GB2619807A - A magnetic sensor - Google Patents

A magnetic sensor Download PDF

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Publication number
GB2619807A
GB2619807A GB2305863.9A GB202305863A GB2619807A GB 2619807 A GB2619807 A GB 2619807A GB 202305863 A GB202305863 A GB 202305863A GB 2619807 A GB2619807 A GB 2619807A
Authority
GB
United Kingdom
Prior art keywords
cylinder
magnetic
sensors
sensor
rotation
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Pending
Application number
GB2305863.9A
Other versions
GB202305863D0 (en
Inventor
Strauss Christopher
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
CONLOG Pty Ltd
Original Assignee
CONLOG Pty Ltd
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by CONLOG Pty Ltd filed Critical CONLOG Pty Ltd
Publication of GB202305863D0 publication Critical patent/GB202305863D0/en
Publication of GB2619807A publication Critical patent/GB2619807A/en
Pending legal-status Critical Current

Links

Classifications

    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01P—MEASURING LINEAR OR ANGULAR SPEED, ACCELERATION, DECELERATION, OR SHOCK; INDICATING PRESENCE, ABSENCE, OR DIRECTION, OF MOVEMENT
    • G01P13/00—Indicating or recording presence, absence, or direction, of movement
    • G01P13/02—Indicating direction only, e.g. by weather vane
    • G01P13/04—Indicating positive or negative direction of a linear movement or clockwise or anti-clockwise direction of a rotational movement
    • G01P13/045—Indicating positive or negative direction of a linear movement or clockwise or anti-clockwise direction of a rotational movement with speed indication
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01D—MEASURING NOT SPECIALLY ADAPTED FOR A SPECIFIC VARIABLE; ARRANGEMENTS FOR MEASURING TWO OR MORE VARIABLES NOT COVERED IN A SINGLE OTHER SUBCLASS; TARIFF METERING APPARATUS; MEASURING OR TESTING NOT OTHERWISE PROVIDED FOR
    • G01D4/00—Tariff metering apparatus
    • G01D4/02—Details
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01D—MEASURING NOT SPECIALLY ADAPTED FOR A SPECIFIC VARIABLE; ARRANGEMENTS FOR MEASURING TWO OR MORE VARIABLES NOT COVERED IN A SINGLE OTHER SUBCLASS; TARIFF METERING APPARATUS; MEASURING OR TESTING NOT OTHERWISE PROVIDED FOR
    • G01D4/00—Tariff metering apparatus
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01D—MEASURING NOT SPECIALLY ADAPTED FOR A SPECIFIC VARIABLE; ARRANGEMENTS FOR MEASURING TWO OR MORE VARIABLES NOT COVERED IN A SINGLE OTHER SUBCLASS; TARIFF METERING APPARATUS; MEASURING OR TESTING NOT OTHERWISE PROVIDED FOR
    • G01D5/00—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable
    • G01D5/12—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable using electric or magnetic means
    • G01D5/14—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable using electric or magnetic means influencing the magnitude of a current or voltage
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01D—MEASURING NOT SPECIALLY ADAPTED FOR A SPECIFIC VARIABLE; ARRANGEMENTS FOR MEASURING TWO OR MORE VARIABLES NOT COVERED IN A SINGLE OTHER SUBCLASS; TARIFF METERING APPARATUS; MEASURING OR TESTING NOT OTHERWISE PROVIDED FOR
    • G01D5/00—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable
    • G01D5/12—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable using electric or magnetic means
    • G01D5/14—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable using electric or magnetic means influencing the magnitude of a current or voltage
    • G01D5/142—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable using electric or magnetic means influencing the magnitude of a current or voltage using Hall-effect devices
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01D—MEASURING NOT SPECIALLY ADAPTED FOR A SPECIFIC VARIABLE; ARRANGEMENTS FOR MEASURING TWO OR MORE VARIABLES NOT COVERED IN A SINGLE OTHER SUBCLASS; TARIFF METERING APPARATUS; MEASURING OR TESTING NOT OTHERWISE PROVIDED FOR
    • G01D5/00—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable
    • G01D5/12—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable using electric or magnetic means
    • G01D5/244—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable using electric or magnetic means influencing characteristics of pulses or pulse trains; generating pulses or pulse trains
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01F—MEASURING VOLUME, VOLUME FLOW, MASS FLOW OR LIQUID LEVEL; METERING BY VOLUME
    • G01F15/00—Details of, or accessories for, apparatus of groups G01F1/00 - G01F13/00 insofar as such details or appliances are not adapted to particular types of such apparatus
    • G01F15/06—Indicating or recording devices
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01F—MEASURING VOLUME, VOLUME FLOW, MASS FLOW OR LIQUID LEVEL; METERING BY VOLUME
    • G01F15/00—Details of, or accessories for, apparatus of groups G01F1/00 - G01F13/00 insofar as such details or appliances are not adapted to particular types of such apparatus
    • G01F15/06—Indicating or recording devices
    • G01F15/065—Indicating or recording devices with transmission devices, e.g. mechanical
    • G01F15/066—Indicating or recording devices with transmission devices, e.g. mechanical involving magnetic transmission devices
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01P—MEASURING LINEAR OR ANGULAR SPEED, ACCELERATION, DECELERATION, OR SHOCK; INDICATING PRESENCE, ABSENCE, OR DIRECTION, OF MOVEMENT
    • G01P3/00—Measuring linear or angular speed; Measuring differences of linear or angular speeds
    • G01P3/42—Devices characterised by the use of electric or magnetic means
    • G01P3/44—Devices characterised by the use of electric or magnetic means for measuring angular speed
    • G01P3/48—Devices characterised by the use of electric or magnetic means for measuring angular speed by measuring frequency of generated current or voltage
    • G01P3/481—Devices characterised by the use of electric or magnetic means for measuring angular speed by measuring frequency of generated current or voltage of pulse signals
    • G01P3/487—Devices characterised by the use of electric or magnetic means for measuring angular speed by measuring frequency of generated current or voltage of pulse signals delivered by rotating magnets
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01D—MEASURING NOT SPECIALLY ADAPTED FOR A SPECIFIC VARIABLE; ARRANGEMENTS FOR MEASURING TWO OR MORE VARIABLES NOT COVERED IN A SINGLE OTHER SUBCLASS; TARIFF METERING APPARATUS; MEASURING OR TESTING NOT OTHERWISE PROVIDED FOR
    • G01D5/00—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable
    • G01D5/12—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable using electric or magnetic means
    • G01D5/14—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable using electric or magnetic means influencing the magnitude of a current or voltage
    • G01D5/142—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable using electric or magnetic means influencing the magnitude of a current or voltage using Hall-effect devices
    • G01D5/145—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable using electric or magnetic means influencing the magnitude of a current or voltage using Hall-effect devices influenced by the relative movement between the Hall device and magnetic fields

