A water meter based on a latching type magneto-resistive sensor

Abstract

The application provides a water meter based on a latch type magnetoresistance sensor, comprising: a magnetic steel vertically arranged at a sampling position of the water meter; two AMR latch type magnetoresistance sensors located at the same side of the magnetic steel, and the centers of the two AMR latch type magnetoresistance sensors are aligned with the center of the magnetic steel, so as to convert the rotation change signal of the magnetic field of the magnetic steel into a level signal; and a processor electrically connected with the two AMR latch type magnetoresistance sensors, and counting according to the level signal change of the two AMR latch type magnetoresistance sensors. The application has simple structure, and has low requirement on the installation position and angle of the AMR latch type magnetoresistance sensor, and can improve the collection accuracy on the basis of keeping the traditional pulse collection frequency.

Description

Technical Field

[0001] This invention relates to a water meter, and more specifically, to a water meter based on a latching magnetoresistive sensor. Background Technology

[0002] Currently, IoT water meters have solved the problem of remote meter reading for water supply companies, reducing the inefficiency and high cost of manual meter reading.

[0003] Common sampling methods for IoT water meters include photoelectric direct reading, camera acquisition, pulse acquisition, and ultrasonic sampling. Among these, pulse acquisition has the lowest cost, simplest process, and best stability. Pulse acquisition technology is implemented using magnetic switch sensors, which include reed switches, Hall effect sensors, and magnetoresistive sensors. Compared to reed switches and Hall effect sensors, magnetoresistive sensors have advantages such as low failure rate, fast response speed, and low power consumption.

[0004] Chinese patent applications such as CN202853675U ("An installation structure for a smart water meter switching magnetoresistive sensor") and CN203929136U ("A metering water meter based on a magnetoresistive sensor") both utilize magnetoresistive sensors for metering. However, due to issues with sampling frequency and power consumption, the metering accuracy can only reach 0.01 tons, and it cannot distinguish between water meter reversal, which leads to metering errors in practical applications.

[0005] While patents such as Chinese patent application CN114383682A ("An IoT Water Meter Based on a Magnetoresistive Sensor"), Chinese patent application CN213714431U ("A Dual-Pulse Water Meter"), and Chinese patent application CN210036855U ("A Bidirectional Counting Device Based on a Latching Magnetoresistive Element") can distinguish between reverse states, their complex structures and demanding manufacturing processes are significant. For example, the "IoT Water Meter Based on a Magnetoresistive Sensor" requires two magnets of different polarities on the water meter's sampling pointer and cannot detect magnetic attack states. In the "Dual-Pulse Water Meter," the sensor installation locations are relatively close, making the manufacturing process difficult to control, and the power consumption during actual sampling is high. The proposed "Bidirectional Counting Device Based on Latching Magnetoresistive Elements" utilizes two latching magnetoresistive elements. By modulating pulse signals into coded signals with bidirectional recognition, the device's operating status is accurately sensed and transmitted to the backend detection system, achieving reverse flow measurement functionality and meeting the precision metering requirements for water meter counting. However, this solution places very strict requirements on the installation position and angle of the latching magnetoresistive elements. Furthermore, all three metering methods mentioned above require higher acquisition frequencies, and the acquisition accuracy cannot exceed 0.01 tons, hindering the water supply company's refined management of water supply services.

[0006] In order to solve the above problems, people have been seeking an ideal technical solution. SUMMARY

[0007] Based on the above-mentioned shortcomings and deficiencies existing in the prior art, one of the purposes of the present patent is to at least solve one or more of the above-mentioned problems existing in the prior art, in other words, one of the purposes of the present patent is to provide a water meter based on latch type magnetoresistive sensor which meets one or more of the aforementioned needs.

[0008] One of the purposes of the present patent is to improve the accuracy of metering collection without affecting power consumption, while reducing the process complexity in the prior art.

[0009] The second purpose of the present patent is to realize the judgment of magnetic attack based on the change of magnetic field before and after the magnetic attack.

