Dwyer Instruments AN24 Series User manual

Bulletin: P-AN2
AN24 & AN28 Annunciators
Instruction Manual
DWYER INSTRUMENTS, INC.
Phone: [phone]
dwyer-inst.com
P.O. BOX 373 • MICHIGAN CITY, IN 46360, U.S.A.
Fax: [phone]
e-mail: [email protected]
•1/8 DIN Annunciators with NEMA 4X, IP65 Front
•Switch, Transistor, and Logic Level Inputs
•4 or 8-Point Monitoring
•8 Field Selectable ISA Sequences Including First-Out
•Multiple-Unit First-Out Indication
•Free Custom Message Labels
•Silence, Acknowledge, and Reset Functions
•Sunlight Readable Indication
•Shallow Depth Case Extends Only 3.6" (91 mm) Behind Panel
•Isolated 24 VDC @ 200 mA Transmitter Power Supply (AC Models)
•2 SPDT Relays for Alarm Activated Devices
•Operating Temperature Range: -40 to 65°C (-40 to 149°F)
•UL & C-UL Listed. E160849; 508 Industrial Control Equipment
•Input Power Options: 85-265 VAC / 90-265 VDC or 12-36 VDC / 12-24 VAC
•Built-in Internal 85 dB Horn with Silence Pushbutton
•3-Year Warranty

AN24 & AN28 Annunciators Instruction Manual
2
Disclaimer
The information contained in this document is
subject to change without notice. Dwyer
Instruments, Inc makes no representations or
warranties with respect to the contents hereof;
and specifically disclaims any implied warranties
of merchantability or fitness for a particular
purpose.
•Read complete instructions prior to installation
and operation of the annunciator.
•Risk of electric shock or personal injury.
•This product is not recommended for life support
applications or applications where malfunctioning
could result in personal injury or property loss.
Anyone using this product for such applications
does so at his/her own risk. Dwyer Instruments,
Inc shall not be held liable for damages resulting
from such improper use.
WARNING
Cancer and Reproductive Harm - www.P65Warnings.ca.gov
Limited Warranty
Dwyer Instruments, Inc warrants this product
against defects in material or workmanship for
the specified period under “Specifications” from
the date of shipment from the factory. Dwyer’s
liability under this limited warranty shall not
exceed the purchase value, repair, or
replacement of the defective unit. See Warranty
Information and Terms & Conditions on
www.dwyer-inst.com for complete details.
© 2020 Dwyer Instruments, Inc.
All rights reserved.
Introduction
The Series AN24/AN28 is a multipurpose panel
mounted alarm annunciator available for four or eight
inputs.
It can be set up to respond to alarm conditions based
on 8 field selectable alarm sequences, including first-
out indication. The alarm channels accept normally
open, normally closed, NPN open collector transistor,
and logic level inputs. Three front panel pushbuttons
are used during sequence operation to silence the
horn, acknowledge the first out alarm, and reset
cleared channels as required by the sequences.
The Series AN24/AN28 has two SPDT relays that can
be used for additional external alarm indication,
additional audible devices, or for process control.
Ordering Information
85-265 VAC*
Model
12-36 VDC*
Model
Description
AN24-1
AN24-2
4 Channel
Annunciator
AN28-1
AN28-2
8 Channel
Annunciator
* All models may be powered from AC or DC, see
Specificationsfor details.
Enclosures
Series
# of
Meters
Material
Mounting
PME-01
1
Low-Cost Plastic
NEMA 4X
Through
Cover
PME-02
2
PME-11
1
Plastic NEMA 4X
Through
Door
PME-12
2
PME-13
3
PME-14
4
PME-15
5
PME-16
6

AN24 & AN28 Annunciators Instruction Manual
3
Table of Contents
Introduction..........................................................................................................2
Ordering Information...........................................................................................2
Quick Setup Guide...............................................................................................5
Sequence Selection.........................................................................................5
NO/NC Inputs...................................................................................................5
Basic Connections..........................................................................................5
Specifications.......................................................................................................5
General.............................................................................................................6
Input..................................................................................................................6
Relays...............................................................................................................6
Compliance Information......................................................................................7
Safety................................................................................................................7
Electromagnetic Compatibility.......................................................................7
Safety Information ...............................................................................................7
Installation............................................................................................................7
Unpacking........................................................................................................7
Panel Mounting................................................................................................7
Dimensions......................................................................................................8
Connections.....................................................................................................8
Connectors Labeling .....................................................................................8
Power Connections.......................................................................................9
Signal Connections .......................................................................................9
Relays and 24 V Output Connections...........................................................9
Switching Inductive Loads...........................................................................10
External Input Types ...................................................................................10
Multiple Unit First-Out Indication Connections............................................10
Setup and Programming...................................................................................11
Overview.........................................................................................................11
Front Panel Pushbuttons and Status LED Indicators................................11
Full Function Test..........................................................................................11
Multiple Unit First-Out Indication.....................................................................11
Shared Front Panel Buttons.........................................................................11
Annunciator Sequence Selection ................................................................12
Sequence Programming..............................................................................12
Sequence Descriptions ...............................................................................12
Normally Open/Normally Closed Input Setup.............................................12
Programming NO/NC Inputs .......................................................................12
NO/NC Programming Example...................................................................13
Relay Operation.............................................................................................13
Relay 1 Operation .......................................................................................13
Relay 2 Operation .......................................................................................13
Relay Fail-Safe............................................................................................13
Programming Relay Fail-Safe.....................................................................13
Relay Fail-Safe Programming Example......................................................14
Relay Operation Overview ..........................................................................14
Audible Horn Enable/Disable .......................................................................14
Enabling/Disabling Silence Option..............................................................14
No Lock-In Sequence Option .......................................................................15
Reset to Factory Defaults.............................................................................15
Troubleshooting.................................................................................................15
Full Sequence Descriptions..............................................................................16
Features......................................................................................................16
Sequence Condition Descriptions...............................................................16
LED Condition Descriptions ........................................................................16
ISA Sequence A.............................................................................................16
ISA Sequence F2A.........................................................................................17

