Radix Parking Ventilation Controller VLC201 is designed to efficiently manage the car park ventilation system. It helps to maintain good air quality when the car park traffic is high and conserve energy when it is low. VLC201 works in conjunction with the JetVent fans, CO and pollutant sensors, exhaust fans and the BMS. VLC201 is developed to increase the energy efficiency of a car park, while ensuring the ventilation output is optimized. It will vary the speed of the car park fans according to the changing requirements and demand in the environment. When the CO pollutant levels within the car park reach a pre-set level, the ventilation fans begin to ramp up in speed. As the levels increase and decrease during the course of the day and night, the speed of the fans and therefore the ventilation rate also increases and decreases. Grouping of inputs is used for zone-wise configuration, with separate channels, set points and relays for easy configuration.