Dwyer CDT - Manual

Series CDT and CDTR Wall Mount Carbon Dioxide and Temperature
Transmitters accurately monitor the CO
2
concentration and temperature in
schools, office buildings, and other indoor environments to help achieve LEED ®
certification. Additionally, the Series CDTR also measures ambient relative
humidity. For increased sensor life, a single- beam dual-wavelength non-dispersive
infrared (NDIR) sensor is used to automatically correct the measurement in both
occupied and unoccupied buildings against aging effects. The single-beam dual-
wavelength sensor technology provides the highest level of accuracy compared to
Automatic Baseline Correction methods, which can unintentionally shift the
calibration based on CO
2
levels and barometric pressure conditions. In order to
achieve a higher level of accuracy, the Series CDT includes digital barometric
pressure adjustment and the ability to field-calibrate the sensor.
Universal outputs allow users to select the transmitter output to be 4 to 20 mA, 0
to 5 VDC, or 0 to 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 or the Model A-449 remote LCD display that
can plug into the mini-connector port on the side of the transmitter. Both the CDT
and CDTR can be configured to display temperature only, CO
2
only, or CO
2
and
temperature together. The 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, but the transmitter can be ordered without the
buttons. To prevent tampering, the action of the buttons can be locked out using
an internal jumper selection. Menu items that can be accessed include:
engineering units, relay output set points, display configuration, transmitter output
scaling, ambient barometric pressure and field calibration of the transmitter.
Single-beam dual-wavelength sensor advantages:
• Automatically corrects for aging effects in occupied and unoccupied buildings
o Perfect for hospitals and manufacturing plants that are occupied 24 hours per
day
• Measures actual unfiltered light intensity directly
o Eliminates error from incorrect assumptions of gas concentration in theoretical
logic assumption methods
Series CDT and CDTR Wall Mount Carbon Dioxide/
Temperature Transmitter
Specifications - Installation and Operating Instructions
Bulletin AQ-CDT/CDTR-W
DWYER INSTRUMENTS, INC.
phone: 219/879-8000 www.dwyer-inst.com
p.O. BOX 373 • MICHIGAN CITY, INDIANA 46360, U.S.A. fax: 219/872-9057 e-mail: [email protected]
SpECIfICATIONS
Range:
CO
2
: 0 to 2000 or 0 to 5000 ppm (depending on model);
RH: 0 to 100%;
Temperature: 32 to 122°F (0 to 50°C);
Accuracy: ±40 ppm + 3% of reading; ±2% (RH).
Temperature Dependence: ±8 ppm / °C at 1100 ppm.
Non-Linearity: 16 ppm.
pressure Dependence: 0.13% of reading per mm of Hg.
Response Time: 2 minutes for 99% step change.
Temperature Limits: 32 to 122°F (0 to 50°C).
Humidity Limits: 10 to 95% RH (non-condensing).
power Requirements: 16 to 35 VDC / 19 to 28 VAC.
power Consumption: Average: 2 watts; Peak: 3.75 watts.
Sensor: Single-beam, dual-wavelength NDIR.
Output:
Current: 4 to 20 mA (max 500 Ω);
Voltage: 0 to 5 VDC or 0 to 10 VDC (min 500 Ω);
Relay: SPST NO 2A @ 30 VDC;
RTD or thermistor per r-t curves (depending on model).
Weight: 5.6 oz (158.8 g).
77
88 [22.35] [22.35]
3-13/32 [86.52]
1-13/32
[50.01]
1-53/64
[46.43]
1-13/32
[35.72]
3X 3/8
[9.53]
4-31/64
[113.9]
35/64
[13.89]
4X 3/16
[4.76]
1-3/16
[30.20]
1-3/16
[30.20]
INSTALLATION
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.
Self calibration feature of the transmitter requires exposure to
normal outdoor equivalent carbon dioxide level once every thirty
days.
NOTICE
WARNING
Upon powering the transmitter, the firmware version will flash on
the display. A warm up period of 30 minutes is required for the
transmitter to adjust to the current CO
2
concentration.
NOTICE
Do not exceed ratings of this device, permanent damage not
covered by warranty may result. CAUTION
Avoid locations where severe shock or vibration, excessive
moisture or corrosive fumes are present.. CAUTION
Use electrostatic discharge precautions (e.g., use of wrist
straps) during installation and wiring to prevent equipment
damage.
CAUTION
LEED® is a registered trademark of the U.S. Green Building Council.