Vaisala DMT143L (Long) Miniature Dew Point Transmitters


  • Vaisala DRYCAPâ technology with auto-calibration
  • Calibration interval of two years
  • Two sensor options cover a dew point measurement range of -60 … +60 °C (-76 … +140 °F)
  • Accuracy ±2 °C (±3.6 °F)
  • Compatible with Vaisala DRYCAPâ Handheld Dew Point Meter DM70
  • Compatible with Vaisala Insight PC software
  • Traceable calibration (certificate included)
  • Analog current (mA) output and 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.

Vaisala DRYCAP® Dew Point Transmitter DMT143L is a small device used for measuring dew point. It can be directly installed into pressurized systems with a maximum pressure of 20 bar (290 psia). It’s made to withstand tough conditions and features Vaisala’s DRYCAP® thin film polymer sensor and autocalibration software. For dry gases and desiccant dryers, the standard sensor choice is the DRYCAP® 180M, while for more humid environments like refrigeration dryers, the DRYCAP® 180S is recommended. These sensors can handle getting wet, making the transmitter ideal for applications with occasional water spikes, such as pipeline condensation during system failures or start-ups. They’re also resistant to particulate contamination, oil vapor, and most chemicals, and they’re not affected by flow rate changes.

Due to its wide measurement range and excellent long-term stability, Vaisala DRYCAP® Dew Point Transmitter DMT143L is an ideal choice for low dew point industrial applications, such as compressed air dryers, plastic dryers, and other OEM applications.


Key Benefits

Convenient size

Miniature size dew point probes for e.g. small industrial dryer applications.

Low maintenance costs

Stable measurement enables long calibration intervals saving maintenance costs.

Easy to use

Analog output options, easy servicing and data transfer. Compatible with handheld meter DM70.

Long Calibration Interval

The DMT143L needs calibration every two years. Also, the Vaisala DRYCAP Handheld Dew Point Meter DM70 can check the DMT143L’s performance without disconnecting it. For any adjustment needs, the transmitter can be sent to Vaisala Service. The auto-calibration software works online while the process is running. If the measurement accuracy is not confirmed, corrections are made automatically.

Easy Installation

Vaisala DMT143L has a variety of features to choose from, including different output and installation options, and alarm LED. Due to its small size and lightweight, Vaisala DMT143L 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 Windowsâ. Insight PC software can also be used for other configuration options (see


Measurement Performance
Sensors DRYCAP 180M
DRYCAP 180S (optimal for refrigeration dryers)
Sensor protection Stainless steel sintered filter
Stainless steel filter for vacuum
Recommended calibration interval to confirm the specified accuracy. 2 years
Measurement range (typical) -60 … +60 °C (-76 … +140 °F)
Different analog output scalings available. 1)
Accuracy with DRYCAP 180M ±2 °C (±3.6 °F) 2)
1) For more information, see the DMT143L Order Form.
2) When the dew point is below 0 °C (32 °F), the transmitter outputs frost point.
Dew Point Accuracy vs. Measurement Conditions
Response time 63 % [90 %] at +20 °C (+68 °F) gas temperature and 1 bar pressure and 1 liter/min flow rate:
-60 -20 °C Td (-76 -4 °F Td) 5 s [10 s] (typical)
-20 -60 °C Td (-4 -76 °F Td) 45 s [10 min] (typical)
Accuracy with DRYCAP 180S ±2 °C (±3.6 °F) 1) (see the graph below)
1) When the dew point is below 0 °C (32 °F), the transmitter outputs frost point
IP rating IP66
EMC compliance EN61326-1, industrial environment
Operating Environment
Temperature 0 … +60 °C (+32 … +140 °F)
Higher temperature peaks Short-term OK
Relative humidity 0 … 100 %RH
Pressure 0 … 20 bara (0 … 290 psia)
Sample flow rate No effect
Storage temperature -40 … +60 °C (-40 … +140 °F)
Inputs & Outputs
Analog current output 4 … 20 mA (3-wire)
Digital output RS-485, non-isolated
Supported protocols Vaisala industrial protocol Modbus RTU
Resolution for current output ±0.002 mA
Accuracy for current output at +20 °C ±0.05 mA
External load for current output Max. 500 Ω
Operating voltage with current output 18 … 28 VDC
Operating voltage with digital output 12 … 28 VDC
Typical temperature dependence 0.0008 mA/°C
Power consumption at 24 VDC Max. 220 mA
Mechanical Specifications
Mechanical connection G1/2″ ISO228-1 with bonded seal ring (U-seal) or NPT1/2″ thread
Housing material Stainless steel (AISI 316L)
G thread model 90 g (3.2 oz)
NPT thread model 100 g (3.5 oz)


Vaisala DMT143L (Long) Miniature Dew Point Transmitters_DpstarGroup