A self-validating digital Coriolis mass-flow meter

A first generation self-validating sensor (SEVA) prototype based on the Coriolis meter consisted of the flowtube and conventional commercial transmitter with a PC. The PC and the modified transmitter together exemplified how a SEVA device would behave. The prototype demonstrated an ability to detect and correct for several fault modes, as well as the generation of SEVA metrics. However, one benefit of carrying out a sensor validation analysis is that it leads to fundamental redesign. The identification of the major limitations and fault modes of an instrument, and their impact on measurement quality, provides strong motivation for improvements in the basic design. The idea of an all-digital transmitter design emerged after this first round of validation activity. The primary intention was to replace all the analogue circuitry (other than essential front-end op-amps) with a small number of digital components, and to carry out almost all functionality within software. This paper describes aspects of the improved performance obtained from the digital transmitter: measurement precision, flowtube control, two-phase flow and batching from empty