GAI-Tronics DEX-202 User manual

Pub.: 42004-679L2D
GAI-Tronics Corporation 400 E. Wyomissing Ave. Mohnton, PA 19540 USA
610-777-1374 800-492-1212 Fax: [phone]
VISIT WWW.GAI-TRONICS.COM FOR PRODUCT LITERATURE AND MANUALS
GAI-TRONICS® CORPORATION
A HUBBELL COMPANY
Model DEX-101, -102, -201, and -202
Hazardous Area Driller’s Intercom Stations
TABLE OF CONTENTS
Confidentiality Notice.....................................................................................................................1
General Information.......................................................................................................................1
Product Overview ...................................................................................................................................1
System Requirements and Limitations.................................................................................................1
Features and Functions ..........................................................................................................................2
Available Models.....................................................................................................................................2
Description of Major Components........................................................................................................2
Installation ......................................................................................................................................3
General Information...............................................................................................................................3
Mounting..................................................................................................................................................5
Conduit Installation................................................................................................................................5
Field Wire Installation............................................................................................................................6
Power........................................................................................................................................................7
AC Models............................................................................................................................................................7
DC Models............................................................................................................................................................7
Auxiliary Devices ....................................................................................................................................8
System Interconnection..........................................................................................................................9
Operation.......................................................................................................................................10
Digital Models DEX-102 and DEX-202...............................................................................................10
Intercom Communication Modes........................................................................................................................10
Volume Control ..................................................................................................................................................10
Paging .................................................................................................................................................................11
Alarms and Music...............................................................................................................................................11
Analog Models DEX-101 and DEX-201..............................................................................................11
Intercom Communication Modes........................................................................................................................11
Volume Control ..................................................................................................................................................11
Paging .................................................................................................................................................................11
Alarms and Music...............................................................................................................................................11
Maintenance..................................................................................................................................12
General Information.............................................................................................................................12
Troubleshooting....................................................................................................................................12
Specifications ................................................................................................................................13

42004-679L2D
GAI-Tronics Corporation 400 E. Wyomissing Ave. Mohnton, PA 19540 USA
610-777-1374 800-492-1212 Fax: [phone]
VISIT WWW.GAI-TRONICS.COM FOR PRODUCT LITERATURE AND MANUALS
GAI-TRONICS® CORPORATION
A HUBBELL COMPANY
Model DEX-101, -102, -201, and -202
Hazardous Area Driller’s Intercom Stations
Confidentiality Notice
This manual is provided solely as an operational, installation, and maintenance guide and contains
sensitive business and technical information that is confidential and proprietary to GAI-Tronics. GAI-
Tronics retains all intellectual property and other rights in or to the information contained herein, and
such information may only be used in connection with the operation of your GAI-Tronics product or
system. This manual may not be disclosed in any form, in whole or in part, directly or indirectly, to any
third party.
General Information
Product Overview
The Driller’s Intercom is a communications system
designed to serve the needs of oil and gas industry on
oil drilling platforms, especially in hazardous areas. It
provides all-call, group call, and point to point
communications, and is available in digital and analog
versions.
The enclosure is rated NEMA-4X, and is factory sealed
to ensure explosion-proof integrity.
System Requirements and Limitations
Each Driller’s Intercom system requires a Central
Switch to operate. The Central Switch must be located
in a non-hazardous area. The configuration parameters
for all components of the system are set in the Central
configuration.
Each central switch can manage up to 16 digital or analog subscribers, and can be expanded to 32
subscribers. Central switches can be linked or a larger switch can be used for increased system size. By
combining central switches, the system is easily expanded at any time.
All stations must be connected in a star configuration to the Central Switch, but power to the stations can
be daisy-chained. Please refer to the “Installation” section for the power cable and system cable distance
limitations.
Additional features and functions (not detailed in this manual) are available. Refer to the Central Switch
manual or contact a GAI-Tronics Corporation representative for more details.
Figure 1. Driller’s Intercom with Keypad

