Fabless sensing chip firm CambridgeIC is providing the technology behind Turck's latest angle sensor family, its Ri Series.
'Resonant inductive position sensing' is CambridgeIC's fundamental technology, which is implemented inside its chip, the CAM204 - announced at Electronica late last year.
The sensor element is a PCB with tracks defining three coils - one for excitation, and two sensor coils which connect to the chip.
This measures displacement or angle compared with a moving target, which consists of a passive LC resonant circuit - a ferrite-cored coil connected to a capacitor, for example.
"The technology is a high-tech version of the older resolver, synchro and RVDT technologies," said CambridgeIC. "A coil and capacitor form a simple electrical resonator which replaces the stator. Using a resonant circuit means large signal levels even at big gaps, so that the sensor can be housed behind a thick plastic housing."
Compared with sensors that detect a magnet's angle using Hall effect or magnetoresistive sensor elements, claims the firm, its system is tolerant of magnetic fields experienced near drives, motors and electrical welders. And no alignment bearings are required because the technology is tolerant of some misalignment.
"We sold magnetostrictive linear position sensors for years and have seen a lot of disadvantages in many industrial applications," said Oliver Marks, v-p of automation systems at Germany-based Turck. "We looked for different technologies in the market and investigated different suppliers. We found out that resonant inductive position sensing fits perfectly due to environmental immunity against magnetic fields and ferromagnetic materials, and because of its flexibility."
Typical applications for the angle sensors are in wind turbines, solar panel position feedback, vehicle assembly plants and industrial process control.
CAM204 IC also works with linear sensors, and can process up to four sensors.
Turck's actually already uses the 204 inside its Li Series of linear sensors for measurements up to 1m.