Design

The annunciator unit is composed of four modules: an alarm annunciator module,

an input/output module, a connection module and a power module, housed

in a rugged aluminium casing.

The alarm annunciator module includes 16 alarm channels. The channels

are activated by normally open or normally closed process contacts.

The required 48 V dc contact circuit voltage is generated and supervised by the

annunciator unit. Each channel can separately be assigned a start delay from

5 ms to 160 s.

On activation of a channel the visual indicator of the channels starts blinking.

One of five standardized blinking systems according to ISA and DIN can be

selected by the operator at commissioning.

The annunciator is provided with a first-out indication given via the four-digit

alphanu merical display on the front panel. The first out alarm is indicated with

a letter A and the channel number.

The annunciator unit is also provided with an event register, which stores the

last nine events in chronological order. The event reg ister can be read via the

push-buttons and the display on the front panel or via the serial interface.

The annunciator holds four output relays, two of which are used as group alarm

output relays. One of five modes of operation can be selected for the realarm

output relays.

One output relay is dedicated for the self supervision system and one for the

control of an audible device, such as a buzzer or a horn. Any information

generated in the annunciator unit can be read by a hierarchically superior

system via the serial interface.