Johnson Controls offers a complete line of carbon dioxide (CO₂) modules that measure and transmit CO₂ levels ranging from 0 to 2,000 parts per million [ppm]. This compact device offers a choice of 0 to 10 V or 0 to 20 mA output signals and features an optional relay output with or without a digital display. Johnson Controls CO₂ transmitters are easy to install and to operate.

The silicon-based CARBOCAP® sensor delivers high accuracy and long-term measurement stability (±100 ppm) over a five year period without calibration. The diffusion aspirated, single-beam, dual-wavelength sensor structure is remarkably simple. It consists of an infrared (IR) source, a sample cell, an IR detector, and a tunable interference filter that enables measurements at two wavelengths. Reference measurements made using a tunable interference filter eliminate the typical weakness of dual-beam sensors and permits shifting the optical pass band electronically. This innovative design provides precise reference readings that eliminate the typically broad deviation expected from a traditional CO₂ sensor.