Differential inductive displacement sensor with integrated electronics and infrared communication capabilities

Differential inductive displacement sensors are widely used in hydraulic applications because they offer good accuracy, large displacement range (up to 200mm) and have a rugged construction. Displacement information is usually extracted with analog electronics techniques - sinusoidal excitation of coils, quadrate modulation and synchronous demodulation but this method is not well suited for implementation in digital embedded systems. Using a novel method for displacement measurement, based on switching voltages applied to the coils of the inductive device, the displacement sensor can be implemented with a standard microcontroller with integrated analog to digital converter and timer. Commissioning, configuring and data communication can be performed using standard serial interface. To avoid wires and cables, an infrared communication based on a standard IrDA transceiver module can be implemented. Presented paper focuses on measurement and construction aspects of an inductive displacement sensor with infrared communication interface option implemented and tested by authors.