Vaisala DMP8 Dew Point & Temperature Probe


  • Dew point measurement range −70 … +80 °C (−94 … +176 °F) Td/f
  • Dew point measurement accuracy up to ±2 °C (±3.6 °F) Td/f
  • Operating pressure of probe head 0 … 4 MPa (0 … 40 bar)
  • Adjustable installation depth
  • Tolerates condensation, oils, dust, and most chemicals
  • Sensor purge provides superior chemical resistance
  • Modbus RTU over RS-485
  • Compatible with Indigo transmitters and Insight PC software
  • Traceable calibration certificate

Dpstar is a leading supplier of environmental measurement sensors for temperature, relative humidity, pressure, dew point, CO2, and other environmental condition monitoring for industrial process application and research. Since the ’90s, we earned a reputation as a trusted partner to our clients through our commitment and dedication. We are an authorized distributor and supplier of measuring sensors solutions from renowned manufacturers Vaisala. Vaisala is a global leader in environmental and industrial measurement. Building on 80 years of experience, Vaisala provides observations for a better world. Vaisala is a reliable partner for customers around the world, offering a comprehensive range of innovative observation and measurement products and services.

Vaisala DMP8 Temperature Probe and DRYCAP Dew Point sensor are made for industrial settings with low humidity and pressures up to 40 bars. Typical applications include industrial drying, compressed air systems, and applications in the semiconductor industry. Vaisala DMP8 can be installed in a 1/2″ NPT or ISO thread with adjustable insertion depth. An optional ball-valve kit lets you install or remove it from a pressurized line. It’s part of the Indigo family and works with Indigo500 and Indigo200 series transmitters. It can be used with Vaisala Insight PC software for easy data visualization, probe setup, and self-calibration.


Key Benefits

Designed For Pressurized Pipelines

Vaisala DMP8 is designed to take dew point measurements in pressurized pipelines with low humidity in various industrial applications. The operating pressure is 0 … 4 MPa (0 … 40 bar). Thanks to its sliding seal, it is easy to adjust the installation depth. When a ball-valve installation kit is used, the probe is easy to insert and remove from pressurized processes.

Fast Reaction Time & Stability At Low Dew Points

The Vaisala DRYCAP sensor is immune to particulate contamination, water condensation, oil vapor, and most chemicals. The sensor is condensation-resistant and recovers perfectly if exposed to water. Its fast reaction time gives it unmatched performance even in dynamic and low dew point applications, and its outstanding stability provides a long, two-year calibration interval.

Use standalone or with an Indigo Transmitter

Vaisala DMP8 is part of the Vaisala Indigo family, so it can also be used with Vaisala Indigo series transmitters. The transmitters offer various additional benefits such as a display for data visualization, easy access to probe configuration, and more extensive options for automation system connectivity, supply voltage, and wiring. Built-in Modbus RTU over RS-485 output means that Vaisala DMP8 can be used as a standalone device and can also be easily integrated into third-party systems. Whether using the Vaisala DMP8 on its own or with an Indigo transmitter, it can be connected to the Vaisala Insight software for easy field calibration, probe configuration, and device analytics.


Measurement Performance
Dew point
Sensor DRYCAP 180M
Measurement range −70 … +80 °C (−94 … +176 °F) Td/f
Measurement range for continuous use −70 … +45 °C (−94 … +113 °F) Td/f
Accuracy up to 20 bar/290 psia ±2 °C/±3.6 °F Td/f
See accuracy graph
Accuracy, 20 … 40 bar/290 … 580 psia Additional inaccuracy +1 °C Td/f
Response time 63 % [90 %] 1)
From dry to wet 5 s [15 s]
From wet to dry 45 s [8 min]
Measurement range 0 … +80 °C (+32 … +176 °F)
Accuracy ±0.2 °C at room temperature
Temperature sensor Pt100 RTD Class F0.1 IEC 60751
Relative Humidity
Measurement range 0 … 70 %RH
Accuracy (RH <10 %RH, at + 20 °C) ±0.004 %RH + 20% of reading
Concentration by volume (ppm)
Measurement range (typical) 10 … 2500 ppm
Accuracy (at + 20 °C, 1 bar) 1 ppm + 20% of reading
1) Tested with sintered filter
Operating Environment
Operating temperature for probe head −40 … +80 °C (−40 … +176 °F)
Operating temperature for probe body −40 … +80 °C (−40 … +176 °F)
Storage temperature −40 … +80 °C (−40 … +176 °F)
Operating pressure for probe head 0 … 40 bar (0 … 580 psia)
Measurement environment For air, nitrogen, hydrogen, argon, helium, oxygen 1), and vacuum
IP rating for probe body IP66
Mechanical durability of probe head Up to +180 °C (+356 °F)
Up to 70 bar/1015 psia
1) Consult Vaisala if other chemicals are present. Consider safety regulations with flammable gases
Inputs & Outputs
Operating voltage 15 … 30 V DC
Current consumption 10 mA typical, 500 mA max
Digital output RS-485, non-isolated
Protocols Modbus RTU
Output Parameters
Absolute humidity (g/m3) Relative humidity (%RH)
Absolute humidity at NTP (g/m3) Relative humidity (dew/frost) (%RH)
Dew point temperature (°C) Temperature (°C)
Dew/frost point temperature (°C) Water concentration (ppmv)
Dew/frost point temperature at 1 atm (°C) Water concentration (wet basis) (vol %)
Dew point temperature at 1 atm (°C) Water mass fraction (ppmw)
Dew point temperature difference (°C) Water vapor pressure (hPa)
Enthalpy (kJ/kg) Water vapor saturation pressure (hPa)
Mixing ratio (g/kg)
EU directives EMC Directive (2014/30/EU)
RoHS Directive (2011/65/EU)
EMC compatibility EN 61326 1, industrial environment
Compliance marks CE, China RoHS, RCM
Mechanical Specifications
Connector M12 5-pin A-coded male
Weight 512 g (18.1 oz)
Probe cable length 2 m (6.56 ft)
Probe AISI 316L
Probe body AISI 316L
Cable jacket FEP
Fitting body ISO R 1/2″ with leak screw ISOFITBODASP
Fitting body ISO R 1/2″ (no leak screw) DRW212076SP
Fitting body NPT 1/2″ (no leak screw) NPTFITBODASP
Sampling cell DMT242SC
Sampling cell with Swagelok connectors DMT242SC2
Ball valve set for pressurized pipelines BALLVALVE-1
Duct installation flange for ISO R 1/2″ thread DM240FASP
Thread adapter ISO 1/2″ to NPT 1/2″ 210662SP
Blind plug ISO 1/2″ 218773
Indigo USB adapter 1) 242659
1) Vaisala Insight software for Windows available at


Vaisala DMP8 Dew Point & Temperature Probe_DpstarGroup