Spiral is a sensor targeted at applications where characteristics such as high accuracy and resolution, absolute position, long life and environmental robustness add value to a vehicle system.
This non-contact sensor is based on magnetic induction and pulse echo resonant coupling with ratiometric, phasor based decoding! The technology can be used with much larger air gaps than are possible with Hall or VR devices.
The sensor is robust to air gap variations during position measurement, which results in less position error. The large air gap capability allows the components to be individually encapsulated and mounted on an automobile as two separate components.
Spiral consists of a sensing track and a small, lightweight, passive target. The name `spiral’ comes from the appearance of the traces on the sensor board. They are overlapping sine waves that spiral across a PCB. The target is a standalone device that does not require leads or bearing surfaces.
The sensor track determines the position of the target in a linear or rotary system using phase based processing methods. An electromagnetic field is coupled to the resonator which is mounted to a moving device. The resonator then creates its own magnetic field, reflecting the coupled energy onto the sensor traces on the sensor track board. This reflected energy creates varying voltage waveforms on the sensor traces that can be processed and interpreted into a precise position measurement.
Invensys Sensor Systems; www.invensyssensors.com
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