RTK NEX7250 User manual

NEX7250 Zone 2 Annunciator
1
Warning
The NEX7250 System described herein operates on a logic voltage of 24VDC and as standard
24VDC is used for the field contact supply voltage. External power supplies using higher voltage
AC/DC primary sources and optional high voltage field contact voltages may be present if this is the
case please ensure the necessary precautions are taken.
REV DATED DESCRIPTION AUTHOR APPROVED
0 26/6/03 Original D.Adams T McLeman
1 29/05/07 Minor corrections D.Adams P.Cartmell
2 19/05/08 Updated to new Standards D.Adams T McLeman
3 05/01/10 Removed high risk impact warning D.Adams P.Hartley
NEX7250 Zone 2 Annunciator

2
© RTK Instruments LTD 2008
The copyright in this work is vested in RTK Instruments Ltd and this document is issued for the
purpose only for which it is supplied. No licence is implied for the use of any patented feature. It must
not be reproduced in whole or in part, or used for tendering or manufacturing purposes except under
an agreement or with the consent in writing of RTK Instruments Ltd and then only on the condition
that this notice is included in any such reproduction. Information furnished is believed to be accurate
but no liability in respect of any use of it is accepted by RTK Instruments Ltd.

NEX7250 Zone 2 Annunciator
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Contents
1. I NTRODUCTION ......................................................................................................6
2. I NSTALLATION G UIDE .............................................................................................7
3. F RONT V IEW E XAMPLES ........................................................................................8
4. NEX7250 E NCLOSURE ..........................................................................................9
4.1 General..................................................................................................................................... 9
4.2 Panel mount ............................................................................................................................. 9
4.3 Wall Mount ............................................................................................................................. 10
4.4 Alarm connections.................................................................................................................. 10
4.5 Relay connections .................................................................................................................. 10
4.6 External power supply............................................................................................................ 11
4.7 Certification ............................................................................................................................ 11
4.8 Labelling ................................................................................................................................. 11
4.9 Documentation ....................................................................................................................... 12
5. P725 D ESCRIPTION AND F EATURES .....................................................................13
5.1 General................................................................................................................................... 13
5.2 Window Colours ..................................................................................................................... 13
5.3 Laser Printed Legends ........................................................................................................... 14
5.4 Adding Or Changing Film Legends ........................................................................................ 14
5.5 LED Illumination ..................................................................................................................... 14
5.6 Window Numbering System................................................................................................... 15
5.7 Alarm Card Types .................................................................................................................. 15
5.8 Pushbutton / Programming Module........................................................................................ 15
5.9 Pushbutton / Programming Module Options .......................................................................... 16
5.10 Fully Field Programmable .................................................................................................... 16
5.11 Sleep Mode .......................................................................................................................... 16
5.12 Automatic Mute Or Automatic Acknowledge........................................................................ 17
5.13 Integral Audible Alarm.......................................................................................................... 18
5.14 Remote Pushbutton Inputs................................................................................................... 19
5.15 Terminations......................................................................................................................... 20
5.16 Failsafe Mode....................................................................................................................... 20
6. I NPUTS ...............................................................................................................21
6.1 Optically Coupled Inputs ........................................................................................................ 21
6.2 Standard Input Configuration ................................................................................................. 21
6.3 Signal Supply Voltage ............................................................................................................ 21
6.4 Input Time Delay – Option AD* .............................................................................................. 22
6.5 Input Wiring Segregation........................................................................................................ 22
6.6 No Master Module.................................................................................................................. 22
7. O UTPUTS ............................................................................................................23
7.1 Common Outputs ................................................................................................................... 23
7.2 Critical Horn Relay - HNA ...................................................................................................... 24
7.3 Non-Critical Horn Relay - HNB............................................................................................... 24
7.4 Critical Group Relay - GPA .................................................................................................... 25
7.5 Critical Group Relay - GPB .................................................................................................... 25
7.6 Reflash Critical Group Relay - GPA ....................................................................................... 25
7.7 Reflash Non-Critical Group Relay - GPB ............................................................................... 25
7.8 Common Relay Function Codes ............................................................................................ 25
7.9 Multi-Function Relay Operating Modes.................................................................................. 25
8. T ECHNICAL SPECIFICATIONS .................................................................................26
8.1 General................................................................................................................................... 27
8.2 Fuse Details - SPR Module.................................................................................................... 27
8.3 Suitable Power Supplies ........................................................................................................ 27
8.4 P725 Annunciator Standard Versions .................................................................................... 27

