STH 102 Temperature and Relative Humidity with RS 485 Output

The sensor of temperature and relative humidity - STH 102 is designed to measure the temperature and relative humidity of the air in spaces protected against water. This combined sensor consists of a plastic ribbing head, where a printed circuit board with the individual sensors and a converter is placed to establish a communication via the RS 485 bus. The temperature and relative humidity are measured by a common internal sensor whose signal is processed in a microprocessor and is converted to an output signal of MODBUS RTU.

The sensor of temperature and relative humidity - STH 102 meet ingress protection IP 30 according to EN 60529, as amended. Suitable design and high-quality material ensure that the sensors do not feel disturbing even in the interiors with high aesthetic requirements. You can choose the colour of the box white or grey. The installation is recommended on an inner wall at the height of 1.5 m, in areas with moving persons, not exposed to direct sunlight and not influenced by heat from walls, heat sources or lighting. 
The sensor of temperature and relative humidity - STH 102 is designed to be operated in a chemically non-aggressive environment; the use must be chosen regarding the temperature and chemical resistance of the sensor head and of the individual sensors.

The operating conditions to establish the correct function are:
  • ambient temperature in the vicinity of the sensor - 40 to 80 °C
  • relative ambient humidity: 0 to 95% (non-condensing humidity)
  • atmospheric pressure: 87 to 106 kPa  

Declarations, Certificates, Calibration

  • Manufacturer provides EU Declaration of Conformity.
  • Calibration – The final metrological inspection – comparison with standards or working instruments – is carried out for all the products. Continuity of the standards and working measuring instruments is ensured within the meaning of the Section 5 of Act no.505/1990 on metrology. The manufacturer offers a possibility to supply the sensors calibrated in SENSIT s.r.o.’s laboratory (according to requirements of the EN ISO/IEC 17025 standard, as amended) or in an Accredited laboratory.


Sensor type STH 102
Temperature measurement range -40 to 80 °C
Temperature measurement accuracy ± 0.5 °C in the range from 0 to 65 °C
± 0.7 °C in the range from 65 to 80 °C
± 1.1 °C in the range from -40 to 0 °C
Relative humidity measurement range 0 to 95 %
Relative humidity measurement accuracy ± 3 % in the range from 10 to 90 %
± 4.5 % in the range from 0 to 10 % and 90 to 95 %
Output signal RS 485 / MODBUS RTU
Galvanically separated no, possible on request
Supply voltage U 15 to 30 VDC
Rated supply voltage Un 24 VDC
Consumption maximum: 500 mW
typical: 300 mW
Ingress protection IP 30 in accordance with EN 60529, as amended
Dimension of the head 71.9 x 59 x 27 mm
Material of the head LEXAN
Weight 35 g
Recommended wire cross section 0.14 to 1 mm2

Dimensional Draft

Wiring Diagram

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