Humidity Transmitter

Industrial Humidity and Temperature Transmitters

Seacom supplies humidity and temperature transmitters for HVAC, building automation, cleanrooms, laboratories and industrial processes. These instruments provide continuous measurements for controllers, building management systems and monitoring equipment.

Choose from wall-mounted, duct-mounted, outdoor and remote-probe designs. Depending on the model, available interfaces include 4–20 mA, voltage outputs, Modbus RTU and BACnet MS/TP. Select the instrument according to the installation conditions, required accuracy and control-system interface.

Choosing a Humidity Transmitter for HVAC

A humidity transmitter for HVAC should measure conditions at a location that represents the space or air stream being controlled. Room, duct and outdoor measurements serve different purposes and may require different probe arrangements and protective accessories.

  • Room humidity: Wall-mounted transmitters measure conditions in occupied spaces, laboratories, storage rooms and controlled environments.
  • Duct humidity: Duct-mounted transmitters measure supply or return air in ventilation systems and air-handling units.
  • Outdoor humidity: Suitable outdoor models provide reference measurements for ventilation control. Consider protection from rain and solar heating.
  • Remote measurement: Separate probes allow the sensing point to be positioned away from the transmitter display or electronics.

HVAC Humidity Transmitter Selection

ApplicationProduct familySelection guidance
Routine room, duct and outdoor HVAC measurement Vaisala HMW80, HMD80 and HMS80 Consider this family for routine building automation. Select the mounting arrangement and analogue output to match the installation.
Higher-accuracy room, duct and outdoor measurement Vaisala HMW110, HMD110 and HMS110 Consider this family when accuracy and calibration documentation are important. Confirm the required output and model configuration.
Wall-mounted measurement in demanding indoor environments Vaisala HMW90 Series Humidity and temperature measurement for indoor HVAC applications requiring accuracy and stability. Confirm the display and output configuration.
Compact sensing and modular installations Vaisala XMP10 Series Compact probes with different sensor and accuracy options, for standalone use or compatible Origo10 transmitters. XMP10T measures temperature only.
Indoor air quality and ventilation monitoring Vaisala XMW85 Series Configurable indoor transmitters for CO₂, humidity and temperature. Confirm the measurements included in the selected configuration.
Accurate compact sensing for equipment and data loggers Vaisala HMP110 Compact HUMICAP humidity and temperature probe. Select the output, filter, cable and mounting accessories for the application.
Cost-conscious equipment integration and general monitoring Vaisala HMP60 Compact humidity and temperature probe with an interchangeable INTERCAP sensor. Confirm the required accuracy, operating conditions and output.
Demanding ventilation ducts and air-handling systems Vaisala HMD60 Series Consider this family for high-performance duct measurement. Analogue, Modbus RTU and BACnet MS/TP options depend on the model.
Modular wall-mounted or duct-mounted HVAC measurement Vaisala Origo10 Series Consider a modular system with interchangeable probes. Confirm the probe, measurement parameters and controller interface.

The families above provide a starting point for HVAC selection. For environmental chambers, elevated temperatures, high humidity, pressurised processes or hazardous locations, review the specialised instruments below with Seacom before specifying a model.

Humidity Measurement for Cleanrooms and Laboratories

When selecting a humidity sensor for a cleanroom or laboratory, consider measurement accuracy, long-term stability, calibration access and the location of the sensing point. The instrument must also suit the cleaning procedures and environmental conditions at that location.

A transmitter connected to a BMS or PLC provides measurement for control and indication. Applications requiring recorded history, alarms and reporting may also need a separate monitoring system. Sensor selection alone does not establish compliance with pharmaceutical or quality-system requirements.

Explore the humidity measurement range for related meters, probes and logging instruments.

Analogue and Digital Output Options

  • 4–20 mA: A common industrial interface for controllers and data-acquisition systems. Confirm loop power, input compatibility and output scaling.
  • Voltage output: Common in HVAC control systems. Match the output range, power supply and wiring requirements to the controller.
  • Modbus RTU: Suitable for compatible RS-485 networks. Confirm the supported registers, communication settings and network wiring.
  • BACnet MS/TP: Available on selected instruments for compatible building-automation networks.

Not every model supports every interface. Specify the complete model configuration rather than relying on the product-family name alone.

What to Check Before Ordering

  • Measurement: Relative humidity only, humidity and temperature, or additional calculated parameters.
  • Operating conditions: Normal and maximum temperature, humidity, pressure and air velocity.
  • Accuracy: Required performance across the actual operating range, not only at a single reference condition.
  • Installation: Wall or duct mounting, probe length, insertion depth, cable length and access for servicing.
  • Environment: Condensation, dust, chemical exposure and required enclosure protection.
  • Integration: Power supply, analogue input type, digital protocol and measurement scaling.
  • Calibration: Certificate requirements, calibration points and arrangements for periodic checks.