AN24 & AN28 Annunciators Instruction Manual
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ISA Sequence F1A.........................................................................................17
ISA Sequence F3A.........................................................................................18
Input Follower Indication .............................................................................19
ISA Sequence M.............................................................................................19
ISA Sequence F1M ........................................................................................19
ISA Sequence F2M ........................................................................................20
Table of Figures
Figure 2. Panel Cutout and Mounting..................................................................7
Figure 3. Case Dimensions –Side View..............................................................8
Figure 4. Case Dimensions –Top View...............................................................8
Figure 5. Connector Labeling for AN24-1............................................................8
Figure 6. Connector Labeling for AN28-1............................................................8
Figure 7. Connector Labeling for AN24-2............................................................8
Figure 8. Connector Labeling for AN28-2............................................................8
Figure 9. Power Connections ...............................................................................9
Figure 10. NO/NC Contact Inputs.........................................................................9
Figure 11. Open Collector NPN Transistor Inputs..............................................9
Figure 12. Relay & 24 V Output Connections......................................................9
Figure 13. AC and DC Loads Protection..............................................................10
Figure 14. Low Voltage DC Loads Protection.....................................................10
Figure 17. System with Multiple Units Share First-Out......................................10
Figure 18. Shared Pushbutton Connections.......................................................11
Figure 19. DIP Switch Location ............................................................................12

AN24 & AN28 Annunciators Instruction Manual
5
Quick Setup Guide
The following overview details how to set up the
annunciator for most common uses.
Sequence Selection
The two most common sequences are ISA A and
ISA F2A. Select the sequence using the four-position
switch on the rear of the unit above the signal
connector. For complete sequence details,
see page 16.
ISA A
ISA F2A
NO/NC Inputs
Each input can be set for normally open (NO) or
normally closed (NC) contacts. Each input channel is
programmed individually. The default setting is for all
inputs to be NO.
To set inputs to NC:
1. Press and hold ACK and RESET for
3 seconds until all LEDs cycle.
2. Press ACK within 3 seconds of release. All
LEDs will blink. If ACK is not pressed within
3 seconds, the unit will return to run mode.
3. Press ACK again within 3 seconds of
release. If ACK is not pressed within
3 seconds, the unit will return to run mode.
The LED for the channel being programmed will
display brightly on or off. All other channel indication
LEDs will be at low intensity to indicate programming
mode.
4. Press the RESET pushbutton to turn LED 1
off for a NO input, or on for a NC input for
channel 1.
5. Press ACK to accept the input type and
program channel 2.
6. Repeat steps 4 and 5 for all input channels.
Press and hold ACK for five seconds to return to
normal operation with the programmed input types.
Basic Connections
All connections are made to removable screw
terminal connectors located at the rear of the
instrument. For complete connection details, see
page 8.
•Use copper wire with 60°C or 60/75°C insulation
for all line voltage connections.
•Observe all safety regulations.
•Electrical wiring should be performed in
accordance with all applicable national, state,
and local codes to prevent damage to the
instrument and ensure personnel safety.
Connector Labeling
The connectors label, affixed to the instrument, shows
the location of all connectors available with requested
configuration. See Connectors Labeling on page 8.
Power Connections
Power connections are made to a two-terminal
connector labeled POWER. The instrument will
operate regardless of DC polarity connection.
The + and - symbols are only a suggested wiring
convention.
Signal Connections
Input signal connections are made to a 14-terminal
connector at terminals labeled INPUT CHANNELS.
The COM (common) terminal is the return for all input
channels.
Relays and 24 V Output
Connections
Relay connections are made to a six-terminal
connector labeled RELAY1, RELAY2. The COM
(common) terminals of the relays should not be
confused with the COM (common) terminal of the
signal connector. The 24 VDC output is available at
the connector labeled 24V OUT, next to the relays
connector.
Additional Information
For additional setup and wiring information, please see
the complete details further in this manual.

