Detection device and detection method thereof

Abstract

The present application discloses a detection device and a detection method thereof, wherein the detection device comprises: a first oscillator, a second oscillator and a frequency comparison module. The first oscillator comprises a first LC resonant circuit and is designed to generate a first continuous oscillation signal at a first resonant frequency; the second oscillator comprises a second LC resonant circuit and is designed to generate a second continuous oscillation signal at a second resonant frequency; the frequency comparison module is designed to perform a comparison of the frequencies of the second continuous oscillation signal and the first continuous oscillation signal to determine the inductance change of one of the first inductor of the first LC resonant circuit and the second inductor of the second LC resonant circuit, wherein one of the oscillators is used as a reference oscillator so that the measurement of the inductance change is not affected by changes in environmental conditions.

Description

Technical Field

[0001] The present application relates to the field of electronic measurement technology, and in particular to a detection device and a detection method thereof. Background Art

[0002] By detecting the change in the inductance of an inductor, it is possible to measure the change in parameters related to a variety of phenomena. For example, the flow rate and / or direction of a fluid (including liquids and gases) can be measured based on the principle of the change in the inductance of an inductor. When an inductor (powered on and carrying alternating current, or at least a changing current) is close to a metal that is moving (e.g., rotating) due to the fluid, a corresponding circuit with the inductor can generate an electrical signal corresponding to the change in the inductance of the inductor, so that the flow rate and / or direction of the fluid can be measured by detecting the electrical signal.

[0003] However, environmental conditions, such as ambient temperature and ambient humidity, which are not due to changes in parameters of the measured phenomenon (such as flow), can also cause changes in inductance, thereby affecting the measurement of parameters (such as fluid flow and / or direction), resulting in erroneous parameter values.

[0004] The present invention relates to techniques for making the measurement of inductance changes independent of changes in environmental conditions, and to applications of such techniques. Summary of the invention

[0005] In view of this, the present application provides a detection device and a detection method thereof to solve the problem that the detection of the existing detection device is affected by environmental factors.

[0006] The present application provides a detection device, comprising: a first oscillator, comprising a first LC resonant circuit, the first oscillator generates a first continuous oscillation signal at a first resonant frequency determined by the first LC resonant circuit, wherein a first inductor of the first LC resonant circuit has a first default inductance value; a second oscillator, comprising a second LC resonant circuit, the second oscillator generates a second continuous oscillation signal at a second resonant frequency determined by the second LC resonant circuit, wherein a second inductor of the second LC resonant circuit has a second default inductance value; a frequency comparison module, used to couple to the first oscillator and the second oscillator to receive the first continuous oscillation signal and the second continuous oscillation signal; wherein, when metal approaches any one of the first inductor and the second inductor, the first default inductance value and the second default inductance value change accordingly, so that the corresponding first resonant frequency and the second resonant frequency change, thereby causing the frequency of the corresponding one of the first continuous oscillation signal and the second continuous oscillation signal to change; wherein the frequency comparison module is designed to compare the frequency of the second continuous oscillation signal with the frequency of the first continuous oscillation signal to determine the corresponding changes of the first default inductance and the second default inductance.

[0007] Optionally, the frequency comparison module is designed to perform comparison by obtaining a ratio between the frequency of the second continuous oscillation signal and the frequency of the first continuous oscillation signal.

[0008] Optionally, it also includes: a third oscillator, the third oscillator includes a third LC resonant circuit, the third oscillator generates a third continuous oscillation signal at a third resonant frequency, wherein the third inductor of the third LC resonant circuit has a third default inductance value; the frequency comparison module is used to receive the frequency of the third continuous oscillation signal, when the metal approaches the third inductor, the third default inductance value changes, so that the third resonant frequency of the third continuous oscillation signal changes; wherein the frequency comparison module is designed to perform another comparison of the frequencies of the third continuous oscillation signal and the first continuous oscillation signal by obtaining the ratio of the frequencies of the third continuous oscillation signal and the first continuous oscillation signal, thereby determining the change of the third default inductance value.

[0009] Optionally, the frequency comparison module includes: a first frequency counter, coupled to the second oscillator, for receiving the second continuous oscillation signal and obtaining a first count value of multiple cycles of the second continuous oscillation signal occurring in a counting window, wherein, when the inductance of the first inductor and the second inductor are respectively equal to the first default inductance value and the second default inductance value, the first measured count value is equal to the first default count value; when the inductance value of any one of the first inductor and the second inductor changes from the corresponding first default inductance value or the second default inductance value, the first count value deviates from the first default count value; a frequency divider, coupled to the first oscillator, for receiving the first continuous oscillation signal and separating the frequency of the first continuous oscillation signal to generate the counting window, the frequency divider is coupled to the first frequency counter to indicate the counting window to the first frequency counter; a logic module, coupled to the first frequency counter, for receiving the first measured count value, the logic module is used to obtain a first count value difference between the first count value and the first default count value, and determine the change amount of the corresponding one of the first default inductance value and the second default inductance value according to the first count value difference.

[0010] Optionally, the frequency comparison module also includes a second frequency counter for receiving the third continuous oscillation signal and the counting window, and the frequency comparison module is used to obtain a second count value of multiple cycles of the third continuous oscillation signal occurring in the counting window, wherein, when the inductance of the first inductor and the third inductor are respectively equal to the first default inductance value and the third default inductance value, the second count value is equal to the second default count value, but when the inductance of the first inductor and the inductance value of a corresponding one of the third inductors change relative to the first default inductance value and the third default inductance value, respectively, the second count value deviates from the second default count value; wherein, the logic module is coupled to the first frequency counter to receive the second measurement count, and the logic module obtains a second count difference between the second count value and the second default count value, and determines the change in the third default inductance value based on the second count difference.

[0011] Optionally, the metal has at least a rotatable surface, which approaches the device during linear motion and / or rotational motion, and the movement of the rotatable surface causes the first default inductance value and the second default inductance value to change accordingly in sequence; the frequency comparison module is designed to determine the speed of the linear motion or the rotational motion by calculating the time difference between the changes in the first default inductance value and the second default inductance value.

[0012] Optionally, the metal includes a portion of a rotatable surface, which is coupled to the fluid via a coupling mechanism, and the coupling mechanism is designed to cause the rotatable surface to rotate at a rate proportional to the flow rate of the fluid, so that the first frequency counter generates a set of multiple values ​​of the first measurement count value in a corresponding counting window; wherein the logic module is designed to determine the flow rate of the fluid based on the set of multiple values ​​and processing of the first default count value.

[0013] Optionally, the rotatable surface is a disk, the metal is in one half and the non-metal is in the other half; the rotation of the rotatable surface is designed to make the metal approach the first inductor and the second inductor in turn during each complete rotation, and in the corresponding part of the rotation, the first default inductance decreases and the first measurement count value increases to be greater than the default count value, and the second default inductance value decreases and the first measurement value count decreases to be less than the default count value; wherein, when the non-metal approaches any one of the first inductor and the second inductor, the inductance values ​​of the first inductor and the second inductor remain unchanged at their respective default values; wherein the logic block is designed to determine the count difference between the value in the set of multiple values ​​and the first default count value, the count difference has a positive value in one part of the corresponding part of each complete rotation and a negative value in the other part, wherein the logic block is designed to determine the flow rate of the fluid based on one or more conversions between the negative value and the positive value, or between the positive value and the negative value.

[0014] Optionally, the metal has a rotatable surface, which is coupled to the fluid through a coupling mechanism, and the coupling mechanism is designed to cause the rotatable surface to rotate at a rate proportional to the flow velocity of the fluid and reflect the flow direction of the fluid; wherein the rotation of the rotatable surface is designed to cause the first frequency counter to generate a first group of multiple values ​​of the first count value in a first group of corresponding count windows, and to cause the second frequency counter to generate a second group of multiple values ​​of the second count value in a second group of corresponding count windows; wherein the logic module is designed to determine the flow direction of the fluid based on processing the first group of multiple values, the second group of multiple values, the first default count value and the second default count value.

