The Vaisala HMW90 Series provides high-accuracy humidity and temperature measurement for demanding indoor HVAC and controlled-environment applications.
The wall-mounted Vaisala HMW90 Series provides accurate and stable humidity and temperature measurement for indoor environments where standard HVAC transmitters may not provide sufficient performance or calibration documentation.
Typical applications include data centres, laboratories, museums, archives, production areas, warehouses and testing facilities. The series offers current, voltage and Modbus RTU models, with optional displays and configurable versions for special output scaling or calculated humidity parameters.
The HMW90 measures relative humidity across the full 0–100% RH range with accuracy up to ±1.7% RH from 0–90% RH within the specified central temperature range. Temperature accuracy reaches ±0.2 °C under normal indoor conditions.
The Vaisala HUMICAP® 180R sensor provides dependable long-term stability for demanding building-automation applications. Each humidity transmitter is supplied with a traceable calibration certificate to support commissioning, quality records and planned calibration programmes.
The HMW90 family includes loop-powered 4–20 mA models, voltage-output models and Modbus RTU models. Versions with a visible local display are available, while selected voltage-output models can also provide a configurable relay.
Depending on the model and configuration, output parameters can include relative humidity, temperature, dew point, mixing ratio, enthalpy, wet-bulb temperature, dew-point depression and absolute humidity.
The humidity and temperature measurement module can be replaced in the field, reducing downtime when calibration or maintenance is required. Configuration, installation and field adjustment are designed to be straightforward for building-automation technicians.
The replacement module and transmitter configuration must match the required measurements, outputs and scaling. Calibration intervals should be determined according to the application conditions, required uncertainty and quality-system requirements.
Select the model according to the measured parameters, building-management-system input and whether a local display or relay is required.
| Model | Measurement | Output | Display | Recommended use |
|---|---|---|---|---|
| HMW92 | Humidity and temperature | 4–20 mA current outputs | No | Loop-powered building-automation systems |
| HMW92D | Humidity and temperature | 4–20 mA current outputs | Yes | Loop-powered systems requiring local indication |
| HMW93 | Humidity and temperature | Voltage outputs | No | Voltage-input controllers; configurable relay available |
| HMW93D | Humidity and temperature | Voltage outputs | Yes | Voltage-input controllers requiring display or relay |
| HMW95 | Humidity and temperature | Modbus RTU | No | Digital building-automation integration |
| HMW95D | Humidity and temperature | Modbus RTU | Yes | Digital integration requiring local indication |
| HMW90 | Humidity and temperature | Configurable analog or digital arrangement | Configuration dependent | Special scaling or calculated-parameter requirements |
| TMW92 | Temperature only | 4–20 mA current output | No | Loop-powered temperature measurement |
| TMW93 | Temperature only | Voltage output | No | Voltage-input temperature measurement |
| TMW90 | Temperature only | Configurable output | Configuration dependent | Special temperature scaling requirements |
Model-number guide: choose HMW92 for 4–20 mA, HMW93 for voltage output or HMW95 for Modbus RTU. Add D when a local display is required. Select an HMW90 configurable model for special scaling or calculated parameters, and a TMW model when only temperature is required.
These Vaisala HVAC transmitter families serve different measurement and control requirements. Choose according to accuracy, mounting location, communication method, calibration documentation and whether carbon-dioxide measurement is required.
| Selection point | Vaisala HMX80 Series | Vaisala HMX110 Series | Vaisala HMW90 Series | Vaisala XMW85 Series |
|---|---|---|---|---|
| Product position | Cost-effective routine HVAC | Balanced high-accuracy HVAC | Premium indoor wall measurement | Smart indoor Modbus and air-quality measurement |
| Measured parameters | Humidity and temperature; temperature-only models available | Humidity and temperature; temperature-only models available | Humidity and temperature; temperature-only models available | Humidity and temperature, with optional CO₂ measurement |
| Humidity accuracy | Up to ±3% RH | Up to ±2% RH | Up to ±1.7% RH | Up to ±3% RH |
| Installation options | Indoor wall, duct, humid-area wall and outdoor | Indoor wall, duct and outdoor | Indoor wall only | Indoor wall only |
| Output and communication | Current, voltage or Modbus RTU, depending on model | 4–20 mA or Modbus RTU, depending on model | Current, voltage or Modbus RTU, depending on model | Modbus RTU on all models |
| Local display | Available on selected models | No display on standard models | Available on selected models | Available on selected models |
| Calibration certificate | Not supplied | Traceable certificate included | Traceable certificate included | Confirm according to selected model and project requirement |
| Main reason to choose | Simple, economical measurement across multiple mounting styles | Better accuracy and documentation for demanding HVAC locations | Highest humidity accuracy for an indoor wall transmitter | Modbus integration or combined CO₂, humidity and temperature measurement |
Quick selection: choose the 80 Series for routine HVAC where cost and mounting flexibility are the priorities. Choose the 110 Series when better accuracy and a traceable certificate are required for wall, duct or outdoor measurement. Choose HMW90 for premium indoor wall measurement. Choose XMW85 for indoor Modbus systems, especially when CO₂ must be measured with humidity and temperature.
Before ordering, confirm the required measurement parameters, 4–20 mA, voltage or Modbus RTU interface, display requirement, relay function, output scaling, operating range, enclosure colour and calibration requirements.
For existing installations, provide the current model number, wiring, controller input and output scaling. This helps ensure that the replacement model matches both the electrical arrangement and building-management-system configuration.
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
Seacom Process Instruments supplies and supports the Vaisala HMW90 Humidity and Temperature Transmitter in Malaysia for data centres, laboratories, museums, archives, controlled warehouses and demanding HVAC applications.
Our team can assist with model selection, output type, display, relay, calculated parameter, special scaling, installation location, controller integration and calibration planning.
Contact Seacom with your required humidity and temperature accuracy, building-management-system interface, display requirement and application conditions so we can recommend a suitable HMW90 configuration.
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