MODBUS CO2 and pressure sensor TSM400-4-CP

TSM400-4-CP is a combined CO2 and barometric pressure sensor with a MODBUS RTU interface.


CO2 (Carbon dioxide) is a colourless and odourless gas. It is the fourth most present gas in the Earth’s atmosphere. Its concentration, especially indoors, is important for the health and efficiency of the people in them.

TSM400-4-CP is a multi parameters sensor that supports MODBUS RTU protocol over the RS-485 interface. The sensor measures barometric pressure and CO2 concentration.

MODBUS device integrates an advanced non-dispersive infrared sensing element (NDIR) for CO2 measurements. NDIR is recently the most popular principle for CO2 concentration measuring. The principle is based on the absorption of infra-red (IR) light with specific wavelengths by CO2 molecules.

The CO2sensing element is realized with built-in humidity and temperature for better accuracy.

Self-calibration is available for carbon dioxide measurements. It is done if the sensor is left in fresh (around 400 ppm CO2 concentration ) air.

The basic sensing element for barometric pressure is factory calibrated and it does not require any lifetime recalibration.

The sensor TSH400-4-CP is housed in a slim plastic enclosure. The bottom part of the enclosure is suitable for installation on standard flush-mounted/cavity wall boxes with a maximum installation opening of 61 mm.