[0015] Optionally, the rotatable surface is a disk, wherein the metal is in one half and the non-metal is in the other half; wherein the rotation of the rotatable surface is designed to make the metal close to the first inductor and the second inductor in the first part of a full rotation, close to the second inductor and the third inductor in the second part of a full rotation, and close to the third inductor and the first inductor in the third part of a full rotation, wherein the first part, the second part and the third part appear in sequence in each complete rotation; the sequence includes a first sequence and a second sequence, the first sequence includes the first part, the second part and the third part in sequence, and the second sequence includes the first part, the third part and the second part in sequence; wherein in the first part, the metal reduces the first default inductance value and the second default inductance value, so that the first count value and the second count value are equal to zero and a positive value respectively, and the third default inductance value remains unchanged; wherein in the second part, the metal reduces the second default inductance value and the second default inductance value, so that the first count value and the second count value are equal to zero and a positive value respectively, and the third default inductance value remains unchanged; wherein the third default inductance value is reduced, so that the first count value and the second count value are respectively equal to a negative value and zero, and the first default inductance value remains unchanged; wherein, in the third part, the metal reduces the first default inductance value and the third default inductance value, so that the first count value and the second count value are both positive values, and the second default inductance value remains unchanged; wherein the logic module is designed to determine, for each of the first part, the second part and the third part, a first count difference between the first count value and the default count value, and a second count difference between the second count value and the default count value; wherein the logic block is designed so that the first count difference is successively equal to zero, a negative value and a positive value, and the second count difference is successively equal to a negative value, zero and a positive value, then the flow direction is determined to be a first direction, wherein the logic block is designed so that the first count difference is successively equal to zero, a positive value and a negative value, and the second count difference is successively equal to a negative value, a positive value and zero, then the logic block is designed to determine the flow direction to be a second direction opposite to the first direction.

[0016] Optionally, the frequency comparison module is designed to perform the comparison by obtaining the difference between the frequencies of the first continuous oscillation signal and the second continuous oscillation signal; wherein, when the difference is positive, the frequency comparison module concludes that the metal is close to the first inductor; wherein, when the difference is negative, the frequency comparison module concludes that the metal is close to the second inductor.

[0017] Optionally, the first default inductance value is equal to the second default inductance value, wherein the first resonant frequency is equal to the second resonant frequency; wherein the comparison enables the frequency comparison module to determine a change in the inductance of any one of the first inductor and the second inductor, wherein the change is caused by factors other than the environmental conditions in which the detection device is located.

[0018] Optionally, the environmental conditions include ambient temperature and ambient humidity.

[0019] Optionally, the second oscillators respectively include amplifiers configured in a positive feedback mode to respectively generate and output the first continuous oscillation signal and the second continuous oscillation signal.

[0020] Optionally, it further includes: a printed circuit board, wherein the first oscillator, the second oscillator, the third oscillator, the first counter, the second counter, the divider and the logic module are all mounted on the printed circuit board; wherein the first inductor, the second inductor and the third inductor are all implemented in the form of conductive traces on the printed circuit board, and are distributed on the printed circuit board at a circumferential interval of 120 degrees.

[0021] Optionally, the plane of the disk is arranged to be parallel to the plane of the PCB, and the center of the disk is aligned with the center of the circumference.

[0022] The present application also provides a detection method for a detection device, the method comprising: receiving a first continuous oscillation signal, the first continuous oscillation signal having a first resonant frequency, generated by a first oscillator having a first LC resonant circuit, wherein the first continuous oscillation signal is determined by the first LC resonant circuit, wherein the first inductance of the first LC resonant circuit has a first default inductance value; receiving a first continuous oscillation signal, the second continuous oscillation signal having a second resonant frequency, generated by a second oscillator having a second LC resonant circuit, wherein the second continuous oscillation signal is determined by the second LC resonant circuit, wherein the second inductance of the second LC resonant circuit has a second default inductance value; and, comparing the frequencies of the first continuous oscillation signal and the second continuous oscillation signal to determine a change in a corresponding one of the first default inductance value and the second default inductance value; wherein the device comprises the first oscillator, the second oscillator and the frequency comparison module.

[0023] The use of a reference oscillator with a reference inductor in the above-mentioned detection device of the present application enables the device to be used to determine parameters related to one or more phenomena that can cause changes in inductance value, and ensures that the measurement results are always unaffected by environmental changes, thereby improving detection accuracy. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For those skilled in the art, other drawings can be obtained based on these drawings without creative work.

[0025] Figure 1A is a block diagram of an example device implemented according to various aspects of the present invention in one embodiment of the present invention;

[0026] Figure 1B is a block diagram of a frequency comparison module in one embodiment of the present invention;

[0027] Figure 2 is an example topology diagram that can be used to implement the oscillator of the present invention according to an embodiment of the present invention;

[0028] Figure 3A is a schematic diagram of determining the flow rate of a fluid (liquid or gas) using a device according to an embodiment of the present invention;

[0029] Figure 3B and 3C is a schematic diagram of a method for calculating fluid flow rate in an embodiment of the present invention;

[0030] Figure 4 is a schematic diagram of a device for determining a fluid flow velocity and a fluid flow direction according to an embodiment of the present invention;

[0031] Figure 5A , 5B 5C is a schematic diagram of a method for determining a fluid flow direction and a fluid flow rate in one embodiment of the present invention;

[0032] Figure 6 is a schematic diagram of a printed circuit board (PCB) containing a sensor in the form of an integrated circuit for determining fluid flow rate and direction in one embodiment of the present invention, and also illustrates the layout of the inductor coil used by the sensor;

[0033] In the above drawings, like reference numerals generally indicate identical, functionally similar, and / or structurally similar elements. The first appearance of a graphic element is indicated by the leftmost digit in the reference numeral. DETAILED DESCRIPTION

[0034] 1. Overview

[0035] The detection device implemented according to one aspect of the present invention includes a first oscillator, a second oscillator and a frequency comparison module; the first oscillator includes a first LC (inductor-capacitor) resonant circuit, and the first oscillator generates a first continuous oscillation signal at a first resonant frequency determined by the first LC resonant circuit; the first inductor of the first LC resonant circuit has a first default inductance value; the second oscillator includes a second LC resonant circuit, and the second oscillator generates a second continuous oscillation signal at a second resonant frequency determined by the second LC resonant circuit; the second inductor of the second LC resonant circuit has a second default inductance value.

[0036] The frequency comparison module is used to receive the first continuous oscillation signal and the second continuous oscillation signal. When metal approaches one of the first inductor and the second inductor, the corresponding one of the first default inductance value and the second default inductance value changes, causing the corresponding one of the first resonant frequency and the second resonant frequency to change, thereby changing the frequency of the corresponding one of the first continuous oscillation signal and the second continuous oscillation signal; the frequency comparison module is designed to compare the frequencies of the second continuous oscillation signal and the first continuous oscillation signal to determine the change amount of the corresponding one of the first default inductance value and the second default inductance value.

[0037] In one embodiment, the frequency comparison module is designed to obtain the frequency ratio of the second continuous oscillation signal to the first continuous oscillation signal, and the frequency comparison module includes a frequency counter, a frequency divider and a logic module. In an exemplary application, the device is used to determine the flow rate of a fluid.

[0038] In another embodiment, the device also includes a third oscillator and another counter; the third oscillator includes a third LC resonant circuit, and the third oscillator generates a third continuous oscillation signal at a third resonant frequency determined by the third LC resonant circuit; the third inductor of the third LC resonant circuit has a third default inductance value; the frequency comparison module is used to obtain the ratio of the frequency of the second continuous oscillation signal to that of the first continuous oscillation signal, and the ratio of the frequency of the third continuous oscillation signal to that of the first continuous oscillation signal; in an exemplary application, the device is used to determine the flow direction of the fluid.

