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.
The Vaisala HUMICAP® Humidity and Temperature Probe HMP9 is designed for tight spaces and rapidly changing environments where fast response, compact installation, measurement accuracy and chemical tolerance are essential.
Its defining feature is a miniature probe head measuring only 5 mm in diameter. The low thermal mass enables the sensor to respond quickly to changing air temperature while preserving Vaisala HUMICAP humidity-measurement stability and low hysteresis.
The HMP9 is suitable for air-handling units, data centres, industrial dryers, test chambers, environmental chambers, glove boxes, incubators, machinery and other installations where a conventional industrial probe is physically too large or responds too slowly.
Built-in RS-485 Modbus RTU enables standalone operation. The probe can also connect to a Vaisala Indigo transmitter for local display, analog outputs, relays, Ethernet connectivity and additional automation-system integration.
| Measurement Specification | Performance |
|---|---|
| Relative-Humidity Range | 0–100% RH |
| RH Accuracy at +23 °C | ±0.8% RH from 0–90% RH |
| RH Factory-Calibration Uncertainty | ±0.7% RH from 0–40% RH; ±1.0% RH from 40–95% RH |
| RH Response Time | 15 seconds, T63 in still air |
| Humidity Sensor | Vaisala HUMICAP® I |
| Temperature Range | −40 to +120 °C |
| Temperature Accuracy at +23 °C | ±0.1 °C |
| Temperature Factory-Calibration Uncertainty | ±0.1 °C at +23 °C |
| Temperature Response Time | 70 seconds, T63 in still air |
| Environmental Specification | Operating Limit |
|---|---|
| Probe-Head Temperature | −40 to +120 °C |
| Probe-Body Temperature | −40 to +60 °C |
| Storage Temperature | −40 to +60 °C |
| Outdoor Operation | Suitable when protected from rain |
| Measurement Media | Air, nitrogen, hydrogen, argon, helium and oxygen; consult Vaisala for other chemicals |
| Probe-Body Protection | IP65 when correctly connected |
The HMP9 can be used where occasional condensation may occur, provided that the probe is protected from direct exposure to liquid water. It is not the preferred probe for continuously condensing conditions.
For persistent high humidity, repeated condensation or applications that require active probe heating, select the Vaisala HMP7 high-humidity probe.
| Feature | Specification |
|---|---|
| Operating Voltage | 15–30 V DC |
| Typical Current Consumption | 5 mA |
| Maximum Current Consumption | 400 mA |
| Digital Interface | RS-485, non-isolated |
| Communication Protocol | Modbus RTU |
| Default Baud Rate | 19,200 bps |
| Default Serial Format | No parity, 8 data bits and 2 stop bits |
| Electrical Connector | M12 five-pin A-coded male |
| Mechanical Feature | Specification |
|---|---|
| Probe-Head Diameter | 5 mm |
| Probe-Head Length | Approximately 94 mm |
| Probe-Body Diameter | 25 mm |
| Probe Material | AISI 316L stainless steel |
| Probe-Body Material | PBT |
| Cable Overmould Material | FEP |
| Fixed Probe Cable | 2 m |
| Approximate Weight | 68 g |
| Included Mounting Accessory | M10 × 1.5 cable gland |
| Transmitter | Recommended Configuration | Product Link |
|---|---|---|
| Indigo200 Series | Standard single-probe transmitter with display and analog, relay or Modbus options | Vaisala Indigo200 |
| Indigo300 | Rugged IP66 metal transmitter for one probe with up to three analog outputs | Vaisala Indigo300 |
| Indigo510 | Simplified flagship for one probe with isolated outputs, Ethernet and Modbus TCP | Vaisala Indigo510 |
| Indigo520 | Full dual-probe flagship with four outputs, two relays, Ethernet and Modbus TCP | Vaisala Indigo520 |
View the Vaisala Indigo80 Portable Meter
The HMP9 is well suited to measurement points where available space is limited or environmental conditions change quickly, including air-handling units, cooling equipment, server racks and airflow paths. Its low thermal mass reduces lag when cooling load or airflow changes.
