Having to interface an analog transducer to a digital control system through an analog-to-digital converter represents an expensive bottleneck in the development of many systems. Some transducer companies are addressing this problem by developing proprietary families of resonant transducers. Resonant transducers are oscillators whose frequency depends in some known way on the physical property being measured. The electrical output from these devices is a train of rectangular pulses whose repetition rate encodes the value of the measurand. Changes in the measurand cause the frequency to shift. The microcontroller detects the frequency shift, runs a validity check on it, and converts it in software to the measurand value. This paper discusses software interfacing techniques between resonant transducers and the 8051. Techniques for measuring frequency and period are discussed and compared for resolution and interrogation time. The 8051 is capable of performing these tasks in extremely short CPU time. Requirements for obtaining n-bit resolution in the measurement are discussed. It is determined that it is always faster to evaluate the measurand to a given level of resolution by measuring the period rather than the frequency, even if the measurand is proportional to the frequency rather than to the period. Numerical and software examples are presented to illustrate the concepts.


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    Title :

    Using the 8051 microcontroller with resonant transducers


    Additional title:

    Verwendung des 8051-Mikrocontrollers in Verbindung mit Messwandlern, bei denen auf eine A/D-Umsetzung verzichtet werden kann


    Contributors:

    Published in:

    Publication date :

    1985


    Size :

    5 Seiten, 1 Bild, 1 Quelle



    Type of media :

    Article (Journal)


    Type of material :

    Print


    Language :

    English