Analysis of Mechanical and Electrical Noise Interfacing the Instrument During Data Acquisition for Measurement of Surface Properties of Textile Fibers

A new compression testing instrument was developed for the assessment of the surface properties of fibers. To measure the variation in compression force during a test, a full-bridge load cell was developed. It was seen that the signal coming from the strain gauges was superimposed with noise. The source of the noise was both electrical and mechanical. An extensive mathematical analysis of mechanical noise and the application of a mechanical noise-reduction technique minimized the mechanical noise component. An analysis of electrical noise showed that the motion control card was interfacing with the data acquisition (DAQ) card via both the RS232 and the ac power line. It was necessary to separate the motion control unit and the DAQ unit to eliminate the electrical noise problem present in the system. After eliminating the noise from the unit, the calibration of the strain gauges has been performed. The coefficient of correlation was found to be 1.00 with a cubic model. It was possible to differentiate the differences between the surface characteristics of different fibers.