Implementation of Data Acquisition System Using 89C2051

A type of MCUs, integrated with a precision analog comparator, provides the condition with which inexpensive DAQs can be made without using a special ADC. A scheme of inexpensive DAQs using a 89c2051 is presented. Two formulas of the time constant, parameters of the R-C circuit are deduced, using percentage expression and n-bits expression of resolution of ADC. The advantage of using assembler language to program a stand-alone DAQ is explained. And also, a distributed DAQ scheme is included. Both stand-alone and distributed projects were tested. Theory and experiment results in this paper have important reference value.