Interrogator Reads Arrays of Strain Sensors
May 2008Technobis Fibre TechnologiesRequest Info
• four channels
• 19.3-kHz per sensor sampling frequency
Technobis Fibre Technologies BV has introduced a demultiplexing interrogator system named Deminsys for high-speed reading of multisensor arrays of fibre Bragg gratings (FBGs). The instrument measures strains to monitor the structural integrity of aircraft and ship hulls, wind-energy generators and civil engineering structures such as bridges and large buildings, providing early warning of hairline cracks.
The interrogator handles up to four optical channels, each typically having eight sensors. It has a maximum sampling frequency of 19.3 kHz per sensor with spectral spacing of 4 nm between sensors and wavelength-measuring accuracy of 2 pm. The standard spectral range is 830 to 870 nm, but others are available. The design is flexible, and it is possible to trade off sampling frequency and dynamic range against the number of FBGs per fibre. The self-calibrating capability allows the engineer on site to connect the interrogator by means of its FC/APC optical connectors to fibres permanently installed in the structure.
The instrument has an integrated microcontroller and data storage capacity as well as a Gigabit Ethernet interface. The user can store data for later transfer to a computer or can operate the device in continuous mode, in which the data streams to a PC for storage and display.
The interrogator measures 80 × 80 × 240 mm and weighs 800 g. It operates at temperatures from –20 to 50 °C and at humidity levels up to 80%. It consumes 14 W from a 12-VDC supply.