Between parallel mirrors — An electronic weighing instrument

The paper presents the assessment way of electronic weighing instruments according to their use. Thus, in mass measurements there are two ways to use a weighing instrument: as a mass comparator, in the dissemination of mass unit from national mass standard to standards of the lowest accuracy and as a direct weighing instrument, a common balance, used in different applications. Even if, in term of constructive and functional points of view the two type of weighing instruments are not different, their use differs and hence, the need to approach different assessment methods. In the paper, it is highlighted the difference between determination of measurable properties by calibration, for both, mass comparators and a common balance (non-automatic weighing instruments-NAWI), making a parallel between them.