Measuring humidity reliably is challenging in environments where humidity is near saturation. Measurements may be corrupted by fog, mist, rain, and heavy dew. A wet probe may not give an accurate measurement in the ambient air.

This is an environment to which Vaisala has designed a patented, warmed probe for reliable measuring. As the sensor head is warmed continuously, the humidity level inside it stays below the ambient level. Thus, it also reduces the risk of condensation forming on the probe.

The HMP155 is especially designed for use in meteorological applications, such as synoptic and hydrological weather stations, aviation, and road weather. It is also suitable in a wide range of instrumentation, for example, recorders, data loggers, and laboratory equipment and monitoring.

• Vaisala HUMICAP180R sensor - superior long-term stability
• Optional warmed humidity probe
• Plug-and-play
• Chemical purge
• USB connection for service use
• Installation kits for Vaisala's DTR radiation shields and also for a Stevenson screen
• Weather-proof housing IP66
• New, fast temperature probe
• Different output possibilities: voltage, RS-485, resistive Pt100
• Applications: meteorological applications, aviation and road weather, instrumentation

New probe for reliability
The new Vaisala HUMICAP Humidity and Temperature Probe HMP155 provides reliable humidity and temperature measurement.

Long-term stability
The HMP155 has a new generation Vaisala HUMICAP180R sensor that has excellent stability and withstands well harsh environments. The probe structure is solid and the sensor is protected with a sintered teflon filter, which gives maximum protection against liquid water, dust, and dirt.

Warmed probe and high humidity environment
Measuring humidity reliably is challenging in environments where humidity is near saturation. Measurements may be corrupted by fog, mist, rain, and heavy dew. A wet probe may not give an accurate measurement in the ambient air.

This is an environment to which Vaisala has designed a patented, warmed probe for reliable measuring. As the sensor head is warmed continuously, the humidity level inside it stays below the ambient level. Thus, it also reduces the risk of condensation forming on the probe.

Fast temperature measurement
What’s more, with its fast response time, the additional temperature probe for the HMP155 is ideal for measurement in environments with changing temperatures.

Long lifetime
Protecting the sensor from scattered and direct solar radiation, and precipitation will increase its lifetime. Thus, Vaisala recommends installing the HMP155 in one of the following radiation shields: DTR503, DTR13, or a Stevenson screen.

Easy maintenance
The probe can be calibrated using a pc with a USB cable, with the push buttons, or with the MI70 indicator.

The HMP155 is especially designed for use in meteorological applications, such as synoptic and hydrological weather stations, aviation, and road weather. It is also suitable in a wide range of instrumentation, for example, recorders, data loggers, and laboratory equipment and monitoring.