System for electromotive force standards comparison based on virtual instrument

This paper presents the design and implementation of a virtual instrument (VI) based automated measuring system for electromotive force (EMF) standards comparisons. The VI is designed in the graphical programming language LabVIEW and enables fast and reliable measurement functions, including data acquisition, real-time graphical display, statistical processing, measurement result archiving, and database management. The VI provides low-cost, efficient, and user-friendly comparisons of EMF standards. The emphasis is given to the system optimization in order to minimize measurement uncertainty, and measurement time consumption. Particular attention was paid to the uncertainty consideration on the part of the measurement system itself. Regular application of the automated system for EMF standard cell comparisons accelerated the measurement procedure by more than ten times, and improved significantly the whole measurement process, compared with the previously used one. In addition, type A standard uncertainty is reduced by more than ten times. The Type B standard uncertainty of the EMF standard is estimated.