AN24 & AN28 Annunciators Instruction Manual
6
Specifications
Except where noted all specifications apply to operation at +25°C.
General
Display
AN24; Four red LED channel/point
indicators.
AN28; Eight red LED channel/point
indicators.
One green LED power indicator.
Alarm
Messages
Custom printed adhesive clear labels.
AN24 Area: 1.25" x .60" (32 mm x 15 mm),
4 messages
AN28 Area: 1.25" x .25" (32 mm x 6 mm),
8 messages
Up to 4 lines (AN24) or 2 lines (AN28) of 14
characters of size 9 fonts.
Programming
Methods
Rear 4-position switch for sequence
selection and horn operation. Three front
panel pushbuttons for NO/NC input
selection, sequence options, and sequence
operation.
Noise Filter
40 ms debounce on inputs (including SIL,
ACK, and RST).
Shared First-
Out Systems
1 ms unit-to-unit delay. Maximum of 200
units in the shared first-out system.
Non-Volatile
Memory
All programmed settings are stored in non-
volatile memory for a minimum of ten years
if power is lost.
Power
Options
85-265 VAC, 50/60 Hz,
90-265 VDC, 20 W max
or 12-36 VDC, 12-24 VAC, 6 W max
Fuse
Required external fuse: UL Recognized,
5 A max, slow blow. Up to 6 annunciators
may share one 5 A fuse
Isolated
Power Supply
24 VDC 10% @ 200 mA max
Standard on 85-265 VAC powered units only.
Isolation
4 kV input/output-to-power line.
Overvoltage
Category
Installation Overvoltage Category II:
Local level with smaller transient
overvoltages than Installation Overvoltage
Category III
Environmental
Operating temperature range: -40 to 65°C
Storage temperature range: -40 to 85°C
Relative humidity: 0 to 90% non-condensing
Connections
Removable screw terminal blocks for 12 to
22 AWG wire.
Enclosure
1/8 DIN, high impact plastic, UL 94V-0,
front color: black
Mounting
1/8 DIN panel cutout required. Two panel
mounting bracket assemblies provided.
Tightening
Torque
Screw terminal connectors:
5 lb-in (0.56 Nm)
Overall
Dimensions
4.68" x 2.45" x 4.19"
(62 mm x 119 mm x 106 mm) (H x W x D)
Weight
9.6 oz (272 g)
Warranty
3 years parts and labor. See Warranty
Information and Terms & Conditions on
www.dwyer-inst.com for complete details.
Input
Input Types
NO or NC switches: No external
excitation required
Open collector transistor (NPN):
Open circuit voltage approximately
3.3 VDC
Logic Levels: LOW = 0 to 0.9 VDC
HIGH = 2.4 to 28 VDC
Update Rate
41 ms following alarm state;
1 ms for alarm state clear
Sequences
Input follower, ISA Sequences A, F1A,
F2A, F3A, M, F1M, F2M and F3M per
ISA Standard ISA-18.1-1979 R2004.
Sequence
Options
A, F1A, F2A, F3A, M, F1M, F2M, and
input follower with selectable options
-1 (silence pushbutton), -4 (no lock-in),
and -6 (no horn) per ISA Standard
ISA-18.1-1979 R2004.
Relays
Rating
2 SPDT (Form C); rated 3 A @ 30 VDC
or 3 A @ 250 VAC resistive load;
1/14 HP @ 125/250 VAC for inductive
loads
Electrical Noise
Suppression
A snubber should be connected to each
relay contact switching inductive loads
to prevent disruption to the
microprocessor’s operation.
Recommended snubber value:
0.01 µF/470 , 250 VAC (PMA-09).
Relay
Operation
Relay 1: Alarm state until alarm is
acknowledged.
Relay 2: Alarm state while any channel
indicating alarm condition.
Fail-Safe
Operation
Programmable
Independent for each relay
Note: In fail-safe mode, relay coil is
energized in non-alarm condition. In
case of power failure, relay will go to
alarm state.

AN24 & AN28 Annunciators Instruction Manua
7
Compliance Information
Safety
UL Listed
USA and Canada
UL 508 Industrial Control Equipment
UL File Number
E212517
Front Panel
UL Type 4X, NEMA 4X, IP65; panel
gasket provided
Low Voltage
Directive
EN 61010-1:2010
Safety requirements for measurement,
control, and laboratory use
Electromagnetic Compatibility
Emissions
EN 55022:2010
Class A ITE emissions requirements
Radiated
Emissions
Class A
AC Mains
Conducted
Emissions
Class A
Immunity
EN 61326-1:2013
Measurement, control, and
laboratory equipment
EN 61000-6-2:2005
EMC heavy industrial generic
immunity standard
RFI - Amplitude
Modulated
80 -1000 MHz 10 V/m 80% AM
(1 kHz)
1.4 - 2.0 GHz 3 V/m 80% AM (1 kHz)
2.0 - 2.7 GHz 1 V/m 80% AM (1 kHz)
Electrical Fast
Transients
±2kV AC mains, ±1kV other
Electrostatic
Discharge
±4kV contact, ±8kV air
RFI - Conducted
10V, 0.15-80 MHz, 1kHz 80% AM
AC Surge
±2kV Common, ±1kV Differential
Surge
1KV (CM)
Power-
Frequency
Magnetic Field
30 A/m 70%V for 0.5 period
Voltage Dips
40%V for 5 & 50 periods
70%V for 25 periods
Voltage
Interruptions
<5%V for 250 periods
Safety Information
•Read complete instructions prior to installation
and operation of the instrument.
•Risk of electric shock.
•Hazardous voltages exist within enclosure.
Installation and service should be performed only
by trained service personnel.
Installation
There is no need to remove the instrument from its
case to complete the installation, wiring, and setup.
Unpacking
Remove the instrument from box. Inspect the
packaging and contents for damage. Report
damages, if any, to the carrier.
If any part is missing or the unit malfunctions, please
contact your supplier or the factory for assistance.
Panel Mounting
•Prepare a standard 1/8 DIN vertical panel cutout
–1.772" x 3.622" (45 mm x 92 mm). Refer to
Figure 1for more details.
•Clearance: allow at least 4" (102 mm) behind the
panel for wiring.
•Panel thickness: 0.04" - 0.25" (1.0 mm - 6.4 mm).
Recommended minimum panel thickness to
maintain Type 4X rating: 0.06" (1.5 mm) steel
panel, 0.16" (4.1 mm) plastic panel.
•Remove the two mounting brackets provided with
the annunciator (back-off the two screws so that
there is ¼" (6.4 mm) or less through the bracket.
Slide the bracket toward the front of the case and
remove).
•Insert the unit into the panel cutout.
•Install mounting brackets and tighten the screws
against the panel. To achieve a proper seal,
tighten the mounting bracket screws evenly until
the front is snug to the panel along its short side.
DO NOT OVER TIGHTEN, as the rear of the
panel may be damaged.
Figure 1. Panel Cutout and Mounting
Panel
Gasket
Mounting
Bracket Mounting
Screw
Removable
Connectors
Square Corners
to 0.060"
(1.5 mm)
Max Radius
Panel Cutout
to DIN 43700
3.622"
(92mm)
1.772"
(45mm)
B
A
Tolerances:
A: +0.032 (+0.8mm)
-0.000 (-0.0mm)
B: +0.024 (-0.6mm)
-0.000 (-0.0mm)
Front View Top View