Installation and Calibration Considerations

Position the sensor where airflow and conditions represent the intended measurement. Avoid local heat sources, stagnant pockets and direct water spray. Follow the selected manufacturer's guidance for mounting, orientation, wiring and environmental protection.

Plan access for inspection and calibration. The appropriate checking interval depends on the environment, required measurement confidence, instrument performance and the site's quality procedures.

Frequently Asked Questions

What is the difference between a humidity sensor and a transmitter?

A humidity sensor is the sensing element. A humidity transmitter combines sensing and signal-processing functions to provide an output that a controller or monitoring system can use. Some probes also contain their own processing electronics and digital interface.

Can one instrument measure humidity and temperature?

Yes. Many transmitters measure both relative humidity and temperature. Selected models also provide calculated parameters such as dew point, wet-bulb temperature or enthalpy. Check the supported measurements and outputs for the chosen configuration.

Which humidity transmitter is suitable for HVAC?

Start with the measurement location: room, duct or outdoor air. Then compare accuracy, operating conditions, output interface and calibration requirements. Routine ventilation and critical controlled environments may require different instruments.

Can an HVAC humidity transmitter measure very dry compressed air?

Do not assume that a standard HVAC transmitter is suitable. Very dry compressed air requires an instrument selected for the dew-point range, process pressure and sampling arrangement. See the dew point meters and transmitters for this application.

Humidity Monitoring for Data Centres

Planning measurements for server rooms or air-handling systems? Explore sensor placement, relative humidity, dew point and monitoring-system requirements.

Read our data centre humidity and temperature monitoring guide

HVAC Sensors for Building Automation

For a broader guide to room, duct and outdoor measurement, explore Vaisala HVAC sensors and transmitters, including selection considerations for building-automation systems.

Read our Vaisala HVAC sensor and transmitter guide

Humidity Transmitter Selection and Technical Support

Seacom Process Instruments is based in Malaysia, with offices in Kuala Lumpur and Penang. Our team can assist with industrial humidity transmitter selection, probe configuration, mounting accessories and control-system compatibility.

Send us the installation location, operating temperature and humidity, required accuracy, output signal and power supply. Include any calibration or documentation requirements so we can recommend a suitable configuration.

Discuss your humidity transmitter application with Seacom .

Humidity Transmitter

Active filters

Vaisala Origo10

Vaisala Trasmitter Origo10 Series

The Vaisala Origo10 Series comprises modular HVAC transmitters with interchangeable probes for humidity, temperature, CO2 and dew-point measurement.

Available with analog, Modbus RTU and BACnet MS/TP outputs, wall or duct mounting, an optional display and an IP65-rated enclosure.

Vaisala HMP60

Vaisala HMP60 Humidity and Temperature Probe

The Vaisala HMP60 is a compact, durable and cost-effective humidity and temperature probe for equipment integration, data loggers, incubators, glove boxes, greenhouses and environmental monitoring systems.

It provides 0–100% RH and −40 °C to +60 °C measurement ranges, low power consumption, interchangeable Vaisala INTERCAP sensor and optional Modbus RTU communication.

Vaisala HMP110

Vaisala HMP110 High-Accuracy Humidity and Temperature Probe

The Vaisala HMP110 is a high-accuracy humidity and temperature probe designed for demanding equipment integration, environmental chambers, data loggers, incubators and controlled-environment applications.

It provides ±1.5% RH accuracy, a 0–100% RH range, −40 °C to +80 °C temperature measurement, a chemically resistant HUMICAP 180R sensor and analog or Modbus RTU output options.

Vaisala Humidity And Temperature Transmitter XMP10

Vaisala XMP10 Series Humidity and Temperature Probes

The Vaisala XMP10 Series comprises compact humidity and temperature probes offering accuracy levels up to ±1% RH and ±0.1 °C for demanding HVAC, data-centre and critical-environment applications.

The probes feature analog or Modbus RTU outputs, a standard M8 connector, an IP65-rated body and compatibility with Vaisala Origo10 modular HVAC transmitters.

Vaisala XMW85 CO2, Humidity and Temperature Modbus Transmitter

Vaisala XMW85 CO2, Humidity and Temperature Modbus Transmitter

The Vaisala XMW85 Series provides reliable indoor CO2, humidity and temperature measurement for demand-controlled ventilation, smart buildings and indoor air-quality monitoring.

