GMT220
CO2Transmitter Series for
Industrial Applications
Reliable and
Innovative Design
FOR HARSH ENVIRONMENTS
The GMT220 series transmitters
HIGH-END MEASUREMENT
are designed to measure CO2 in
TECHNOLOGY
harsh and humid environments.
The housing is dust and water
The GMT220 series transmitters
proof to IP65/NEMA4. The
incorporate the new industrial
materials have been chosen for
CARBOCAP® sensor. The
good corrosion resistance.
patented sensor has unique
reference measurement
The transmitters are particularly
capabilities. Its critical parts are
well suited for industrial CO2
made of silicon. This gives the
applications, such as:
sensor an outstanding stability
" horticulture and fruit storages
over both time and temperature.
" safety alarming and leakage
For the user this means that the
monitoring
calibration interval can be
extended compared to many " demand controlled
other NDIR instruments on the ventilation in harsh
market. environments
The CARBOCAP® Operating Principle
TUNABLE
SAMPLE CELL
INTERFERENCE FILTER
The CARBOCAP® sensor is a
SIGNAL
Single-Beam Dual-Wavelength
PROCESSI NG
NDIR sensor. It features a tunable
IR-SOURCE
interference filter which enables
I R-DETECTOR
reference measurements without
DIFFUSION MEMBRANE
the problems frequently
encountered in other types of The ratio of the two signals
wavelength of the gas. The
Dual-Wavelength sensors. The indicates the degree of light
detector measures the strength of
modulated infrared source emits absorption in the gas and so the
the signal that gets through.
light into the sample cell, where gas concentration. Since the
the gas absorbs photons of a Then the pass band of the filter is tunable interference filter is made
certain wavelength. The filter is shifted to a band with no by silicon micro-machining, all
electrically tuned so that its pass interfering absorption lines. This parts prone to mechanical wear
band coincides with the absorption constitutes the reference signal. have been eliminated.
Easy to Use
CO2
SIMPLE INSTALLATION
A separate mounting plate makes
the installation of the transmitter
easy. After the mounting plate has
been attached to the wall, the
transmitter body is locked onto it.
To simplify installation, the plastic
plate protecting the electronics
inside the housing includes
instructions on how to make the
electrical connections.
EASY FIELD MAINTENANCE
Since the probes of the GMT220
series transmitters are truly
interchangeable, they facilitate
easy field maintenance. The
probes can either be replaced by
The transmitter can be newly calibrated probes or
OPTIMAL MEASUREMENT
connected to various separate ones that can be used as
RANGE FOR EACH
measurement systems. In a reference for calibration
APPLICATION
addition to standard analog, checking. This minimizes down-
The user has a choice of voltage and current outputs, time. The end-user can take care
measurement ranges up to there are also two configurable of the field maintenance without
20 %CO2. The GMT220 series is alarm relay outputs. Activated any additional equipment or
comprised of two transmitters: the relays are indicated by LED heavy and expensive calibration
GMT221 is designed for higher lights on the cover. An optional gas bottles. Replaced probes can
and the GMT222 for lower CO2 LonWorks® digital interface is be sent to Vaisala for re-
concentrations. also available. calibration.
Flexible
THE GMM220 SERIES INTERCHANGEABLE PROBES
MODULES
Since the probes are truly
interchangeable, they can be
The GMT221 and GMT222
removed and re-attached or
transmitters are also available as
replaced at any time  without
corresponding modules, GMM221
any need for calibration and
and GMM222.
adjustment. Furthermore, they
The modules are particularly
can be attached directly to the
suitable for incubator, fermentor,
transmitter body or used remotely
or other OEM applications.
with the help of a probe cable.
This enables installation of the
probe into hard-to-reach places.
THE GMT220 SERIES
TRANSMITTERS
The compact GMT221 and
GMT222 transmitters are wall
mounted.
Options
DIGITAL LCD DISPLAY
probe can be installed in an
SPARE PROBES
The LCD display shows four digits, area where there is a danger of
the ppm or % (CO2) symbols, as The interchangeable probes CO2 leaks and the transmitter
well as diagnostics. The display is GMP221 and GMP222 can be body mounted outside that area.
backlit and can therefore be seen ordered separately.
PROBE ATTACHMENT GEAR
even in dark locations.
PROBE CABLE
Remote installation of the probe
LONWORKS® MODULE
The probe cable is two meters e.g. in a duct, a chamber, or on a
A LonWorks® module is available long. It facilitates remote wall is possible with a mounting
as a digital interface option. installation of the probe. The flange or two clips.