AN24 & AN28 Annunciators Instruction Manual
8
Dimensions
All units: inches [mm]
Figure 2. Case Dimensions –Side View
Figure 3. Case Dimensions –Top View
Connections
All connections are made to removable screw
terminal connectors located at the rear of the
instrument.
•Use copper wire with 60°C or 60/75°C insulation
for all line voltage connections.
•Observe all safety regulations.
•Electrical wiring should be performed in
accordance with all applicable national, state,
and local codes to prevent damage to the
instrument and ensure personnel safety.
Connectors Labeling
The connectors label, affixed to the instrument, shows
the location of all connectors available with requested
configuration.
Figure 4. Connector Labeling for AN24-1
Figure 5. Connector Labeling for AN28-1
Figure 6. Connector Labeling for AN24-2
Figure 7. Connector Labeling for AN28-2
4.18"
(106mm)
2.50"
(64mm)
3.56"
(91mm)
2.33"
(59mm)
1.73"
(44mm)
3.1"
(79mm)
3.4"
(86mm)
0.39"
(10mm)

AN24 & AN28 Annunciators Instruction Manual
9
Power Connections
Power connections are made to a two-terminal
connector labeled POWER. See Connectors Labeling
on page 8. The instrument will operate regardless of
DC polarity connection. The + and - symbols are only a
suggested wiring convention.
AC or DC
POWER
Recommended External Fuse:
5 A max, Slow Blow
POWER CONNECTOR
+ -
Figure 8. Power Connections
Signal Connections
Input signal connections are made to a 14-terminal
connector at terminals labeled INPUT CHANNELS.
See Connectors Labeling on page 8. The COM
(common) terminal is the return for all types of input
signals.
Normally Open (NO) or Normally
Closed (NC) Switches
The following figure shows an example of normally
open or normally closed contact inputs.
Programming a channel for a normally open or
normally closed contact is done with the front panel
pushbuttons (see page 12). All channels are initially set
for normally open contacts. Each contact is wired
across an input channel and common.
COM
SIGNAL CONNECTOR
CH3 CH1CH2CH4
NO
CONTACT NC CONTACT
Figure 9. NO/NC Contact Inputs
Open Collector NPN Transistor
Each transistor collector is connected to a separate
input channel and all emitters connected to common.
All channels are factory set for transistor inputs
normally in the cutoff or “off” state. For normally
active/saturation state or “on” transistors, program
inputs for normally closed input operation; see page 12.
Open circuit voltage is approximately 3.3 VDC provided
by a 47 kΩ internal pullup resistor.
The following figure shows an example of open
collector NPN transistor inputs.
COM
SIGNAL CONNECTOR
CH3 CH1CH2CH4
NPN
Transistor
CBEC BE
Figure 10. Open Collector NPN Transistor Inputs
Logic Level Inputs
Each logic level input is connected to an input channel
with common as the return.
Logic level inputs are factory set for normally high
active logic level inputs. For normally low input logic
levels, program inputs for normally closed input
operation, see page 12.
Logic Level Low: 0 to 1.4 VDC
Logic Level High: 1.5 to 28 VDC
Input Impedance: Approximately 47 kΩ
Relays and 24 V Output Connections
Relay connections are made to a six-terminal
connector labeled RELAY1 and RELAY2. See
Connectors Labeling on page 8. The COM (common)
terminals of the relays should not be confused with
the COM (common) terminal of the signal connector.
The 24 VDC output is available at the connector
labeled 24V OUT, next to the relays connector.
24V OUT
P+ P-
RELAY 2 RELAY 1
NC NCCNO CNO
Figure 11. Relay & 24 V Output Connections

AN24 & AN28 Annunciators Instruction Manual
10
Switching Inductive Loads
The use of snubbers to suppress electrical noise is
strongly recommended when switching inductive loads
to prevent disrupting the microprocessor’s operation.
The snubbers also prolong the life of the relay contacts.
Suppression can be obtained with resistor-capacitor
(RC) networks assembled by the user or purchased as
complete assemblies. Refer to the following circuits for
RC network assembly and installation:
RELAY 1
NC
NO
C
C
R
C
R
+
-
L
O
A
D
Figure 12. AC and DC Loads Protection
Choose R and C as follows:
R: 0.5 to 1 for each volt across the contacts
C: 0.5 to 1 µF for each amp through closed contacts
Notes:
1. Use capacitors rated for 250 VAC.
2. RC networks may affect load release time of
solenoid loads. Check to confirm proper
operation.
3. Install the RC network at the annunciator's relay
screw terminals. An RC network may also be
installed across the load. Experiment for best
results.
RELAY 1
NC
NO
C
+
-
L
O
A
D
Figure 13. Low Voltage DC Loads Protection
RC Networks (Snubbers) Available
from Dwyer
RC networks are available from Dwyer and should be
applied to each relay contact switching an inductive
load. Part number: PMA-09.
External Input Types
The external Silence (SIL), Acknowledge (ACK), and
Reset (RST) inputs may be contacts (i.e.
pushbuttons, relay contacts, etc.), open collector
inputs (OC), or TTL signals. However, throughout this
manual, the term “pushbutton” is used to describe
these external inputs. Please refer to the chart below
for signal logic.
External Input Type
Active When
Switch/Contact
Closed
Open Collector (OC)
On
TTL
Low
Multiple Unit First-Out Indication
Connections
Multiple AN28 and AN24 units can keep a single first-
out channel indicated for all connected units. An
unlimited number of units may be connected. It is
recommended that all units follow the same
sequence.
The following figure shows shared first-out indication
wiring connections for 3 units. Up to 200 units may be
connected for first-out indication.
UNIT 2
FI
SIL
RST
ACK
COM
FO
FI
SIL
RST
ACK
COM
FO
UNIT 1 UNIT 3
FI
SIL
RST
ACK
COM
FO
Figure 14. System with Multiple Units Share First-Out
Use a diode with a
reverse breakdown
voltage two to three
times the circuit
voltage and forward
current at least as
large as the load
current.

