2. Product Overview
2.1 Introduction to DMT143
Vaisala DRYCAPâ Dew Point Transmitter DMT143 is a small and lightweight dew point
transmitter suitable for a wide range of OEM applications. DMT143 is easy to install and the
mechanics have been designed for harsh environments requiring protection against dust, dirt
and splashed water.
There are 2 variants of the DMT143 transmitter, DMT143 and DMT143L. DMT143 and DMT143L
oer dierent sensor, installation and output options to meet the requirements of varying dew
point measurement applications.
• DMT143 with DRYCAPâ 180D sensor
• either G1/2” ISO228/1 or NPT1/2” mechanical connection
• measurement range -70 ... +60 °C (-94 ... +140 °F)
• operating pressure up to 50 bar
a 
(725 psi
a
)
•
voltage (V) or current (mA) analog output 
1)
• RS-485 digital output with Modbus RTU support
• DMT143L with DRYCAPâ 180M sensor
• G1/2” ISO228/1 mechanical connection
• measurement range -70 ... + 60 °C° (-94 ... +140 °F)
• operating pressure 0 ... 20 bar
a
 (0 ... 290 psi
a
)
•
current (mA) analog output 
1)
• RS-485 digital output with Modbus RTU support
• DMT143L with DRYCAPâ 180S sensor
• G1/2” ISO228/1 mechanical connection
• measurement range -50 ... + 60 °C° (-58 ... +140 °F)
• operating pressure 0 ... 20 bar
a
 (0 ... 290 psi
a
)
• current (mA) analog output 
1)
• RS-485 digital output with Modbus RTU support
The accuracies of the dierent sensors used in DMT143 and DMT143L have been optimized for
dierent parts of the sensors’ measurement ranges.
DMT143 transmitters use the Vaisala DRYCAPâ polymer sensor for dew point measurement.
DRYCAPâ technology has low maintenance needs due to its excellent long term stability and
durability against condensation. The calibration interval of DMT143 transmitters is 2 years.
Table 3 Output Parameters of the DMT143
Parameter Abbreviation Metric Unit Non-Metric Unit
Dew point/frost point temperature T
d/f
°C °F
Dew point/frost point temperature,
converted to atmospheric pressure
T
d/f
atm °C °F
1) The analog output is not available in devices ordered with digital output only.
Chapter 2 – Product Overview
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