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9. M ECHANICAL D ETAILS .........................................................................................28
9.1 Panel Mounting Clamps (panel mount version only) ............................................................. 28
10. A LARM S EQUENCES ..........................................................................................29
10.1 Summary .............................................................................................................................. 29
10.2 Audible Alarm Grouping ....................................................................................................... 29
10.3 Ringback Audible ................................................................................................................. 29
11. A DDITIONAL F EATURES .....................................................................................30
11.1 Automatic Reset ................................................................................................................... 30
11.2 Non-Latch Sequence (No Lock-In)....................................................................................... 30
11.3 Reflash Feature.................................................................................................................... 30
11.4 Ringback Sequence ............................................................................................................. 30
11.5 Two Pushbutton Operation .................................................................................................. 30
11.6 First-Up Sequences ............................................................................................................. 30
12. S EQUENCE C ONFIGURATION AND T ABLES ...........................................................31
12.1 ISA-Sequence M - Manual Reset......................................................................................... 31
12.2 ISA-Sequence A................................................................................................................... 32
12.3 ISA-A-4 Sequence ............................................................................................................... 33
12.4 ISA-R Sequence - ................................................................................................................ 34
12.5 ISA-F1A Sequence .............................................................................................................. 36
12.6 ISA-F2M-1 Sequence........................................................................................................... 37
12.7 ISA-F3A Sequence - ............................................................................................................ 39
13. O PTIONS ...........................................................................................................41
13. O PTIONS ...........................................................................................................41
13.1 General................................................................................................................................. 41
13.2 LED Assemblies (Option LED)............................................................................................. 41
13.3 Tropicalisation (Option TRO) ............................................................................................... 41
13.4 Individual Channel Repeat Relays (Option RLY)................................................................. 41
13.5 Individual Channel Dual Repeat Relays (Option RL2)......................................................... 42
13.6 Customer Specified Response Time (Option CRT**) .......................................................... 42
13.7 Adjustable Response Time (Option AD*)............................................................................. 42
13.8 Disable Integral Horn (Option DHN)..................................................................................... 42
13.9 Supply Input/Output Module (Option SI/O) .......................................................................... 43
13.10 RS485 Serial Communications (Option COM) Part No. CB6357POP1............................. 43
13.11 Individual Channel Repeat Relays Powered By The Field Contact Voltage (Option RAV)43
13.12 Three Horn Relay Outputs (Option 3HN)........................................................................... 43
13.13 Three Group Relay Outputs (Option 3GP)........................................................................ 43
13.14 Repeat Pushbutton Output (Option RPB) .......................................................................... 43
13.15 Group Relays Follow Inputs (Option GFI).......................................................................... 44
13.16 Additional Group Relay Contact (Options 2GA or 2GB) ................................................... 44
13.17 Total Group Relay (Option RTG) ....................................................................................... 44
13.18 SPR Module (Supply-Pushbuttons-Relay Module) ............................................................ 44
13.19 Logic Power Connections .................................................................................................. 44
13.20 Signal Supply Voltage Connections................................................................................... 44
14. NEX7250 C ONNECTION D ETAILS .......................................................................45
14.1 Typical Panel mount wiring .................................................................................................. 45
14.2 Typical Wall mount wiring .................................................................................................... 46
14.3 Cable Entry........................................................................................................................... 46
15. L ARGE W INDOW A LARM M ODULE WIRING ...........................................................47
15.1 Standard Unit Without Repeat Relay Facility....................................................................... 47
15.2 Optional Unit With Repeat Relay Facility ............................................................................. 47
15.3 Large Window Versions Fitted With An Odd Number Of Alarms......................................... 48
15.4 Standard Unit Without Repeat Relay Facility....................................................................... 48
15.5 Optional Unit With Repeat Relay Facility ............................................................................. 48
16. M EDIUM W INDOW A LARM M ODULE W IRING .........................................................49
16.1 Standard Version Without Repeat Relay Facility ................................................................. 49

