The UFS1107 is a combined sensor to measure CO2 concentration, relative humidity and air temperature indoors, in living or office rooms.

The readings are available via RS485 interface using ModbusRTU protocol. The sensor has calibration registers for 2-point calibration for maximum accuracy for every metered item. Readings are available both as raw data from the sensor element (SCD41 from Sensirion), or converted and calibrated to ppm, dC and d% values.

The novel sensor element in use (SCD41 from Sensirion) is based on the photoacoustic sensing principle for CO2 measuring. The photoacoustic sensing principle allows extreme miniaturization of the CO2 sensor without compromising sensor performance due to the fact that the sensor sensitivity is independent of the optical cavity size.

The SCD41 sensor is mounted on a PCB with a microprocessor, taking care of protocol conversion and calibration data based linear conversions. The linear conversion is in use to convert the raw readings into actual (ppm, %, C) values while improving the actual accuracy for the measurement range (see below about the calibration).

The power consumption of the sensor is very low, minimizing the effect of self-heating to the temperature and relative humidity readings.

The cased sensor mounts on the wall and is suited to cover the recessed installation box (to bring in the UTP cable). Supply voltage range is from 10 to 25 V DC, consumed current is less than 20 mA on average (even 7 mA in default low-power mode).


Technical specifications

  • Temperature range: -45..60 degC
  • Humidity range: 10..100 %
  • CO2 range: 400..4000 ppm
  • Measurements: 86 x 86 x 25 mm
  • Supply voltage: 10..25 V DC
  • Current consumption: less than 7 mA average in the default low-power mode (1 reading per 30 s),
  • less than 20 mA in normal mode (1 reading per 5 s), at 12 V supply voltage
  • Communication interface: RS485
  • Communication protocol: ModbusRTU
  • Communication speeds: 9600 or 19200 bps (factory default is 19200)
  • Communication parity: even or no parity, 8 data bits, 1 stop bit (factory default is 8E1)
  • Modbus address range: from 1 to 247 (factory default is 22)


User manual

UFS1107 manual