Magnetic Method to Detect Cover Removal in a Meter

摘要

An arrangement for use in a utility meter includes a sensor and a processing circuit supported by a base of the meter, and a magnetic element carried by the cover of the meter, in which the cover is removably mounted to the base. The sensor includes at least two magnetizable elements, such as inductors, that are magnetized at opposite polarities when the meter is closed and operable. The magnetizable elements are positioned in very close proximity so that as cover is removed the magnetic element passes the elements to cause the magnetizable elements to assume the same polarity. The processing circuit continuously polls the magnetizable elements to evaluate their respective polarities and is configured to issue a tamper indication when the detected polarities are the same.

主权项

1. An arrangement for use in a utility meter, comprising:
two magnetizable elements supported on a first meter structure and each configured to be magnetized to a first polarity and an opposite second polarity; a processing circuit operably coupled to the two magnetizable elements to determine the relative polarity of the two magnetizable elements to generate a tamper indication if the two magnetizable elements have the same polarity; and a magnetic element supported on a second meter structure configured to be physically connected to the first meter structure, the magnetic element positioned such that removal of the second meter structure from the first meter structure causes the magnetic element to move past the two magnetizable elements, the magnetic element configured to cause the two magnetizable elements to have the same polarity upon passage of the magnetic element.