NEX7250 Zone 2 Annunciator
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16.2 Optional Version With Repeat Relay Facility ....................................................................... 49
17. S MALL W INDOW A LARM M ODULE W IRING ...........................................................50
17.1 Standard Version Without Repeat Relay Facility ................................................................. 50
17.2 Optional Version With Repeat Relay Facility ....................................................................... 50
18. D UAL R EPEAT R ELAY O PTION ............................................................................51
18.1 Optional Version With Dual Repeat Relay Facility (Option RL2) ......................................... 51
19. S IGNAL S UPPLY V OLTAGE O PTIONS ...................................................................52
19.1 Standard Systems With Combined Logic And Signal Supply.............................................. 52
19.2 Standard Systems Using Externally Powered Inputs........................................................... 53
20. S YSTEMS F ITTED W ITH S ERIAL C OMM .’ S ............................................................54
20.1 Connections ......................................................................................................................... 54
21. S YSTEM C ONFIGURATIONS AND P ROGRAMMING ..................................................55
21.1 Programming Mode.............................................................................................................. 55
21.2 Changing A Function Setting ............................................................................................... 56
21.3 Programming Example......................................................................................................... 57
21.4 Checking Programmed Settings .......................................................................................... 57
21.5 Systems With Unarmed Ways ............................................................................................. 57
21.6 Points To Note When Programming .................................................................................... 57
22. F UNCTION N O K EY A ND D ESCRIPTIONS ..............................................................58
23. F UNCTION D ESCRIPTIONS ..................................................................................59
24. A LARM C ARD A DDRESS S ETTINGS .....................................................................65
24.1 Set Output Drive To Operate With LED ............................................................................... 65
24.2 Alarm Card DIL Switch SW1 Address Settings 0 To 40 ...................................................... 66
Alarm Card DIL Switch SW1 Address Settings 41 To 80 ............................................................ 67
Alarm Card DIL Switch SW1 Address Settings 81 To 120 .......................................................... 68
Alarm Card DIL Switch SW1 Address Settings 121 To 127 ........................................................ 69
25. A DJUSTABLE R ESPONSE T IMES .........................................................................70
26. S YSTEMS WITH S ERIAL COMMUNICATIONS ...........................................................71
27. S ERIAL C OMMUNICATION C ARD ..........................................................................73
28. S ERIAL C OMMUNICATION P ORT ..........................................................................75
29. S YSTEMS LINKED TO 3
RD
P ARTY D EVICES ............................................................79
30. P725 TO P725 S ERIAL L INKS ............................................................................80
31. C OMMISSIONING ................................................................................................81
32. M AINTENANCE ..................................................................................................82
32.1 No Special Tools .................................................................................................................. 82
32.2 Removing Filter Assemblies................................................................................................. 82
32.3 Changing Film Legend ......................................................................................................... 82
32.4 Changing LED Assemblies .................................................................................................. 82
32.5 Fuse Replacement ............................................................................................................... 82
32.6 Position Of Fuses On The Supply Card............................................................................... 82
33. S PARE P ARTS D ESCRIPTION ..............................................................................83
34. O THER RTK P RODUCTS ....................................................................................85
35. EC D ECLARATION OF C ONFORMITY ....................................................................86

