Alliance Sensors. Variable inductance position sensors, known as LVITs (Linear Variable Inductance Transducers), have been around for several decades. Recent advancements in electronics and flexibility of package designs have made LVIT variable inductance sensors cost effective for mainstream in-cylinder applications. This contactless technology offers many significant advantages regarding product life and long-term reliability over some competitive technologies, and competes very favorably in performance with all competitors for specifications such as non-linearity, resolution, and frequency response, but at a significantly lower cost.
Equally important is the fact that LVIT sensors can typically withstand greater shocks and vibration, such as those commonly found in heavy industrial and mobile equipment applications for cylinders. Linear variable inductance sensors operate by measuring the resonant frequency of an oscillator that uses a simple inductive probe. Its inductance is varied by the position of a conductive tube or gun-drilled rod that surrounds it. LVITs are typically offered in full-scale ranges from 4 inches (100 mm) to 36 inches (900 mm). Both port-mounted and internally embedded packages are available, with either connector or cable terminations. These sensors produce an analog DC voltage or current output, with a digital output available for OEM applications.