• Automatic dew point measurement instrument
  • High measuring certainty and accuracy
  • Internal sample pump
  • Robust construction and easy handling


The automatic dew point measurement instrument Dewchecker 3.1 is a portable device used for measuring the dew point temperature of gases.

Per definition, the dew point is the temperature of a body at which the water vapors start to condensate on its surface, respectively the balance adjusted between condensing and evaporating water. The level of the dew point depends on the moistness of the measuring gas. Due to the direct measurement of the dew point temperature, the measurement is accurate and long-term stable. With this device, it is possible to measure dew point temperatures lower than the ambient temperature. Moreover, the device itself requires very low maintenance.

Dewchecker 3.1 measures the dew point value completely automatically. A beam of light, from the emitting diode, is aimed at the mirror’s surface and a photodetector monitors the reflected light. The Mirror is constructed from a material with good thermal conductivity and it is cooled down by using a thermoelectric cooler until the condensation begins. As the amount of reflected light decreases, due to the absorption, the photodetector output decreases also. An internal control system monitors the mirror’s temperature at the dew point level over reflected photodetector voltage.

The device is available for either 230 V or 115 V supply voltage.



Design: Portable steel housing
Dimensions: 330x310x320 mm (WxHxD)
Weight: Approx. 17 kg
Degree of Protection: Housing IP 20 according to IEC 60529
Front panel IP 40 according to IEC 60529
Power Supply: 230 or 115 VAC ±10% 50…60 Hz (please specify)
Measuring Range:: -25…+30°C (direkte Messung mit Spiegel)
Measuring Gas Connectors (hose connectors): Input: Tube outer diameter 5…6 mm
Output: Tube outer diameter 5…6 mm
Built-in measuring pump
Measuring Gas Pressure: ±50 mbar
Digital Output: Relay 1; 5A/250V Indication of good measurement result
Analog Output: –25…+25 °C , 0…20 mA or 4…20 mA or 0…10 V
galvanic isolated, 4…20 mA is predefined setting
Humidity: Up to 70 %, non-condensing
Ambient Temperature: 10…40 °C during operation
0…50 °C during storage
Gas Flow: Approx. 1l/min.
Resolution in steps of: 0,1°C
Maintenance Interval: Every year
Communication: Either RS-485 / RS-422 four-wire or RS-485 two-wire (please specify)
Isolated interface with Modbus-protocol


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