Vaisala DMT143 Miniature Dew Point Transmitters


  • ISO17025 calibration by VAISALA
  • 2 years calibration interval
  • Vaisala DRYCAP technology with a unique auto-calibration function
  • Dew point measurement range −70 … +60 °C (−94 … +140 °F)
  • Accuracy ±2 °C (±3.6 °F)
  • Withstands condensation
  • Compatible with Vaisala DRYCAPâ Handheld Dew Point Meter DM70
  • Compatible with Vaisala Insight PC software
  • Traceable calibration
  • Voltage (V) or current (mA) analog output
  • RS-485 digital output with Modbus RTU support
  • LED alarm for exceeded dew point level
  • Fast response time

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.

Due to its wide measurement range and excellent long-term stability, Vaisala DRYCAP Dew Point Transmitter DMT143 is an ideal choice for small compressed air dryers, plastic dryers, and other OEM applications.


Key Benefits

Vaisala DRYCAP Technology

Vaisala DRYCAP Dew Point Transmitter DMT143 is a miniature dew point measurement instrument. The transmitter can be installed directly into pressurized systems at 50 bar (725 psia) maximum pressure. The longterm high performance is achieved with Vaisala DRYCAP  technology. The sensor fully withstands getting wet, and therefore, the transmitter performs exceptionally well in applications that occasionally experience process water spikes, such as pipeline condensation during a system failure or start-up. The sensor is also highly resistant to particulate contamination, oil vapor, and most chemicals, and is insensitive to the flow rate.

Long Calibration Interval

The calibration interval of DMT143 is 2 years. Additionally, Vaisala DRYCAP Handheld Dew Point Meter DM70 can be used to confirm the performance of DMT143 without disconnecting the transmitter. For any adjustment needs, the transmitter can be sent to Vaisala Service. The unique autocalibration function, developed by Vaisala, detects possible measurement inaccuracies and automatically corrects dry-end drift in the calibration curve. This ensures accurate measurements and long calibration intervals.

Easy Installation

DMT143 has a variety of features to choose from, including different output and installation options, and alarm LED. Due to its small size and lightweight, DMT143 is quickly and easily installed in tight spaces or in small-size pipelines. The alarm LED indicates too high dew point in the process. The trigger point is preset at the factory. It can be later adjusted with Vaisala DRYCAP Handheld Dew Point Meter DM70, or the convenient Vaisala Insight PC software for Windows. Insight PC software can also be used for other configuration options.


Measurement Performance
Sensor DRYCAP 180D
Sensor protection Stainless steel sintered filter
Recommended calibration interval to confirm the specified accuracy 2 years
Dew Point Temperature
Measurement range (typical) −70 … +60 °C (−94 … +140 °F) Td
Accuracy in air or N2 1) ±2 °C (±3.6 °F) Td (see graph below)
Analog Output Scalings:
Option 1 −80 … +20 °C (−112 … +68 °F) Td
Option 2 −80 … +20 °C (−112 … +68 °F) Td dew point at ambient pressure
Option 3 Free scaling
Response time 63 % [90 %]: 2)
−70 → −20 °C Td (−94 → −4 °F Td) 5 s [15 s] (typical)
−20 → −70 °C Td (−4 → −94 °F Td) 45 s [10 min] (typical)
Water concentration by volume (ppm)
Measurement range (typical) 10 … 40 000 ppm
Accuracy at +20 °C (+68 °F), 1 bar 1 ppm + 20 % of reading
1) When the dew point is below 0 °C (32 °F), the transmitter outputs frost point.
2) At +20 °C gas temperature and 1 bar pressure and 1 liter/min flow rate.
Operating Environment
Measurement environment For air, nitrogen, hydrogen, argon, helium, and oxygen 1)
Temperature 2) −40 … +60 °C (−40 … +140 °F)
Relative humidity 0 … 100 % RH
Pressure 2) 0 … 50 bara (725 psia)
Sample flow rate No effect for measurement accuracy
Storage temperature −40 … +60 °C (−40 … +140 °F)
1) Consult Vaisala if other chemicals are present. Consider safety regulations with flammable gases.
2) For extended temperature below 0 °C (+32 °F) or pressure above 20 bara (290 psia) the supply voltage must be 24 … 28 VDC.
Inputs & Outputs
Analog output (scalable) 4 … 20 mA (3-wire), 0 … 1 V / 5 V, 1 … 5 V
Resolution for current output 0.002 mA
Resolution for voltage output 0.3 mV
Accuracy for current output at +20 °C ±0.05 mA
Accuracy for voltage output at +20 °C ±0.01 V
Operating voltage with digital output 12 … 28 VDC
Operating voltage with voltage output 12 … 28 VDC
Operating voltage with current output 18 … 28 VDC
Load for current output Max. 500 Ω
Load for voltage output Min. 10 kΩ
Typical temperature dependence 0.005 % of span/°C
Digital output RS-485, non-isolated
Supported protocols Vaisala industrial protocol
Modbus RTU
Connector 4-pin M8 (IEC 60947-5-2)
Supply current at +20 °C (Uin 24 VDC)
Normal measurement 10 mA + load current (typical)
During self-diagnostics 220 mA pulsed (typical)
Mechanical Specifications
Mechanical connection ISO 228-1 G1/2″
1/2″ NPT
3/4″-16 UNF
5/8″-18 UNF
Housing material Stainless steel (AISI316L)
G thread and UNF thread versions 90 g (3.2 oz)
NPT thread version 100 g (3.5 oz)
IP rating IP66
EMC compliance EN 61326-1, industrial electromagnetic environment
Spare Parts & Accessories
Connection cable for DM70 219980SP
USB cable for PC connection 1) 219690
Loop powered external display 226476
Loop powered external display with relays 234759
Sampling cells
Basic sampling cell DMT242SC
With Swagelok 1/4″ male connectors DMT242SC2
With quick connector and leak screw DSC74SP
Two-pressure sampling cell DSC74BSP
Cooling/venting coil DMCOILSP
1) Vaisala Insight software for Windows is available at


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