Mode of operation

Humidity and flow are monitored by measuring temperature gradients along the cable in a media. In most cases a heated sensor cable is used to achieve an adequate temperature difference between wet and dry sections of the cable. This shortcoming can be remedied by artificially heating the sensor.

Langes Bewässerungssystem auf einem abgeernteten Feld unter einem dramatischen Wolkenhimmel, genutzt zur Feuchtigkeitskontrolle in der Landwirtschaft.

Heated sensor cables have a hybrid construction of a glass fiber sensor combined with a copper or metallic wire heating element. Combined with an external heating source, the wires temporarily raise the cable temperature. Depending on the cross-section design, sensor cables can be optimized for a variety of humidity and flow applications over short of long distances.

Humidity can be measured either in the warm-up or cool-down phases as more humid sections dissipate heat more quickly than dry sections, sensor cables will warm more slowly in these locations. In the case of cooling humid areas will cool more quickly.

With optimization of the heated cable design over its length, sensing distances up to 2’500m can be achieved.

For the most demanding applications over extended distances a combination of electronic and optical switches can be utilized. These must be carefully designed for proper performance.


  • Measurement and Heating: Hybrid cables for measurement and heating all in one

  • Special design: Special designs available to optimize insert length

  • Determination of sediment level: Heated cables can also be used for sediment level determination

Your contact person

Andrea Fasciati
Director Sales

Application Examples

Natural Reservoirs and Sediment Ponds

Moisture and seepage are a threat for levees and reservoirs. They must be detected both at their origin under the geomembrane as within the levee, rather than when they become apparent as a leak. Continuous monitoring of the ground liner’s integrity for ponds containing dangerous chemical agents is critical in order to avoid contamination of groundwater.

Installed Products:

Farming and Agriculture

Climate change is causing large agricultural areas to become hotter and dryer. This has prompted farmers to be more cautious with their use of water resources. Solifos’ distributed fiber optic sensors enable intelligent sprinkler systems to deliver water only when and where it is needed.

Installed Products:

Smart Cities

Smart Cities are proliferating around the globe. City managers strive to provide a high quality of life in urban centers including green areas for recreation and leisure, even in arid regions like the Middle East and southern Europe. Solifos’ sensing cables are used with smart systems to ensure urban plants receive just the water they need to remain green and vital. Smart cities also require intelligent monitoring of their district heating and cooling systems, where Solifos’ cables are once again used for distributed monitoring and control.

Installed Products:




Distributed fiber optic temperature sensor cable with metal loose tube, steel wire armouring and copper conductor for actively heated fiber optic measurements



Distributed fiber optic temperature sensor cable with metal loose tube, steel wire armouring and a PA outer sheath