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Series CDT and CDTR Wall Mount Carbon Dioxide/
Temperature Transmitter
Specications - Installation and Operating Instructions
Bulletin AQ-CDT/CDTR-E/N-3
Series CDT and CDTR Wall Mount Carbon Dioxide Temperature Transmitters
accurately monitor the CO
2 concentration and temperature in schools, ofce buildings,
and other indoor environments to help achieve LEED
®
certication. Additionally, the
Series CDTR also measures ambient relative humidity. In order to achieve a higher
level of accuracy, the Series CDT includes digital barometric pressure adjustment.
Universal outputs allow users to select the transmitter output to be 4-20 mA, 0-5 VDC,
or 0-10 VDC to work with virtually any building management controller. An optional
relay with user adjustable set points can be used to control exhaust fans, open
actuated windows or dampers, or signal a light or horn.
For applications that require visual indication, the Series CDT and CDTR can be
ordered with an integral LCD display, Model A-449 or Model A-449A remote LCD
display that can plug into the mini-connector port on the side of the transmitter. Both the
CDT and CDTR can be congured to display temperature only, CO
2 only, or CO2 and
temperature together. The Series CDTR can also display relative humidity or CO
2 and
relative humidity together. Push buttons are standard on the transmitters for access
to the menu structure in models with displays. To prevent tampering, the action of the
buttons can be locked out using an internal dip switch selection. Menu items that can
be accessed include: engineering units, relay output set points, display conguration,
transmitter output scaling, ambient barometric pressure and eld calibration of the
transmitter.
The Series CDT and CDTR CO
2 transmitters are available with a -S option that
provides the necessary attributes and parameters to be e with DSA requirements for
monitoring CO
2 levels in schools. There is a front facing LED that illuminates when the
CO
2 level exceeds 1100 PPM.
Automated CO
2 Baseline Correction (ABC)
The Series CDT and CDTR CO
2 transmitters are maintenance free instruments
with the ability to adjust the CO
2 calibration by using the on-board ABC logic for
intermittently occupied spaces. The ABC algorithm accounts for long term drift by
making small adjustments to it’s zero calibration point based on the lowest CO
2
readings it measures. CO
2 calibration adjustments are made every eight days by the
ABC algorithm. For environments occupied 24 hours per day it is recommended to
periodically expose the CO
2 sensor to outside ambient air.
INSTALLATION
SPECIFICATIONS
Sensor: NDIR, 15 year life expectancy.
Range: CO
2: 0 to 2000 or 0 to 5000 PPM (depending on model); Temperature: 32
to 122°F (0 to 50°C).
Accuracy**: CO
2: ±40 PPM + 3% of reading (2000 PPM CO2); ± 50 PPM + 5%
of reading (5000 PPM CO
2); RH: ±2% (10 to 90% RH) (for units congured with
humidity output); Temperature: ±1°C @ 25°C.
Response Time: 2 min for 90% step change.
Temperature Limits: 32 to 122°F (0 to 50°C).
Humidity Limits: 0 to 85% (non-condensing).
Power Requirements: 16-35 VDC or 19-28 VAC.
Power Consumption: Average: 2 w; Peak: 3.75 w.
Output: Current: 4-20 mA (max. 500 Ω); Voltage: 0-5 VDC or 0-10 VDC (min. 500
Ω); Relay: SPST NO rated 2A @ 30 VDC; RTD or thermistor per r-t curves on page
4 (depending on model).
Compliance: CE.
**The specied CO
2 accuracy is only guaranteed after three weeks of continuous
operation in environments which are intermittently occupied.
North American DSA* compliant option -S
Disconnect power supply before installation to prevent electrical
shock and equipment damage.
Make sure all connections are in accordance with the job wiring diagram and in
accordance with national and local electrical codes. Use copper conductors only.
CAUTION
Use electrostatic discharge precautions (e.g., use of wrist straps)
during installation and wiring to prevent equipment damage.
Avoid locations where severe shock or vibration, excessive
moisture or corrosive fumes are present.
Do not exceed ratings of this device, permanent damage not
covered by warranty may result.
Upon powering the transmitter, the rmware version will ash on
the display. A warm up period of 30 minutes is required for the
transmitter to adjust to the current CO
2 concentration.
Self calibration feature of the transmitter requires exposure to
normal outdoor equivalent carbon dioxide level once every thirty
days.
NOTICE
NOTICE
NOTICE
NOTICE
NOTICE
4-1/2
[1
14.30]
2-51/64 [71.12]
1-3/32
[27.69]
*Division of the State Architect - California
®
www.calcert.com [e-mail]1.888.610.7664
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