Measuring the CO (NO) concentration

         It is important to ensure that the gas concentrations in the tunnel do not exceed the defined limits. So to provide a continuous measurement of the CO (NO) concentration in the tunnel air, the VISIC100SF tunnel sensor is also equipped with electrochemical sensors. These electrochemical sensors meet the requirements of EN 50545. When it comes to measurement quality and maintenance complexity, they are on a par with infrared measuring systems.

  • Visibility (K value) measured according to the scattered light measurement principle
  • CO and NO concentration measured using electrochemical sensors in accordance with EN 50545
  • Software developed in accordance with EN 61508 (SIL1)
  • Highly reliable – no moving parts
  • Combines visibility measurement with two different gas measurements
  • IP 6K9K enclosure rating thanks to a rugged stainless-steel housing
  • Fog compensation through integrated heating (option)


Making traffic routes more efficient, safer, and environmentally friendly