FES Sensor Technology Gassensoren Hydrogen-Sensor H2-CNI 4-20mA-I & H2-CNI 4-20mA-I ULTD

H2-CNI 4-20mA-I and H2-CNI 4-20mA-I ULTD are four-pin calorimetric hydrogen sensors with a catalytically highly active and siloxaneresistant sensor element and is based on a nonisothermal calorimetric operation principle. The sensor contains on-board electronics to reduce the effect of ambient temperature changes on hydrogen sensitivity, featuring a secure 4-20 mA current interface. It is designed for use in a variety of applications which require an accurate hydrogen determination in air.


  • Accurate detection of hydrogen levels up to 100% LEL with 100 ppm resolution in air
  • Negligible sensitivity against typical catalyst poisons such as volatile siloxanes and carbon monoxide
  • Fast response and recovery times
  • Negligible humidity-induced base line drift
  • Applicable in relative humidity (rh) between 0 % to 100 %
  • Industrial temperature range -40 °C to +80 °C
  • Linear output up to 100 % LEL
  • Available with ultra-low thermal drift (ULTD) and test protocol
  • 4-20 mA current-loop transmitter with reverse voltage operation and over-voltage surge protection
  • Supply voltage with reversed bias protection

Documents & downloads

Specification Sheet H2-CNI 4-20mA-I and -I ULTD Rev. 1.0
Christian Kallen
Christian Kallen
Account Manager
cka@alders.de +49 2152 8955-230