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Features and Functions
•Digital and analog models •Factory sealed
•120–240 V ac and 24 V dc models •Suitable for Div. 1 & 2 and Zone 1 & 2 Hazardous Areas
•NEMA-4X rated enclosure •Suitable for high noise areas
•18-watt speaker amplifier •Hands-free duplex and simplex communication
•Speaker volume control •All-call and group paging
•Beacon control (digital models only) •Broadcast of alarm and music signals
•Footswitch input •Master/slave and point-to-point communications
•Call status indicator •System upgrade and expansion capability
•UL Approved
Available Models
DEX-101 Analog Intercom Station - 24 V dc (UL)
DEX-201 Analog Intercom Station – 120 V ac (UL)
DEX-102 Digital Intercom Station with keypad – 24 V dc (UL)
DEX-202 Digital Intercom Station with keypad – 120 V ac (UL)
Description of Major Components
The Driller’s Intercom stations consist of a factory-sealed enclosure (top) and a termination enclosure
(bottom). Refer to Figure 1 for details. The factory-sealed configuration eliminates the need for external
seals on this unit; however, additional seals may be required on auxiliary devices.
The audio, control, and power components for this assembly are contained in the factory-sealed
enclosure. The front panel of the factory-sealed enclosure contains the user interface components
(microphone, status LED, and keypad [digital models only]).
All system terminations (power, speaker, system, footswitch, and beacon) are to be made in the
termination enclosure.
This station requires an external speaker (sold separately) to operate. Also, a customer-supplied beacon
(digital models only) and footswitch can be added to this unit for visual status indication and talk/listen
control.
CAUTION Use only suitably listed components for the hazardous area.

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Installation
General Information
WARNING Always remove power to this station and any associated equipment before
beginning any installation.
Install equipment without modification and according to all applicable local and national electrical codes.
Consult the National Electrical Code (NFPA 70), Canadian Standards Association (CSA 22.1), and local
codes for specific requirements regarding your installation. Class 2 circuit wiring must be performed in
accordance with NEC 725.55.
CAUTION
The factory-sealed section of this station is only to be opened for maintenance or repair by factory
authorized personnel. Refer to the “Maintenance” section for more details.
WARNING
After installing station and before applying power, verify that the bolts on the factory-sealed section
of the station are set at 30 ft-lbs.
This station has a highly sensitive microphone that allows the user to communicate at a distance from the
station. This station also contains a high gain amplifier that enables operation in high noise
environments.
To prevent feedback problems in the system, the ambient noise levels, volume settings, and station
placement must be taken into consideration. In most cases, stations can be mounted perpendicular to the
same surface and be placed 150 feet apart. This minimum spacing requirement between stations can be
reduced under the following conditions:
•the stations are installed in a high noise environment;
•they are configured for simplex mode (depressing Tbutton);
•they contain speaker L-pads;
•they are placed in separate rooms.

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Figure 2. Driller’s Intercom Outline

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Mounting
The station consists of two enclosures that
are connected by a union. The mounting
location must be a flat, vertical surface that
provides proper clearance, rigidity and
strength to support the station.
The suggested mounting height for stations is
54 inches (137 cm) up to the center of the
factory-sealed enclosure.
To maintain the explosion-proof integrity of
these stations, they are designed with all
mounting hardware located outside the
enclosures. Refer to Figure 3 for mounting
hole and slot dimensions.
Securely fasten the factory-sealed and
termination enclosures to the mounting
location using steel mounting bolts and
washers, or washer-head bolts (hardware not
included).
Conduit Installation
Install the conduit using an approved
electrical conducting-type lubricant on the
threads. The termination enclosure on the
station has one conduit entry on each side
and two on the bottom of the enclosure.
The UL-approved Driller’s Intercom models contain ¾-inch NPT conduit entries. The bottom entries are
plugged from the factory and can be removed to allow use of the entry. Refer to Figure 2 for locations.
All unused conduit openings must be plugged using a close-up plug approved for the specific hazardous
location where the enclosure is used. All conduit connections must meet minimum thread engagements
as specified by the applicable electrical codes.
Figure 3. Rear view showing mounting slots

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Field Wire Installation
Remove the termination enclosure cover and pull all wiring into the termination enclosure. Make all
connections as described below.
NOTE:All field wiring is to be completed in the termination enclosure (bottom enclosure) only.
NOTE: Consult the National Electrical Code (NFPA 70), Canadian Standards Association (CSA 22.1),
and local codes for the specific requirements regarding your installation. Install all equipment without
modification and according to the local and national codes. Install conduit and seals where required.
Class 2 circuit wiring must be performed in accordance with NEC 725.55.
Figure 4. DC Model Installation Diagram (See note below.)
Figure 5. AC Model Installation Diagram (See note below.)

