What Sensor Calibration Is and Why Readings Drift
Calibration maps sensor error against traceable standards, while drift stems from physical aging, mechanical strain, and environmental stress over time.
NDIR Optical Drift
Gas Measurement
Non-dispersive infrared sensors detect the concentration of specific gases by measuring the absorption of light at a particular wavelength. Ndir optical drift describes the gradual change in the sensor reading caused by the aging of the infrared source or the accumulation of dust on the optical path.
Sensor Degradation
The intensity of the light emitted by the internal lamp or light-emitting diode decreases as the component nears the end of its operational life. In ndir optical drift, this reduction in light is often misinterpreted by the electronics as an increase in gas concentration. Manufacturers frequently include a reference channel that measures light at a wavelength not absorbed by the target gas to subtract these common-mode changes from the final reading.
Environmental Interference
Fluctuations in ambient temperature and pressure alter the density of the gas and the sensitivity of the detector. Regular zero-point calibrations are necessary to reset the ndir optical drift and ensure the accuracy of carbon dioxide or methane monitoring systems.
Maintenance Cycle
Periodic cleaning of the gas chamber and the replacement of aging light sources prevent excessive errors. Controlling ndir optical drift is essential for the long-term reliability of indoor air quality and industrial safety equipment.