Interfacing to Sensors
Anton F P. van Putten · 2019
This chapter discusses aspects of interfacing related to sensors. For interfacing sensors a distinction must be made between self-generating and modulating transducers. The chapter considers the most common possibilities for implementing sensor elements in a bridge configuration. Suppose the sensor elements are strain-sensitive elements and one strain gauge element is subjected to strain and the other to stress; then the output voltage will change sign when strain and stress are reversed for the two strain gauges. Autozeroing in a transducer differs from autozeroing for pure electronics. A physical reference signal is needed which must be connected to the input at the right time. The circuit also provides a constant operational temperature and consequently constant sensor parameters are guaranteed. Also AC powering is used, or a kind of pulse mode powering, offering some other advantages with respect to drift sensitivity and format of output signal.