[0039] Several aspects of the present invention are described below with reference to examples. However, those skilled in the relevant art will recognize that the present invention can be implemented without one or more of the specific details, or using other methods, components, materials, etc. In other cases, well-known structures, materials, or operations are not shown in detail to avoid obscuring the features of the present invention. In addition, the described features / aspects can be implemented in various combinations, although for the sake of brevity, only some of these combinations are described herein.

[0040] 2. Example Device

[0041] Figure 1A Schematic diagram of the structure of an exemplary device in one embodiment of the present invention.

[0042] The device 100 shown includes an oscillator 160B (LC oscillator-0), an oscillator 160A (LC oscillator-1), a frequency comparison module 190, and a printed circuit board (PCB) 110. The oscillator 160B, the oscillator 160A, and the frequency comparison module 190 are mounted on the circuit board 110. In some embodiments, the oscillator 160B, the oscillator 160A, and the frequency comparison module 190 are implemented by discrete modules or components. However, in some alternative embodiments, only the inductor 120A and the inductor 120B can be implemented in the form of discrete devices, while the frequency comparison module 190 is implemented in the form of an integrated circuit (IC). In this case, the inductor 120A and the inductor 120B are located outside the IC chip and are mounted on the printed circuit board (PCB) 110 together with the IC chip.

[0043] Oscillator 160B includes capacitor (CAP) 132B, inductor 120B and amplifier (AMP) 135B. Capacitor 132B and inductor 120B form an LC (inductor-capacitor) resonant circuit, and the values ​​of L (inductance) and C (capacitance) determine the resonant frequency of oscillation. The output of the LC tank circuit is coupled to amplifier (AMP) 135B, which introduces positive feedback (not shown) and produces a sustained oscillation on oscillator 161B having a resonant frequency F0 (i.e., an oscillation that does not decay over time when the oscillator is powered on). The magnitude of the resonant frequency F0 is inversely proportional to the square root of the inductance value L0 of inductor 120B.

[0044] Oscillator 160A includes capacitor (CAP) 132A, inductor 120A and amplifier (AMP) 135A. Capacitor 132A and inductor 120A form another LC resonant circuit, and the values ​​of L (inductance) and C (capacitance) determine the resonant frequency of oscillation. The output of the LC tank circuit is connected to amplifier (AMP) 135A, which introduces positive feedback (not shown) and generates continuous oscillation on path 161A with resonant frequency F1. The magnitude of resonant frequency F1 is inversely proportional to the square root of the inductance value L1 of inductor 120A.

[0045] Inductor 120A and inductor 120B can be implemented by coils having one or more turns and are respectively located on opposite surfaces (or each half side, depending on the shape of printed circuit board (PCB) 110) of printed circuit board (PCB) 110 to maximize the measurement sensitivity of device 100. However, inductors can also be arranged in other forms or positions. The oscillations on path 161A and path 161B can be sinusoidal signals in nature.

[0046] The following is a detailed description of an embodiment of the present invention. Inductors 120A and 120B are configured to have the same inductance value and tolerance level. Similarly, capacitors 132A and 132B are also configured to have the same capacitance value and tolerance level, so that the oscillation (resonance) frequency of the signals on path 161A and path 161B (i.e., the output signal of the oscillator) is the same. However, it should be noted that the inductance and capacitance values ​​of the two LC resonant circuits may usually be different, resulting in different oscillation frequencies on path 161A and path 161B. In this case, the frequency comparison module 190 and the logic module 170 (as follows) can achieve measurement by corresponding changes to the technology (compared to when the oscillation frequencies of the signals on path 161A and path 161B are equal). Before being deployed to the measurement site, the device 100 may need to be calibrated. In addition, for different resonant frequencies, a fixed offset will be generated in the frequency difference or CD (count difference, both of which are annotated in the following section), but it will not affect the measurement capability of the device 100 herein.

[0047] Figure 2 A method for implementing oscillator 160A and oscillator 160B (and Figure 4 An example topology of one of the oscillators in FIG. Figure 2 The oscillator topology shown comprises two cross-coupled transistors 220A and 220B, with an LC resonant circuit (inductor 250 and capacitor 240 connected in parallel) as a load. A power supply Vdd (299) is connected to the center tap of the inductor 250. A current source 210 is connected between the source terminals of the transistors 220A and 220B and the ground terminal GND (201). The inductance value of the inductor 250 and the capacitance value of the capacitor 240 determine the resonant frequency of the oscillator. The combination of the inductor 250 and the capacitor 240 corresponds to Figure 1A and Figure 4 LC resonant circuit in the oscillator. The cross coupling (from the drain of one transistor to the gate of the other transistor) provides positive feedback and ensures continuous (non-damped) oscillation at the resonant frequency, which is available as a differential signal between nodes 225A and 225B, or as a single-ended signal between either node 225A or 225B and ground GND, corresponding to Figure 1Aand Figure 4 The output signal of the oscillator (eg, the signal of path 161A, the signal of path 161B). Figure 2 The working mode of the circuit is well known in the relevant field and will not be described here for the sake of brevity. It should also be noted that other existing technologies and topologies can also be used to replace Figure 2 For example, a circuit having a negative resistance device (such as a tunnel diode) can be combined with an LC resonant circuit to implement the oscillator of this article.

[0048] Each of oscillators 160A and 160B has a "default oscillation frequency". The "default oscillation frequency" herein refers to the oscillation frequency of the oscillator when the inductance value in the oscillation circuit does not change and is not affected by external factors, such as the proximity of the oscillator (or inductor to be more precise) to metal, environmental factors (such as temperature, humidity, etc.). Similarly, inductors 120A and 120B also have a "default inductance value" of the inductance, and the default inductance value is the value used when designing and applying the inductance. However, the inductor may be affected by external factors, such as the proximity of the inductor to metal, environmental factors (such as temperature, humidity, etc.), causing the default inductance value to change.

[0049] As described above, the change in the inductance of an inductor can be used to measure parameters related to several phenomena. It is well known that when there is a metal object with current flowing near the inductor, the inductance value will change. The magnitude of the change in inductance value usually depends on the distance between the metal and the inductor. Therefore, when the metal is close to the inductor, it will appear as a change in the inductance value, causing it to deviate from its default inductance value. However, at least some of such changes will not be distinguishable from changes in the inductance value caused by environmental factors. For example, changes in ambient temperature will also cause corresponding changes in inductance. According to one aspect of the present invention, in addition to the oscillator 160A as the main oscillator, a reference oscillator 160B with a reference inductor 120B is also used in the device. Environmental factors will simultaneously affect the inductance value L1 of the inductor 120A and the inductance value L0 of the inductor 120B, thereby simultaneously affecting the resonant frequencies F1 and F0, ultimately resulting in equal changes in F1 and F0. Therefore, by comparing F1 and F0, changes in L1 or L0 (if any) due to factors other than environmental factors can be determined and used in multiple applications.

[0050] The presence of metal near the inductor 120A changes the inductance value L1 of the inductor 120A, thereby changing the resonant frequency F1. Similarly, the presence of metal near the inductor 120B also changes the inductance value L0 of the inductor 120B, thereby changing the resonant frequency F0. The mounting positions of the inductors 120A and 120B need to be sufficiently separated so that the metal near the inductor 120A does not significantly affect the inductance value L0 of the inductor 120B, and the metal near the inductor 120B does not significantly affect the inductance value L1 of the inductor 120A.

[0051] Continue to refer Figure 1A The frequency comparison module 190 receives the signals on the path 161A and the path 161B (hereinafter directly described as the signal 161A and the signal 161B), and compares the two signals to determine whether the respective resonant frequencies F1 and F0 have any changes from their default values. Based on the comparison result, the frequency comparison module 190 outputs a corresponding signal on the path 191 to indicate that the inductance of the corresponding inductor (120A or 120B) has changed.