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1. Introduction
The NEX7250 combines the RTK 725 Series Alarm Annunciator installed in an IP rated enclosure
and self certified to comply with the international standard IEC 60079-15. The unit is self certified to
Ex nA [nL] IIC T4, with an ambient temperature range of -20°C to +50°C. The IP rated enclosure is
available in two forms: A wall mount IP55 rated enclosure or a panel mount IP54 rated enclosure.
The annunciator is manufactured from universal cells, each 60 x 60mm, which can be assembled in
an array to provide the number of rows and columns required to suit individual panel designs.
Each cell within the annunciator is able to contain either: - ONE large, TWO medium or FOUR small
alarm windows, which can be illuminated by “fit and forget” LED assemblies.
The assembled unit is fully field programmable which allows the user to enable a number of pre-
defined features to control the operation of the annunciator with regards to alarm sequence, horn
groups, common alarm groups or optional Modbus communications.
Selection of features is on a per channel basis with no special tools or programming knowledge
required. All programming is carried out from the front of the unit using the integral pushbutton /
programming module, which allows changes to be easily made during commissioning or at a later
date after the equipment has been installed.
Large and medium window version alarm cards are fully interchangeable within the annunciator, on
small window versions an additional card type is used for the 2
nd
pair of alarm channels but cards of
the same type remain fully interchangeable.
Reliability of operation is increased over conventional annunciators as each alarm card is fitted with
its own application specific integrated circuit (ASIC), which is capable of complete system control.
During initial power up one of the alarm cards will automatically act as a master controller with
regards to flash rates etc and in the event that this card fails or is removed another card will
automatically take over the role of master controller.
The standard unit is supplied with five integrally mounted common output relays, which are used to
provide 2 horn relay outputs, 2 group relay outputs and a multifunction relay output with
programmable function.
Additional options exist for more complex requirements including integrally mounted signal
duplicating relays on a per channel basis, bi-directional RS485 serial communications link and user
selectable time delays on each channel.
Accessibility for normal maintenance, LED changes, legend/filter changes and programming is
accomplished from the front of the panel without the use of special tools.

NEX7250 Zone 2 Annunciator
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2. Installation Guide
This product has been certified to be mounted in a zone 2 (equipment category 3) hazardous area.
Equipment must be installed in accordance to IEC60079-14 (Electrical installation in hazardous
areas).
There are various requirements that need to be met in order for this equipment to be used safely.
These requirements are as follows:
1. The IP rating of the enclosure should not be compromised when mounted or when inserting
the cable glands
2. All external earthing should use 4mm cable as a minimum
3. Any fuses used will be marked with a label giving type and rating. Fuses should not be
replaced with the power connected as this may cause sparks, which could potentially cause
explosions.
4. All Relays are energy limited and are pre-wired to energy limited terminals. Any connections
to these terminals must meet the safety parameters specified in the product certificate
These are shown below:
Ui=24V, Ii = 45mA, Pi = 1.3W, Ci = 0, Ii = 0
5. Any external equipment connected outside the enclosure but still within the Zone 2 area
must meet IEC60079-0 requirements.

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3. Front View Examples
SIX
WINDOW
COLOURS
AVAILABLE
BATTERY
LOW
VOLTS
LEVEL
TRANS
FAILURE
SMALL
WINDOW
VERSION
30 X 30 MM
NO 2
AIR COOLER
FAILURE
NO 1
AIR COOLER
FAILURE
LAMP
OR
LED
VERSIONS
SIX
LED
COLOURS
AVAILABLE
PROTECTION
TRIP
FULLY
FIELD
PROGR
MOTOR 1
HIGH
TEMP
LASER
PRINTED
FILM
LEGENDS
OPTIONAL
SERIAL
INTERFACE
CARD
MOTOR 2
HIGH
TEMP
LAMP
TEST
PLC
FAILURE
GAS
PRESSURE
LOW
Small Window Version
SIX
WINDOW
COLOURS
MEDIUM
WINDOW
VERSION
30 X 60 MM
LAMP OR LED
ILLUMINATION
LARGE
WINDOW
VERSION
60 X 60 MM
LAMP OR LED
ILLUMINATION
SIX
WINDOW
COLOURS
SIX
LED
COLOURS
LASER
PRINTED
FILM
LEGENDS
OPTIONAL
SERIAL
INTERFACE
CARD
Medium Window Version Large Window Version

