TH-AP Modbus

Modbus Temperature and Humidity Sensor


The Temperature and humidity sensor TH-AP Modbus measures temperature and humidity in indoor and outdoor areas and calculates the dew point.

The device is a Modbus slave with a RS485 interface and a RTU protocol. The Modbus master, such as PC, SPS or MC can read the measurement values with "Function 04h (Read Input Register)".

Functions Temperature and humidity sensor TH-AP Modbus:

  • Temperature measurement
  • Humidity measurement
  • Dewpoint calculation

Notes on dew point calculation:
The TH-AP Modbus calculates the dew point of the ambient air. This value can be used for dew point monitoring. This would require another sensor for measuring the surface temperature of the wall or pipe. Also, the dew point needs to be monitored (compare with temperatures) in the Modbus master.
Monitoring predetermines the possible condensate build-up on the surface, giving a chance for timely countermeasures.

HousingPlastic, Sensor sleeve metall
AssemblySurface mounting
Protection categoryTH-AP Modbus:
Housing: IP65
Exterior sensor: IP43
Dimensionsapprox. 65 × 91 × 38 (W × H × D, mm)
Weightapprox. 77 g
Ambient temperature Operation -40…+80°C, Storage -40…+85°C,
avoid condensation
Operating voltage12...40 V DC. An appropriate power supply unit can be purchased from Elsner Elektronik
Cable cross-sectionMassive conductors of up to 0,8 mm²
Currentmax. 15 mA
Interfac RS485
RS485 bus load1/8 unit load according to RS485 standard
RS485 driver performancemin. 2.4 V at 54 Ohm bus load
(corresponds to 32 standard RS485 unit loads)
Measurement range temperature-40...+80°C
Measurement range humidity0% rH … 100% rH