Vaisala HMP8 Relative Humidity & Temperature Probe



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  • HUMICAP R2 composite RH sensor
    • 0 to 100% RH range
    • Up to 0.8% RH accuracy
  • Pt100 RTD Class F0.1 IEC 60751 temperature sensor
    • -94 to +356°F (-70 to +180°C) range
    • Up to 0.18°F (0.1°C) accuracy
  • 15 to 30 VDC operating voltage
  • RS-485, non-isolated digital output
  • M12/5 connector
  • IP66 rating

The Vaisala HMP8 relative humidity and temperature probe is designed to be freely adjusted and hot-swapped from pressurized pipelines (< 40 bar) using the Vaisala installation valve. Common applications include compressed air systems, refrigerant dryers, and other pressurized industrial applications. The HMP8's IP66-rated housing makes it suitable for indoor or outdoor use.

With a HUMICAP R2 composite sensor, the HMP8 offers measurement ranges of 0 to 100% relative humidity and temperature from -94 to +356°F (-70 to 180°C). Vaisala's thin-film capacitive technology allows for RH accuracy up to 0.8% and the Pt100 RTD Class F0.1 IEC 60751 temperature sensor provides accuracy up to 0.18°F (0.1°C).

The Vaisala HMP8 is also part of the Indigo product family and compatible with Indigo 201 and 202 transmitters. The HMP8 is plug and play compatible with Vaisala's Indigo series of transmitters, or it can be used as a standalone digital Modbus RTU transmitter over RS-485 serial bus. If analog output is required the probe must be paired with an Indigo 201 transmitter.

Required Components

These additional components are required for the operation of your product. We strongly advise you to purchase these components unless you already own them or own a suitable alternative.

Vaisala Indigo 200 Series Remote Probe Cable
Replacement cable to connect remote probe to Indigo 201 & 202 transmitters
Vaisala HMP8 Installation Ball Valve
Ball valve with ISO 1/2in welding joint for installation of HMP8 into pressurized pipelines less than 40 bar


Please consider these optional accessories.

Vaisala Indigo 200 Series Transmitter
Plug-and-play connection for compatible CO2, vaporized hydrogen peroxide, humidity & temperature probes
Vaisala HM47280SP Sintered Filter
SS sintered filter 12mm diameter
Vaisala HM47453SP SS Filter Guard
SS filter guard for vacuum applications
Vaisala DRW010281SP PPS Grid
12mm diameter, female thread, metallized PPS plastic grid with stainless steel mesh with 15µm pore size
Vaisala DRW010276SP Plastic PPS Grid Filter
12mm diameter, female thread, metallized PPS plastic with 6.5mm gaos between grids
Vaisala 242659 Connection Cable
M12/5 N female to USB cable used to connect Indigo probes to a PC for use with Insight software
In Stock
Vaisala Indigo Compatible Probe Cable
Shielded 5-socket M12 female connection to open wire
In Stock
Vaisala Indigo Compatible Right Angle Probe Cable
90° shielded 5-socket M12 female connection to open wire