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CN-121986250-A - Tamper detection system

CN121986250ACN 121986250 ACN121986250 ACN 121986250ACN-121986250-A

Abstract

A tamper detection system (510) for a utility meter (500) is disclosed. The system includes at least one sensor (515, 520) configured to sense a magnetic field. The system includes a processing circuit (525) coupled to the at least one sensor and configured to generate a pulse for incrementing a pulse counter in response to a level of at least one signal from the at least one sensor being outside a first threshold range. When the processing circuit determines that the pulse counter has not been incremented within the tamper detection interval, the processing circuit determines whether the magnetic field sensed by the at least one sensor has changed beyond a second threshold range based on the level of the at least one signal.

Inventors

  • R. KUMAR
  • P. KUMAR
  • V. PRAKASH
  • T.LI
  • VEEN JEROEN

Assignees

  • 兰迪斯+盖尔股份有限公司

Dates

Publication Date
20260505
Application Date
20240923
Priority Date
20230927

Claims (15)

  1. 1. A tamper detection system (510) for a utility meter (500), the system comprising: At least one sensor (515, 520) configured to sense a magnetic field, and Processing circuitry (525) coupled to the at least one sensor and configured to generate pulses for incrementing a pulse counter in response to a level of at least one signal from the at least one sensor being outside a first threshold range, Wherein when the processing circuit determines that the pulse counter has not been incremented within the tamper detection interval, the processing circuit determines whether the magnetic field sensed by the at least one sensor has changed beyond a second threshold range based on the level of the at least one signal.
  2. 2. The tamper detection system (510) of claim 1, wherein the processing circuit (525) is configured to determine that the magnetic field sensed by the at least one sensor (515, 520) has changed beyond a second threshold range by determining a difference between a maximum level and a minimum level of the at least one signal.
  3. 3. The tamper detection system (510) of claim 1 or 2, wherein when the processing circuit (525) determines that the magnetic field change sensed by the at least one sensor (515, 520) does not exceed the second threshold range, the processing circuit is configured to: incrementing an iteration counter; increasing the sampling time; sampling the at least one signal from the at least one sensor after the sampling time, and It is further determined whether the magnetic field sensed by the at least one sensor has changed beyond the second threshold range.
  4. 4. The tamper detection system (510) of claim 3, wherein the processing circuit (525) is configured to determine that no tamper event has occurred when the iteration counter reaches a predetermined maximum iteration value.
  5. 5. The tamper detection system (510) of claim 4, wherein the processing circuit (525) is configured to increase the sampling time when the iteration counter is incremented to a value less than the predetermined maximum iteration value.
  6. 6. The tamper detection system (510) of claim 3, 4 or 5, wherein increasing the sampling time comprises doubling the sampling time.
  7. 7. The tamper detection system (510) according to any one of the preceding claims, wherein between sampling at least one signal level from the at least one sensor (515, 520) and determining whether the magnetic field has changed beyond a second threshold range, the processing circuit (525) is further configured to: if the level of the sampled signal is outside a tamper threshold range, a tamper event is determined to have occurred, wherein the tamper threshold range is greater than the second threshold range.
  8. 8. The tamper detection system (510) according to any of the preceding claims, wherein when the processing circuit (525) has determined that the magnetic field sensed by the at least one sensor (515, 520) has changed beyond a second threshold range, the processing circuit is further configured to: If the tamper state is not set to suspect, the tamper state is set to suspect, or If the tamper state is set to suspect, a suspect tamper counter is incremented.
  9. 9. The tamper detection system (510) of claim 8, wherein the processing circuit (525) is configured to determine that a tamper event has occurred when the suspected tamper counter reaches a predetermined maximum value.
  10. 10. The tamper detection system (510) of any one of the preceding claims, wherein: the at least one sensor (515, 520) comprises a first sensor (515) and a second sensor (520), and The at least one signal includes a first signal from the first sensor and a second signal from the second sensor.
  11. 11. The tamper detection system (510) of claim 10 when dependent on claim 7, wherein: The processing circuit (525) is configured to generate pulses for incrementing the pulse counter using the first signal, and The second sensor (525) and/or the processing circuit are configured to generate an interrupt if the processing circuit determines that the second signal is outside the tamper threshold range.
  12. 12. The tamper detection system (510) of any one of the preceding claims, wherein the at least one sensor (515, 520) comprises a hall effect sensor.
  13. 13. A utility meter (500), comprising: the tamper detection system (510) according to any of the preceding claims, and A dial wheel (530) configured such that rotation of the dial wheel induces a varying magnetic field at the at least one sensor (515, 520).
  14. 14. The utility meter (500) of claim 13, configured for metering a flow of fluid, wherein the flow of fluid causes rotation of the dial wheel (535).
  15. 15. A method of tamper detection, the method comprising: Processing circuitry (525) coupled to the at least one magnetic field sensor (515, 520) is configured to generate pulses when at least one signal from the at least one sensor is outside a first threshold range and count the generated pulses; determining that no pulses are counted within a tamper detection interval, and Determining whether the magnetic field sensed by the at least one sensor has changed beyond a second threshold range based on the level of the at least one signal.