Technical Specifications
GENERAL GMM221/222
Analog output signals 0...20 or 4...20 mA
Measurement ranges
0...1 V, 0...2 V, 0...2.5 V or 0...5 V
GMT221/GMM221
Resolution of analog outputs 0.03 %FS
for high concentrations 0...2% CO2
Recommended external load
0...3% CO2
current output max. 200 Ohm
0...5% CO2
voltage output min. 1 kOhm
0...10% CO2
Power supply 11...20 or 18...30VDC
0...20% CO2
Power consumption <2.5 W
GMT222/GMM222
Warm-up time <15 minutes
for low concentrations 0...2000 ppm
Operating temperature range -20...+60 °C
0...3000 ppm
Storage temperature range -30...+70 °C
0...5000 ppm
Operating humidity range
0...7000 ppm
probe 0...100 %RH
0...10 000 ppm
non-condensing
Accuracy at 25 °C against certified factory references
mother board 0...85 %RH
GMT221/GMM221 <Ä…[0.02% CO2 + 2% of
non-condensing
reading]
Probe housing material PC plastic
GMT222/GMM222 <Ä…[20 ppm CO2 + 2% of
Probe housing classification IP65/NEMA4
reading]
Weight:
(incl. repeatability and calibration uncertainty)
GMP221 probe max. 40 g
Nonlinearity <Ä…0.5 %FS
GMP222 probe max. 60 g
Temperature dependence
Mother board (incl. 2 m cable) max. 140 g
of output (typical value) 0.1 %FS /°C
Pressure dependence (typ.) 0.15% of reading/hPa
ACCESSORIES
Long-term stability <Ä…5 %FS/2 years
GMP221, GMP222 spare probe
Response time (63%)
(use the order form to define the measurement
GMT 221/GMM221 20 seconds
range etc.)
GMT 222/GMM222 30 seconds
25245GM clips (2 pcs) for
attaching the probe
GMT221/222
GM45156 mounting flange for the probe
Analog output signals 0...20 or 4...20 mA
19040GM serial COM adapter
0...10 V
Resolution of analog outputs 0.03 %FS
GMT221/222 only:
Recommended external load
25665 GM 2.0 m probe cable
current output max. 400 Ohm
GML220 LonWorks® module
voltage output min. 1 kOhm
Two pre- or user-defineable relay outputs
Relay contact ratings max. 30 VAC/ 60 VDC, 0.5 A
Power supply nominal 24 VAC/DC
Power consumption <4 W
The GMT221/222 and GMM221/222 comply with the
Warm-up time <15 minutes
following EMC standards and have passed the following
Operating temperature range -20...+60 °C
tests:
Storage temperature range -30...+70 °C
EN 50081-1
Operating humidity range 0...100 %RH
(EN 55022 class B = CISPR 22)
non-condensing
EN 50082-1
Housing material
(IEC 1000-4-2, 8 kV air)
transmitter body ABS plastic
(IEC 1000-4-3, 80 - 1000 MHz, 80% AM, 3 V/m)
probe PC plastic
(IEC 1000-4-4, 500V)
Housing classification IP65/NEMA4
(IEC 1000-4-6, 0.15 - 80 MHz, 80% AM, 3 V/m)
Weight:
GMT221 max. 280 g
(IEC 1000-4-5, 500 V) [GMT221/222 only]
GMT222 max. 300 g
Probe cable length 2 m (optional)
CARBOCAP® is a registered trademark of Vaisala Oyj.
Specifications subject to change without prior notice.
© Vaisala Oyj
Dimensions
GMP221 PROBE
GMT220 SERIES
TRANSMITTER BODY
GMP222 PROBE
MOUNTING PLATE
GMM220 SERIES MODULE MOUNTING FLANGE
Dimensions in mm (inches)
Head office: Vaisala Pty Ltd
Vaisala Oyj 3 Guest Street
P.O. Box 26 Vaisala GmbH Vaisala Inc. Hawthorn. VIC 3122
FIN-00421 Helsinki Postfach 540267 100 Commerce Way AUSTRALIA
FINLAND 22502 Hamburg 54 Woburn, MA 01801-1068 Phone int.: [phone]
Phone int.: [phone] GERMANY USA Telefax: [phone]
Telefax: [phone] Phone int.: [phone] Phone int.: [phone] A.C.N. 006 500 616
http://www.vaisala.com Telefax: [phone] Telefax: [phone]
Vaisala Beijing
[e-mail]
Vaisala (UK) Ltd Vaisala KK Representative Office
Vaisala Malmö Suffolk House, Fordham Rd 42 Kagurazaka 6-chome Room 520, Wangfujing Hotel
Drottninggatan 1 D Newmarket Shinjuku-ku No. 57, Wangfujing Street
212 11 Malmö Suffolk CB8 7AA Tokyo 162-0825 Beijing 100006
SWEDEN UNITED KINGDOM JAPAN PEOPLE S REPUBLIC OF CHINA
Phone nat.: 0200 848 848 Phone int.: [phone] Phone int.: [phone] Phone int: [phone]
Telefax: 0200 849 849 Telefax: [phone] Telefax: [phone] Telefax: [phone]
Ref. A625en 1999-09.
Brewery and fruit storage
photos/ courtesy by Lehtikuva Oy.