NEX7250 Zone 2 Annunciator
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4. NEX7250 Enclosure
4.1 General
The NEX Systems are manufactured to meet individual customer's requirements as long as they are
within the maximum parameters of equipment certificate.
4.2 Panel mount
The panel mount version consists of an IP54 rated stainless steel door with a Perspex viewing
window, the 725 unit is then mounted in an IP54 rated box which is mounted in the viewing window.
The size of this enclosure is depended on the cell size of the annunciator, as long as the box doesn’t
exceed the maximum size stated on the certificate.
Layout of panel mount box
This type of NEX7250 allows the user to connect external pushbuttons which can then be mounted in
a suitable control panel. If this panel is situated in the Zone 2 area, zone 2 certified pushbuttons
must be used. The customer may also incorporate a Zone 2 isolator into the enclosure to allow then
to drive an external I.S horn.
12
11
16
15
6
5
4
2
3
1
10
9
814
137
20
19
TEST RESET
MUTE
POWER
ACK
LAMP
TEST
SYST
RESET
FIRST
18
17
22
21
CERT' LABEL

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4.3 Wall Mount
The wall mount version consists of an IP65 rated box with an IP65 rated viewing window. The 725
unit is then mounted in an IP54 rated box which is mounted in the viewing window. The enclosures
used are manufactured externally so the size of the unit is dependent of the sizes available from the
manufacturer. The wall mount version has the external pushbuttons mounted on the enclosure and
also gives the option for audible and visual devices to be mounted to the enclosure. It is also
possible to mount the customer power supply within the enclosure.
Layout of Wall mount box
4.4 Alarm connections
Due to the type of application the NEX7250 is used in the user may connect their alarms from any
zone. If these alarms are associated with a hazardous area suitable protection must be used.
For connections to a safe area it is recommended fused terminals are used, either in the enclosure or
from the area in which they are coming from.
If fused terminals are used the correct type and value and type of fuse shall be shown on a label next
to the fuse holder. A warning label will also be present stating DO NOT REMOVE FUSE WHEN
ENERGISED.
4.5 Relay connections
Because of the certification type used for the NEX7250 all relays within the 725 must via suitable
energy limited terminals, this includes both group and repeat relays.
BEACON
PUSHBUTTONS
4
3
2
8 12
7
6
11
10
1 5 9
AUDIBLE
16
15
14
LAMP
20 TEST
SYST
TEST
19
18 22
13 17 21
RESET
ACK
POWER
MUTE RESET
FIRST

NEX7250 Zone 2 Annunciator
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4.6 External power supply
If the customer is mounting the power supply externally, but still within the Zone 2 a certified power
supply must be used.
4.7 Certification
The NEX7250 is self-certified to Ex nA [nL] IIC T4 (where [nL] is for associated apparatus connected
to the relays) conforming to IEC60079-15. The [nL] is used because that the unit contains relays
which could cause sparking in normal operation. To conform to the standard the unit must contain
the following information:
Name of manufacturer or his registered trade mark – RTK Instruments Limited
Manufacturers type identification – NEX7250
Marking – Ex nA [nL] IIC T4 (where [nL] is for associated apparatus connected to the relays)
Ambient temperature range – Tamb -20°C to 50°C
A serial number or batch identification code
The name or mark of the organisation that issues the certificate and the number of the certificate –
RTK08ATEX0222X
For energy limited apparatus (relays) all safety parameters
Ui=24V, Ii = 45mA, Pi = 1.3W, Ci = 0, Ii = 0
IEC60079-0 gives additional information – the marking shall also include:
The year in which the equipment was constructed.
Specific marking of explosion protection
Hexagon followed by equipment group and category (II 3 G) group II category 3 gas (G)
WARNING: POTENTIAL ELECTROSTATIC CHARGING HAZARD – SEE INSTRUCTIONS
Special Conditions for Safe Use:
•The equipment shall not be directly installed in any area where its enclosure might be
electro-statically charged by the rapid flow of dust-laden air or a nonconductive media and
must be cleaned only with a damp cloth.
•Cable glands when installed in accordance with the instructions shall provide a degree of
protection of at least IP54 as defined in EN60529.
4.8 Labelling
The following labels will be mounted inside the enclosure:
•Relays MUST be connected via an energy-limited supply ONLY. (see installation
instructions)
•WARNING: DO NOT REMOVE FUSES WHEN ENERGISED
•Enclosure shall carry a warning near the terminals stating – WARNING: DO NOT
SEPARATE WHILE ENERGISED
•Enclosure earthing MUST be connected to normal installation plant earth