Abstract

A magnetic sensor 10 has first and second magnetic sensors 12,14 (e.g. hall sensors) orientated at an angle C of between 40-70 degrees with respect to a cylinder plane of a diametrically magnetised cylinder 18 (fig 3). The first and second magnetic sensors are located at opposite ends of the cylinder in relation to its central axis B (fig 3). The e.g. hall sensors may be unidirectional sensors each having two output triggers, one output triggers on detection of magnetic north and the second output triggers on detection of magnetic south. Analysis of the sensor outputs by a processor 34 determines if the cylinder is rotating, a rate of rotation, and if the cylinder is static the static position of the cylinder. The direction of rotation may also be calculated. Preferably the magnetic sensor for use in a water meter.

Description

A MAGNETIC SENSOR
BACKGROUND OF THE INVENTION
The present application relates to a magnetic sensor.
One example application of this is for a mechanical water meter which typically includes a diametrically magnetised cylinder that completes a full rotation for a known volume, for example 1 litre.
Typically, an auxiliary probe is supplied with a magnetic sensor such as a small reed switch or hall sensor to detect the magnetic field as the cylinder rotates. The output of the probe is a digital signal where each transition between 1 and 0 or 0 and 1 represents a fixed measured volume. The auxiliary probe thereby counts the transitions to track the volume measured over time.
However, these probes have a number of drawbacks in that they cannot determine flow direction, do not have a very good resolution, they cannot determine an absolute position of the magnetic cylinder and cannot determine if the probe has been removed.
The present invention seeks to address this.
SUMMARY OF THE INVENTION
According to one example embodiment there is provided a magnetic sensor to detect if a diametrically magnetised cylinder is rotating and a rate of rotation of the cylinder, the diametrically magnetised cylinder including two bases located in a cylinder plane and a side wall extending between the two bases, the cylinder in use rotating in the cylinder plane about a central axis, wherein the sensor includes: first and second magnetic sensors each including a magnetic sensing element body, wherein the first magnetic sensor is located adjacent the cylinder on one side of the central axis about which the cylinder rotates, and the second magnetic sensor is located adjacent the cylinder, on the other side of the central axis, further wherein the first and second magnetic sensing element bodies are orientated at an angle of between 40 and 70 degrees with respect to the cylinder plane; and a processor connected to the two magnetic sensors for receiving signals from the magnetic sensors and using the received signals to determine if the cylinder is rotating and a rate of rotation of the cylinder, and if the cylinder is static the static position of the cylinder.
The two magnetic sensors are typically hall sensors.
The two magnetic sensors are preferably unidirectional sensors each having two outputs, wherein one of the two outputs triggers on detection of magnetic north and the other triggers on detection of magnetic south.
BRIEF DESCRIPTION OF THE DRAWINGS
Figure 1 is a block diagram illustrating a water meter with a cut away housing and a magnetic sensor; Figure 2 is a side view illustrating the angle between the magnetic sensor and the cylinder; Figure 3 is a perspective view illustrating the angle between the magnetic sensor and the cylinder; Figure 4 is a block circuit diagram showing the components of the sensor; Figure 5 is a schematic diagram showing the North and South sides of the cylinder as it rotates in relation to the magnetic sensor; and Figure 6 shows the outputs from the magnetic sensors where active states are shown as a "low".
DESCRIPTION OF EMBODIMENTS
The present invention relates to a magnetic sensor.
Referring to the accompanying Figures, a magnetic sensor 10 includes a first magnetic sensor 12 and a second magnetic sensor 14.
In one example embodiment, the two magnetic sensors 12 and 14 are hall sensors. The prototype sensor 10 included two unidirectional hall sensors each having two outputs. One output triggers on detection of magnetic north and the other triggers on detection of magnetic south.
In the illustrated embodiment, the magnetic sensor 10 is used in an application of a mechanical water meter 16.
The water meter 16 includes a diametrically magnetised cylinder 18. However, it will be appreciated that the magnetic sensor 10 could be used in other applications where a diametrically magnetised cylinder is used.
In the illustrated example, water flowing through pipe 20 causes the rotation of the cylinder 18 via a series of cogs 22.