[0052] Based on the disclosure provided herein, the resonant frequency F1 and the resonant frequency F0 can be compared in various ways, which is obvious to those skilled in the art. For example, the frequency comparison module 190 can obtain the difference between F1 and F0 within a certain counting window. If F1 is greater than F0, the frequency comparison module 190 concludes that the inductance value L1 of the inductor 120A decreases within the counting window; if F1 is less than F0, the frequency comparison module 190 concludes that the inductance value L0 of the inductor 120B decreases within the counting window. The frequency comparison module 190 can also further infer the presence of metal near the corresponding oscillator / inductor based on the comparison result. In addition, based on the degree of frequency difference, the frequency comparison module 190 can also determine other conditions, for example, based on the principle that the inductance change of the inductor is inversely proportional to the distance between the inductor and the metal, the distance between the metal and the corresponding oscillator / inductor can be determined.

[0053] Alternatively, the frequency comparison module 190 can achieve comparison by obtaining the ratio (rather than the difference) between F1 and F0 and draw a corresponding conclusion. The frequency comparison module 190 can convert the sinusoidal oscillation signals on the paths 161A and 161B into digital square wave signals (for example, using a comparator) internally before comparison, and for convenience, the obtained digital signals are also referred to as signals 161A and 161B in this article.

[0054] In one embodiment of the present invention, the frequency comparison module 190 is designed to compare F1 and F0 by obtaining the ratio of F1 and F0, and Figure 1BAs shown in the implementation. Figure 1B As shown, the frequency comparison module 190 includes a counter 140 , a frequency divider 150 and a logic module 170 .

[0055] The counter 140 is used to count the number of cycles of the signal 161A. As an example, the counter 140 can be implemented using a chain of sequentially connected triggers and receives a signal 154 from the frequency divider 150. For example, the signal 154 can be connected to the "enable" terminal of the counter 140, which is used to enable the counting operation of the counter 140. The signal 154 indicates the start and end instants of the operation of the counter 140, which is used to define a "counting window". The counter 140 can be implemented in a known manner. Therefore, the counter 140 can be used to obtain the number of oscillations (cycles) of the oscillator 160A (represented by the signal 161A or a signal derived therefrom) by counting the number of rising edges or falling edges of the signal 161A occurring within a fixed duration (counting window). The counting window is set by the frequency divider 150 via the path 154, please refer to the following description for details:

[0056] The count value obtained by the counter 140 in the counting window depends on the signal frequency on the path 161A and the path 161B, and the signal frequency is inversely proportional to the inductance values ​​L1 and L0 of the inductor 120A and the inductor 120B, respectively (usually F is inversely proportional to 1 / √L). As is well known in the related art, when there is electromagnetic coupling between the inductor and the metal (when the inductor is energized and carries AC), the inductance value of the inductor will change, and the degree of change in the inductance value usually depends on the proximity between the metal and the inductor.

[0057] Frequency divider 150 is a digital module for dividing the frequency of signal 161B by a fixed value (although the value itself is programmable or easily changed) to generate a frequency-divided signal on path 154. In one embodiment, the duration of the logic high (or the duration of the logic low, or a cycle / phase) of the frequency-divided signal can be used to enable counter 140 to count, thereby defining a counting window. Alternatively, instead of sending the frequency-divided signal itself through path 154, a signal derived from the frequency-divided signal can be forwarded on path 154 to set the counting window. The signal on path 154 (hereinafter referred to as signal 154) can be synchronized with the signal on path 161B to obtain an accurate counting window, which can be expressed as an integer multiple of the time period of signal 161B. Signal 161A is gated by signal 154 (within counter 140, details not shown). When signal 154 is asserted (e.g., logic high), counter 140 obtains a periodic input and starts counter operation. When signal 154 is toggled (eg, logic low), counter 140 is frozen (stops incrementing / counting) and the count value is sent to logic module 170. Thus, the count value on path 147 represents the ratio of resonant frequencies F1 and F0.

[0058] Logic module 170 receives the count value that occurs in the count window on path 147 and processes the count value. One way of processing is to determine whether the count value has changed compared to a default count value (a count value when the inductance value of the inductor does not change). From the change, logic module 170 can determine which (but not both) of the inductances of inductor 120A and inductor 120B has changed. If the environmental factor affects both inductors to the same extent, then the change only indicates the impact of factors other than the environmental factor on the inductor.

[0059] Assuming that the N-cycle time range of the oscillation of signal 161B covers the "counting window" of counter 140, the count value generated by counter 140 on path 147 is equal to (N*F1) / F0, where F1 and F0 are the default oscillation frequencies of signal 161A and signal 161B respectively, "*" represents the multiplication operator, and "N" represents the number of cycles of F0 in the counting window 154.

[0060] The logic module 170 obtains the count value difference (CD) given by the expression [N-(N*F1) / F0]. CD represents the change in the inductance value of one of the inductor 120A and the inductor 120B. Therefore, when the default inductance values ​​of the two inductors are equal, the default resonant frequencies are equal, and the inductance values ​​L1 and L0 do not change, CD is equal to zero. When CD is a negative value, it means that the resonant frequency F1 increases in the counting window (F0 remains unchanged at the default value), so the inductance value L1 of the inductor 120A decreases in the counting window. A positive CD value means that F0 increases in the counting window (F1 remains unchanged at the default value), so the inductance value L0 of the inductor 120B decreases in the counting window. A CD value of zero means that neither the inductance values ​​L0 nor L1 has changed or both have changed the same. When metal approaches either of the two inductors, the inductance value of the corresponding inductor decreases, so the resonant frequency of the corresponding oscillator increases. Therefore, based on the sign of CD, logic module 170 can determine which inductor is close to the metal and generate a corresponding signal on path 191. In addition, logic module 170 can also determine the metal and the inductor based on the size of CD.

[0061] Environmental changes, such as changes in heat and / or humidity, typically affect the inductance values ​​of inductor 120A and inductor 120B equally, i.e., in the same manner and to the same extent. Based on the above description, it can be understood that as long as changes in the environment (e.g., heat and humidity) affect the inductance of both inductors 120A and inductor 120B in the same manner and to the same extent, i.e., affect the resonant frequencies F1 and F0 in the same manner / to the same extent, the count difference (CD) will remain zero. Therefore, using a reference oscillator with a reference inductor in the device 100 (as in some prior art, in addition to only one oscillator) enables the device 100 to be used to determine parameters related to one or more phenomena (e.g., fluid flow) that can cause changes in inductance values, and enables the measurement results to always be unaffected by environmental changes.

[0062] The device 100 can be used to detect, for example, displacement, linear motion, and rotational motion of a metal object, and determine parameters of several phenomena based on such detection results. In one embodiment, the detection device 100 is used to measure the flow rate of a fluid that causes a metal object to rotate in a circular motion, as described in detail in the following embodiments.

[0063] 3. Determine fluid flow rate

[0064] Figure 3A Instructions for use Figure 1B The device 100 in the embodiment of the present invention determines the flow rate of a fluid (liquid or gas). Figure 3A , 3BIn FIG. 3 and FIG. 3C , only the printed circuit board (PCB) 110 and the inductor 120A and the inductor 120B are shown. However, it should be understood that the device 100 will also include Figure 1A-1B All other components / modules, inductor 120A and inductor 120B are arranged as shown.

[0065] The printed circuit board (PCB) 110 is placed adjacent to the disk / plate 260, for example, with the center of the disk 260 aligned with the axis 240, and the planes of the disk 260 and the printed circuit board (PCB) 110 being substantially parallel to each other. Half of the disk is metal 220, and the other half is non-metal 230. Alternatively, the disk 260 may include only metal 220, and the other half of the disk 260 may not include any material. In other alternative embodiments, the metal 220 may cover a larger portion or a smaller portion of the disk, rather than exactly half, and accordingly, the technology applied in the logic module 170 needs to be modified accordingly to determine the fluid flow rate, and such modifications will be apparent to those skilled in the relevant art when reading the disclosure herein.