[0010] In order to achieve one of the purposes of the present patent, the technical solution adopted by the present patent is to design a water meter based on latch type magnetoresistive sensor, which comprises:

[0011] A magnetic steel is vertically arranged at the sampling position of the water meter;

[0012] Two AMR latch type magnetoresistive sensors are located on the same side of the magnetic steel, and the centers of the two AMR latch type magnetoresistive sensors are aligned with the center of the magnetic steel, so as to convert the rotation change signal of the magnetic field of the magnetic steel into a level signal;

[0013] A processor is electrically connected with the two AMR latch type magnetoresistive sensors, and counts according to the change of the level signal of the two AMR latch type magnetoresistive sensors.

[0014] In one embodiment, counting according to the change of the level signal of the two AMR latch type magnetoresistive sensors comprises:

[0015] In the initial state, the level signals of the two AMR latch type magnetoresistive sensors are high and low;

[0016] When the change sequence of the level signals of the two AMR latch type magnetoresistive sensors is high-low-> low-low-> low-high, it is determined that it rotates one round along the first direction, and the first direction count is added by 1;

[0017] When the change sequence of the level signals of the two AMR latch type magnetoresistive sensors is high-low-> high-high-> low-high, it is determined that it rotates one round along the second direction, and the second direction count is added by 1.

[0018] In one embodiment, the sampling position of the water meter is coaxially rotated with 0.0001 position, and the included angle formed by the center of the two AMR latch type magnetoresistive sensors and the center of the magnetic steel is at least:

[0019] (360° / f) / (3600 / Q)

[0020] Wherein, f is the highest sampling frequency, Q is the overload flow of the water meter.

[0021] In one embodiment, the distance between the two AMR latching type magnetoresistance sensors and the magnetic steel satisfies: when the magnetic steel is directly above any one of the AMR latching type magnetoresistance sensors, both of the AMR latching type magnetoresistance sensors sense the magnetic field of the magnetic steel.

[0022] In order to achieve the second purpose of the present application, the water meter further comprises a non-latching magnetoresistance sensor, which is arranged at a position on the side of the magnetic steel that is not affected by the magnetic field of the magnetic steel.

[0023] The present application has outstanding substantial features and significant progress compared with the prior art. Specifically, the present application only arranges one magnetic steel at the sampling position and arranges two AMR latching type magnetoresistance sensors on the side of the magnetic steel, the centers of which are aligned with the center of the magnetic steel, so as to obtain metering data and positive and negative inversion data according to the level signal changes of the two AMR latching type magnetoresistance sensors, which has simple structure, does not have high requirements for the installation position and angle of the AMR latching type magnetoresistance sensor, and can improve the collection accuracy on the basis of maintaining the traditional pulse collection frequency. BRIEF DESCRIPTION OF DRAWINGS

[0024] Figure 1 is an AMR latching type magnetoresistance sensor diagram.

[0025] Figure 2 is a structure schematic view of the water meter based on the latching type magnetoresistance sensor according to embodiment 1.

[0026] Figure 3 is a distance schematic view of the AMR latching type magnetoresistance sensor and the magnetic field in embodiment 3.

[0027] Figure 4 is a structure schematic view of the water meter based on the latching type magnetoresistance sensor according to embodiment 4.

[0028] In the figure, 1. magnetic steel; 2. AMR latching type magnetoresistance sensor A; 3. AMR latching type magnetoresistance sensor B; 4. non-latching magnetoresistance sensor. DETAILED DESCRIPTION

[0029] The AMR latching type magnetoresistance sensor is a kind of latching type magnetoresistance sensor, as shown in Figure 1 The AMR latching type magnetoresistance sensor outputs low level when sensing the magnetic field in X direction, outputs high level when sensing the magnetic field in Y direction, and maintains latching state between the two, and outputs high level under the condition of no initial sensing of magnetic field after power-on.

[0030] This invention proposes an Internet of Things (IoT) water meter based on an AMR latching magnetoresistive sensor.

[0031] The technical solution of the present invention will be further described in detail below through specific embodiments.

[0032] Example 1

[0033] like Figure 2 As shown, this embodiment provides a water meter based on a latching magnetoresistive sensor, comprising:

[0034] A magnet 1 is vertically installed at the water meter sampling position. In specific implementation, since the AMR latching magnetoresistive sensor only senses whether there is a magnetic field in the X and Y directions and has no requirements on the polarity of the magnetic field, the magnet can be installed arbitrarily when it is installed vertically, and there is no need to deliberately distinguish the polarity of the magnet.

