Signal conditioning of a resistive potentiometric displacement sensor with a floating slide

Resistive potentiometric type displacement sensors suffer wear and tear due to the sliding contact. The wear and tear can be reduced considerably by using a floating, contactless slide. The coupling capacitor that arises due to the use of a floating slide makes it difficult to obtain an output that linearly varies with the displacement. A signal conditioning circuit presented in this work operates on a resistive potentiometer type displacement sensor element with a floating slide and provides an output that is directly proportional to the displacement of the slide. Apart from the displacement, the output from the signal conditioning circuit depends only on a couple of dc reference voltages thus ensuring a good degree of accuracy and linearity. The results obtained from simulation studies and experimentation performed on a prototype unit built and tested establishes the efficacy of the proffered method.