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XNX Universal Transmitter
Product Description

The Transmitter

The transmitter is a comprehensive gas detection system
designed to operate in hazardous locations
sensor technologies –catalytic bead, electrochemical (EC),
or infrared (IR)– to detect toxic gases, flammable gases, and
oxygen depletion gas hazards. Each technology has a dedicated
personality board.
Catalytic bead technology is used with the mV personality
board. Catalytic bead sensors respond to a wide variety of
combustibles so are typically used for flammable gas detection.
Electrochemical technology is used with the electrochemical
board. EC sensors measure toxic gases in low concentrations.
The EC sensors employ the patented Reflex™ cell fault
diagnosis routine. Reflex checks for cell presence, cell dry-out,
and cell open or short circuit. Reflex is automatically initiated
by the transmitter at eight-hour intervals. It is also initiated on
power up or sensor exchange. In the event of a cell failing this
test, a sensor fault code is displayed. Reflex diagnostics occur in
the first minutes of the power up sequence.
Infrared technology is used with the IR board. IR sensors
optically absorb gases that fall into the infrared spectrum.
For additional information about any of these sensor types, refer
to the applicable data sheet for the supported sensor in Figure 1.
The transmitter also allows for an optional communication
board. There are three types of boards: relay, Modbus
There are three main types of gas hazards: flammable, toxic, and asphyxiant. A flam-
1
mable gas hazard is one in which there is a risk of fire and/or explosion (e.g., a situation
in which a gas such as methane, butane, or propane is present). A toxic gas hazard is
one in which there is a risk of poisoning (e.g., a gas such as carbon monoxide, hydrogen
sulfide, or chlorine is present). An asphyxiant hazard would include a risk of suffocation
through oxygen deficiency. (Oxygen can be consumed or displaced by another gas.)
Introduction
FOUNDATION
additional information.
1 and utilize multiple
Personality Personality
, or
®
.
The transmitter relies on 4-20mA output, refreshed at least every
two seconds (once per second is typical), in which the output is
proportional to the gas concentration.
11
Fieldbus. See the
TM
XNX Universal Transmitter
CI H NH O HCI
2 2 3 2
CIO H S NO PH
2 2 3
CO HF NO SO
2 2
F HCN EtO O
2 3
Sensor Type Sensor Type y T T
IR Point and Open-Path Infrared Searchpoint Optima Plus, Searchline Excel
mV Flammable and Toxic
XNX EC Toxic and O Sensing
2
Figure 1. XNX Universal Transmitter and supported sensing technologies
Communications section for
Searchpoint Optima Plus
705
705HT
Sensepoint
Infrared Flammable
Sensepoint HT
Infrared Methane/CO
Supported Sensors Supported Sensors
705, 705HT, Sensepoint, Sensepoint HT, MPD
(Catalytic Bead Flammable, IR Flammable and IR CO
Electrochemical sensors, with Hot Swap, pre-calibrated
through Intrinsically Safe (IS) barrier
Searchline Excel
Multi-Purpose
Detector (MPD)
Catalytic Bead
2
)
2