Specifications

81
GMM 11 and GMM 12 CO
2
Modules
for Custom Applications
FEATURES / BENEFITS
 Excellent long term stability
 Low cost
 High accuracy
 Available in four CO
2
measurement ranges
 Operates over full relative humidity range
 Quick warm up cycle and response time
VERSATILE SOLUTIONS FOR
OEM APPLICATIONS
Vaisalas CO
2
detectors use a single wavelength non-
dispersive infrared (NDIR) gas sensor. This technique
makes the sensor CO
2
specific, meaning it is not
sensitive to the presence of other gases, including
water vapor. The GMM modules provide high
accuracy and excellent long term stability with low
power consumption. They are available in various
sensitivity ranges to cover the spectrum of measure-
ment requirements. Output for the GMM 11 is 0 to 1V
(non-linear). For the GMM 12, the output is linear
and user selectable between 0 to 20 mA, and 4 to 20
mA. Linear voltage outputs are also possible with the
addition of a resister soldered on the PCB, by the
user. The versatility and long term stability of these
sensor modules make them excellent solutions for a
wide variety of OEM applications.
DIFFUSION OR PUMP ASPIRATION
All GMM 11/12 models can be pump aspirated with a
pump supplying 0.3...1.0 l/min air flow (pump/part
#18515). Also, GMM 11AD and GMM 12AD can be
aspirated with a fixed or remote diffusion tube.
When using pump aspiration, an appropriate filter
(part #18179, or any other with 1 mm filtration)
should always be used to avoid sensor contamina-
tion. With the diffusion tube the filtration is not
needed. For the GMM 11AD/12AD models, use
Vaisala part #18191 when a fixed diffusion tube is
needed, and part #19255 GM for remote use. The
pump, filter and neoprene tubing (for the remote
diffusion tube) must be ordered separately.
GMM 11B
GMM 11A
APPLICATIONS
 Environmental chambers
 HVAC (DCV, Energy Management)
 Industrial process control
 Laboratories
 Food processing/packaging
 Breweries/wineries
 Greenhouses
 Mushroom growing