All models support Modbus RTU over RS-485, with two-in-one and three-in-one measurement configurations and optional metric or non-metric displays.

Vaisala Transmitter Indigo300

Vaisala Indigo300 Industrial Transmitter

The Vaisala Indigo300 is a rugged industrial transmitter for one Vaisala Indigo-compatible smart probe, providing local measurement display and up to three configurable analog outputs.

Its corrosion-resistant IP66 metal enclosure, flexible probe mounting and interchangeable probe design make Indigo300 suitable for humidity, temperature, dew point, CO2, moisture in oil and other demanding industrial measurements.

Smart Humidity and Temperature Probe for high temperature HMP5

Vaisala HMP5 High-Temperature Humidity and Temperature Probe

The Vaisala HMP5 provides high-accuracy humidity and temperature measurement in ovens, dryers, kilns and other processes operating at temperatures up to +180 °C.

  • Humidity accuracy up to ±0.8% RH
  • Temperature accuracy up to ±0.1 °C
  • −70 to +180 °C probe-head measurement range
  • Standalone Modbus RTU or Vaisala Indigo transmitter operation
Smart Humidity and Temperature Probe for wall mounting HMP1

Vaisala HMP1 Wall-Mounted Humidity and Temperature Probe

The Vaisala HMP1 is a high-accuracy, interchangeable humidity and temperature probe for indoor spaces. It connects directly to an Indigo200 or Indigo300 transmitter to create a compact wall-mounted measurement system.

  • Humidity accuracy up to ±1.0% RH
  • Temperature accuracy up to ±0.2 °C
  • 0–100% RH and −40 to +60 °C measurement ranges
  • Modbus RTU and full Vaisala Indigo compatibility
Smart Humidity and Temperature Probe for high pressure HMP4

Vaisala HMP4 High-Pressure Humidity and Temperature Probe

The Vaisala HMP4 provides high-accuracy humidity and temperature measurement in compressed air, breathing air, industrial gases, vacuum systems and other processes operating at pressures up to 100 bar.

  • Operating pressure below 100 bar, including vacuum applications
  • Humidity accuracy up to ±0.8% RH
  • Temperature range from -70 °C to +180 °C
  • Standalone Modbus RTU or connection to an Indigo transmitter
Biogas Methane, Carbon Dioxide and Humidity Multigas Probe MGP261

Vaisala MGP261 Biogas Methane, Carbon Dioxide and Humidity Probe

The Vaisala MGP261 measures methane, carbon dioxide and humidity directly in raw biogas. Its in-situ design avoids a separate sampling system and helps operators monitor gas quality while protecting downstream equipment.

  • Measures CH4, CO2 and water vapour in one probe
  • 0–100 vol-% measurement range for methane and carbon dioxide
  • Humidity output as 0–25 vol-% H2O or −10 to +60 °C dew point
  • Heated optics help prevent condensation in wet biogas
  • Three isolated 4–20 mA outputs and RS-485 Modbus RTU
  • Ex-certified construction for direct installation in hazardous process areas

Ask Seacom about the MGP261

Vaisala HMM100 Humidity Module for Environmental Chambers

Vaisala HMM100 Humidity Module for Environmental Chambers

The Vaisala HMM100 provides reliable humidity measurement and a configurable analog output for integration into environmental chambers and OEM equipment.

  • 0–100% RH measurement range
  • Relative-humidity or dew-point output
  • Current and voltage output options
  • Plastic or stainless-steel probes for temperatures up to +180 °C
CO2, Temperature and Humidity Transmitter Series GMW90

Vaisala GMW90 Series CO₂, Temperature and Humidity Transmitters

The Vaisala GMW90 Series provides stable wall-mounted carbon-dioxide and temperature measurement, with optional humidity, for demanding HVAC and building-automation applications.

  • Carbon-dioxide measurement from 0 to 5000 ppm
  • CO₂ accuracy up to ±(30 ppm + 2% of reading)
  • Temperature measurement from −5 to +55 °C
  • Optional HUMICAP® relative-humidity measurement from 0 to 95 %RH
  • Voltage, current or Modbus RTU output models
  • Display and CO₂ status-indicator options
  • Field-exchangeable calibrated measurement modules
  • Traceable three-point CO₂ calibration certificate included
Vaisala HMT370EX Intrinsically Safe Transmitter | Seacom

Vaisala HMT370EX & DMP370 Intrinsically Safe Humidity, Temperature and Dew Point Measurement

The Vaisala HMT370EX provides intrinsically safe humidity and temperature measurement with HMP-series probes. The new DMP370 configuration combines the HMT370EX transmitter with a DMP37X DRYCAP® probe for low-dew-point measurement in hazardous locations.

