Vaisala HUMICAP® Humidity and Temperature Probe HMP4 is designed for high-pressure applications such as compressed air systems in maritime, breathing air, and industrial applications, where measurement performance and chemical tolerance are essential. The HMP is part of the Indigo product family and compatible with Indigo 200 Series Host Devices.

Key Benefits

  • Proven Vaisala HUMICAP Performance
    Vaisala is the original innovator of the thin-film capacitive humidity measurement technology, which has now become the industry standard in humidity measurement.
  • Chemical Purge Minimizes Effects of Contaminants
    In environments with high concentrations of chemicals and cleaning agents, the chemical purge option helps to maintain measurement accuracy between calibration intervals.
  • Flexible Connectivity
    The probe is plug and play compatible with Vaisala Indigo host devices, can be used as a standalone digital Modbus RTU transmitter, or connected to Vaisala Insight™ PC Software.


  • ​Accurate measurement (see accuracy specifications on the datasheet)
  • Wide temperature measurement range (see the exact range on the datasheet)
  • Operating pressure (see pressure specifications on the datasheet)
  • Sensor purge provides superior chemical resistance
  • Modbus RTU over RS-485
  • Plug & play compatible with Indigo™ series of transmitters
  • Traceable calibration certificate: 5 points for humidity, 1 point for temperature