Vaisala introduces mini-sized humidity and temperature probe

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The novel Vaisala HMP9 incorporates world leading measurement accuracy and superb thermal response time in a compact package; truly mini-sized probe weights only a few grams and the probe head is only 5 mm of diameter. The low thermal mass of the probe offers superior response time compared to any capacitive humidity measurement product on the market. Probe’s compact body does not only adapt to the changing environment faster, but it also makes it suitable for installation in tight spaces, which allows measurements in locations where the traditional sized probes cannot fit.

The HMP9 is designed for rapidly changing or condensing environments. The smart probe is optimized for dryers, air handling units, test chambers or other systems and processes where measuring humidity can make a difference in saving energy or improving the product or the process. It also brings added value to a variety of applications or locations with temperatures under 120°C (248°F) that don’t involve high pressure, but where the accurate humidity and temperature measurement is a critical factor.

In addition to relative humidity and temperature, the HMP9 smart probe provides measurements of other calculated humidity parameters, such as dew point temperature, wet-bulb temperature, absolute humidity, mixing ratio, water concentration, water vapor pressure and enthalpy.


The new HMP9 contains a HUMICAP® sensor that provides industry-standard humidity measurement performance. The sensor is equipped with chemical purge option, which heats the sensor to remove harmful chemicals, helping to maintain measurement accuracy between calibrations.

Vaisala HMP9 is a part of the modular Indigo product family and is plug-and-play compatible with the Indigo 201 and Indigo 202 transmitters, which can provide local displays and analog or digital outputs when needed. The probe can also be used as a standalone probe with a digital Modbus RTU output. For on-site configuration, diagnostics, and calibration the probe can be connected to Vaisala Insight PC Software