A FPGA-based General Purpose Multi-Sensor Data Acquisition System with Nonlinear Sensor Characteristic and Environment Compensation

In this paper a general purpose multi-sensor data acquisition module with broadcasting capabilities and a field programmable logic array (FPGA) at its core is presented. The system, through its FPGA core, has the ability to directly measure sensor impedance and implements a 4^th-order multivariable polynomial regression (MPR) to model and compensate both each sensor nonlinear characteristic and the influence of the environment, monitored through other connected sensors. An application is shown of a magnetic field transducer with temperature compensation. The sensing element is a magnetoresistance with a nonlinear characteristic of 4% of full scale whose value can vary almost 25% in the experimental operating temperature range (-25degC to 125degC) and a two terminal semiconductor temperature sensor. The application is well adapted to conveniently model strongly non-linear transducer characteristics as it leads to an improvement of magnetic transducer's accuracy from 25% to well above 1%