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A certification label must also be present on the front of the unit as shown below:
Certificate No: RTK08ATEX0222X
WARNING: POTENTIAL ELECTROSTATIC DISCHARGING
HAZARD - SEE INSTRUCTIONSS
Serial No: SP829-XXXXX
NEX7250 ZONE 2 ALARM ANNUNCIATOR
II 3 G Ex nA [nL] IIC T4 -20°C<Ta< +50°C
KNARESBOROUGH UK.
INSTRUMENTS
__
Ui=24V, Ii=45mA, Pi=1.3W
4.9 Documentation
All NEX7250 systems will be supplied with there own Certificate. A complete test report detailing the
system conforming to IEC60079-15 is available on request.

NEX7250 Zone 2 Annunciator
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5. P725 Description and Features
5.1 General
Annunciators are manufactured to meet individual customer's requirements using separate "cells"
which can be assembled in configurations from 1 to 16 cells high and 1 to 16 cells wide as required.
The finished array is “picture framed” using standard lengths of aluminium extrusion. Individual alarm
channels can be displayed in one of three sizes as shown below
Large, Medium & Small Window Sizes
LAR GE
W INDOW
VERSIO N
60 X 60 m m
MEDIUM
W IN DO W
VERS IO N
30 X 60 m m
SM ALL
W IN DO W
VER SIO N
30 X 30 m m
5.2 Window Colours
Each channel is equipped with its own removable lens assembly, which contains a white diffuser,
coloured filter and a laser printed film legend.
Part Small Window Medium Window
Large Window
Bezel ID-SLC-3WF-B ID-SLC-3WH-B ID-SLC-3WG-B
Clear Lens ID-SLC-3LF ID-SLC-3LH ID-SLC-3LG
White Diffuser ID-SLC-3PF-WH ID-SLC-3PH-WH ID-SLC- 3PG-WH
Clear filter
(used with white windows) ID-SLC-3PF-C ID-SLC-3PH-C ID-SLC- 3PG-C
Red filter ID-SLC-3PF-R ID-SLC-3PH-R ID-SLC- 3PG-R
Amber filter ID-SLC-3PF-A ID-SLC-3PH-A ID-SLC- 3PG-A
Yellow filter ID-SLC-3PF-Y ID-SLC-3PH-Y ID-SLC- 3PG-Y
Blue filter ID-SLC-3PF-B ID-SLC-3PH-B ID-SLC- 3PG-B
Green filter ID-SLC-3PF-GD ID-SLC-3PH-GD ID-SLC- 3PG-GD

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5.3 Laser Printed Legends
Laser printed film legends are easily generated, from within Microsoft Excel, in a font style and size
to suit individual applications. A software template is available, free of charge from RTK, which allows
the user to produce film legends locally if required. Completed film legends are located between the
clear front lens of the removable window assembly and the associated coloured filter and diffuser.
5.4 Adding Or Changing Film Legends
Each lens assembly has a small slot in the upper ridge of the surround bezel, which allows a flat
blade terminal screwdriver to be used to gently lever the assembly forward. Once the assembly has
been removed the diffuser, coloured filter and film legend can be accessed using a flat blade
screwdriver to gently lever the lens clear of the associated parts as indicated in the diagram below.
This MUST be levered on the side NOT the top or bottom
LASER
PRINTED
FILM
LEGEND
Diffuser
Coloured Filter
Film Legend
Slot to aid
lens removal
Lens
Bezel
5.5 LED Illumination
All units are suitable for “fit and forget” LED assemblies part no. P725-LED-** specify colour
RD = red,
YW = yellow,
AM = amber,
BL = blue,
GN = green,
WT = white.