[0066] Reference again Figure 3A , it can be observed that the positions of the inductors L0 and L1 are such that they are located in the two side areas of the printed circuit board (PCB) 110, respectively, so that it can be ensured that the metal 220 is electromagnetically coupled (at least mainly) to only one of the inductors during each half-turn of the disk 260. In the following description, it is assumed that the disk 260 is circular, although other shapes can also be used, and the disk 260 is fixed on the shaft 240. The combination of the printed circuit board (PCB) 110 and the disk 260, as well as the shaft 240, can be assembled to be contained in a structure (e.g., a cylinder) not shown. Using a suitable mechanism (not shown), the disk 260 can be rotated around the shaft 240 (as shown by arrow 250) by a fluid (e.g., water flowing in a pipe, the valve disc is connected to the inside of the pipe by a suitable mechanism), and the flow rate of the fluid is to be measured. The number of rotations of the disk 260 per unit time is represented as the flow rate of the fluid. Mark 210 represents the electromagnetic connection between the inductor L0 and the metal 220, which causes a current to flow in the metal 220, thereby reducing the inductance of the inductor L0. In the embodiment described below, the default inductance values ​​(values ​​that remain unchanged through interaction with metal, environment, etc.) of inductor 120A and inductor 120B are equal, and the capacitances of capacitor 132A and capacitor 132B are equal, so the default value of resonant frequency F1 is equal to the default value of resonant frequency F0.

[0067] When the device 100 is powered on and in operation, and the disk 260 is rotated by the fluid flow (as shown at 250), during each rotation of the disk 260, the metal 220 is alternately moved to a position close to the inductor 120A (L1) and the inductor 120B (L0). Figure 3B and 3CIn FIG. 1 , the inductor close to the metal 220 is represented by a dot-filled circle, while the inductor close to the non-metal 230 is represented by a circle without dot-filled circle. Therefore, Figure 3B 2 shows the state when the metal 220 is close to the inductor L0 (for example, located directly below), and Figure 3C A state is shown when the metal 220 is close to (eg, located directly below) the inductor L1 .

[0068] like Figure 3B As shown, when the metal 220 approaches the inductor L0, the amplitude of L0 decreases (as above), while the amplitude of L1 remains unchanged (i.e., equal to the default value). As above, the count value generated by the counter 140 is equal to (N*F1) / F0. Due to the proximity of the metal 220, L0 decreases from its default value, while F0 increases from its default value (F1 remains unchanged because L1 does not change), and the count value generated by the counter 140 becomes less than the default value of [(N*F1) / F0]. The default value of [(N*F1) / F0] is the default count value when the values ​​of the inductors L0 and L1 are not affected by any metal.

[0069] When the metal 220 is close to the inductor L1, as Figure 3B As shown, the amplitude of L1 decreases, while the amplitude of L0 remains unchanged (i.e., equal to the default value). Due to the presence of metal 220, L1 decreases from its default value, F1 increases (since L0 does not change, F0 remains unchanged), and the count value generated by counter 140 becomes greater than the default value of [(NxF1) / F0].

[0070] The default value of [(N*F1) / F0] is denoted as “default count value (NC)”, and the count value (C) generated by the counter 140 is denoted as “measured count value (MC)” when the disk 260 rotates, and then the count value difference (CD) is equal to [“measured count value” – “default count value”], and CD alternates between positive and negative values ​​during each rotation of the disk 260. The logic module 170 maintains a local copy of NC, which can be programmed into the logic module 170. The logic module 170 is also used to continuously calculate CD.

[0071] During the half rotation of the disk 260, the metal 220 is close to the inductor L1, and the counter 140 may generate one or more MCs. The specific number of MCs generated depends on the rotation speed of the disk 260. However, it can be understood from the above description that each value of MC will be greater than NC. Therefore, during this half rotation of the disk 260, each of the CDs calculated by the logic module 170 will be positive.

[0072] During the other half of the rotation of disk 260, metal 220 is close to inductor L0, and there may be one or more MC instances generated by counter 140. The specific number of MC instances depends on the rotation speed of disk 260, as described above. However, it can be understood from the above description that each instance of MC will be less than NC. Therefore, during this half rotation of disk 260, each of the CD calculations of logic module 170 will be negative.

[0073] The logic module 170 can also be used to calculate the transition time between the positive and negative values ​​of CD. Twice the calculated transition time is equal to the time for the disk 260 to rotate one circle. The logic module 170 can maintain a real-time clock internally, and using this real-time clock, the logic module 170 can be used to calculate the time of a single rotation. Based on the obtained time of a single rotation, the number of rotations per second (rps) or the number of rotations per minute (rpm) is calculated. Based on the rps or rpm, and (if necessary) based on the way the disk 260 is coupled to the fluid (for example, the specific details of the coupling mechanism, such as gears, transmission ratios, etc., the parameters related to which can be pre-stored in the logic module 170 by the system deployer), the logic module 170 can determine the fluid flow rate (for example, in meters per second) and provide a corresponding value on the path 171.

[0074] Due to the above reasons, the calculated fluid flow rate may not be affected by changes in the inductance values ​​of the inductor 120A and the inductor 120B caused by environmental changes.

[0075] It should be noted that the above techniques for detecting the rotational motion of metals can also be applied to detecting the linear motion of metal objects. Figure 3A The device 100 shown can be placed proximal to (and parallel to) a surface moving in a straight line, such as a conveyor belt. A metal object placed on the moving surface will cause the inductances L0 and L1 (such as Figure 3B and 3C As the surface moves in a straight line, the corresponding one of F0 or F1 changes when the metal passes under the corresponding inductor, thereby causing the count difference CD to change. The logic module 170 can be used to calculate the transition time between the positive and negative (or vice versa) values ​​of CD to determine the surface speed.

[0076] By using two inductors (120A and 120B), only the fluid flow rate can be detected, but the fluid movement direction cannot be detected. Therefore, the device 100 can only be used to measure unidirectional fluid flow.

[0077] According to another aspect of the present invention, a device capable of measuring fluid flow rate and direction is implemented using an additional third inductor, as follows.

[0078] 4. Determine flow direction and flow rate

[0079] Figure 4 4 is a schematic diagram of an apparatus 400 implemented in accordance with the present invention, which is capable of determining the flow rate and flow direction of a fluid. The apparatus 400 shown includes an oscillator (LC oscillator-2) 405A, an oscillator 405B (LC oscillator-1), an oscillator 405C (LC oscillator 0), a frequency comparison module 490, and a PCB 410. The oscillator (LC oscillator-2) 405A, the oscillator 405B (LC oscillator-1), the oscillator 405C (LC oscillator 0), and the frequency comparison module 490 are mounted on the PCB 410, and in one embodiment, are implemented using discrete modules / components. However, in another embodiment, only the inductors 420A (L42), 420B (L41), and 420C (L40) are implemented in the form of discrete devices, Figure 4 The remaining components and / or modules of the PCB 410 are all implemented in the form of an integrated circuit (IC). In such an embodiment, the inductors L42, L42 and L40 are located outside the IC, and all the inductors L42, L41 and L40 and the integrated circuit IC are mounted on the PCB 410.

[0080] Typically, any one of oscillator 405A, oscillator 405B, and oscillator 405C is connected to Figure 1A Similar to the oscillator in .

[0081] As shown, oscillator 405C includes capacitor 432C, inductor 420C and amplifier 435C. Capacitor 432C and inductor 420C form an LC (inductor-capacitor) resonant circuit, and the values ​​of L and C determine the resonant frequency of the oscillation. The output of the LC resonant circuit is connected to amplifier 435C, which introduces positive feedback (not shown) and produces a continuous oscillation on path 409C with a resonant frequency F40 (i.e., an oscillation that does not decay over time as long as the oscillator is powered).

