User guide

AN24 & AN28 Annunciators Instruction Manual

FULL ALARM TYPE DESCRIPTIONS

The following section describes the operation of the various sequences

available in the alarm annunciator.

Features

Acknowledge Pushbutton: Momentary alarms will not clear until the

alarmed channels have been acknowledged with the ACK pushbutton.

This will also reset the first out indication. Used in all ISA sequences.

Automatic Reset: Acknowledged momentary alarms will clear

automatically when the inputs return to normal. The automatic reset is

present in all automatic (A) sequences.

First-Out Indication: The sequence provides a distinct visual indication

for the first channel to alarm.

First-Out Reset Pushbutton: Resets the first-out display and assigns

the first-out channel to display as a subsequent alarm without any other

changes to the sequence. The next alarm input will be a new first-out

alarm. Used only in sequence F3A.

Reset Pushbutton: Acknowledged momentary alarms will only clear

when reset with the RESET pushbutton. Used in any manual reset (M)

sequence.

Alarm Condition Descriptions

The following terms are used in describing the alarm behavior in the

following tables:

Alert: The input is in alarm state, and the channel has not been

acknowledged with the ACK pushbutton.

Acknowledge: The alarm state is acknowledged with the ACK

pushbutton. This will restart the first-out indication.

First Out Reset (F3A Only): The RESET pushbutton is used to reset

the first-out indication only.

Normal: Inputs are in the normal state.

LED Condition Descriptions

Pt: Indicates the behavior of the first-out alarm channel only.

Next Pt: The behavior of subsequent alarm channels; channels that

enter the alarm state after the first-out alarm.