Measuring and determination device for calculating an output

Abstract

An electronic measuring device utilizes multiple different transducers for supplying signals exhibiting predetermined and typically nonlinear relationships to the multiple input variables sensed by the transducers. The measuring device includes a microcomputer containing stored linearizing information therein relating to the predetermined nonlinear relationship of the signals supplied by the transducers and the variables sensed by the transducers. The microcomputer linearizes each of the signals supplied by the transducers and thereby obtains highly accurate signals indicative of the variables sensed. Depending upon the ultimate determination to be obtained by the device, the linearized signals representative of the input variables may be employed in a polynomial equation calculation conducted by the computer to obtain the output determination. The polynomial equation includes a plurality of constants, and different values of the constants are stored in memory for various segments of the curve defined by the polynomial equation. The values of the constants also constitute stored linearizing information and the different values are available for use in the calculation to obtain the best accuracy of simulating the mathematical curve of the polynomial equation to the actual curve of the quantity under determination. The device is particularly useful as an electronic thermometer employing a thermocouple for measuring temperature and a thermistor for measuring the cold electrical connection junction of the thermocouple. The device is also advantageously used to measure density altitude, dew point and superheat temperature, among other things.