and type

SPGU 48B2 for the supply voltage range 18…80 V dc. The power supply

module forms the internal voltages required by the annunciator.