Dwyer Instruments Series CDT, Series CDTR Installation and Operating Instructions
Series CDT and CDTR Duct Mount Carbon Dioxide/
[84.14]
11-49/64˝
®
Temperature/Relative Humidity Transmitter
Specications - Installation and Operating Instructions
Bulletin AQ-CDT/CDTR
Series CDT and CDTR Duct Mount Carbon Dioxide/ Temperature/Relative
Humidity Transmitters accurately monitor the CO2 concentration and temperature
in schools, ofce buildings, and other indoor environments to help achieve LEED
certication. 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 dualwavelength sensor technology provides the highest level of accuracy, compared to
Automatic Baseline Correction methods, which can unintentionally shift the calibration
based on CO
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 the Model A-449 remote LCD display that can plug into the mini-connector
port on the internal circuit board. Both the CDT and CDTR can be congured to display
temperature only, CO
display relative humidity or CO
be accessed include: engineering units, relay output set points, display conguration,
transmitter output scaling, and ambient barometric pressure.
Single-beam dual-wavelength sensor advantages:
• Automatically corrects for aging effects in occupied and unoccupied buildings
◦ Perfect for hospitals and manufacturing plants that are occupied 24 hours per
• Measures actual unltered light intensity directly
◦ Eliminates error from incorrect assumptions of gas concentration in theoretical
2 levels and barometric pressure conditions. In order to achieve a higher
2 only or CO2 and temperature together. The CDTR can also
2 and relative humidity together. Menu items that can
day
logic assumption methods
Ø1-15/64˝
[31.35]
[298.85]
1/8˝
[3.17]
Ø3-5/16˝
SPECIFICATIONS
Range: CO
®
(for units congured with humidity output); Temperature: 32 to 122°F (0 to 50°C).
Accuracy: ±40 PPM + 3% of reading (CO
humidity output); Temperature: ± 1°C @ 25°C.
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: 16-35 VDC / 19-28 VAC.
Power Consumption: Average: 2 watts; Peak: 3.75 watts.
Sensor: Single-beam, dual-wavelength NDIR.
Output: Current: 4-20 mA (max 500 Ω); Voltage: 0-5 VDC or 0-10 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).
Agency Approvals: CE.
INSTALLATION
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.
4-25/32˝
[121.44]
4-9/32˝
[108.74]
2: 0 to 2000 or 0 to 5000 PPM (depending on model); RH: 0 to 100%
WARNING
CAUTION
CAUTION
Disconnect power supply before installation to prevent electrical
shock and equipment damage.
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.
2-13/16˝
[71.44]
2); RH: ±2% (for units congured with
DWYER INSTRUMENTS, INC.
CAUTION
NOTICE
transmitter to adjust to the current CO
NOTICE
days.
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
Self calibration feature of the transmitter requires exposure to
normal outdoor equivalent carbon dioxide level once every thirty
2 concentration.
MOUNTING
TURE
POWER
TEMP OR RH
ENTER PUSH BUTTON
OUTPUT SELECTION
RH OUTPUT SELECTION
TVO
0-20 mA
4-20 mA
0-10 mA
2-10 mA
1. Cut hole into duct large enough to insert probe.
2. Attach housing ears to duct using the two self-tapping screws provided.
3. Knock out an opening in the housing and attach an electrical tting to route
electrical wiring. PG11 & PG16 knockouts are molded into the housing.
WIRING
Use maximum 18 AWG wire for wiring to terminals. Refer to Figure 4 for wiring
information.
UP PUSH BUTTON
REMOTE DISPLAY
CONNECTOR
DOWN PUSH
BUTTON
CONFIGUATION
SWITCHES
Figure 1: Diagram of circuit board
TERMINAL
BLOCK
Current / Voltage Outputs
The transmitter may be wired for current or voltage output for both carbon dioxide and
temperature. The transmitter can be powered with either 16-35 VDC or 19-28 VAC.
Wire the transmitter according to Figure 4.
NOTICE
Optional relay can be used as either a dry contact or low voltage
switched circuit up to 2 A at 30 VDC.
SUPPLY
RECEIVER
CO2
RECEIVER
RELAY
CONTACT
PASSIVE
TEMPERA
SENSOR
Selection of Current and Voltage Outputs
Prior to wiring, verify that the current/voltage conguration switches (positions 1 and
2) are set to the desired output type. Refer to Figure 1 to locate the conguration
switches. See Figure 2 for diagram of the current/voltage selection switches. For
voltage output selection, the output can be 0-10 VDC, 0-5 VDC, 2-10 VDC or 1-5
VDC. See Figure 3 for the type of voltage output selection switches (positions 3 & 4).
LTAGE CURRENT
CO2 CONCENTRATION
0-10 V
Figure 3: Output range selection jumper
Figure 2: Current/voltage output
Selection jumper (PJ1 And PJ2)
2-10 V
VOLTAGE CURREN
TEMPERATURE/
0-5 V
1-5 V
Figure 4: Active output wiring diagram
Thermistor and RTD Outputs
Thermistor and RTD passive outputs are located on terminals 7 and 8 and do not
require any power. Passive temperature outputs are not polarity sensitive.
Remote Display
Remote display Model A-449 can be used to display the relative humidity, temperature,
and carbon dioxide. The mini USB plug of the remote display plugs into the receptor on
the side of the housing. After a short warm up time, the display will begin to show the
current temperature and carbon dioxide measurements unless congured by the user
to show only temperature or only carbon dioxide.
ACCESSING MENU PARAMETERS
Step 1: To enter the menu structure, press “Up” and “Down” simultaneously for 5
seconds (display will show RON parameter).
Step 2: Press “Up” or “Down” to cycle between menu items.
Step 3: Press “Enter” to edit the value for the displayed menu item (SET will appear
on
display).
Step 4: Press “Up” or “Down” to adjust the value of the menu item.
Step 5: Press “Enter” to save the changes (SET will disappear).
Step 6: Repeat Steps 2 through 5 for each of the parameters.
Step 7: To exit the menu at any time, press and hold “Down” and “Up” simultaneously
for 5 seconds or wait 10 seconds without pushing any buttons.
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