A low-cost and high-precision resistance measurement system and its measurement method

Abstract

A low-cost and high-precision resistance measurement system and its measurement method, including a current source, a multi-channel linkage switch, a voltage measurement circuit, a processor, and a display module. The processor switches the input resistance through the multi-channel linkage switch to a standard resistance R1 in sequence , R2, read the output of the voltage measurement circuit, and substitute into the transmission equation to solve, then switch the input to measure the resistance, obtain the value of the measurement resistance according to the transmission equation and the voltage measurement circuit output voltage; in the present invention, only the linearity of the voltage measurement circuit The error is small enough, and the error of the measured resistance is only related to the standard resistance, which theoretically eliminates the errors caused by the current source and voltage measurement circuits, such as differential processing circuits, A / D converters, etc. The low-cost current source and voltage measurement circuit can realize the purpose of measuring resistance with high precision; the standard resistance in the present invention must be used in the precision current source of conventional resistance measurement circuit, and no need to increase the cost.

Description

technical field [0001] The present invention relates to a measurement method, especially a system and method for calibrating and measuring resistance according to the standard resistance of the input terminal by using an online calibration method, specifically a low-cost and high-precision resistance measurement method and a device using the method measuring system. [0002] Background technique [0003] At present, many sensors (such as thermistors) used to measure physical quantities convert the signal to be measured into a resistance signal, and then obtain the actual value of the measured physical quantity by measuring the resistance signal; therefore, the accuracy of the measurement of the resistance signal The accuracy directly determines the accuracy of the measured physical value. [0004] The traditional measurement method is to add a known current to the resistance signal output by the sensor, then measure the voltage value at both ends, calculate the resistance ...

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Problems solved by technology

[0006] The purpose of the present invention is to aim at the instrument in the process of measuring the physical quantity, in order to improve the measurement accuracy of the resistance, it is necessary to use an expensive, high-precision, low-temperature drift current source and voltage measurement circuit, and even so the problem that the error cannot be completely eliminated , a low-cost high-precision resistance measurement system and its measurement method are proposed; specifically, the on-line calibration method is used to calibrate the measurement resistance according to the standard resistance at the input end, which completely eliminates the problems introduced by the current source and voltage measurement circuit in theory. Error, in order to achieve the purpose of high-precision measurement with low-cost circuits

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