How does a fan adjust its volume flow based on CO² value determinations?

Contrary to the automatic humidity control and the odour detection, the CO2-guided automatic operation is carried out without averaging or background reference. Increased CO2 values indicate an increased ventilation requirement. The fan regulates its volume flow according to the present and measured CO2 values in eight stages, i.e. practically steplessly. The configured basic ventilation stage is exited as soon as the set lower switching threshold of the CO2 value has been exceeded. The demand ventilation stage is executed when the upper threshold value is exceeded. If the CO2 content of the room air cannot be reduced by this, additional support must be provided by opening the windows.