Time-domain measurement methods for R, L and C sensors based on aversatile direct sensor-to-microcontroller interface circuit
tIn the paper new time-domain measurement methods for determining values of resistive (R), inductive(L) and capacitive (C) sensors based on a versatile direct sensor-to-microcontroller interface for microcon-trollers with internal analog-to-digital converters (ADCs) and analog comparators (ACs) are presented.The interface circuit consists of a reference resistor Rrworking as a voltage divider, a given R, L or C sensorand a microcontroller (its peripherals: an ADC, an AC, a timer, I/O pins buffered by an inverter). A pro-totype of the proposed complete solution of a compact smart sensor based on an 8-bit microcontrollerhas been developed and tested. The maximum possible relative inaccuracy of an indirectly measurableresistance, inductance and capacitance were analysed. Also, experimental researches were made. Thefollowing relative errors of the sensor value determination were achieved: for the R sensor less than 3%,as well as very good results for the L sensor (less than 0.3%) and for the C sensor (less than 0.2%).
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