Humidity measurement in air, gas and oil

Humidity measurement in processes or in the environment is a determining parameter that has to do with the quality and efficiency of production.

Vaisala has a complete humidity measurement products for different applications whether it is in environment, different pressurized gases and oil.

Measurement variables:
· Relative humidity
· Dew point
· Carbon dioxide (CO2)
· Moisture present in oil
· Gas dissolved in oil
· Portable

Relative humidity

HMP3 temperature and humidity probe for general purpose humidity and temperature applications with interchangeable sensor.

HMP3 Series


Relative humidity accuracy up to 0.8% RH and temperature accuracy down to 0.1° C

Temperature measurement range -40...+120° C (-40... +248° F)

Compatible with Indigo series of transmitters

PPS plastic mesh filter with stainless steel mesh delivered as standard

Modbus RTU over RS-485 for flexible connectivity

Includes calibration certificate with traceability

HMT330 series temperature and humidity meter for demanding applications.

HMT330 Series


Range 0… 100% RH

Temperature up to +180° C, depending on the model

Pressure up to 100 bar, depending on the model

Excellent performance in extreme conditions; good chemical compatibility

Corrosion resistant IP65 / IP66 housing

Traceable calibration for measurements and analog outputs (certificates included)

RS232 / 485/422 LAN

Modbus protocol compatibility (RTU / TCP)

Optional graphic display and keyboard for convenient operation

Dew point

Dew point meter DMT132 for cooling dryers

DMT 132 Series


Range -30 to 50° C

Operational temperature range -20 to 60° C

Relative humidity 0 to 100% RH

Analog output from 4 to 20 mA at 2 threads

Precision of ±0.05 % on complete scale

Protection IP65 (NEMA 4)

Measured gas: non corrosive

DPT146 transmitter for Dew point and pressure for compressed air measurement

DPT 146 Series



Dew Point from -70 to 30° C

Absolute pressure from 1 to 12 bar

Temperature -40 to 80° C


Dew Point: ± 2° C

Pressure: ± 0.4 % complete scale

Temperature: ± 0.5° C

IP66 Protection

Digital output RS485, non-isolated, Vaisala protocol, Modbus RTU

Outputs 2 channels (0 to 20 and 4 to 20 mA) and voltage (0 to 5 V, 0 to10 V)

Measured Gas: Air and non-corrosive gases

Carbon dioxide (CO2)

CO2 Probe GMP251 for % level measurements in biology incubators, cold storage and other demanding applications.

GMP251 Series


Measurement range from 0 to 20% CO2

Smart, probe with analog output (V, mA) and digital (RS485)

CARBOCAP® Tech providing long term stability

Broad operational temperature range from -40 to +60° C

Case with IP65 protection

Temperature and pressure compensation

Gas, O2 and humidity compensation

Sensor’s head gets heated to prevent condensation

Humidity present in oil

Humidity and temperature oil transmitter MMT162 for transformer applications and OEM systems.

Serie MMT162


Measuring range from 0 to 1 aw

Accuracy in water:

From 0 to 0.9 aw: ± 0.02 aw

From 0,9 to 1,0 aw: ± 0.03 aw

Temperature accuracy: ± 0.2 °C

Digital outputs: RS-485, non-isolated, Vaisala protocol, Modbus RTU protocol

Analog current output from 0 to 20 mA, 4 to 20 mA

Analog voltage output from 0 to 5 V, 0 to 10 V

Humidity probe present in oil MMP8 for continuous measurement in line

MMP8 Series


Continuous in line humidity and temperature measurement present in oil

Temperature measurement range -70 +180 °C (-94 … +356 °F)

Measuring precision up to ±0,02 aw/ 2 % RS

Temperature measurement precision up to ±0,1 °C (±0,18 °F)

HUMICAP® Vaisala sensor, 15 years in oil applications

Modbus RTU on RS-485 for flexible connectivity

Includes calibration certification with traceability: 5 points for humidity, 1 point for temperature

Compatible with Indigo transmitter series

The sensor has an excellent sensitivity in the dry end of the range

Dissolved gas in oil

MHT410 temperature, humidity and hydrogen transmitter for in-line monitoring of power transformers.

MHT410 Series


It measures humidity and hydrogen directly over the transformer’s oil

Compatible with mineral oil, natural ester or synthetic

It provides anticipated warnings about possible failures in transformers

The probe’s unique design allows a direct measure of the oil

5 year standard warranty

Solid design which provides reliable functioning and without false alarms

No maintenance needed

No sensitivity crossed to other gases

Compatible with Indigo 520 and easy access to measuring data

Dissolved gas in oil application


Portable measuring instrument with interchangeable probes, for humidity, temperature, dew point, CO2 and oil humidity.

MI70 Series


Backlight LCD Screen, graphic view of tendencies on any parameter

Probe max amount: 2

Sound alarm

Operational temperature from -10 to 40° C

IP54 protection

Data registry capacity of up to 2,700 points

Rechargeable or alkaline battery feed

Multilanguage menu

ECN Automation
offers comprehensive solutions.

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