NEX7250 Zone 2 Annunciator
15
5.6 Window Numbering System
RTK have adopted the following window numbering system to aid with the location of the film legend
and the associated alarm cards. This method is used to ensure that the legend matches the functions
selected for the designated alarm.
SY S T EM
TE S T
FI R S T
RE S ET
7
M U T E
PO W ER
RE S ET
1
5
3
A CK
LA M P
TE S T
RE S E T
F IR S T
RE S E T
6
2
3
4
L AM P
TE S T A C K
MU T E
SY S T E M
T ES T
PO W E R
15
F IR S T
RE S E T
RE S E T
2
SY S T EM
TE S T
PO W E R
M U T E
A CK
LA M P
T ES T
13
6
8
4
2
12
10
9
11
M ed ium W in do w V ersio n S m all W in do w V ersio n
Large W indow V ersio n
5.7 Alarm Card Types
There are 4 basic types of dual channel alarm cards
PART NO DESCRIPTION USED ON
CB5674POP1 2 Channel alarm card
(Without repeat relays)
Large, medium and small window versions
Locates in the upper slot of the associated cell
CB5674POP2 2 Channel alarm card
(With repeat relay facility)
Large, medium and small window versions
Locates in the upper slot of the associated cell
CB5674POP3 2 Channel alarm card
(Without repeat relays)
Small window versions
Locates in the lower slot of the associated cell
CB5674POP4 2 Channel alarm card
(With repeat relay facility)
Small window versions
Locates in the lower slot of the associated cell
Alarm cards are plugged into the rear of the annunciator and once inserted automatically connect to
a pre-tested passive display motherboard.
5.8 Pushbutton / Programming Module
The pushbutton/programming module is located in the bottom right hand corner of the annunciator
when viewed from the front unless otherwise specified. It has a power-on LED, integral audible and
six pushbuttons to cover all of the possible sequence combinations. The six pushbutton are:- Lamp
Test, Functional Test, Mute, Acknowledge, Reset and First Reset

16
5.9 Pushbutton / Programming Module Options
The pushbutton/programming module is normally integrally mounted within the annunciator however
if required it can be supplied as a stand alone item suitable for panel mounting, DIN-rail mounting or
wall mounting.
5.10 Fully Field Programmable
In addition to controlling the alarm sequence the pushbutton module is also used as a configuration
tool to programme the required features on the annunciator. To access the programming functions
the pushbutton fascia must be hinged down to reveal a configuration switch (labelled CONF) located
on the inner face of the assembly. Once the unit is in the CONF mode the user is able to enable or
disable a range of pre-defined features and options. The dual function pushbutton assembly allows
the user to enable any of the 25 embedded features on a per channel basis without having to remove
the power to the annunciator or to remove light-boxes, back-planes or alarm cards.
All programmed information is stored in EEPROM, with a minimum 20-year retention, giving
repeatability and reliability without the need for battery backup.
Note:- Alarm sequences will operate in accordance with any of the standard sequences defined in
the ISA publication "Alarm Sequences and Specifications S18.2 - 1979 (R1985)"
5.11 Sleep Mode
Sleep mode is typically used in sub station applications where the visual and audible outputs are
disabled during unmanned periods to reduce the drain on the associated station batteries.
Whilst in sleep mode the logic of the annunciator will continue to react in the normal way including
the operation of common alarm relays, watchdog relay and optional signal duplicating relays, only the
drive signals to the lamp and audible drives are disabled.
Before sleep mode can be enabled a jumper link must be pre-set on the SPR card located inside the
pushbutton / programming cell. To gain access to the SPR card first remove the back-plate on the
SPR module and then remove the associated circuit card assembly using a flat blade screw driver to
gently lever the assembly out using the white nylon pillar. Once the card has been removed locate
the 3 pin header marked FR and SP which is located on the lower of the two cards and check that
the 2 way shorting bar is in the SP position as shown below. Once the jumper has been placed into
the correct position and the card assembly placed back into the annunciator the unit can be set to
sleep mode using a remote mounting normally open maintained switch with one side of the switch
connected to +V (+24VDC) and the other side of the switch connected to terminal FR located on the
rear of the pushbutton / programming cell. Whilst the switch is maintained in the closed position the
unit will remain in sleep mode.
Note: - All normal pushbutton functions are inhibited during sleep mode to ensure that the operator
can view any alarms that occur as soon as the unit is returned to its normal operational state.