[0082] Oscillator 405B includes capacitor 432B, inductor 420B and amplifier 435B. Capacitor 432B and inductor 420B form an LC (inductor-capacitor) oscillating circuit, with the values ​​of L and C determining the resonant frequency of the oscillation. The output of the LC resonant circuit is connected to amplifier 435B, which introduces positive feedback (not shown) and generates a continuous oscillation on path 409B having a resonant frequency F41 (i.e., an oscillation that does not decay over time as long as the oscillator is powered).

[0083] As shown, oscillator 405A includes capacitor 432A, inductor 420A and amplifier 435A. Capacitor 432A and inductor 420A form an LC (inductor-capacitor) oscillating circuit, with the values ​​of L and C determining the resonant frequency of the oscillation. The output of the LC resonant circuit is connected to amplifier 435A, which introduces positive feedback (not shown) and produces a continuous oscillation on path 409A having a resonant frequency F42 (i.e., an oscillation that does not decay over time as long as the oscillator is powered).

[0084] and Figure 1A , each of the frequencies F40, F41 and F42 has a default value. Each of the inductor 420A, the inductor 420B and the inductor 420C has a respective default inductance value. In the following description, the inductor 420A, the inductor 420B and the inductor 420C each have the same default inductance value and manufacturing tolerance level. Similarly, the capacitor 432A, the capacitor 432B and the capacitor 432C are implemented to have the same capacitance value and tolerance level. Therefore, the default values ​​of F42, F41 and F40 are the same. However, L42, L41 and L40, as well as F42, F41 and F40, can also have different default values ​​generally, which for different resonant frequencies, will result in a fixed offset of the frequency difference or the count difference CD1 and / or the count difference CD2. The frequency comparison module 490 and the logic module 470 (both described below) are implemented by corresponding changes to the techniques described below to account for this fixed offset during the actual measurement process without affecting the functionality of the apparatus 400 described herein. Figure 1A Similarly, metal near an inductor will change the frequency of the corresponding oscillator.

[0085] Frequency comparison module 490 receives signals 409A, 409B and 409C. Frequency comparison module 490 compares the frequencies of signal 409A and signal 409C and signal 409B and signal 409C to determine whether any change from the default value has occurred in respective frequencies F42, F41 and F40. Based on the result of the comparison, frequency comparison module 490 indicates that the inductance of the corresponding inductor has changed on path 491. The operation of frequency comparison module 490 is similar to the operation of frequency comparison module 190, and for the sake of brevity, only briefly described below. Therefore, frequency comparison module 490 can be performed by obtaining the difference of the corresponding frequency pair (F42 and F40, and F42 and F41), or by obtaining the ratio of the corresponding frequency pair to perform the above-mentioned comparison.

[0086] In one embodiment of the present invention, the frequency comparison module 490 is designed to compare the frequency pairs (F42 and F40, and F42 and F41) by obtaining the ratios of F42 and F40 and F42 and F41, and Figure 4 As shown in the implementation. Figure 4 In the embodiment, the frequency comparison module 490 includes a counter 440 and a counter 460 , a frequency divider 450 and a logic module 470 .

[0087] Inductor 420A, inductor 420B and inductor 420C may be implemented in the form of coils, and in one embodiment, inductor 420A, inductor 420B and inductor 420C are annularly spaced at intervals of 120 degrees (relative to center 620 ) to maximize the sensitivity and measurement range of device 400 . Figure 6 A schematic diagram of such a layout of the inductor is shown, and in addition a PCB 410 and a sensor IC (integrated circuit) 600 are shown. Figure 6 In the embodiment, the coils of inductor 420A, inductor 420B and inductor 420C can be printed on PCB 410 in the form of conductive traces. A small portion of each conductive trace is printed on the other side of the PCB 410 to make the layout of each coil as shown in FIG. Figure 6 410 . Thus, for example, for inductor 420B, vias 621 and 622 connect a small portion 623 (indicated by the dashed lines) of a trace printed on opposite side surfaces of PCB 410. Inductor 420A and inductor 420C are implemented similarly. In alternative embodiments, other angles and / or layouts of the inductors may be employed. In addition, while each inductor coil is shown as having two turns, they may typically have more or fewer turns. Rectangular bars such as 631 and 632 represent signal pads for connecting to pins of sensor IC (integrated circuit) 600. Each of inductor 420A, inductor 420B, and inductor 420C is connected between two corresponding pins of sensor IC (integrated circuit) 600.

[0088] exist Figure 6 In the example of FIG. 1 , the sensor IC (integrated circuit) 600 includes Figure 4 All circuit blocks / components except logic module 470, which is implemented in the form of a microcontroller outside sensor IC (integrated circuit) 600 and PCB 410. However, it should be noted that Figure 4 Fewer or all modules may be implemented separately from PCB 410. Figure 6 The output of sensor IC 620 corresponds to Figure 4 The signals on path 467 and path 447 are provided on path 601 and path 608, respectively. Sensor IC (integrated circuit) 600 can also provide Figure 6 Other signals not shown, such as Figure 4400. The sensor IC 600 may be connected to the external microcontroller via the connector.

[0089] For the sake of simplicity, the following description assumes that Figure 3A As shown, the arrangement of the plate / disk 260 with the shaft 240 and the coupling mechanism corresponding to the fluid (whose direction is to be measured) is used with the device 400 and will not be repeated here. The PCB 410 or device 400 is generally similar to the above description of Figure 1A The printed circuit board (PCB) 110 is placed near the plate 260. In addition, it is assumed that the default values ​​of the inductors L40, L41 and L42 all correspond to a default resonant frequency.

[0090] In one embodiment, the disk 260 is placed close to the PCB 410, the planes of the PCB 410 and the disk 260 are substantially parallel to each other, and the center of the circular area 620 including the three inductors ( Figure 6 ) is aligned with axis 240 (is on the same line as axis 240).

[0091] Above Figure 2 The example topology of can be used to implement any one of oscillators 405A, 405B and 405C. Sinusoidal signals F40, F41 and F42 can be converted into digital square wave signals by front-end components (such as comparators) included in counters 440 and 460 and frequency divider 450. It is also noted here that oscillators 405A, oscillators 405B and oscillators 405C can be implemented in other forms and can also use other topological structures, which is common knowledge in the relevant field.

[0092] Counter 460 counts the number of cycles of signal 409A. For example, counter 460 can be implemented using a chain of flip-flops connected in sequence and receives signal 454 from distributor 450. For example, signal 454 can be connected to an "enable" terminal of counter 460, which enables the counting operation of counter 460. Signal 454 defines a "counting window" of counter 460 by indicating the start and end times. Counter 460 can be implemented in a known manner. Therefore, counter 460 can be used to obtain the number of oscillations (cycles) of oscillator 405A by counting the number of rising or falling edges of signal 409A occurring within a fixed duration (counting window).

[0093] The operation of counter 440 is similar to that of counter 460 described above (except that counter 440 receives signal 409B instead of signal 409A), and for the sake of brevity, the description is not repeated. Counter 440 and counter 460 forward their respective determined count values ​​to logic module 470 via respective paths 447 and 467.

[0094] Frequency divider 450 is a digital module that divides the frequency of signal F40 by a fixed value (although the value itself is programmable or can be easily changed) to generate a divided signal on path 454. For example, the logic high duration (or logic low duration, or one cycle / cycle) of the divided signal enables both counter 440 and counter 460 to count, thereby defining a counting window. Alternatively, rather than forwarding the divided signal itself on path 454, a signal derived from the divided signal can be forwarded on path 454 to set the counting window.

[0095] Regarding the above Figure 1A Similarly, the counts obtained by counter 440 and counter 460 depend on the frequencies of signals 409A / 409C and 409B / 409C, respectively. The frequencies of signals 409A, 409B, and 409C are inversely proportional to inductances L42, L41, and L40, respectively. The degree of change in inductance depends on the proximity of the metal to the corresponding inductance.