AN24 & AN28 Annunciators Instruction Manua
11
Setup and Programming
Overview
There are no jumpers involved in the setup process
of the annunciator. The sequence selector switch
located on the rear of the annunciator above the
signal connector must be set accordingly for
annunciator sequence desired.
Normally open or normally closed input setup,
relay fail-safe, and additional sequence options
are programmed with the front panel pushbuttons.
After power and signal connections have been
completed and verified, and the sequence selector
switch has been set appropriately, apply power to
the annunciator.
For Quick Setup Guide go to page 5.
Front Panel Pushbuttons and
Status LED Indicators
Button
Description
Silence Horn
Acknowledge
Alarm
Reset Clear
Input Channels
LED
Description
Red
Indicators1
Channel status
indicators
Green
Indicator
Indicates power
is on.
1. Quantity 4 red LED on the AN24
Quantity 8 red LED on the AN28
Pushbutton Descriptions
SILENCE
Silences the audible alarm without affecting the
indication sequence states. This pushbutton may be
disabled (see Audible Horn Enable/Disable, page 14).
ACK (Acknowledge)
Acknowledges alarmed channels. See selected
sequence details for complete function description
(see Full Sequence Descriptions, page 16).
RESET
Resets all acknowledged channels. This button is not
used on ISA sequences A, F1A, and F2A, which reset
acknowledged channels automatically. See selected
sequence details for complete function description
(see Full Sequence Descriptions, page 16).
LED TEST (SILENCE & ACK)
Press and release the SILENCE and ACK
pushbuttons to flash the channel indicator LEDs
for a lamp test.
Full Function Test
Press and hold SILENCE and ACK for 5 seconds to
perform a function test. This tests the sequence
operation and hardware by simulating alarm inputs
that are cleared in the normal sequence progression.
During the function test, all channels enter a
simulated alarm state for 3 seconds. All LEDs,
pushbuttons, relays, and the audible alarm will follow
the selected sequence as if the simulated alarm
inputs were real. After 3 seconds, the alarms may be
cleared as normal for the selected sequence.
Multiple Unit First-Out Indication
If multiple annunciators are connected for multiple unit
shared first-out indication (see page 10), only one
input from all connected devices will display as a first-
out alarm.
Each individual annunciator will acknowledge and
reset the channels on that unit using the pushbuttons
on that unit, and independent of all other connected
units. Only the unit displaying the first-out will sound
the audible alarm.
It is recommended that all connected units be set for
the same first-out sequence.
Shared Front Panel Buttons
To control all the units from any of the front panels,
connect the SIL, ACK, RST, and COM terminals on
each unit.
SIL RSTACKCOM SIL RSTACKCOM
UNIT 1
SIGNAL CONNECTOR UNIT 2 SIGNAL CONNECTOR
Figure 15. Shared Pushbutton Connections

AN24 & AN28 Annunciators Instruction Manual
12
Annunciator Sequence
Selection
The alarm sequence is selected with the DIP switch
located above the signal connector.
Changing sequences while the unit is on will restart
the unit.
Sequence Programming
Set switches to the positions shown below for the
desired sequence. The annunciator will immediately
automatically restart and operate with the new
sequence.
Figure 16. DIP Switch Location
ISA A
ISA F2A
ISA F1A
ISA F3A
Follower
ISA M
ISA F1M
ISA F2M
Sequence Descriptions
See Page 16 for complete sequence descriptions.
Normally Open/Normally Closed
Input Setup
Each input channel is independently programmed for
a normally open or normally closed input. All channels
are initially programmed at the factory for normally
open inputs.
Alarm Conditions for normally open
inputs:
1. A closed contact between an input
channel and common will cause an
alarm condition.
2. An “on” or active transistor between an
input channel and common will cause
an alarm condition.
3. An active logic level low on an input
channel will cause an alarm condition.
Alarm Conditions for normally closed
inputs:
1. An open contact between an input
channel and common will cause an
alarm condition.
2. An “off” or cutoff state transistor
between an input channel and common
will cause an alarm condition.
3. An active logic level high or no supplied
active logic level on an input channel will
cause an alarm condition.
Programming NO/NC Inputs
1. Press and hold ACK and RESET for
3 seconds until all LEDs cycle, then release
2. Press ACK within 3 seconds of release while
LEDS cycle.1
3. Press ACK within 3 seconds of release while
LEDs blink.1
4. Press the RESET pushbutton to turn LED
1 off for a NO input, or on for a NC input on
input channel 1.
5. Press ACK to accept the input type and
program channel 2.
6. Repeat steps 4 and 5 for all input channels.
7. Press and hold ACK for five seconds to
return to normal operation with the
programmed input types.
During programming, the LED for the channel being
programmed will display as either off or brightly on. All
other LEDs will be dim.
The green power LED will blink slowly to indicate the
unit is in NO/NC setup mode. The unit will
automatically leave setup mode if no pushbutton is
pressed for 3 minutes.
1The unit will automatically leave setup mode if steps
2 and 3 are not followed.
Sequence Selector Switch

