Roctest FOT-F & FOT-N Temperature Sensors

FOT-F and FOT-N temperature transducers combine all the desired characteristics expected from an ideal sensor. Their compact size, immunity to EMI/RFI/Lightning, resistance to corrosive environments, high accuracy and reliability make them the best choice for temperature measurements in harsh environments. Fiber-optic temperature gauges are based on the thermal expansion of highly stable glass allowing for precise, stable, and repeatable measurements.

The protection tube of the FOT-N is smaller in size than the FOT-F which comes equipped with an NPT stainless steel fitting. The FOT-F can be installed on vacuum and high pressure environments or high voltage applications whereas the FOT-N is mainly used for the embedment in concrete or in open air. Both models are fitted with the extrinsic Fabry-Perot fiber-optic transducers enclosed inside a protective stainless steel tube.

Readout units and data loggers are designed for civil engineering, R&D, industrial applications. Then have a built-in data logging capability for up to 50 000 measuring points. The fiber-optic lead cable can be up to several kilometers long.

Close block


  • Load and strain measurement in rock and soil anchors (stressing and bond zones)
  • Load and strain measurement in cable bolts used for rock support (tunnels, underground excavations, underground and open pit mine chambers)
  • Load and strain measurement in prestressed and post-tension concrete.


  • Intrinsically safe
  • Immune to EMI/ RFI/ Lightning
  • Resistance wire protected by Teflon sheath and further protected by being inserted into spiral grooves of cable
  • Safe in temperatures up to 250°C
  • High accuracy
  • Miniature and rugged sensor
  • Compatible with all of Roctest’s Fiber-optic readout units and data loggers