The cogs 22 also cause the numbers 24 displayed to increase as water flows through the pipe and the meter is setup so that the number will increment with each litre of water that flows through the pipe 20.
As can best be seen in Figures 2 and 3, the diametrically magnetised cylinder 18 includes two round bases 26 located in a cylinder plane A and a side wall 28 extending between the two round bases 26.
The cylinder 18 in use rotates in the cylinder plane A about a central axis B. The first and second magnetic sensors 12, 14 each include a magnetic sensing element body 12a, 14a.
The first magnetic sensor 12 is located adjacent the cylinder 18 on one side of the central axis B about which the cylinder rotates, and the second magnetic sensor 14 is located adjacent the cylinder 18, on the other side of the central axis B. The first and second magnetic sensing element bodies 12a, 14a are orientated at an angle C of between 40 and 70 degrees with respect to the cylinder plane A As can be seen in the accompanying drawings, the first and second magnetic sensors 12 and 14 are connected to a body 30 which is located inside a housing 32.
A processor 34 is connected to the two magnetic sensors 12 and 14 for receiving signals from the magnetic sensors and using the received signals to determine if the cylinder is rotating and a rate of rotation of the cylinder, and if the cylinder is static the static position of the cylinder. This will be described in more detail below.
The processor 34 is also located on the body 30.
In addition, a memory 36 is connected to the processor 34.
Alternatively, the processor 34 and memory 36 are external to the body 30 and connected to the sensors by signal wires.
Referring to Figure 5, It will be appreciated that when the cylinder 18 is in a first position shown in Figure 5A, one of the magnetic sensors will detect N while the other of the magnetic sensors will detects. If the cylinder 18 rotates 1800 (half a turn) the polarity will invert (Fig 50). However, if the cylinder 18 is rotated 900, in a prior art system, both magnetic sensors will be situated so that they neither pickup N nor S because the flux lines run parallel to the sensor (Fig 5B).
With the present magnetic sensors placed at an angle as described above, moving from Position 5A to position 5B, the magnetic sensors 12 and 14 are now positioned so that at least one sensor still captures the flux lines and triggers for all positions of the cylinder 18 including the 90-degree position shown in Fig 5B when previously neither sensor could detect the field.
The 4 outputs consisting of 2 outputs each of the two sensors overlap as can be seen in Figure 6, thereby ensuring at least one sensor is always triggered in all positions of the cylinder 18. This results in a sensor 10 with 8 absolute states and a predictable progression from one state to the next depending on the direction of rotation. The 8 states represent one full rotation of the cylinder.
It will be appreciated that the direction of rotation of the cylinder 18 can now be determined. The magnetic sensors will now fire in a predictable sequence. If the direction of the cylinder 18 rotation is reversed then the sequence is also reversed.
The table below illustrates the sensor states for a clockwise progression: State 1 2 3 4 5 6 7 8 sensor1 s I I I sensor2 n I I I Sensor1 n I I I Sensor2 s I I I The table below illustrates the sensor states for an anti-clockwise progression: State 1 2 3 4 5 6 7 8 sensor1 s I I I sensor2 n I I I Sensor1 n I I I Sensor2 s I I I The above clockwise and anti-clockwise detection sequences are stored in the memory 36.
In use, the processor 34 receives back from the sensors a positive detection of a magnet, which is a "1", in the above table and compares the received positive detections with the sequence patterns stored in the memory 36. In this way the processor is able to determine if the cylinder is rotating in forward or reverse direction and will be able to store in the memory the amount of times the cylinder completes a partial or full rotation by comparing a received detection sequence with the stored detection sequences.
The processor 34 determines if the cylinder is static by comparing which sensors are detecting a magnet with the stored sequence and the static position of the cylinder can then be determined.
It will also be appreciated that the removal of the probe can now be detected as an illegal state. This is because if the sensor 10 is removed no sensors will fire and all signals will be high which is an illegal state.
Lastly the effective resolution of the probe has been increased to 1/8 of a rotation resulting in a more sensitive feedback to detect low flow rates such as leaks and more accurate control of the auxiliary devices.