  • HMP probes for relative humidity and temperature
  • DMP370 dew-point measurement from −70 to +10 °C Td/f
  • Two two-wire 4–20 mA outputs
  • Certified configurations for hazardous gas and dust areas, up to Zone 0 / 20
  • Detachable probes and traceable calibration

DMP370 availability: Vaisala plans first deliveries for Q1 2027. Contact Seacom for configuration and project lead time.

Indigo200 Series Transmitters for Vaisala smart probes for Vaisala Smart Probes

Vaisala Indigo200 Series Transmitters

The Vaisala Indigo200 Series is the standard transmitter platform for one interchangeable Indigo-compatible smart probe, providing local display and practical automation-system connectivity.

  • Indigo201 with three analog outputs and two relays
  • Indigo202 with Modbus RTU and two relays
  • Colour display with numerical and graphical views
  • IP65 enclosure for industrial measurement applications
Vaisala HMP9

Vaisala HMP9 Compact Humidity and Temperature Probe

The Vaisala HMP9 combines a miniature 5 mm probe head with fast-response, high-accuracy humidity and temperature measurement for tight spaces and rapidly changing environments.

  • Humidity accuracy up to ±0.8% RH
  • Temperature accuracy up to ±0.1 °C
  • −40 to +120 °C probe-head measurement range
  • Standalone Modbus RTU or Vaisala Indigo transmitter operation
Vaisala HMP8

Vaisala HMP8 Humidity and Temperature Probe for Pressurised Pipelines

The Vaisala HMP8 provides high-accuracy humidity and temperature measurement in compressed air, refrigerant dryers and pressurised industrial processes up to 40 bar.

  • Humidity accuracy up to ±0.8% RH
  • Operating pressure from vacuum to 40 bar
  • Adjustable insertion depth with two probe lengths
  • Optional ball valve for insertion and removal under process conditions
Vaisala HMP7

Vaisala HMP7 High-Humidity and Temperature Probe

The Vaisala HMP7 is designed for continuously humid, rapidly changing and near-condensing environments. Probe heating helps prevent condensation while maintaining reliable process measurement.

  • Humidity accuracy up to ±0.8% RH
  • Probe heating for condensation prevention
  • −70 to +180 °C probe-head measurement range
  • Standalone Modbus RTU or Vaisala Indigo transmitter operation
Vaisala HMP3

Vaisala HMP3 General-Purpose Humidity and Temperature Probe

The Vaisala HMP3 is a high-accuracy, field-maintainable probe for industrial HVAC, air-handling units, cleanrooms, paint booths and environmental chambers.

  • Humidity accuracy up to ±0.8% RH
  • Temperature measurement from −40 to +120 °C
  • Field-replaceable filter and HUMICAP sensor option
  • Standalone Modbus RTU or Vaisala Indigo transmitter operation
Humidity and Temperature Transmitter (Meteorological Grade) HMP155

Vaisala HMP155 Meteorological Humidity and Temperature Probe

The Vaisala HMP155 provides stable humidity and temperature measurement for automatic weather stations, road-weather systems, airports, research sites and demanding outdoor monitoring.

  • Relative-humidity measurement from 0 to 100 %RH
  • Operating range from −80 to +60 °C
  • HMP155A with two analogue voltage outputs
  • HMP155D with RH voltage output and passive four-wire Pt100 temperature
  • HMP155E with RS-485 digital output
  • Optional warmed probe, chemical purge and additional temperature sensor
Vaisala Indigo510 Indigo520 Malaysia

Vaisala Indigo510 and Indigo520 Flagship Transmitters

The Vaisala Indigo500 Series provides flagship industrial measurement integration: choose Indigo510 for a simplified single-probe system or Indigo520 for full dual-probe capability.

  • Indigo510: one probe and two isolated analog outputs
  • Indigo520: two probes, four isolated outputs and two relays
  • Ethernet web interface and Modbus TCP communication
  • Rugged IP66 and NEMA 4 metal enclosure
Vaisala HMT360 Intrinsically Safe Humidity and Temperature Transmitter – Discontinued

Vaisala HMT360 Intrinsically Safe Humidity and Temperature Transmitter – Discontinued

The Vaisala HMT360 Series was an intrinsically safe transmitter platform for humidity, temperature and moisture measurement in hazardous areas. It is discontinued and replaced by the Vaisala HMT370EX with an application-specific probe.

