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. Configuration is also possible via Modbus network.

The CDT-MOD-2000 series transmitters calibrate themselves automatically using ABC logic^TM. The ABC logic^TM 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. CDT-MOD-2000-DC is a dual channel model with a measuring channel and a reference channel that makes a continuous comparison and the necessary adjustment accordingly. CDT-MOD-2000-DC is also suitable for buildings that are continuously occupied.