[0096] Logic module 470 receives the respective count values ​​of counter 460 and counter 440 appearing in the count windows on respective paths 467 and 447 and processes the count values ​​to determine the fluid flow direction and flow rate as follows.

[0097] and Figure 1A Similarly, oscillator 405C may be considered a "reference" oscillator, and inductor L40 may be considered a "reference" inductor. Due to the use of a reference inductor, the measurement of the low pressure direction of the fluid may not be affected by changes in environmental conditions (eg, temperature and humidity).

[0098] Reference below Figure 4 and Figure 5A-Figure 5C The manner in which the device 400 determines the direction of fluid flow is described. Figure 5A , 5B In each of 5C, only PCB 410 and inductors L42, L41 and L40 are shown, although it should be understood that other components / modules of device 400 will also be present. The locations of inductors L40, L41 and L42 are indicated by circles with inner reference numerals 40, 41 and 42, respectively. Figure 5A , 5B In each of the Figures 5C and 5C, the filled circle (e.g., Figure 5A40 and 41 in the figure) indicate that when the disk rotates due to the fluid flow, the metal portion 220 of the disk 260 is close to the corresponding inductor, rather than the filled circle (e.g., Figure 5A The circles with labels 42 in the figure indicate corresponding inductors to which the non-metallic portions of the disk 260 approach when the disk 260 rotates due to fluid flow.

[0099] As the disk 260 rotates, Figure 5A , 5B and the situation shown in 5C. Figure 5A 2 shows the situation when the inductors L40 and L41 are close to the metal 220 of the disk 260, and the inductor L42 is close to the non-metal 230 of the disk 260. Therefore, the inductance values ​​of L41 and L40 are reduced from their default values, while the inductance of L42 remains unchanged at its default value.

[0100] According to the above description, when the disk 260 rotates, when the corresponding inductors L42, L41 and L40 approach the metal 220, the values ​​of the corresponding frequencies F42, F41 and F40 change (increase) relative to their default values.

[0101] exist Figure 5A , L41 decreases from its default value, L42 remains at its default value, and L40 decreases from its default value. Correspondingly, F40 and F41 increase based on their default values, while F42 remains unchanged at its default value. Therefore, the output of counter 460 decreases below the default value of [(N*F42) / F40], and the output of counter 440 remains unchanged at the default value of (N*F41) / F40]. Therefore, the count difference (CD2) = ["measured count value" - default count value"] calculated by the logic module 470 will be a negative value, and the count value difference (CD1) = ["measured count value" - default count value"] calculated by the logic module 470 based on the counter 440 will be zero.

[0102] Following the above logic, for Figure 5B In this case, the count value difference (CD2) = [“measured count value” – default count value”] calculated by the logic module 470 according to the counter 460 will be zero, and the count value difference (CD1) = [“measured count value” – default count value”] calculated by the logic module 470 according to the counter 440 will be a negative value.

[0103] Similarly, for Figure 5C In this case, the count value difference (CD2) = [“measured count value” – “default count value”] calculated by the logic module 470 according to the counter 460 will be a positive value, and the count value difference (CD1) = [“measured count value” – “default count value”] calculated by the logic module 470 according to the counter 440 will also be a positive value.

[0104] Combined with reference Figure 5A , 5B and 5C, the disk 260 is in accordance with Figure 5A , Figure 5B , Figure 5C , Figure 5A The disk 260 rotates in a clockwise direction. Figure 5A , Figure 5C , Figure 5B , Figure 5A The sequential cycle indicates that the disk 260 rotates in a counterclockwise direction.

[0105] Based on the above, the logic module 470 can determine the rotation direction of the disk 260 as follows:

[0106] a) If the changing sequence of CD1 is zero, negative, positive, and the changing sequence of CD2 is negative, zero, positive, then the rotation direction of disk 260 is clockwise.

[0107] b) If the changing sequence of CD1 is zero, then positive, then negative, and the changing sequence of CD2 is negative, then positive, then zero, then the rotation direction of disk 260 is counterclockwise.

[0108] Based on determining whether the rotation of disk 260 is clockwise or counterclockwise, logic module 470 feeds back the direction of fluid flow (eg, left or right, north or south, etc.) on path 471 .

[0109] It should be noted that the fluid flow rate may be determined by the logic module 470 based on the time required for CD1 or CD2 to complete a change cycle, which is obvious to those skilled in the relevant art.

[0110] It should also be noted that due to the above techniques (including the use of a reference oscillator), the oscillator frequency can be measured with high accuracy (e.g., by a counter), thereby enabling detection of small inductance changes. This can allow the distance between disk 260 and the inductor coil to be greater than would otherwise be possible.

[0111] References in this specification to "one embodiment" or "an embodiment" and similar language mean that a particular feature, structure, or characteristic described in conjunction with the embodiment is included in at least one embodiment of the present disclosure. Therefore, the appearances of the phrases "in one embodiment," "in an embodiment," and similar language throughout this specification may, but do not necessarily, all refer to the same embodiment.

[0112] exist Figure 1A , 1B, 2, 4 and 6, although the terminals / nodes are shown directly connected to various other terminals, it should be understood that there may be other components in the path (to suit the particular environment), and therefore, the connections can be considered to be "electrically coupled" to the same connection terminals.

[0113] The above are merely embodiments of the present application and are not intended to limit the patent scope of the present application. Any equivalent structural or equivalent process transformations made using the contents of the specification and drawings of the present application, such as the mutual combination of technical features between the embodiments, or direct or indirect application in other related technical fields, are also included in the patent protection scope of the present application.

Claims

1. A detection device, characterized in that: include: A first oscillator, comprising a first LC resonant circuit, wherein the first oscillator generates a first continuous oscillation signal at a first resonant frequency determined by the first LC resonant circuit, wherein a first inductor of the first LC resonant circuit has a first default inductance value; a second oscillator, comprising a second LC resonant circuit, wherein the second oscillator generates a second continuous oscillation signal at a second resonant frequency determined by the second LC resonant circuit, wherein a second inductor of the second LC resonant circuit has a second default inductance value; a frequency comparison module, configured to be coupled to the first oscillator and the second oscillator to receive the first continuous oscillation signal and the second continuous oscillation signal; When metal approaches the first inductor or the second inductor, the first default inductance value or the second default inductance value changes accordingly, so that the corresponding first resonant frequency or the second resonant frequency changes, thereby changing the frequency of the first continuous oscillation signal or the second continuous oscillation signal; The frequency comparison module is designed to compare the frequency of the second continuous oscillation signal with the frequency of the first continuous oscillation signal to determine corresponding changes in the first default inductance value and the second default inductance value.

2. The detection device according to claim 1, characterized in that: The frequency comparison module may perform comparison by obtaining a ratio between the frequency of the second continuous oscillation signal and the frequency of the first continuous oscillation signal.

3. The detection device according to claim 2, characterized in that: Also includes: a third oscillator, the third oscillator comprising a third LC resonant circuit, the third oscillator generating a third sustained oscillation signal at a third resonant frequency, wherein a third inductor of the third LC resonant circuit has a third default inductance value; The frequency comparison module is used to receive the frequency of the third continuous oscillation signal; When metal approaches the third inductor, the third default inductance value changes, so that the third resonant frequency of the third continuous oscillation signal changes; The frequency comparison module is designed to perform another comparison of the frequencies of the third continuous oscillation signal and the first continuous oscillation signal by obtaining a ratio of the frequencies of the third continuous oscillation signal and the first continuous oscillation signal, thereby determining a change in the third default inductance value.