[0035] Two AMR latching magnetoresistive sensors are located on the same side of the magnet 1, and the centers of the two AMR latching magnetoresistive sensors are aligned with the center of the magnet 1, so as to convert the rotational change signal of the magnetic field of the magnet 1 into a level signal.

[0036] The processor is electrically connected to two AMR latching magnetoresistive sensors and performs counting based on the changes in the level signals of the two AMR latching magnetoresistive sensors.

[0037] In practical implementation, counting is performed based on the changes in the level signals of the two AMR latching magnetoresistive sensors, including:

[0038] Initially, the voltage levels of the two AMR latching magnetoresistive sensors are high and low.

[0039] When the level signals of the two AMR latching magnetoresistive sensors change in the order of high-low -> low-low -> low-high, it is determined that the sensor rotates one full revolution in the first direction, and the count in the first direction is incremented by 1.

[0040] When the level signals of the two AMR latching magnetoresistive sensors change in the order of high-low → high-high → low-high, it is determined that the sensor rotates one full revolution in the second direction, and the count in the second direction is incremented by 1.

[0041] To facilitate understanding of the working principle of this embodiment, Figure 2 For example, the magnet 1 is installed on the sampling position of the mechanical water meter without polarity, and the AMR latching magnetoresistive sensor A2 and the AMR latching magnetoresistive sensor B3 are AMR latching magnetoresistive sensors used for forward and reverse rotation measurement.

[0042] Suppose the initial state is that the magnetic steel 1 is at the M position between the AMR latch type magnetoresistance sensor A 2 and the AMR latch type magnetoresistance sensor B 3. At this time, the AMR latch type magnetoresistance sensor A 2 detects the magnetic field in the Y direction, and the output state is high level; the AMR latch type magnetoresistance sensor B 3 detects the magnetic field in the X direction, and the output state is low level.

[0043] When the magnetic steel 1 rotates clockwise with the dial to the Q position, the AMR latch type magnetoresistance sensor A 2 detects the magnetic field in the X direction, and the output state is low level; the AMR latch type magnetoresistance sensor B 3 state latches, and the output state is low level.

[0044] When the magnetic steel 1 rotates clockwise with the dial to the N position, the AMR latch type magnetoresistance sensor A 2 state latches, and the output state is low level; the AMR latch type magnetoresistance sensor B 3 detects the magnetic field in the Y direction, and the output state is high level.

[0045] It can be seen that, in the clockwise rotation, the level signal change sequence of the AMR latch type magnetoresistance sensor A 2 and the AMR latch type magnetoresistance sensor B 3 is: high-low->low-low->low-high.

[0046] Similarly, if counterclockwise rotation, the level signal change sequence of the AMR latch type magnetoresistance sensor A 2 and the AMR latch type magnetoresistance sensor B 3 is: high-low->high-high->low-high.

[0047] Therefore, the processor can count according to the level signal change of the two AMR latch type magnetoresistance sensors. When the level signal change sequence of the AMR latch type magnetoresistance sensor A 2 and the AMR latch type magnetoresistance sensor B 3 is high-low->low-low->low-high, it is determined that the forward rotation is one round, the forward counter is added by one, and the metering function is realized; when the level signal change sequence of the AMR latch type magnetoresistance sensor A 2 and the AMR latch type magnetoresistance sensor B 3 is high-low->high-high->low-high, it is determined that the reverse rotation is one round, the reverse counter is added by one, and the metering function is realized.

[0048] It can be seen that, in the clockwise rotation, the level signal change sequence of the AMR latch type magnetoresistance sensor A 2 and the AMR latch type magnetoresistance sensor B 3 is: high-low->low-low->low-high.

[0049] Embodiment 2

[0050] This embodiment gives the specific installation mode of the magnetic steel 1 and the AMR latch type magnetoresistance sensor.

[0051] Specifically, the magnetic steel 1 is vertically arranged at a water meter sampling position coaxial with the 0.0001 position; the included angle between the centers of the two AMR latching type magnetoresistive sensors and the center of the magnetic steel 1 is at least:

[0052] (360° / f) / (3600 / Q)

[0053] Wherein, f is the highest sampling frequency, and Q is the water meter overload flow.

