| 摘要 |
In order to carry out an automatic weighing, beam-scales are used provided with electromagnetic balancing (5, 6), substitution counterweight and digital display (11). An indicator (3) signals the position of the beam (1) to a microprocessor (4). The balancing is achieved through a limited number of distinct electromagnetic compensation forces, having a constant amplitude, which are generated by a corresponding number of constant currents of a discreet value. The values of the current are graded according to the decreasing powers of an appropriate base system of numbers, generally such as the decimal system in units and in powers of ten to these units. From upper power decades to lower power decades, and in each decade, the number of compensation force units required to overcompensate the charge (M) is counted. To this effect - without determining precisely the rest position of the beam - it is just a matter of checking for each compensation step whether the load (M) is higher or smaller than the compensation force. As soon as the indicator (3) signals an overcompensation, the preceding counting step is considered as the weighing result of the decade in question. At each compensation step of each decade, correction digital values are allocated. The weighing result proceeds from the sum of weighing results of all the decades plus the sum of the correction values which have been allocated to the compensation values measured in each decade. |