4. The detection device according to claim 3, characterized in that: The frequency comparison module comprises: a first frequency counter, coupled to the second oscillator, receiving the second continuous oscillation signal, and obtaining a first count value of a plurality of cycles of the second continuous oscillation signal in a counting window, wherein when the inductances of the first inductor and the second inductor are respectively equal to the first default inductance value and the second default inductance value, the first measured count value is equal to the first default count value; and when the first default inductance value or the second default inductance value changes, the first count value deviates from the first default count value; a frequency divider coupled to the first oscillator to receive the first continuous oscillation signal and separate the frequency of the first continuous oscillation signal to generate the counting window, the frequency divider coupled to the first frequency counter to indicate the counting window to the first frequency counter; A logic module is coupled to the first frequency counter to receive the first measured count value, and the logic module is used to obtain a first count value difference between the first count value and the first default count value, and determine a change amount of a corresponding one of the first default inductance value and the second default inductance value according to the first count value difference.

5. The detection device according to claim 4, characterized in that: The frequency comparison module further comprises a second frequency counter for receiving the third continuous oscillation signal and the counting window, the frequency comparison module being used to obtain a second count value of a plurality of cycles of the third continuous oscillation signal occurring in the counting window, wherein when the inductance of the first inductor and the inductance of the third inductor are respectively equal to the first default inductance value and the third default inductance value, the second count value is equal to the second default count value, but when the inductance value of a corresponding one of the first inductor and the third inductor changes relative to the first default inductance value and the third default inductance value, the second count value deviates from the second default count value; The logic module is coupled to the first frequency counter to receive the second measurement count, obtains a second count difference between the second count value and the second default count value, and determines a change in the third default inductance value according to the second count difference.

6. The detection device according to claim 1, characterized in that: The metal has at least a rotatable surface, the rotatable surface approaches the device in a linear motion and / or a rotational motion, and the motion of the rotatable surface causes the first default inductance value and the second default inductance value to change accordingly in sequence; The frequency comparison module is designed to determine the speed of the linear motion or the rotational motion by calculating a time difference between the change in the first default inductance value and the change in the second default inductance value.

7. The detection device according to claim 4, characterized in that: The metal includes a portion of a rotatable surface, the rotatable surface is coupled to a fluid by a coupling mechanism, the coupling mechanism is designed to rotate the rotatable surface at a rate proportional to the flow rate of the fluid, thereby causing the first frequency counter to generate a set of multiple values ​​of the first measurement count value in corresponding count windows; The logic module is designed to determine the flow rate of the fluid based on processing of the set of multiple values ​​and the first default count value.

8. The detection device according to claim 7, characterized in that: The rotatable surface is a disk, the metal being in one half and the non-metal being in the other half; wherein the rotation of the rotatable surface is designed to cause the metal to approach the first inductor and the second inductor in sequence during each complete rotation, and in corresponding parts of the rotation, the first default inductance decreases and the first measurement count value increases to be greater than the default count value, and the second default inductance value decreases and the first measurement count value decreases to be less than the default count value; Wherein, when the non-metal is close to any one of the first inductor and the second inductor, the inductance values ​​of the first inductor and the second inductor remain unchanged at respective default values; wherein the logic block is designed to determine a count difference between a value in the set of multiple values ​​and the first default count value, the count difference having a positive value in one portion of the corresponding portion of each complete rotation and a negative value in the other portion; Therein, the logic block is designed to determine the flow rate of the fluid based on one or more transitions between the negative value and the positive value, or between the positive value and the negative value.

9. The detection device according to claim 5, characterized in that: The metal has a rotatable surface, the rotatable surface is coupled to the fluid via a coupling mechanism, the coupling mechanism is designed to rotate the rotatable surface at a rate proportional to the flow velocity of the fluid and reflect the flow direction of the fluid; wherein the rotation of the rotatable surface is designed to cause the first frequency counter to generate a first set of multiple values ​​of the first count value in a first set of corresponding count windows, and to cause the second frequency counter to generate a second set of multiple values ​​of the second count value in a second set of corresponding count windows; The logic module is used to determine the flow direction of the fluid according to processing of the first group of multiple values, the second group of multiple values, the first default count value and the second default count value.

10. The detection device according to claim 9, characterized in that: The rotatable surface is a disk wherein the metal is in one half and the non-metal is in the other half; wherein the rotation of the rotatable surface is designed to bring the metal into proximity with the first inductor and the second inductor in a first portion of a full rotation, into proximity with the second inductor and the third inductor in a second portion of a full rotation, and into proximity with the third inductor and the first inductor in a third portion of a full rotation, wherein the first portion, the second portion, and the third portion appear in sequence in each full rotation; the sequence includes a first sequence and a second sequence, the first sequence includes the first portion, the second portion, and the third portion in sequence, and the second sequence includes the first portion, the third portion, and the second portion in sequence; Wherein, in the first part, the metal reduces the first default inductance value and the second default inductance value, so that the first count value and the second count value are equal to zero and a positive value respectively, and the third default inductance value remains unchanged; wherein, in the second portion, the metal reduces the second default inductance value and the third default inductance value, so that the first count value and the second count value are equal to a negative value and zero, respectively, and the first default inductance value remains unchanged; Wherein, in the third portion, the metal reduces the first default inductance value and the third default inductance value, so that the first count value and the second count value are both positive values, and the second default inductance value remains unchanged; wherein the logic module is configured to determine, for each of the first portion, the second portion, and the third portion, a first count difference between the first count value and the default count value, and a second count difference between the second count value and the default count value; The logic block is designed such that if the first count difference is equal to zero, a negative value, and a positive value in sequence, and if the second count difference is equal to a negative value, zero, and a positive value in sequence, then the flow direction is determined to be the first direction; The logic block is designed so that the first count difference is equal to zero, a positive value and a negative value in sequence, and the second count difference is equal to a negative value, a positive value and zero in sequence, and the flow direction is a second direction opposite to the first direction.

11. The detection device according to claim 1, characterized in that: The frequency comparison module is designed to compare by obtaining the difference between the frequencies of the first continuous oscillation signal and the second continuous oscillation signal; Wherein, when the difference is positive, the frequency comparison module concludes that the metal is close to the first inductor; When the difference is negative, the frequency comparison module concludes that the metal is close to the second inductor.

12. The detection device according to claim 2, wherein the first default inductance value is equal to the second default inductance value, and wherein the first resonant frequency is equal to the second resonant frequency; in, The comparison enables the frequency comparison module to determine a change in the inductance of either the first inductor or the second inductor, the change being caused by factors other than environmental conditions in which the detection device is located.

13. The detection device according to claim 12, characterized in that: The environmental conditions include environmental temperature and environmental humidity.

14. The detection device according to claim 2, characterized in that: The first oscillator and the second oscillator respectively include amplifiers configured in a positive feedback mode to respectively generate and output the first continuous oscillation signal and the second continuous oscillation signal.

15. The detection device according to claim 10, characterized in that: Also includes: Printing A circuit board, wherein the first oscillator, the second oscillator, the third oscillator, the first counter, the second counter, the frequency divider and the logic module are mounted on the printed circuit board; The first inductor, the second inductor and the third inductor are all implemented in the form of conductive lines on the printed circuit board and are distributed at 120-degree circumferential intervals on the printed circuit board.

16. The detection device according to claim 15, characterized in that: The plane of the disk is arranged parallel to the plane of the PCB, and the center of the disk is aligned with the center of the circumference.

17. A detection method for a detection device, characterized in that: The detection method of the detection device comprises: receiving a first continuous oscillation signal, wherein the first continuous oscillation signal has a first resonant frequency and is generated by a first oscillator having a first LC resonant circuit, wherein the first continuous oscillation signal is determined by the first LC resonant circuit, wherein a first inductance of the first LC resonant circuit has a first default inductance value; receiving a second continuous oscillation signal, wherein the second continuous oscillation signal has a second resonant frequency and is generated by a second oscillator having a second LC resonant circuit, wherein the second continuous oscillation signal is determined by the second LC resonant circuit, wherein a second inductance of the second LC resonant circuit has a second default inductance value; comparing the frequencies of the first continuous oscillation signal and the second continuous oscillation signal to determine a change in a corresponding one of the first default inductance value and the second default inductance value; Wherein, the detection device includes the first oscillator, the second oscillator and the frequency comparison module.

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