Gear-tooth sensor module is self-calibrating

Citation

(1998), "Gear-tooth sensor module is self-calibrating", Sensor Review, Vol. 18 No. 4. https://doi.org/10.1108/sr.1998.08718dad.008

Gear-tooth sensor module is self-calibrating

Gear-tooth sensor module is self-calibrating

Keyword Magnetic (Hall effect)

The new ATS612 dynamically coupled gear-tooth sensor from Allegro MicroSystems is a peak-detecting device that uses gain control to provide extremely accurate gear edge detection down to low operating speeds (see Plate 5).

Each sensor subassembly consists of a plastic shell which houses a samarium cobalt magnet, a pole piece and a dynamically coupled differential open-collector Hall-effect integrated circuit that has been optimised to the magnetic circuit.

The small mechanical size ­ 9mm in diameter x 7mm in length ­ means that the device can be easily assembled and used in conjunction with a wide variety of gear shapes and sizes.

Plate 5 The ATS612 dynamically coupled gear-tooth sensor module from Allegro MicroSystems

The sensor incorporates a dual-element Hall integrated circuit which switches in response to differential magnetic signals created by ferrous targets. The processing circuitry contains a self-calibrating 5-bit A/D/A/convertor which normalises the internal gain of the device to minimise the effect of air-gap variations.

A patented peak-detecting filter circuit eliminates magnet and system offsets, and allows the device to compensate for relatively fast changes caused by tilt, gear wobble or eccentricities, while still providing stable operation at very low speed.

The sensor module is ideal for gathering speed, position and timing information in automotive and industrial applications. It is particularly suited to automotive crankshaft applications and other areas which require extremely accurate duty-cycle control or accurate edge detection.

For further information contact Allegro MicroSystems Europe Ltd, Balfour House, Churchfield Road, Walton-on-Thames, Surrey KT12 2TD, UK. Tel: +44 (0)1932 253355; Fax: +44 (0)1932 246622; www.allegromicro.com