AN24 & AN28 Annunciators Instruction Manual
13
NO/NC Programming Example
The following is an example of NO/NC setup. Input
channel 1 and 2 are changed from the default settings
of NO to be NC inputs.
1. Press and hold ACK and RESET for 3
seconds. When all LEDs cycle, release.
2. Press ACK within 3 seconds. All LEDs blink in
unison.
3. Press ACK again while LEDs blink
4. LED 1 will be off
indicating a NO input
for channel 1. All
other LEDs will be
dim.
5. Press RESET to
change LED 1 from
off to on, setting
channel 1 for a NC
input.
6. Press ACK to confirm
the NC setting and
proceed to program
channel 2.
7. Press RESET to
change LED 2 from
off to on, setting
channel 2 for a NC
input.
8. Press ACK to confirm the NC setting and
program channel 3.
9. Press and hold ACK for five seconds to return
to normal operation.
Relay Operation
Relays 1 and 2 have standard functionality as defined
below.
Relay 1 Operation
Relay 1 enters alarm state when there is a new alarm.
This relay will clear when the alarm is acknowledged,
generally by pressing the ACK pushbutton.
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.
Relay Fail-Safe
In fail-safe operation, a relay coil is energized in non-
alarm condition. In case of power failure, relays will go
to alarm state. Fail-safe operation is set
independently for each relay.
Programming Relay Fail-Safe
1. Press and hold ACK and RESET for 3
seconds. When all LEDs cycle, release.
2. Press RESET within 3 seconds of release
while LEDs cycle.1
3. Press RESET within 3 seconds of release
while LEDs blink.1
4. Press the RESET pushbutton to turn LED 1
off for normal operation, or on for fail-safe
operation of Relay 1.
5. Press ACK to accept the type of operation
for Relay 1.
6. Press the RESET pushbutton to turn LED 2
off for normal operation, or on for fail-safe
operation of Relay 2.
7. Press ACK to accept the type of operation
for Relay 2.
8. Press and hold ACK for five seconds to
return to operation.
During programming, LEDs 1 through 4 will light. The
LED being programmed will display as either off or
brightly on. The other 3 LEDs will be dim. On a AN28,
LEDs 5 through 8 will be off.
The green power LED will blink quickly to indicate the
unit is in the advanced programming mode. The unit
will automatically leave setup mode if no pushbutton
is pressed for 3 minutes.
Note: LED 3 and 4 are used for the silence
pushbutton enable/disable option (see page 14) and
no lock-in option (see page 15)
1The unit will automatically leave setup mode if steps 2 and 3
are not followed.

AN24 & AN28 Annunciators Instruction Manual
14
Relay Fail-Safe Programming Example
The following is an example of relay fail-safe setup.
Relays 1 and 2 are changed from the default settings
of normal operation to fail-safe operation.
1. Press and hold ACK and RESET for 3
seconds. When all LEDs cycle, release.
2. Press RESET within 3 seconds of release
while LEDs cycle. All LEDs blink in unison.
3. Press RESET again within 3 seconds while
LEDs blink
4. LED 1 will be off
indicating normal
operation of relay 1.
LEDs 2 through 4
will be dim.
5. Press Reset to
change LED 1 from
off to on, setting
relay 1 for fail-safe
operation.
6. Press ACK to
confirm the setting
for relay 1and
proceed to program
relay 2.
7. Press RESET to
change LED 2 from
off to on, setting
relay 2 for fail-safe
operation.
8. Press ACK to confirm the setting for relay 2.
9. Press and hold ACK for 5 seconds to return
to normal operation.
Note: LEDs 3 and 4 are used for the silence
pushbutton enable/disable option (see page 14)
and no lock-in option (see page 15)
Relay Operation Overview
The following figure illustrates the operation of the
relays.
ACK
Pressed
ON
OFF
Relay 1
ON
OFF
Relay 2
ON
OFF
Relay 1
ON
OFF
Relay 2
NORMAL
FAIL-SAFE
Alarms
Cleared
Alarm
Occurance
Relay On: Relay is energized
Relay Off: Relay is de-energized.
Alarm Occurrence: A new alarm occurs when there
is no previous unacknowledged alarm.
ACK Pressed: The Acknowledge pushbutton is
pressed, acknowledging the alarm.
Alarms Cleared: All LED indicators are cleared of
alarm state indication
Audible Horn Enable/Disable
The annunciator contains an audible internal horn.
This horn may be disabled with the rear-mounted
switch located above the signal connector. To enable
the horn, move switch 4 to the ON position. To
disable the horn, move switch 4 to the OFF position.
Sequence
F2A
Horn
Enabled
Sequence
F2A
Horn
Disabled
Enabling/Disabling Silence
Option
ISA sequence option 1, Silence Pushbutton, includes
a silence pushbutton. This option may be disabled,
removing any effects of the silence pushbutton or
silence pushbutton external contact. This option is
enabled by factory default.

