Keywords
Citation
(1998), "Self-calibrating Hall-effect gear-tooth sensors offer ease of installation", Sensor Review, Vol. 18 No. 3. https://doi.org/10.1108/sr.1998.08718cad.006
Publisher
:Emerald Group Publishing Limited
Copyright © 1998, MCB UP Limited
Self-calibrating Hall-effect gear-tooth sensors offer ease of installation
Self-calibrating Hall-effect gear-tooth sensors offer ease of installation
Keywords Allegro, Sensors
The ATS632 Series from Allegro MicroSystems is a range of magnetic gear-tooth sensor assemblies which provide extremely accurate tooth-edge detection when used with large-pitch targets (see Plate 5).
The devices feature built-in self-calibration circuitry, and their non-oriented operation means that they can be easily installed in any plane and used with a variety of gear configurations.
Each sensor subassembly consists of a high temperature plastic shell that holds together a compound samarium cobalt magnet and a single-element self-calibrating Hall-effect IC that has been optimised to the magnetic circuit.
The Hall-effect device switches in response to absolute magnetic signals created by a ferrous target, with the digital output being low over a tooth and high over a valley.
Built-in processing circuitry includes self-calibrating six-bit A/D convertors that adapt the switching thresholds to the peak-to-peak signals to minimise the effects of variation in the application air gap on the switch-point timing accuracy.
The effects of system and device offsets are minimised by using active offset cancellation circuitry. The digital algorithm used provides zero-speed detection capabilities without the associated running jitter inherent in classical digital solutions.
The ATS632 Series claims to be ideal for gathering speed, position and profile information from ferrous targets in automotive and industrial applications. The devices are particularly suited to large tooth/valley sensing applications where high timing accuracy is required.
Plate 5 The ATS632 series of Hall-effect
gear-tooth sensors from Allegro MicroSystems
The devices are available in a cylindrical package for stand-alone mounting (ATS632LSC) or for PCB mounting (ATS632LSA).
For further information contact: Allegro MicroSystems Europe Ltd, Balfour House, Churchfield Road, Walton-on-Thames, Surrey KT12 2TD, UK. Tel: +44 (0) 1932 253355.