The present application relates generally to scales used to weigh items, and more particularly to a scale that includes a self-calibration operation that takes into account gravity strength at a location of scale operation.
Scales have been used in stores such as supermarkets and groceries to weigh and price food items and to generate a pricing label for such food items. Applicable regulations require a level of precision in such scales that can be defeated by differences in gravity strength depending upon scale location. Accordingly, it would be desirable to provide a scale including a self-calibration operation to determine the gravity strength applicable to a location of scale operation.
In one aspect, a method of scale calibration involves: (a) identifying to the scale an operating location for the scale; (b) the scale identifying a gravity value corresponding the operating location; and (c) the scale associating the identifying gravity value into a weighing algorithm stored in memory of the scale. In one implementation of such a method, step (a) involves identifying address information to the scale and step (b) involves (i) accessing a coordinates database that provides latitude and longitude information corresponding to the address information and (ii) using the latitude and longitude information to calculate the gravity strength value or retrieve the gravity strength value from a database.
In another aspect, a scale incorporating a self-calibrating feature includes a weighing station for receiving items to be weighed, the weighing station including a load cell for outputting a weight indicative signal. An input device is provided. A controller is operatively connected with the input device and the load cell, the controller including associated memory storing at least one weighing algorithm. The controller includes a calibration mode in which it operates such that upon input of a scale location via the input device, the controller automatically determines a gravity strength value corresponding to the scale location, and the controller stores the gravity strength value in its memory in association with the weighing algorithm.
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A stored weighing algorithm is used to calculate weight based upon an output signal of a load cell. The weighing algorithm incorporates a gravity strength value into the calculation. The controller is configured to perform a self-calibration operation in order to determined and use an appropriate gravity strength value for a location at which the scale operates.
In one example, referring to the process diagram 50 of
The scale controller then uses the coordinates to determine the gravity strength value at 56. In one example, the controller may submit the coordinates (e.g., latitude and longitude, or latitude, longitude and altitude) to a remote computer system (e.g., at a web site) that uses the coordinates to calculate and return a gravity strength value via a gravity strength algorithm or that uses the coordinates to retrieve the gravity strength value from a gravity strength database. In another example, the scale includes the gravity strength algorithm in its memory, and internally makes the gravity strength calculation based upon the coordinates, or the scale may incorporate the gravity strength database in its memory.
The scale controller subsequently stores the obtained (e.g., calculated or retrieved from a database) gravity strength value in its memory for use in association with the weighing algorithm at 58. In this manner, any given scale can automatically determine an appropriate gravity strength value for its location based upon the input of store address information, or other store location information, simplifying scale calibration and improving scale performance.
The foregoing operations could be carried out while the scale is actually located in the store or other building (e.g., during delivery and set-up). Alternatively, where the intended scale location is known in advance the operations could be carried out before the scale is located within the store or other building (e.g., at a local distribution site or even at the manufacturing facility).
In an alternative embodiment, a hand-held unit 84 could be used to communicate store location information to the scale controller via the communications interface 36, or the store computer 82 may communicate the information to the scale controller. In another embodiment, the scale could incorporate an internal GPS module 86 that would be used to identify the store location information when triggered to do so during the set-up or calibration mode. Alternatively, the hand-held unit 84 could include the GPS module and communicate the GPS information to the controller.
It is to be clearly understood that the above description is intended by way of illustration and example only and is not intended to be taken by way of limitation. Other changes and modifications could be made.