  • HMT361 wall mounting → HMP371
  • HMT363 ducts and confined spaces → HMP373
  • HMT364 high pressure and vacuum → HMP374
  • HMT365 high temperature → HMP375
  • HMT367 high humidity → HMP377
  • HMT368 pressurised pipelines → HMP378
Vaisala HMT330 Humidity and Temperature Transmitter Series – Discontinued

Vaisala HMT330 Humidity and Temperature Transmitter Series – Discontinued

The Vaisala HMT330 Series was a flagship industrial transmitter platform for humidity, temperature and calculated moisture parameters. It is discontinued and replaced by an Indigo500 transmitter with the HMP probe selected for the application.

  • HMT331 wall mounting → HMP1 with Indigo500
  • HMT333 ducts and tight spaces → HMP3 or HMP9 with Indigo500
  • HMT334 high pressure and vacuum → HMP4 with Indigo500
  • HMT335 high temperature → HMP5 with Indigo500
  • HMT337 high humidity → HMP7 with Indigo500
  • HMT338 pressurised pipelines → HMP8 with Indigo500
Vaisala HMD80, HMW80 and HMS80 HVAC Humidity Transmitters

Vaisala HMD80, HMW80 and HMS80 HVAC Humidity Transmitters

The Vaisala HMDW80 Series provides cost-effective humidity and temperature measurement for routine HVAC and building-automation applications.

  • Humidity accuracy up to ±3% RH
  • Wall, duct and outdoor installation models
  • Current or voltage output configurations
  • Replaceable INTERCAP® humidity sensor
Vaisala HMW90 High-Accuracy Humidity and Temperature Transmitter

Vaisala HMW90 High-Accuracy Humidity and Temperature Transmitter

The Vaisala HMW90 Series provides high-accuracy humidity and temperature measurement for demanding indoor HVAC and controlled-environment applications.

  • Humidity accuracy up to ±1.7% RH
  • Analog or Modbus RTU output models
  • Optional display and configurable relay
  • Replaceable measurement module with calibration certificate
Vaisala HMT120 and HMT130 Transmitters – Are Being Replaced by Origo10

Vaisala HMT120 and HMT130 Transmitters – Are Being Replaced by Origo10

The Vaisala HMT120 and HMT130 provide accurate, stable humidity and temperature measurement for cleanrooms, laboratories, data centres and demanding HVAC applications.

Product transition: HMT120/HMT130 are expected to be phased out. For new projects, the Vaisala Origo10 is the recommended replacement platform.

  • Humidity accuracy up to ±1.5% RH
  • HMT120 loop-powered 4–20 mA output
  • HMT130 voltage outputs, RS-485 and relay
  • Interchangeable fixed or remote measurement probe
  • Origo10 recommended for new installations
Vaisala PTU300 Pressure, Humidity and Temperature Transmitter – Discontinued

Vaisala PTU300 Pressure, Humidity and Temperature Transmitter – Discontinued

The Vaisala PTU300 combined barometric pressure, relative humidity and temperature in one transmitter. The series is discontinued and has been replaced by a suitable Indigo520 barometric-pressure configuration with an application-specific HMP probe.

  • Legacy three-in-one pressure, humidity and temperature transmitter
  • PTU301, PTU303, PTU304, PTU305, PTU307 and PTU308 variants
  • Former applications include laboratories, meteorology and semiconductor measurement
  • Current replacement platform: Indigo520 with barometric-pressure measurement
  • Humidity probe selected according to mounting and process conditions
  • Existing wiring, outputs and process connections require migration review
Vaisala HMM105 Digital Humidity Module for Environmental Chambers

Vaisala HMM105 Digital Humidity Module for Environmental Chambers

The Vaisala HMM105 provides reliable humidity measurement for integration into environmental chambers, incubators and OEM equipment.

  • 0–100% RH measurement range
  • I2C output for relative humidity or dew point
  • Detachable 12 mm probe with 300 mm flexible cable
  • Probe withstands +180 °C continuously and +200 °C temporarily
Vaisala HMT140 Wi-Fi Data Logger – Discontinued, Replaced by RFL100

Vaisala HMT140 Wi-Fi Data Logger – Discontinued, Replaced by RFL100

The Vaisala HMT140 Wi-Fi Data Logger has been discontinued and is no longer recommended for new monitoring systems.

  • Primary replacement: Vaisala RFL100 with AP10 VaiNet Access Point
  • Existing HMT140 installations can continue to be supported
  • Migration should be checked against the existing sensor and input type
  • Contact Seacom for replacement selection and viewLinc compatibility
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