A Method of Improving the Precision of Analog-to-Digital Conversion of Analog Acquisition Device

Abstract

The invention belongs to the technical field of analog-to-digital conversion, and particularly relates to a method for improving analog-to-digital conversion accuracy of an analog quantity collection device. The method includes that Vref in a calculation formula Va=Vd*Vref / (2n-1) is taken as a variable, actual reference voltage Vref is measured by an independent voltage measuring device, and the reference voltage Vref acquired through actual measuring is transmitted by an upper computer into the calculation formula for calculation through a communication port of the upper computer. The method has the advantages that measuring of the Vref is realized by the independent voltage measuring device, accuracy of the Vref in the calculation formula depends on the independent voltage measuring device, accuracy of the voltage measuring device can reach 1mv or more according to actual application occasions, and requirements on ADC accuracy of 12 bits and above can be met, so that analog-to-digital conversion accuracy of the collection device is greatly improved, and adopting of an expensive high-accuracy power source to reach high accuracy of the Vref is avoided. The method is simple in step and low in cost.

Description

technical field [0001] The invention belongs to the technical field of analog-to-digital conversion, and in particular relates to a method for improving the precision of analog-to-digital conversion of an analog quantity acquisition device. Background technique [0002] In the field of control, it is necessary to collect various analog quantities, such as voltage, current, temperature, humidity, etc. For the convenience of data analysis, a single-chip microcomputer is generally used to process the data in real time. For various analog quantities, for the convenience of processing, after conversion by various circuits, they are finally expressed as voltage quantities, which are sampled, quantized, and encoded by ADC (Analog-to-Digital Converter), and converted into binary form, so that the single-chip microcomputer For data identification and processing. [0003] The digital quantity formed after the ADC conversion is completed is: [0004] Vd=Vin / Vref*(2 n -1) (1) [000...

AI Technical Summary

Problems solved by technology

[0011] The existing problem is: according to the principle of ADC, in the process of ADC conversion, the actual voltage to be converted and the reference voltage (Vref) are binary sequences obtained after successive comparisons, and Vref in formula (1) is the actual The reference voltage, while the Vref in equation (2) 理 is the theoretical value of the actual reference voltage, which can be understood as a constant

But in fact, a power supply with an accuracy of more than 0.5% is more expensive, and a power supply with an accuracy of more than 0.1% is more difficult to obtain. In the field of ordinary ADCs, it is sensitive to cost and difficult to promote.

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