Compact Humidity and Temperature Probe HMP9

for rapidly changing environments

The Vaisala HUMICAP® Humidity and Temperature Probe HMP9 is designed for easy installation in rapidly changing environments where a fast response time, measurement performance, and chemical tolerance are essential. The compact size enables installation even in tight spaces, with the probe head only 5 mm (0.2 in) in diameter. For duct and chamber installations, a duct installation kit is available for the probe. 

Indigo Family

The HMP9 complements the Indigo product family and is ideal for applications such as inlet monitoring in dryers, air handling units, data centers,  and other humidity measurement applications with temperatures under 120 °C (248 °F) that don’t involve high pressure or long exposure to condensing conditions. The HMP9 is compatible with Indigo500 and Indigo300 series transmitters and Insight PC Software.

Click here to download bid specs for USA.

Key benefits

Miniature probe head

The 5 mm diameter probe head contains a new-generation HUMICAP® sensor that provides industry-standard humidity measurement performance. The HMP9 is a stable instrument with a fast response time and low hysteresis in a wide range of applications.

Minimized effects of contaminants

In environments with high concentrations of chemicals and cleaning agents, the chemical purge option heats the sensor to remove harmful chemicals, helping to maintain measurement accuracy between calibration intervals. The chemical purge process can be initiated manually or programmed to take place at set intervals.

Flexible connectivity

The probe is plug-and-play compatible with the Vaisala Indigo series transmitters, which offers a variety of connectivity options through analog signals or digital outputs, configurable relays, and a wireless (WLAN) configuration interface. It can also be used as a standalone digital Modbus RTU transmitter over RS-485 serial bus. For easy-to-use access to field calibration, device analytics, and configuration functionality, the probe can be connected to Vaisala Insight software (for Windows® 7, 8.1, and 10; see

Indigo Selector

Discover your ideal Indigo compatible probe and transmitter combinations with the Indigo Selector tool.

Indigo Selector

Product Resources