ADVANCES IN SELF-VALIDATING INSTRUMENTATION

摘要

This paper provides an overview into recent developments in self-validating sensors. This concept assumes the availability of internal computing power for self-diagnostics, and of digital communications to convey measurement and diagnostic data. A generic set of metrics are proposed for describing measurement quality, including online uncertainty. A SEVA instrument, based on the Coriolis mass flow meter is described; its ability to detect and compensate for the effects of two-phase flow has been implemented in a commercial meter. SEVA has been incorporated into a British Standard, which is currently being extended. Other related standardisation efforts include work by the European user organisations WIB and NAMUR, who are collaborating on an initiative to develop a common framework for describing sensor diagnostics on-line. Comparison with the SEVA Coriolis meter show some of the limitations of the WIB approach. Recent theoretical developments in SEVA include a simple technique for combining the outputs of redundant SEVA sensors for consistency checking and the calculation of a combined best estimate.