This paper presents a novel digital converter for a contactless displacement transducer. The sensor part of the proposed transducer employs a floating (contactless) wiper that moves over a resistive element. A novel signal-conditioning circuit presented here operates on the contactless resistive potentiometer element and provides a digital output that linearly varies with the position of the wiper. The signal-conditioning circuit is developed such that the digital output is independent of the coupling capacitor that arises between the floating wiper and the resistive element, thus eliminating the effect of any jitter that may arise in the movement of the wiper. Results from a prototype circuit built and tested using a prototype sensor establish the efficacy of the proffered scheme. © 2015 IEEE.

Boby George

Department of Electrical Engineering

Varadarajan Jagadeesh Kumar

Supriya Vilanguppam Thathachary

Frequency converters

Potentiometers (electric measuring instruments)

Potentiometers (resistors)

signal processing

strain measurement

transducers

Voltage dividers

Contactless measurement

DIGITAL POTENTIOMETER

DUAL-SLOPE TECHNIQUE

POTENTIOMETRIC

VOLTAGE CONVERSION

Signal conditioning circuits

IIT Madras is a public technical and research university located in Chennai, Tamil Nadu. Founded in 1959, it is recognised as an Institute of National Importance.

IIT Madras has been ranked as the top engineering institute in India for four years in a row by the National Institutional Ranking Framework of the MHRD

It currently offers undergraduate, postgraduate and research degrees across 16 disciplines in Engineering, Sciences, Humanities and Management. About 596 faculty belonging to science and engineering departments and centres of the Institute are engaged in teaching, research and industrial consultancy.

IIT Madras

Digital Converter for a Contactless Displacement Sensor

IEEE Transactions on Instrumentation and Measurement

The limited operating life of conventional resistive displacement sensor is due to wear and tear because the wiper has to rub against the resistive element during operation. This problem can be eliminated by using a floating wiper. However, the absence of electrical contact between the wiper and the resistive element demands the use of complex signal conditioning circuitry to obtain an output proportional to displacement. We now propose a simple self-balancing signal conditioning circuit suitable for a floating wiper resistive displacement sensor that provides an output linear to the displacement. The proposed signal conditioning circuit employs only a single dc reference voltage and provides an output that is independent of the coupling capacitance that arises between the floating wiper and the resistive element. Hence, errors due to mismatch between reference voltages and variations in the coupling capacitance are completely eliminated. The results obtained from simulation studies and the tests conducted on a prototype built, establish the efficacy of the proposed method. Analysis of the proposed scheme presented here establishes the ground rules for avoiding pitfalls in the design stage itself. © 2001-2012 IEEE.

IEEE Sensors Journal

Self-balancing signal conditioning circuit for a floating-wiper resistive displacement sensor

A non-contact inductive voltage divider (IVD) type displacement transducer that directly provides a digital output proportional to the displacement of the non-contact (floating) wiper is presented here. The floating wiper IVD becomes an integral part of a suitably modified dual slope type digital converter (DSDC) and the logic of conversion ensures that the digital output of the DSDC is not affected by the changes in the distance between the floating wiper and the inductive element. Simulation and emulation studies have been carried out to establish the feasibility and functionality of the proposed method. Experimentation on a prototype non-contact inductive angular displacement sensor built in the laboratory further corroborates the efficacy of the proffered technique. © 2017 IEEE.

I2MTC 2017 - 2017 IEEE International Instrumentation and Measurement Technology Conference, Proceedings

Non-contact inductive displacement-to-digital converter

A sigma-delta-type digital converter (SDC) suitable for a resistive-potentiometer-type displacement sensor with a floating slide is presented here. The delta modulator in a conventional SDC is suitably altered to incorporate, as its integral part, a resistive-potentiometer-type displacement sensor with a floating slide. The operation of the 1-b quantizer in the SDC is modified such that the digital output of the SDC directly indicates the displacement being sensed. The results obtained from simulation studies, emulation studies, and experimentation conducted on a prototype sensor establish the efficacy of the proffered scheme. © 2016 IEEE.

Sigma-Delta Digital Converter Suitable for a Resistive Displacement Sensor with a Floating Slide

Though conventional potentiometric type resistive transducers are simple to construct and use, they are not popular owing only to the fact that a sliding contact needs to be employed. In this paper, a potentiometric type resistive displacement transducer that uses a contactless slide is presented. A dedicated signal conditioning circuit proposed here operates on the output of a slide that moves, without having a physical contact, on the resistive element and provides an output voltage directly proportional to the quantity being sensed (displacement or velocity). Since the output of the circuit is dependent only on a dc reference voltage and the measurand, an acceptable level of accuracy can be obtained with ease. Results of simulation studies and experimentation establish the efficacy of the proposed scheme. © 2013 IEEE.

Proceedings of the International Conference on Sensing Technology, ICST

A resistive potentiometric type transducer with contactless slide

A linear variable differential capacitive transducer for the measurement of planar angles (from 0° to 360°) is presented in this paper. The sensor part of the transducer is made of parallel plates of standard and easy-to-fabricate shapes, and the signal-conditioning electronics are realized, employing a couple of simple relaxation oscillators. The output of the transducer is only dictated by a pair of dc reference voltages, and hence, high accuracy and linearity over the entire range (from 0° to 360° are easily obtained by the use of precision dc reference voltages. Detailed analysis indicates that the sensitivity of the transducer is minimal for variations in different parameters. Experimental results obtained on a prototype transducer that has been built and tested establish the efficacy of the proposed transducer. The worst-case error of the prototype transducer is found to be less than 0.1%. © 2008 IEEE.

A linear variable differential capacitive transducer for sensing planar angles

A novel switched capacitor signal-conditioning circuit for differential capacitive sensors is proposed. The main advantage of the proffered method lies in the fact that it accepts sensors possessing either linear or inverse characteristics and provides a linear output. Moreover, the output is dependent only on a pair of dc reference voltages and the transformation constant of the sensor. Hence, increased linearity and accuracy is easily achieved by employing precision dc reference voltages. Results from the tests on a prototype elucidate the practicality of the proposed method. © 2007 IEEE.

Switched capacitor signal conditioning for differential capacitive sensors

i-manager's Journal on Power Systems Engineering

Computation of Available Transfer Capability in Electrical Transmission System - A Review

Measurement of Local Chest Wall Displacement by a Custom Self-Mixing Laser Interferometer

Journal	Data powered by TypesetIEEE Transactions on Instrumentation and Measurement
Publisher	Data powered by TypesetInstitute of Electrical and Electronics Engineers Inc.
ISSN	00189456
Open Access	No