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EP-4060296-B1 - WEIGHING APPARATUS

EP4060296B1EP 4060296 B1EP4060296 B1EP 4060296B1EP-4060296-B1

Inventors

  • TARUMOTO, Yoshinori
  • TAJIRI, SHOKO
  • HAYASHIDA, Kohei

Dates

Publication Date
20260506
Application Date
20220304

Claims (7)

  1. A weighing apparatus (1) comprising: a transport unit (2) capable of transporting an article (P); a weighing unit (4) connected to the transport unit (2), the weighing unit (4) being configured to: generate and output a first original signal for weighing the article (P) and a second original signal for adjusting a zero point, wherein the first and second original signals are generated while the transport unit is in operation, wherein the first original signal is generated while the article is completely disposed on the transport unit, and wherein the second original signal is generated while the article is not disposed on the transport unit; and a weighing control unit (21) configured to output a weighing value of the article (P) by processing the first original signal, wherein the weighing control unit (21) is configured: to determine whether or not to adjust a zero point on the basis of a determination signal obtained by applying a first filter to the second original signal, and wherein the weighing control unit (21) is configured to, in a case where the weighing control unit (21) determines that the zero point is to be adjusted: generate an adjustment signal obtained by applying a second filter having more stages than the first filter to the second original signal or the determination signal and perform adjustment of the zero point on the basis of the adjustment signal.
  2. The weighing apparatus (1) according to claim 1, Wherein, in a case where a peak included in the determination signal exceeds a predetermined threshold value, the weighing control unit (21) is configured: to determine that the zero point is not to be adjusted; and not to adjust the zero point until a predetermined time has elapsed from the determination.
  3. The weighing apparatus (1) according to claim 1 or 2, wherein, in a case where a peak included in the determination signal exceeds a predetermined threshold value, the weighing control unit (21) is configured: to determine that the zero point is not to be adjusted, and to generate another determination signal obtained by applying the first filter to another second original signal output after the determination signal is acquired.
  4. The weighing apparatus (1) according to claim 1, wherein the weighing control unit (21) is configured: to specify a generation timing of a peak exceeding a predetermined threshold value among peaks included in the determination signal, to delete data generated during a predetermined period including the generation timing from the adjustment signal, and to perform adjustment of the zero point on the basis of the adjustment signal from which the data has been deleted.
  5. The weighing apparatus (1) according to any one of claims 1 to 4, wherein the first filter does not include a low-pass filter.
  6. The weighing apparatus (1) according to any one of claims 1 to 5, wherein a time for applying the second filter to the second original signal is longer than a time for applying the first filter to the second original signal.
  7. The weighing apparatus (1) according to any one of claims 1 to 6, wherein at least one of the first filter and the second filter is configured by combining a plurality of digital filters.

Description

TECHNICAL FIELD The present disclosure relates to a weighing apparatus. BACKGROUND An example of a weighing apparatus is an apparatus that measures a weight of an article (an object to be weighed) conveyed by a transport conveyor. A weighing apparatus that includes a weighing means for outputting a weighing signal related to a weight of each of products sequentially loaded at a predetermined loading interval, a signal processing means for executing a filtering process in which a high frequency component is removed from the weighing signal with a first filter and a second filter having different filter characteristics from each other, and a weighing value calculating means for calculating a weighing value on the basis of the weighing signal subjected to the filtering process is disclosed in Japanese Patent No. 4781982. This weighing apparatus further has a zero point correction means and calculates a zero point which is a reference of the weighing value on the basis of the weighing signal subjected to the filtering process to correct its zero point. The filter to be used for the filtering process is selected according to the loading interval of the articles, and filtering conditions of the second filter are variably set according to the loading interval. In Japanese Patent No. 4781982, the filtering process for adjusting the zero point is surely executed for the weighing signal even at a short loading interval. JP 2016 156784 A discloses a transport measuring device which weighs articles transported at intervals while transporting them. JP 2016 133415 A discloses a weighing device which weighs articles conveyed at intervals while conveying them. SUMMARY In the weighing apparatus described in Japanese Patent No. 4781982, the filtering process is performed on the weighing signal for a period corresponding to the loading interval. In a case where the zero point is adjusted within such an interval or the like, in order to improve the adjustment accuracy of the zero point, it is conceivable to perform multi-stage filtering process if possible (that is, to perform the filtering process for as long as possible) on an original signal. Here, in general, the longer the filtering process, the lower a responsiveness to the original signal. Therefore, when sudden noise (for example, noise generated by a collision of an operator with the weighing apparatus, occurrence of an earthquake, or the like) is included in the original signal, the noise may also be used for adjusting the zero point. In this case, when adjustment of the zero point is performed, the adjusted zero point may actually deviate from a real zero point. An object of an aspect of the present disclosure is to provide a weighing apparatus capable of accurately performing adjustment of a zero point. A weighing apparatus according to an aspect of the present disclosure, as set out in appended claim 1, includes: a transport unit capable of transporting an article; a weighing unit connected to the transport unit, the weighing unit being configured to generate and output a first original signal for weighing the article and a second original signal for adjusting a zero point; and a weighing control unit configured to output a weighing value of the article by processing the first original signal, wherein the weighing control unit is configured: to determine whether or not to adjust a zero point on the basis of a determination signal obtained by applying a first filter to the second original signal, and wherein the weighing control unit is configured to, in a case where the weighing control unit determines that the zero point is to be adjusted: to generate an adjustment signal obtained by applying a second filter having more stages than the first filter to the second original signal or the determination signal; and perform adjustment of the zero point on the basis of the adjustment signal. According to this weighing apparatus, the weighing control unit first determines whether or not to adjust the zero point on the basis of the determination signal obtained by applying the first filter having a smaller number of stages than the second filter (that is, a filter having higher responsiveness than the second filter) to the original signal. As a result, the weighing control unit can accurately determine whether or not the original signal includes sudden noise. Then, the weighing control unit generates an adjustment signal obtained by applying a second filter having more stages than the first filter to the original signal or the determination signal in a case where it is determined that the zero point is to be adjusted. As a result, it is possible to perform adjustment of the zero point on the basis of the adjustment signal from which noise has been satisfactorily removed. Therefore, the above weighing apparatus can accurately perform adjustment of the zero point. In a case where a peak included in the determination signal exceeds a predetermined threshold value, the weighi