... carbon dioxide ,Monitoring range of 0 ~ 20,000 ppm, can be customized 0 ~ 50,000 ppm3. Self-diffusion NDIR infrared sensor technology, sensor ... relay dry contact outputs (programmable corresponding carbon dioxide CO2, temperature or humidity)7. Carbon dioxide concentration adjustment range: 0 ~ 20 ... technology. For 14 days, the indoor concentration of carbon dioxide CO2 reduced to at least 3 times the ...