Dwyer Instruments AN24 Series, Instruction Manual

Page: 16 / 21

AN24 & AN28 Annunciators Instruction Manual
16
Full Sequence Descriptions
The following section describes the operation of the
various sequences available in the Series AN24/AN28
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.
Sequence Condition Descriptions
The following terms are used in describing the
sequence 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
1
st
Pt: Indicates the behavior of the first-out channel
only.
Next Pt: The behavior of subsequent alarm channels;
channels that enter the alarm state after the first-out
alarm.
ISA Sequence A
Acknowledge Pushbutton and Automatic Reset
Momentary Alarm Maintained Alarm
Sequence A Switch Positions
Sequence A Flow Chart
Condition LED Horn Condition LED Horn
Normal Off Off Normal Off Off
Alert Flash On Alert Flash On
Normal Flash On ACK Pushbutton
ACK Pushbutton Acknowledge Steady Off
Acknowledge Off Off Normal Off Off
Condition Normal
LED Off
Horn Off
Condition Alert
LED Flash
Horn On
Condition Alert
LED Steady
Horn Off
Alarm Condition
Ack when
Inputs Normal
Return
to Normal
Ack
Pressed
Relay Operation
For complete details on relay function, see page 13 .
Relay 1 Operation
Relay 1 enters alarm state when there is a new alarm.
This relay will clear when the alarms are acknowledged.
Relay 2 Operation
Relay 2 enters alarm state when any channel displays in
alarm state. This relay will clear when all indication
LEDs are cleared.