[0054] The applicant found through tests that when the sampling frequency is greater than 5 Hz, the low-power performance of the processor will be greatly affected (more than 20 microamperes). The sampling pulse time of the traditional pulse collection technology is generally less than 200 milliseconds, that is, the sampling frequency is greater than 5 Hz, because the length of the response time of the non-latching magnetoresistive sensor, that is, the pulse width, completely depends on the distance between the magnetic steel and the non-latching magnetoresistive sensor. The closer the distance, the wider the pulse width. Since the traditional pulse collection technology needs to use two magnetoresistive sensors to determine the attack state, the distance between the magnetic steel and the magnetoresistive sensor cannot be too close. Therefore, after weighing the sampling frequency and power consumption, the sampling accuracy of the traditional pulse collection technology cannot be less than 0.01 tons, and the sampling pulse time is greater than 200 milliseconds.

[0055] The water meter based on the latching type magnetoresistive sensor provided by the patent adopts the AMR latching type magnetoresistive sensor, at this time, the pulse width no longer depends on the distance between the magnetic steel 1 and the magnetoresistive sensor, but depends on the angle between the center of the AMR latching type magnetoresistive sensor and the center of the magnetic steel.

[0056] Taking a DN15 caliber as an example, the water meter overload flow Q is 3.125 m 3 / h, and the magnetic steel coaxial with the 0.0001 position needs 3600 / 3125≈1.152 seconds to rotate one circle.

[0057] In order to ensure that the sampling frequency is greater than 200 milliseconds, that is, less than 5 Hz, the included angle between the centers of the two AMR latching type magnetoresistive sensors and the center of the magnetic steel is at least:

[0058] (360° / 5Hz) / 1.152 seconds=62.5°.

[0059] It should be noted that the included angle between the center of the AMR latch type magnetoresistive sensor A 2 and the center of the magnetic steel and the center of the magnetic steel cannot be too large, and the distance between the AMR latch type magnetoresistive sensor A 2 and the AMR latch type magnetoresistive sensor B 3 cannot be too large, wherein the maximum angle and the maximum distance need to meet the following design requirements: when the magnetic steel 1 is directly above any one AMR latch type magnetoresistive sensor, both AMR latch type magnetoresistive sensors can sense the magnetic field of the magnetic steel. That is, when the magnetic steel 1 is directly above the AMR latch type magnetoresistive sensor A 2, the AMR latch type magnetoresistive sensor B 3 can sense the magnetic field of the magnetic steel, and when the magnetic steel 1 is directly above the AMR latch type magnetoresistive sensor B 3, the AMR latch type magnetoresistive sensor A 2 can sense the magnetic field of the magnetic steel.

[0060] Embodiment 3

[0061] This embodiment gives a specific implementation of embodiment 2.

[0062] In this embodiment, the included angle between the center of the two AMR latch type magnetoresistive sensors and the center of the magnetic steel 1 is 72°, and the shortest pulse width time is:

[0063] 1.152*72° / 360°≈230ms.

[0064] At this time, the sampling frequency is 4.35Hz, which meets the design requirement that the sampling frequency is less than 5Hz.

[0065] Further, the magnetic range of the magnetic steel 1 is set to 2500Gs-3000Gs, and the minimum value is 2500Gs. When the magnetic steel is directly above the AMR latch type magnetoresistive sensor A 2, the maximum distance between the magnetic steel and the AMR latch type magnetoresistive sensor A 2 is 8cm (including glass thickness, shell thickness, design allowance, etc.), and the maximum distance of the AMR latch type magnetoresistive sensor sensing the magnetic field of the 2500Gs magnetic steel is 11cm, according to the maximum process error of 1cm, 10cm is taken. As shown in Figure 3 The distance between the two AMR latch type magnetoresistive sensors is calculated as 6cm, wherein the magnetic steel 1 is represented by S, and the two AMR latch type magnetoresistive sensors are represented by A and B respectively.

[0066] Embodiment 4

[0067] The technical concept of this embodiment is to realize magnetic attack judgment based on the change of magnetic field before and after magnetic attack.

[0068] Specifically, the water meter in this embodiment includes the structure of the water meter described in embodiment 1 or embodiment 2, and further includes a non-latch magnetoresistive sensor C 4, as shown in Figure 4As shown, the non-latching magnetic resistance sensor C 4 is arranged at a position where the magnetic steel 1 magnetic field does not affect the magnetic steel 1. Specifically, the non-latching magnetic resistance sensor C 4 is electrically connected to the processor.

