JPS6431017A - Sensor controller - Google Patents

Abstract

PURPOSE:To reduce an error of measurement even for an input of a sensor having complicated characteristics, by identifying a section wherein an input from the sensor is found, and by conducting input conversion by means of scale straight lines corresponding to the identified section. CONSTITUTION:A sensor of a linear current output is connected to an amplifier circuit 16 amplifying an input signal from the sensor, and an output of the circuit 16 is subjected to A/D conversion 17 and read in an arithmetic circuit 18. The circuit 18 determines a scale straight lines for the respective sections of characteristic points, and based on these straight lines, it converts the input from the sensor and compares the conversion value with a discrimination value (target value Sp + or - deviation value Dev). An output circuit 20 outputs three kinds of signals in accordance with the result of comparison of the conversion value with the target value Sp in the circuit 18. When it is assumed that a sensor output has a characteristic shown by a curve in relation to a detected physical amount, the input conversion is conducted on the basis of a plurality of straight lines connecting the characteristic points. The characteristic curve of the output of the sensor is approximated by a plurality of scale straight lines, according to this constitution, and therefore an error from an actually detected physical amount can be made smaller than the result obtained from the conversion by using one scale straight line.