This paper describes the use of microcomputers for the acquisition and analysis of data in an experimental laboratory. Stanford University Petroleum Engineering Department uses several microcomputers in the laboratory for the collection of measurements during core displacement and flow model experiments. Since 1984 we have accumulated experience in the use of several data-acquisition systems including an 8-bit system and several different 12-bit systems.

The paper describes the way in which these systems have been used, and the way in which they performed. There was little difference in ease of application between the data acquisition boards, the principle differences lay in the technical capability of each system.

Two principle considerations in data acquisition are accuracy and frequency of measurement. It was impossible to obtain sufficient accuracy with the 8-bit board, and we have always used 12-bit boards ever since. Although the analog/digital converters are capable of very high frequencies of sampling, in practise the measurement rate is governed more by the CPU work involved in processing the data during the measurement process. Using programs in BASIC, we were able to achieve data rates of about 100 voltage measurement per second, including the time required to convert the voltage, write it to RAM-disk and graph the answers on the display. The data still required post-processing after the experiment. This post-processing and the subsequent analysis were all performed using the same microcomputer that acquired the data.

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