Vaisala HMP7 Probe for High Humidity and Condensing Conditions
The Vaisala HUMICAP® Humidity and Temperature Probe HMP7 is designed for constant high humidity, rapid humidity changes and environments where condensation on an unheated sensor would interrupt reliable measurement.
Typical applications include drying and test chambers, combustion air, industrial humidifiers, environmental chambers, meteorological installations and other demanding processes operating close to saturation.
The HMP7 can heat the complete probe head above the process dew-point temperature. This prevents condensation from forming on the sensing surface and allows the probe to continue measuring the process dew point during extremely humid conditions.
For calculated relative humidity at the actual process temperature while probe heating is active, use an external temperature reference such as the Vaisala TMP1 temperature probe. An Indigo520 can combine both probe inputs in one transmitter.
Why Choose the Vaisala HMP7?
- Continuous High-Humidity Measurement: Designed for processes operating near saturation or subject to rapid humidity changes.
- Heated Probe Head: Heating the complete sensing head above the dew point helps prevent condensation on the probe.
- High Measurement Accuracy: Provides humidity accuracy up to ±0.8% RH and temperature accuracy up to ±0.1 °C under specified conditions.
- Wide Temperature Range: The probe head measures from −70 to +180 °C.
- Vapour- and Pressure-Proof Construction: Suitable for demanding process and outdoor measurement environments at pressures below 10 bar.
- Sensor Purge: Available sensor options use periodic heating to reduce contamination from chemicals and cleaning agents.
- H₂O₂-Resistant Sensor Option: The HUMICAP 180VC option supports applications involving vaporised hydrogen peroxide, subject to its specified operating limitations.
- Standalone Modbus RTU: Built-in RS-485 communication supports direct integration with an automation system.
- Indigo Compatibility: Add display, analog outputs, relays, Ethernet, Modbus TCP and dual-probe temperature compensation using a compatible Indigo transmitter.
- Traceable Calibration: Supplied with a certificate covering six humidity points and one temperature point.
How HMP7 Probe Heating Prevents Condensation
Condensation occurs when the sensor surface temperature falls to the process dew-point temperature. HMP7 probe heating raises the entire probe head above the dew point so that liquid water does not form on the sensor.
Important: When probe heating changes the temperature of the HMP7 sensing head, the probe-head temperature is not the same as the actual process temperature. Use an external temperature reference when accurate process RH calculation is required during heating.
Recommended HMP7 and TMP1 Configuration
HMP7 Measurement Performance
Operating Environment
Electrical and Communication Specifications
Mechanical Specifications
Measured and Calculated Parameters
- Relative humidity
- Temperature
- Absolute humidity
- Dew point and dew/frost point temperature
- Wet-bulb temperature
- Enthalpy
- Mixing ratio
- Water-vapour pressure
- Water concentration and water mass fraction
HMP7, HMP5 or HMP9?
Compatible Vaisala Indigo Transmitters
The distance between the HMP7 and a compatible Indigo transmitter can be extended to approximately 30 m using the correct Vaisala cable arrangement.
View the Vaisala Indigo80 Portable Meter
Common HMP7 Applications
- High-Humidity Test Chambers: Maintaining reliable measurement during rapid changes and near-saturated conditions.
- Industrial Humidifiers: Monitoring humid air where condensation on an unheated sensor is likely.
- Drying Chambers: Measuring humidity across changing process stages, including high-humidity portions of the cycle.
- Combustion Air: Humidity and temperature measurement in demanding intake-air conditions.
- Meteorological Measurement: Outdoor humidity monitoring using the appropriate radiation shield and mounting accessories.
- Bio-Decontamination: Suitable configurations using the H₂O₂-resistant HUMICAP 180VC sensor.
- Environmental Chambers: Condensation-resistant monitoring in validation, research and product testing.
- Fuel Cells and Humidified Gas Systems: High-humidity gas measurement following application and material-compatibility review.
Installation Accessories
Installation Guidance
- Install the probe head in representative airflow and avoid stagnant locations.
- Keep the probe body within its −40 to +80 °C operating range.
- When probe heating is enabled, provide a separate process-temperature measurement if true RH is required.
- Use pressure-tight fittings and appropriate sealing methods for pressurised or vapour-tight installations.
- Confirm the configured process pressure for accurate calculated humidity parameters.
- Use a radiation shield for outdoor measurements exposed to sunlight.
- Select the correct HUMICAP sensor according to chemical exposure and H₂O₂ requirements.
Other Vaisala Indigo-Compatible Probes
Calibration and Maintenance
The HMP7 is calibrated and adjusted before delivery. Calibration and adjustment can be performed using Vaisala Insight PC software, a compatible Indigo transmitter or an Indigo80 handheld indicator.
Before calibration, allow the probe to stabilise and ensure that heating or purge cycles are not active unless the calibration procedure specifically requires them. Determine the calibration interval according to process severity, contamination, required uncertainty and quality-system requirements.
Vaisala HMP7 Supplier in Malaysia
Seacom Process Instruments supplies and supports the Vaisala HMP7 high-humidity and temperature probe in Malaysia for chambers, humidifiers, drying systems, combustion air, meteorological measurement and near-condensing industrial processes.
Our team can assist with selecting the humidity sensor, probe-heating configuration, cable length, installation accessory, TMP1 temperature reference and Indigo transmitter required for the application.
Contact Seacom for Vaisala HMP7 Selection
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TMP1 Catalogue
- Smart Temperature Transmitter TMP1
(218.81k)