NEX7250 Zone 2 Annunciator
17
Sleep Mode Jumper Location
FR
SP
SUPPLY 24VDC
SPR
FR
OV O VC +V +VC T A R ST M
MULTGPBGPAHNBHNA
Side View
Assy Pt No
CB4642POP1
Sleep Mode Switch
5.12 Automatic Mute Or Automatic Acknowledge
Each annunciator is equipped with an integral timer that can be enabled to allow the user to
automatically mute or acknowledge alarms after a pre-set time delay. To set the automatic mute or
acknowledge feature the pushbutton / programming module must be hinged down by inserting a
small flat blade screw driver into the recess on the upper face of the associated surround bezel and
gently levering the pushbutton assembly forward to reveal the information plate which is visible on
the inside face of the module. The two pozidrive screws and washers in the centre of the plate should
be removed to allow access to DIL switch SW7, which is used to set the unit to automatically silence
or acknowledge and to set the required time delay.

18
Auto Mute / Ack Delay Switch Location (Information Plate
Removed)
A4219-*
Posidrive
screws
CB4072POP
ON
SW7
ON OFF
1
OFF
3
2
4
SW7
Automatic Acknowledge or Silence Time Selection
FUNCTION SW7-1 SW7-2 SW7-3 SW7-4
Automatic acknowledge ON
UNUSED
Automatic mute OFF
Disable automatic timer OFF OFF
Enable 1 minute time delay ON OFF
Enable 4 minute time delay OFF ON
Enable 8 minute time delay ON ON
5.13 Integral Audible Alarm
Each annunciator is equipped with an internal 3.5kHz 95dB(A) audible located behind the integral
pushbutton module. The audible is supplied with an adjustable volume control using a single turn
potentiometer. The potentiometer can be accessed by hinging down the integral pushbutton module
using a small flat blade screwdriver in the slot of the surround bezel. The potentiometer is located in
the top right hand corner of the cell as shown below. On systems with channels configured to
activate either the urgent or non-urgent audible relays it is important to note that the internal audible
will only operate on channels set to operate the critical audible relay HNA (see Function F23).

NEX7250 Zone 2 Annunciator
19
Integral Horn Volume Adjustment Location
CAL
FUNCTION
STATUS
Internal audible
volume adjustment
Increase
5.14 Remote Pushbutton Inputs
Because the NEX7250 has to be mounted in an IP rated enclosure these pushbuttons will not be
accessible in the Zone 2 area. Remote pushbuttons can be connected to the P725 SPR module
either in place of or in addition to the integral pushbuttons or to allow multiple annunciators to share
common pushbuttons for example a common mute pushbutton mounted in the operator desk
console.
The Pushbuttons should be of the Normally Open, Momentary type and it is recommended that if
long cable runs are required through electrically noisy environments a screened cable is used with
the screen connected to a suitable instrument earth at one end only.
If the pushbuttons are to be located in a classified hazardous area they must be certified for use in
that area. We recommend that Pushbuttons are pre mounted or supplied as part of the NEX7250
equipment.
Please note:- When the annunciator is in the configuration mode with the CONF switch in the ON
position all integral or remote pushbutton inputs are disabled until the unit has been returned to its
normal operating state.

20
Remote Pushbutton Wiring
SUPPLY 24VDC
SPR
HNA HNB GPA GPB MULT
FIRST RESET
MUTE
SYSTEM TEST
RESET
ACKNOWLEDGE
LAMP TEST
T A R ST M FR
OV OVC +V +VC
5.15 Terminations
All active cells within the annunciator are provided with quick disconnect (2) part pluggable, rising
clamp, terminals capable of accepting up to 2.5mm² cable. In the unlikely event that a card fails the
associated field wiring can remain connected and the terminal temporary unplugged to allow removal
and replacement of the associated card.
5.16 Failsafe Mode
All relays are configured in their default setting as energised. The relays will de-energise on trip or in
the case of a power failure.