Merlin RSVCO21 Carbon Dioxide Detector – Up to 4500ppm CO₂, Temperature & Humidity Sensor The Merlin RSVCO21 Carbon Dioxide Detector is a high accuracy CO₂, temperature and humidity room sensor for air quality monitoring in residential, commercial, public and light industrial environments. Made in the UK, this multi-function detector has analog, digital and relay outputs for integration with building management systems (BMS) via Modbus RTU or BACnet MS/TP protocols. With its non-dispersive infrared (NDIR) CO₂ sensing technology, self-calibrating function and excellent long term stability the RSVCO21 gives consistent performance and accuracy. It’s perfect for indoor environments such as classrooms, off