For broader guidance on probe placement, room monitoring, chilled-water measurement and data-centre cooling control, see Seacom’s Vaisala Data Centre Environmental Monitoring Guide.
| Accessory | Purpose |
|---|---|
| M10 × 1.5 Cable Gland | Included for mounting the probe head through a suitable wall or panel |
| HMP9 Duct Installation Kit ASM214055 | Supports installation in ventilation ducts |
| DTR502B Radiation Shield | Protects the probe head for suitable outdoor meteorological measurement |
| HMK15 Calibration Adapter ASM213801 | Supports humidity calibration using the Vaisala HMK15 calibrator |
| Indigo USB Adapter USB2 | Connects the probe to Vaisala Insight PC software |
The HMP9 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.
Because the miniature sensor head does not use the heavier replaceable filters found on some other HMP probes, it should be protected from mechanical damage and direct contamination. Calibration frequency should be determined according to process criticality, operating conditions and quality-system requirements.
Vaisala HMP1, HMP3, HMP4, HMP5, HMP7, HMP8 and HMP9 can be connected to the Vaisala Indigo80 Handheld Indicator using a compatible connection cable.
Portable measurement and field servicing: use Indigo80 to display live humidity and temperature readings, record measurement data, check probe performance, configure settings, and perform field calibration and adjustment. The same Indigo80 can support different compatible probes, making it practical for servicing multiple measurement points.
Vaisala Indigo-compatible HMP probes share the same measurement platform, but their mechanical design and installation method suit different conditions. Use the table below to identify the best starting point for your application.
| Probe | Main strength | Recommended application | Product |
|---|---|---|---|
| HMP1 | Compact wall-mounted probe for indoor environments | Cleanrooms, laboratories, data centres, warehouses and demanding HVAC | Vaisala HMP1 |
| HMP3 | Field-maintainable general-purpose 12 mm probe | Ducts, chambers, paint booths, air-handling units and industrial HVAC | Vaisala HMP3 |
| HMP4 | High-pressure measurement up to 100 bar | Compressed air, breathing air, industrial gases and vacuum systems | Vaisala HMP4 |
| HMP5 | Long probe for high temperatures up to +180 °C | Ovens, kilns, baking processes and high-temperature dryers | Vaisala HMP5 |
| HMP7 | Heated probe for continuous high humidity | Near-condensing chambers, humidifiers, drying processes and other persistently humid conditions | Vaisala HMP7 |
| HMP8 | Adjustable-depth probe for pressurised pipelines | Compressed-air lines, refrigerant dryers and industrial pipelines requiring easy probe removal | Vaisala HMP8 |
| HMP9 | Compact 5 mm probe head with fast response | Tight spaces, rapidly changing air, compact equipment, ducts and data centres | Vaisala HMP9 |
Seacom Process Instruments supplies and supports the Vaisala HMP9 compact humidity and temperature probe in Malaysia for data centres, air-handling units, dryers, environmental chambers, incubators and other space-constrained or rapidly changing applications.
Our team can assist with selecting the mounting arrangement, duct kit, radiation shield, connection cable and Indigo transmitter required for the application.
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.
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.
The Vaisala GMW90 Series provides stable wall-mounted carbon-dioxide and temperature measurement, with optional humidity, for demanding HVAC and building-automation applications.
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.
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.
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.
The Vaisala HMM100 provides reliable humidity measurement and a configurable analog output for integration into environmental chambers and OEM equipment.
The Vaisala HMP8 provides high-accuracy humidity and temperature measurement in compressed air, refrigerant dryers and pressurised industrial processes up to 40 bar.
The Vaisala Indigo520 Supervisor manages up to 100 compatible compact humidity and temperature probes through one host unit. It provides local visibility for the maintenance team and Modbus TCP communication for data centre BMS integration.
Expected availability: early 2027. Enquire with Seacom for configuration and delivery confirmation.
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.
DMP370 availability: Vaisala plans first deliveries for Q1 2027. Contact Seacom for configuration and project lead time.
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.
The Vaisala HMP7 is designed for continuously humid, rapidly changing and near-condensing environments. Probe heating helps prevent condensation while maintaining reliable process measurement.
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.
The Vaisala HMM105 provides reliable humidity measurement for integration into environmental chambers, incubators and OEM equipment.
The Vaisala Indigo200 Series is the standard transmitter platform for one interchangeable Indigo-compatible smart probe, providing local display and practical automation-system connectivity.
The Vaisala HMD60 Series provides high-accuracy humidity and temperature measurement for demanding HVAC ducts and light-industrial applications.