Description

Tamper detection system Technical Field The present disclosure relates to a tamper detection system for utility meters, particularly for utility meters such as gas tables including rotary dial wheels (dial-wire). The present disclosure also relates to a method of tamper detection. Background Flow-based metering devices may be used to meter consumption of a resource, such as gas or water. Such metering devices (which may be commonly referred to in the art as utility meters) may be installed at residential, commercial, and/or industrial premises for metering consumption of resources in order to enable utility providers to charge consumers based on the level of resource consumption. Such known utility meters may include, for example, rotary or turbine meters, wherein measurable rotation of one or more mechanical components may be caused by the flow of fluid through the meter. In some known examples, one or more magnetic field sensors may be implemented to sense rotation of one or more mechanical components to enable derivation of the volume of fluid consumed. In some examples, such utility meters may locally store data corresponding to the volume of fluid consumed, or may transmit such data to a remote system. In order to accurately meter any such measurement of the volume of fluid flowing through the meter is essential. Further, because such utility meters may be installed in a large number of premises (e.g., residential applications), it is also essential that such utility meters be relatively low cost to implement and exhibit a high level of reliability. It is also desirable to deter and (where possible) detect any tampering with the utility meter. In one example, the consumer may tamper with the meter to reduce and/or prohibit metering the consumption of gas or water at the premises. In some cases, a consumer may tamper directly with one or more sensors within the utility meter. In some cases, known steps may be taken to prevent such tampering, such as by making the housing of the utility meter sturdy to be difficult to open, and/or by providing means to detect the opening of the housing. In some cases, the consumer may tamper with one or more sensors within the utility meter indirectly, such as by interfering with signals sensed by the one or more sensors. Such tampering may be more difficult to detect and/or prevent. It is therefore desirable to implement a system for detecting any tampering with utility meters that may affect the metering of resource consumption. It is particularly desirable that any such system be relatively low cost to implement, yet highly reliable and accurate. Furthermore, it is also essential that any such system exhibit relatively low power consumption, as in some cases the metering portion of such utility meters may be battery powered. It is therefore an object of at least one embodiment of at least one aspect of the present disclosure to obviate or at least mitigate at least one of the above-mentioned disadvantages of the prior art. Disclosure of Invention The present disclosure relates to a tamper detection system for utility meters, particularly for gas meters that include a rotating dial wheel. The present disclosure also relates to a method of tamper detection. According to a first aspect of the present disclosure, a tamper detection system for a utility meter is provided. The tamper detection system includes at least one sensor configured to sense a magnetic field. The tamper detection system includes a processing circuit coupled to the at least one sensor and configured to generate a pulse for incrementing an (increment) pulse counter in response to a level of at least one signal from the at least one sensor being outside a first threshold range. When the processing circuit determines that the pulse counter has not been incremented within the tamper detection interval, the processing circuit determines whether the magnetic field sensed by the at least one sensor has changed beyond a second threshold range based on the level of the at least one signal. Advantageously, further determining whether the magnetic field sensed by the at least one sensor has changed beyond the second threshold range may effectively detect tampering due to a weak external magnet, which may otherwise be undetectable. Further, the disclosed tamper detection system may help avoid unnecessary tamper detection, thereby helping to reduce the overall power consumption of the tamper detection system. The processing circuit may be configured to determine that the magnetic field sensed by the at least one sensor has changed beyond the second threshold range by determining a difference between a maximum level and a minimum level of the at least one signal. The processing circuit may be configured to increment the iteration counter when the processing circuit determines that the magnetic field change sensed by the at least one sensor does not exceed the second threshold range, and the processing circuit may b