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Power
A separate power feed is recommended for stations in Div. 1 areas so that the stations can be de-energized
for maintenance without disrupting the power supply to the other equipment in the Div. 1 area. Refer to
Figure 4 and Figure 5 for wiring details. Remove the termination enclosure cover and pull all wiring into
the termination enclosure. Terminal block TB2 is provided for connection of power to the station.
Terminate all conductor ends using #6-32 screws lugs.
AC Models
Terminate the 120-240 V ac 50/60 Hz feed on TB2. This terminal block can also be used to connect 120-
240 V ac 50/60 Hz to the next station. The maximum current of the ac feed shall not exceed 20 amperes.
Refer to Figure 5 for more details.
DC Models
Refer to Figure 4. Terminate the 24 V dc feed on TB2. This terminal block can also be used to connect
24 V dc to the next station. The maximum current of the dc feed shall not exceed 20 amperes. Power
must be supplied by an isolated 24 V dc power source. Additional power feeds may be required to
increase the system distance and/or the number of stations.
NOTE:Isolated dc power sources must be used for this installation. The 24 V dc source should be
located as close to the system center as possible.
Grounding the negative side of the power source at one point is recommended to ensure hum and noise-
free operation. Noise present on dc power lines can negatively affect station operation. Therefore, noise
should be limited to 10 mV or less.
When installing this equipment, the power cable length is an important consideration. Refer to Table 1
for the recommended wire sizing details and the maximum cable lengths. This table is a guideline that is
useful in most applications; however, the installer must take into consideration any parameters specific to
their application.
Table 1. Maximum Distance between
Driller’s Intercom Stations (in feet)* (DC)
# of AWG Wire
Stations 12 14 16 18
1 906 570 358 225
2 302 190 119 75
3 151 95 59 37
4 90 57 35 -------
5 60 38 ------- -------
6 43 27 ------- -------
7 32 ------- ------- -------
8 25 ------- ------- -------
*This chart is based on the following
parameters:
1. V(max) = 27 V
2. V(min) = 21 V
3. Cable temperature rating = 90º C
4. The American Wire Gauge
resistance table
For V(max) of 24 V, multiply the
distance shown by a factor of 0.47.

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Auxiliary Devices
Terminal block TB1 is provided for connection of the speaker, system cable, footswitch, and beacon.
This terminal block accepts a #12-22 AWG wire. Refer to Table 2 for the recommended conductor sizes.
Conductor ends can be stripped and terminated with or without a wire ferrule.
Table 2. Recommended Cable Sizes
Cable Use Size
System Digital: 2-conductor twisted pair, No. 22 AWG is typical
Analog: 4-conductor twisted pair (A/B twist; C/D twist), No. 22 AWG is typical
Power 3-conductor, No. 12 AWG is typical
Beacon 2-conductor, No. 18 AWG is typical (for digital models only)
Footswitch 2-conductor, No. 22 AWG is typical
Speaker Cable 2-conductor twisted pair, No. 18 AWG is typical
1. Install the system cable on TB1 system terminals A-D. Each system cable must be home run to the
Central. Digital stations require termination of a 2-conductor twisted pair cable on system terminals
A and B only. Analog stations require termination of a 4-conductor twisted pair cable (A/B twist &
C/D twist) on system terminals A-D. Refer to Table 3 for the maximum system cable lengths.
Table 3. Maximum System Cable Lengths
Digital Models Analog Models
Cable Capacitance 22 AWG 20 AWG 22 AWG 20 AWG
30.5 nf/1000 feet 6562 feet 6562 feet 4921 feet 6562 feet
13.7 nf/1000 feet 9843 feet 9843 feet
2. Install the speaker cable on TB1 Speaker terminals LS1 and LS2. Refer to Table 2 for recommended
conductor sizes.
3. Install the beacon control cable on TB1 terminals C1 and C2. This control output is available on
digital stations only. Refer to Table 2 for recommended conductor sizes.
4. Install the footswitch cable on TB1 terminals N.O. and C. Refer to Table 2 for recommended
conductor sizes.
After all connections are made, inspect and clean the machined and threaded surfaces of both the
termination cover and box. Clean the surfaces by wiping with a clean, lint-free cloth. Apply a light coat
of Killark LUBG lubricant to the cover threads. Install and hand-tighten the cover to the box.

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System Interconnection
Refer to Figure 6 for a typical system wiring diagram. Consult the Central Switch manual for further
details on equipment connections to the central switch.
Figure 6. Typical system interconnection diagram