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Dwyer Series CDT

Carbon Dioxide/Temperature Transmitter
NDIR Sensor, Universal Outputs, Optional Relay
Dwyer Series CDTSeries CDT Carbon Dioxide and Temperature Transmitters accurately monitor the CO2 concentration and temperature in schools, office buildings, and other indoor environments to help achieve LEED® certification. 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 singlebeam dual-wavelength sensor technology provides the highest level of accuracy compared to Automatic Baseline Correction methods which can unintentionally shift the calibration based on CO2 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 can be ordered with an integral LCD display or the Model A-449 remote LCD display that can plug into the miniconnector port on the side of the transmitter. The display can be configured to display temperature only, CO2 only, or CO2 and temperature 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
Perfect for hospitals and manufacturing plants that are occupied 24 hours per day
Measures actual unfiltered light intensity directly
Eliminates error from incorrect assumptions of gas concentration in theoretical logic assumption methods

Range: CO2: 0 to 2000 or 0 to 5000 ppm (depending on model);
Temperature: 32 to 122°F (0 to 50°C).
Accuracy: ±40 ppm + 3% of reading.
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.
Ambient Operating Temperature: 32 to 122°F (0 to 50°C).
Ambient Operating Humidity: 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.
Current: 4 to 20 mA (max 500 Ohms);
Voltage: 0 to 5 VDC or 0 to 10 VDC (min 500 Ohms);
Relay: SPST NO 2A @ 30 VDC;
RTD or thermistor per r-t curves (depending on model).
Weight: 5.6 oz (158.8 g).

Ordering Details: