HMP4 Relative Humidity and

Temperature Probe

For Pressurized and Vacuum Processes

Features

• RH accuracy up to 0.8 %RH

• Temperature accuracy up to 0.1 °C

(0.18 °F)

• Temperature measurement range

-70 ... +180 °C (-94 ... +356 °F)

• Operating pressure 0 ... 10 MPa

(0 ... 100 bar)

• 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

Vaisala HUMICAPâ 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.

Proven Vaisala HUMICAPâ

Performance

Vaisala is the original innovator of the

thin-film capacitive humidity

measurement technology, which has now

become the industry standard in

humidity measurement.

HUMICAPâ technology results from

Vaisala's 40-year experience in industrial

humidity measurement, providing the

best stability, fast response time, and low

hysteresis in a wide range of

applications.

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.

The chemical purge involves heating the

sensor to remove harmful chemicals. The

function can be initiated manually or

programmed to occur at set intervals.

Flexible Connectivity

The probe is plug and play compatible

with Vaisala Indigo™ series of

transmitters, or it can 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

(see www.vaisala.com/insight).

Vaisala Indigo™ Product Family

Indigo transmitters offer a variety of

connectivity options through analog

signals or digital outputs, configurable

relays, and wireless (WLAN)

configuration interface, providing a

suitable solution for all industrial

humidity measurements. The cable

length between the probe and

transmitter can be extended to up to 30

meters. For more information, see

www.vaisala.com/indigo.

Services You Can Count On

Each probe is manufactured and

individually calibrated in Vaisala's world-

class facility in Finland. The traceable

factory calibration certificate is included

also in electronic format in the probe.

The interchangeable probes minimize

the downtime associated with

maintenance. Validate and maintain the

accuracy by calibrating the instrument

on the field or use the easy and thorough

calibration service in Vaisala's service

facilities in Helsinki, Boston, Beijing and

Tokyo.