AN24 & AN28 Annunciators Instruction Manua
15
Silence Pushbutton
Enable/Disable
1. Press and hold ACK and RESET for 3
seconds until all LEDs cycle, then release.
2. Press RESET within 3 seconds of release
while LEDs cycle.1
3. Press RESET within 3 seconds of release
while LEDs blink.1
4. Press the ACK pushbutton twice until LED 3
is either off or brightly on.
5. Press the RESET pushbutton to turn LED 3
off to disable the silence pushbutton or
brightly on to enable the silence pushbutton.
6. Press ACK to accept the silence pushbutton
setting.
7. Press and hold ACK for five seconds to
return to normal operation.
The green power LED will blink quickly to indicate the
unit is in the advanced programming mode. The unit
will automatically leave setup mode if no pushbutton
is pressed for 3 minutes.
Note: LED 1 and 2 are used for relay fail-safe setup
(see page 13)
1The unit will automatically leave setup mode if steps
2 and 3 are not followed.
No Lock-In Sequence Option
ISA sequence option 4 no lock-in, may be added to
any sequence. Momentary alarms will clear without
the ACK pushbutton. Sequences A, F1A, F2A, and
F3A will automatically clear any momentary alarm.
Sequences M, F1M, and F2M will clear all momentary
alarms when the RESET pushbutton is used,
regardless of what channels have previously been
acknowledged with ACK.
Selecting No Lock-In Operation
1. Press and hold ACK and RESET for 3
seconds until all LEDs cycle, then release.
2. Press RESET within 3 seconds of release
while LEDs cycle.1
3. Press RESET within 3 seconds while LEDs
blink.1
4. Press the ACK pushbutton three times until
LED 4 is either off or brightly on.
5. Press the RESET pushbutton to turn LED 4
off to disable the
no lock-in option or on to enable the no lock-
in option.
6. Press ACK to accept the option setting.
7. Press and hold ACK for five seconds to
return to operation.
The green power LED will blink quickly to indicate the
unit is in the advanced programming mode. The unit
will automatically leave setup mode if no pushbutton
is pressed for 3 minutes.
Note: LED 1 and 2 are used for relay fail-safe setup
(see page 13), and LED 3 is used for silence
pushbutton enable/disable (see page 14).
1The unit will automatically leave setup mode if steps
2 and 3 are not followed.
Reset to Factory Defaults
1. Hold the ACK and RESET pushbuttons for 3
seconds until all red LEDs cycle. Release once the
LEDs begin to cycle.
2. Press and hold the RESET button for 5 seconds. If
the RESET button is not pressed within 3 seconds
of releasing ACK and RESET, the unit will return
to run mode without reset.
3. Reset the 4-position switch on the rear of the
control to the indicated default settings.
Factory
Default
Switch
Positions
Troubleshooting
If the annunciator is not working as expected, refer to
the recommendations below.
Troubleshooting Tips
Symptom
Check/Action
Power LED off
Check power at power
connector
Audible alarm does not
sound when alarm state
detected
Check:
1. Rear switch position 4
is ON.
2. No external pushbutton
contacts on the input
connector are shorted.
Power light blinks and
channel/point indicators
flash intermittently when
powered up.
Check that no external
pushbutton contacts on the
signal connector are shorted
to common.
Display sequence does not
function as expected.
Check:
1. Verify sequence selection
as shown on page 12.
2. Check that no external
pushbutton contacts on the
input connector are
shorted.
If the display locks up or
the unit does not respond
at all
Cycle the power to restart the
microprocessor.
Relay operation is
reversed
Check:
1. Fail-safe settings as shown
on page 13.
2. Wiring of relay contacts
Other symptoms not
described above
Call Technical Support for
assistance.
To reset unit to factory default settings of sequence
F2A-1, first out indication with silence and
acknowledge pushbuttons with automatic reset,
see Reset to Factory Defaults.

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
1st 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.

AN24 & AN28 Annunciators Instruction Manual
17
ISA Sequence F2A
First-Out Indication with Acknowledge Pushbutton
and Automatic Reset
Momentary Alarm
Momentary Alarm
Sequence F2A Switch Positions
Sequence F2A Flow Chart
ISA Sequence F1A
First-Out Indication with Acknowledge Pushbutton, No
Lock-In of Subsequent Alarms, and Automatic Reset
Momentary Alarm
Momentary Alarm
Sequence F1A Switch Positions
Sequence F1A Flow Chart
Condition
LED
Horn
1st Pt
Next Pt
Normal
Off
Off
Off
Alert
Flash
Steady
On
Normal
Flash
Steady
On
ACK Pushbutton
Acknowledge
Off
Off
Off
Condition
LED
Horn
1st Pt
Next Pt
Normal
Off
Off
Off
Alert
Flash
Steady
On
ACK Pushbutton
Acknowledge
Steady
Steady
Off
Normal
Off
Off
Off
Condition
LED
Horn
1st Pt
Next Pt
Normal
Off
Off
Off
Alert
Flash
Steady
On
Normal
Flash
Off
On
ACK Pushbutton
Acknowledge
Off
Off
Off
Condition
LED
Horn
1st Pt
Next Pt
Normal
Off
Off
Off
Alert
Flash
Steady
On
ACK Pushbutton
Acknowledge
Steady
Steady
Off
Normal
Off
Off
Off
Condition
Normal
1st Pt LED
Off
Next Pt LED
Off
Horn
Off
Condition
Alert
1st Pt LED
Flash
Next Pt LED
Steady
Horn
On
Condition
Alert
1st Pt LED
Steady
Next Pt LED
Steady
Horn
Off
Alarm Condition
Ack when
Inputs Normal
Return
to Normal
Ack
Pressed
Ack
Pressed
Condition
Normal
1st Pt LED
Off
Next Pt LED
Off
Horn
Off
Condition
Alert
1st Pt LED
Flash
Next Pt LED
Steady
Horn
On
Condition
Alert
1st Pt LED
Steady
Next Pt LED
Steady
Horn
Off
Alarm Condition
Return
to Normal
Ack
Pressed
Condition
Normal
1st Pt L D
Flash
Next Pt LED
Off
Horn
On
Return
to Normal