[0069] Normally, the non-latching magnetic resistance sensor C 4 does not sense the magnetic field of the magnetic steel 1. When a magnetic attack occurs, the magnetic attack must have a magnetic property greater than that of the magnetic steel 1, which can affect the non-latching magnetic resistance sensor C 4, so that the non-latching magnetic resistance sensor C 4 detects a magnetic field, thereby determining that the non-latching magnetic resistance sensor C 4 is subjected to a magnetic attack. The existence of the magnetic attack will affect the metering, at which time the processor will immediately make a judgment, record fault information, and upload the fault information through the Internet of Things module.

[0070] In a specific implementation, the non-latching magnetic resistance sensor C 4 is arranged close to the magnetic field influence area of the magnetic steel 1.

[0071] In one embodiment, the non-latching magnetic resistance sensor C 4 selects a full-pole non-latching magnetic resistance sensor with a maximum distance of 9 cm for sensing the magnetic property of a magnetic steel of 2500Gs, and the boundary distance of the magnetic field influence area of the magnetic steel 1 from the rotation center of the magnetic steel 1 is 4 cm. According to the maximum process error of 1 cm, the non-latching magnetic resistance sensor C is placed at a position 14 cm away from the rotation center of the magnetic steel 1. At this time, normally, the non-latching magnetic resistance sensor C does not sense the magnetic field of the magnetic steel, and when a magnetic attack occurs, the non-latching magnetic resistance sensor C 4 senses a magnetic field.

[0072] Finally, it should be noted that: the above embodiments are only used to illustrate the technical solutions of the present application rather than limit them; although the present application has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the specific implementation of the present application can be modified or some technical features can be replaced by equivalent; without departing from the spirit of the technical solutions of the present application, they should be covered in the technical solution range of the present application claimed.

Claims

1. A water meter based on a latching magnetoresistive sensor, characterized in that, include: A magnet is vertically installed at the water meter sampling position, which rotates coaxially with the 0.0001 position. Two AMR latching magnetoresistive sensors are located on the same side of the magnet, and the centers of both sensors are aligned with the center of the magnet to convert the rotational change signal of the magnet's magnetic field into a level signal; the angle between the centers of the two AMR latching magnetoresistive sensors and the center of the magnet is minimal. (360° / f) / (3600 / Q) Where f is the highest sampling frequency and Q is the water meter overload flow rate; The processor is electrically connected to two AMR latching magnetoresistive sensors and performs counting based on the changes in the level signals of the two AMR latching magnetoresistive sensors.

2. The water meter based on a latching magnetoresistive sensor according to claim 1, characterized in that, Counting is performed based on the level signal changes of two AMR latching magnetoresistive sensors, including: Initially, the voltage levels of the two AMR latching magnetoresistive sensors are high and low. When the level signals of the two AMR latching magnetoresistive sensors change in the order of high-low -> low-low -> low-high, it is determined that the sensor rotates one full revolution in the first direction, and the count in the first direction is incremented by 1. When the level signals of the two AMR latching magnetoresistive sensors change in the order of high-low → high-high → low-high, it is determined that the sensor rotates one full revolution in the second direction, and the count in the second direction is incremented by 1.

3. The water meter based on a latching magnetoresistive sensor according to claim 1 or 2, characterized in that, The distance between the two AMR latching magnetoresistive sensors and the magnet satisfies the following condition: when the magnet is directly above either AMR latching magnetoresistive sensor, both AMR latching magnetoresistive sensors will sense the magnetic field of the magnet.

4. The water meter based on a latching magnetoresistive sensor according to claim 1 or 2, characterized in that: It also includes a non-latch magnetoresistive sensor, which is disposed on one side of the magnet at a position unaffected by the magnetic field of the magnet, and the non-latch magnetoresistive sensor C is electrically connected to the processor.

5. The water meter based on a latching magnetoresistive sensor according to claim 3, characterized in that: It also includes a non-latch magnetoresistive sensor, which is disposed on one side of the magnet at a position unaffected by the magnetic field of the magnet, and the non-latch magnetoresistive sensor C is electrically connected to the processor.

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