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Multifunctional CO2 transmitters for building automation systems

CDT series air quality transmitters are engineered for building automation systems in the HVAC/R industry. The CDT series measures carbon dioxide (CO2) utilizing the industry standard NDIR measurement principle, and temperature (T). Optional relative humidity (rH) measurement is also available in the same device. CDT series devices are available with large touchscreen display making configuration of the device quick and easy.

The CDT2000 series transmitters calibrate themselves automatically using ABC logicTM. The ABC logicTM requires that the space in which the transmitter is used needs to to be unoccupied for four hours per day so that the indoor CO2 concentration drops to the outside level. CDT2000-DC is a dual channel model with a measuring channel and a reference channel that makes a continuous comparison and the necessary adjustment accordingly. CDT2000-DC is also suitable for buildings that are continuously occupied.

CDT series devices include:
• Separate field configurable output for each measurement parameter (CO2, rH, T)
• Proportional output options including: voltage (0–10 V, 2–10 V) and current (4–20 mA)

CDT2000 series device options offer:
• 2” x 3” touchscreen display
• Field configurable relay for any of the three parameters
• Modbus configuration


Technical details

Accuracy: CO2: ±40 ppm + 2 % of reading, DC model: 75 ppm or 10 % of reading (whichever is greater)
Temperature: <0.5 °C
Relative humidity: ±2…3 % rH at 0…50 °C and 10…90 % rH
Total error band includes accuracy, hysteresis and temperature effect over 5...50 °C and 10–90 % rH
Measurement elements: Pt1000 temperature sensor, Non Dispersive Infrared (NDIR) CO2 sensor, thermoset polymer capacitive sensing element for humidity
Measuring units: ppm, °C, % rH
Calibration: Automatic self-calibration, ABC LogicTM or continuous comparison (DC)
Supply voltage: 24 VDC/VAC ±10 %
Current consumption: max 90 mA (at 24 V) + 10 mA for each voltage output or 20 mA for each current output
Output signal 1: 0/2…10 V (linear to CO2), L min 1 kΩ or 4…20 mA (linear to CO2), L max 500 Ω
Output signal 2: 0/2…10 V (linear to rH), L min 1 kΩ or 4…20 mA (linear to rH), L max 500 Ω
Output signal 3: 0/2…10 V (linear to Temp), L min 1 kΩ or 4…20 mA (linear to Temp), L max 500 Ω
Optional relay output: Potential free SPDT 250 VAC, 6 A / 30 VDC, 6 A with adjustable switching point and hysteresis
Operating temperature: 0...+50°C
Protection standard: IP20