AN24 & AN28 Annunciators Instruction Manual
18
ISA Sequence F3A
First-Out Indication with Acknowledge Pushbutton,
Automatic Reset, and First-Out Reset Pushbutton
Sequence F3A Switch Positions
Momentary Alarm (RESET before ACK)
Condition
LED
Horn
1st Pt
Next Pt
Normal
Off
Off
Off
Alert
Intermittent
Flash
Fast Flash
On
Normal
Intermittent
Flash
Fast Flash
On
RESET Pushbutton
1st Out
Reset
Fast Flash
Fast Flash
On
ACK Pushbutton
Acknowledge
Off
Off
Off
Momentary Alarm (ACK before RESET)
Condition
LED
Horn
1st Pt
Next Pt
Normal
Off
Off
Off
Alert
Intermittent Flash
Fast Flash
On
Normal
Intermittent Flash
Fast Flash
On
ACK Pushbutton
Acknowledge
Slow Flash
Off
Off
RESET Pushbutton
Reset
Off
Off
Off
Maintained Alarm (RESET before ACK)
Condition
LED
Horn
1st Pt
Next Pt
Normal
Off
Off
Off
Alert
Intermittent Flash
Fast Flash
On
RESET Pushbutton
1st Out Reset
Fast Flash
Fast Flash
On
ACK Pushbutton
Acknowledge
Steady
Steady
Off
Normal
Off
Off
Off
Maintained Alarm (ACK before RESET)
Condition
LED
Horn
1st Pt
Next Pt
Normal
Off
Off
Off
Alert
Intermittent
Flash
Fast Flash
On
ACK Pushbutton
Acknowledge
Slow Flash
Steady
Off
RESET Pushbutton
1st Out Reset
Steady
Steady
Off
Normal
Off
Off
Off
Sequence F3A Flow Chart
Condition
Normal
1st Pt LED
Off
Next Pt LED
Off
Horn
Off
Condition
Alert
1st Pt LED
Intermittent Flash
Next Pt LED
Fast Flash
Horn
On
Alarm Condition
Ack while
Normal
Reset
Pressed
Condition
Any
1st Pt LED
Fast Flash
Next Pt LED
Fast Flash
Horn
On
Ack while
Normal
Condition
Alert
1st Pt LED
Steady
Next Pt LED
Steady
Horn
Off
Condition
Normal
1st Pt LED
Slow
Flash
Next Pt LED
Off
Horn
Off
Condition
Alert
1st Pt LED
Slow
Flash
Next Pt LED
Steady
Horn
Off
Ack
while
Alarmed
Ack while
Alarmed
Return
to Normal
Return
to Normal
Reset
Pressed

AN24 & AN28 Annunciators Instruction Manua
19
Condition
Normal
1st Pt LED
Off
Next Pt LED
Off
Horn
Off
Condition
Alert
1st Pt LED
Flash
Next Pt LED
Steady
Horn
On
Condition
Alert
1st Pt LED
Steady
Next Pt LED
Steady
Horn
Off
Alarm Condition
Ack
Pressed
Reset while
Normal
Ack
Pressed
Condition
Normal
1st Pt LED
Flash
Next Pt LED
Off
Horn
On
Reset while
Normal
Condition
Normal
1st Pt LED
Steady
Next Pt LED
Off
Horn
Off
Reset
while
Normal
Input Follower Indication
Simple Indication
ISA Sequence M
Acknowledge and Reset Pushbuttons
Momentary Alarm
Maintained Alarm
Sequence M
Switch Positions
Sequence M Flow Chart
ISA Sequence F1M
First-Out Indication with Acknowledge and Reset
Pushbuttons, and No-Lock-In of Subsequent Alarms
Momentary Alarm
Maintained Alarm
Sequence F1M
Switch Positions
Sequence F1M Flow Chart
Condition
LED
Horn
Normal
Off
Off
Alert
Steady
On
Normal
Off
Off
Condition
LED
Horn
Normal
Off
Off
Alert
Flash
On
Normal
Flash
On
ACK Pushbutton
Acknowledge
Steady
Off
RESET Pushbutton
Reset
Off
Off
Condition
LED
Horn
Normal
Off
Off
Alert
Flash
On
ACK Pushbutton
Acknowledge
Steady
Off
Normal
Steady
Off
RESET Pushbutton
Normal
Off
Off
Condition
LED
Horn
1st Pt
Next Pt
Normal
Off
Off
Off
Alert
Flash
Steady
On
Normal
Flash
Steady
On
RESET Pushbutton
Reset
Flash
Off
On
ACK Pushbutton
Acknowledge
Steady
Off
Off
RESET Pushbutton
Normal
Off
Off
Off
Condition
LED
Horn
1st Pt
Next Pt
Normal
Off
Off
Off
Alert
Flash
Steady
On
RESET Pushbutton
Alert
Flash
Steady
On
ACK Pushbutton
Acknowledge
Steady
Steady
Off
Normal
Steady
Steady
Off
RESET Pushbutton
Normal
Off
Off
Off
Switch
Positions
Condition
Normal
LED
Off
Horn
Off
Condition
Alert
LED
Flash
Horn
On
Condition
Alert
LED
Steady
Horn
Off
Alarm Condition
Reset while
Normal
Ack
Pressed
Condition
Any
LED
Steady
Horn
Off
Reset while
Normal
Reset while
Alarmed

AN24 & AN28 Annunciators Instruction Manual
20
ISA Sequence F2M
First-Out Indication with Acknowledge and Reset
Pushbuttons
Momentary Alarm
Maintained Alarm
Sequence F2M
Switch Positions
Sequence F2M Flow Chart
Condition
LED
Horn
1st Pt
Next Pt
Normal
Off
Off
Off
Alert
Flash
Steady
On
Normal
Flash
Steady
On
ACK Pushbutton
Acknowledge
Steady
Steady
Off
RESET Pushbutton
Reset
Off
Off
Off
Condition
LED
Horn
1st Pt
Next Pt
Normal
Off
Off
Off
Alert
Flash
Steady
On
ACK Pushbutton
Acknowledge
Steady
Steady
Off
Normal
Steady
Steady
Off
RESET Pushbutton
Normal
Off
Off
Off
Condition
Normal
1st Pt LED
Off
Next Pt LED
Off
Horn
Off
Return
to Normal
Reset
while Normal
Condition
Alert
1st Pt LED
Flash
Next Pt LED
Steady
Horn
On
Condition
Normal
1st Pt LED
Steady
Next Pt LED
Steady
Horn
Off
Condition
Any
1st Pt LED
Steady
Next Pt LED
Steady
Horn
Off
Ack Pressed
Alarm Condition