Claims (5)

  1. CLAIMS: 1 A magnetic sensor to detect if a diametrically magnetised cylinder is rotating and a rate of rotation of the cylinder, the diametrically magnetised cylinder including two bases located in a cylinder plane and a side wall extending between the two bases, the cylinder in use rotating in the cylinder plane about a central axis, wherein the sensor includes: first and second magnetic sensors each including a magnetic sensing element body, wherein the first magnetic sensor is located adjacent the cylinder on one side of the central axis about which the cylinder rotates, and the second magnetic sensor is located adjacent the cylinder, on the other side of the central axis, further wherein the first and second magnetic sensing element bodies are orientated at an angle of between 40 and 70 degrees with respect to the cylinder plane; and a processor connected to the two magnetic sensors for receiving signals from the magnetic sensors and using the received signals to determine if the cylinder is rotating and a rate of rotation of the cylinder, and if the cylinder is static the static position of the cylinder.
  2. 2. A sensor according to claim 1 wherein the two magnetic sensors are hall sensors
  3. 3. A sensor according to claim 1 or claim 2, wherein the two magnetic sensors are unidirectional sensors.
  4. 4. A probe according to claim 3, wherein the unidirectional sensors each have two outputs.
  5. 5. A probe according to claim 4, wherein one of the two outputs triggers on detection of magnetic north and the other triggers on detection of magnetic south.
GB2305863.9A 2022-04-22 2023-04-21 A magnetic sensor Pending GB2619807A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
ZA202204492 2022-04-22

Publications (2)

Publication Number Publication Date
GB202305863D0 GB202305863D0 (en) 2023-06-07
GB2619807A true GB2619807A (en) 2023-12-20

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GB2305863.9A Pending GB2619807A (en) 2022-04-22 2023-04-21 A magnetic sensor

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GB (1) GB2619807A (en)

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP2077438A1 (en) * 2006-10-25 2009-07-08 The Furukawa Electric Co., Ltd. Rotation angle detector
US20090206827A1 (en) * 2006-11-21 2009-08-20 Hitachi Metals, Ltd. Rotation-angle-detecting apparatus, rotating machine, and rotation-angle-detecting method
US20100321008A1 (en) * 2008-02-07 2010-12-23 Hitachi Metals, Ltd. Rotation-angle-detecting apparatus, rotating machine and rotation-angle-detecting method
US9671214B2 (en) * 2013-07-17 2017-06-06 Infineon Technologies Ag Discrete magnetic angle sensor device, a magnetic angle sensor arrangement, a method for generating an angle signal and a method for providing a sensor signal

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP2077438A1 (en) * 2006-10-25 2009-07-08 The Furukawa Electric Co., Ltd. Rotation angle detector
US20090206827A1 (en) * 2006-11-21 2009-08-20 Hitachi Metals, Ltd. Rotation-angle-detecting apparatus, rotating machine, and rotation-angle-detecting method
US20100321008A1 (en) * 2008-02-07 2010-12-23 Hitachi Metals, Ltd. Rotation-angle-detecting apparatus, rotating machine and rotation-angle-detecting method
US9671214B2 (en) * 2013-07-17 2017-06-06 Infineon Technologies Ag Discrete magnetic angle sensor device, a magnetic angle sensor arrangement, a method for generating an angle signal and a method for providing a sensor signal

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Publication number Publication date
GB202305863D0 (en) 2023-06-07

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