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114
GMD/W20 Series Carbon Dioxide Transmitters
for Demand Controlled Ventilation Applications
The duct mounted Vaisala
CARBOCAP
®
Carbon Dioxide
Transmitter Series GMD20 and
wall mounted GMW20 are specially
designed for Demand Controlled
Ventilation (DCV). They are easy to
install and require no maintenance.
The recommended calibration
interval is ve years.
Vaisala CARBOCAP®
Technology
The GMD/W20 Series Transmitters
use the silicon-based Vaisala
CARBOCAP
®
Sensor. The simple
structure and reference measurement
capabilities make this Single-Beam,
Dual-Wavelength NDIR sensor
extremely stable and reliable.
The temperature and ow
dependences of the sensor
are negligible. In addition, the
measurement accuracy is not
The GMD/W20 series transmitters are designed for use in ventilation-related
applications.
affected by dust, water vapor and
most chemicals.
Versatile Transmitters
The GMD/W20 series transmitters
can be used independently, or
incorporated into building energy
management systems. The series
consists of duct mount units
GMD20/D and wall mount units
GMW21/D and GMW22/D. Version D
has a display. The two sizes in the
wall-mount series make them easy
to install for most standard junction
boxes.
The duct units' compact sensor head
design requires only a small hole in a
ventilation duct, thereby minimizing
the risk of leaking gaskets and
measurement errors.
In addition to the standard
0 ... 20 mA, 4 ... 20 mA and 0 ... 10 V
outputs, there are three other
options: two LonWorks
®
interfaces
and a relay output. The relay output
is standard with the display units.
Improve Indoor Air at
Minimal Energy Costs
The use of the GMD/W20 series
transmitters ensures the best
possible control of air quality and
results in considerable savings in
energy consumption, maintenance
and recalibration costs.
Temperature Option
The GMA20T temperature module,
an option with the GMW21 wall
mount unit, combines both CO
2
and
temperature measurement into one
transmitter. The GMA20T has an
output of 0 ... 10 V corresponding to a
temperature range of 0 ... +50 °C
(+32 ... +122 °F).
Features/Benefi ts
▪
Versatile transmitters
▪
Duct and wall mount models
▪
Incorporates Vaisala
CARBOCAP® Sensor - the
silicon-based NDIR sensor
▪
Excellent long-term stability
▪
Negligible temperature
dependence
▪
Ease of installation
4-Carbon-Dioxide-Pages-100-119-Vaisala-Catalog-2011.indd 114 24.10.2011 9.22
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