CN112050865A

CN112050865A - Nonmagnetic induction measuring device and calculation method of rotation information of rotating plate assembly

Info

Publication number: CN112050865A
Application number: CN202010957842.1A
Authority: CN
Inventors: 渠峻松; 张勋; 谢松超; 王谦; 王彪
Original assignee: WUHAN SAN FRAN ELECTRONICS CORP
Current assignee: WUHAN SAN FRAN ELECTRONICS CORP
Priority date: 2020-09-11
Filing date: 2020-09-11
Publication date: 2020-12-08
Anticipated expiration: 2040-09-11
Also published as: CN112050865B

Abstract

The application provides a no magnetism response measuring device and rotor plate subassembly rotation information's computational method, and measuring device includes: the rotating plate assembly is used for rotating under the pushing of the fluid to be measured, and a metal layer is arranged on a preset area on the rotating plate assembly; the induction circuit board is arranged opposite to the rotating plate assembly at intervals, and a measuring circuit is arranged on the induction circuit board; the measurement circuit includes: the device comprises a pulse generating unit, a plurality of resonance units and a central processing unit. The central processing unit is used for sampling the voltage value of each resonance unit and calculating the rotation information of the rotating plate assembly between the current sampling and the last sampling according to the voltage values of the resonance units. Compared with the prior art, the detection period is shorter, the anti-magnetic interference capability is stronger, the generation of invalid excitation current is reduced, and the power consumption of the whole machine is reduced.

Description

Nonmagnetic induction measuring device and calculation method of rotation information of rotating plate assembly

Technical Field

The invention relates to the technical field of meter measurement, in particular to a nonmagnetic induction measuring device and a method for calculating rotation information of a rotating plate assembly.

Background

At present, the conventional mechanical water meter converts the metering data of the mechanical water meter into electronic data through electromechanical conversion, which is a mainstream mode in the field of civil small-caliber water meters. Currently, there are several main methods for electromechanical conversion:

1. the magnetic steel is arranged on the pointer of the water meter, and then the reed switch is arranged on the mechanical water meter to sense the rotation of the pointer, so that the metering is realized; 2. the reed switch is improved on the basis of the first scheme, and the reed switch is replaced by a Hall device or a magnetic resistance device with low power consumption; 3. the method is characterized in that a photoelectric direct reading conversion mode is adopted to reform a print wheel of the water meter, through a correlation or reflection mode, the read number of the print wheel is encoded by utilizing a photoelectric combination geminate transistor, and then the actual read number of the print wheel is read out by reading the encoded data of the photoelectric combination geminate transistor.

On the basis of the three schemes, numerous water meter manufacturers provide nonmagnetic metering, namely, electromechanical conversion of the water meters is completed in a nonmagnetic induction mode without mounting magnetic steel on the water meters. There are two common methods for non-magnetic induction metering technology, one is to adopt an induction measurement mode, and the other is to realize non-magnetic metering by a PCB coil mode.

For the solution of non-magnetic measurement implemented by PCB coil, a directly-excited angular position sensing measurement device is proposed in the patent application No. 201910853176.4. In the measuring device, an excitation signal is simultaneously applied to the induction coil A, B, C, D through a capacitor 156, and four induced voltage changes on the resistors R1-R4 are measured through induced current changes of the four induction coils, so that the rotation angle of the metal disc is judged. Since the comparator 1551 can only compare two signals, two of the four signals are output to the comparator 1551 by the sampling switching circuit 154. That is to say, the excitation signal is loaded on the four induction coils at the same time, no matter whether the induction voltage of the corresponding path is measured, the induction currents on the four induction coils are synchronously generated, two paths of induction currents are always generated, and the generated power consumption waste is obvious.

Disclosure of Invention

An object of the embodiments of the present application is to provide a non-magnetic sensing measurement apparatus and a method for calculating rotation information of a rotating plate assembly, so as to improve the above technical problems.

In order to achieve the above purpose, the present application provides the following technical solutions:

in a first aspect, an embodiment of the present application provides a nonmagnetic induction measuring device, including: the rotating plate assembly is used for rotating under the pushing of the fluid to be measured, and a metal layer is arranged on a preset area on the rotating plate assembly; the induction circuit board is arranged opposite to the rotating plate assembly at intervals, and a measuring circuit is arranged on the induction circuit board; the measurement circuit includes: the sampling device comprises a pulse generating unit, a plurality of resonance units and a central processing unit, wherein a first end of each resonance unit is respectively connected with the pulse generating unit and a sampling end of the central processing unit, a second end of each resonance unit is grounded, each resonance unit comprises an induction coil and a resonance capacitor which are connected in parallel, and the induction coils are distributed along a rotating shaft of a rotating plate component; the pulse generating unit is used for outputting pulse signals to each resonance unit in sequence, the central processing unit is used for sampling the voltage value of the first end of each resonance unit when each resonance unit receives the pulse signals, and the rotation information of the rotating plate assembly between the current sampling and the last sampling is calculated according to the voltage values of the resonance units.

In the scheme, the pulse generating unit respectively sends the excitation pulse signals to the induction coils, so that the generation of invalid excitation current can be reduced, the power consumption of the whole machine is reduced, the sampling end of the central processing unit directly acquires a voltage value, and the judgment of whether the signal allowance range of the whole machine is large enough after the assembly of the non-magnetic induction measuring device is completed in batch production is facilitated. And compared with an inductive non-magnetic metering scheme, the detection period is shorter, and the anti-magnetic interference capability is stronger.

In an optional embodiment, the measurement circuit further comprises: a gating switch; the gating switch comprises an output end and a plurality of input ends, the input ends are respectively correspondingly connected with the first ends of the resonance units, the output end of the gating switch is connected with the sampling end of the central processing unit, and the gating switch is used for connecting one input end of the input ends with the output end.

When the resources of the sampling end of the central processing unit are insufficient, the sampling of the multi-path voltage signals can be realized by adding a gating switch outside the central processing unit, and the effect and the amplitude of signal sampling are not influenced.

In an optional embodiment, the measurement circuit further comprises: a plurality of signal excitation resistors; at least one signal excitation resistor is arranged between the pulse generating unit and the first end of at least one resonance unit and used for adjusting the amplitude-frequency characteristic of the connected resonance unit.

The amplitude-frequency characteristic of the resonance unit can be adjusted by the signal excitation resistor connected with the resonance unit, namely the steepness degree of the resonance curve of the resonance unit, if the resistance value of the signal excitation resistor is extremely small, the resonance curve of the resonance unit is extremely steep, once the effective inductance of the induction coil changes a little, the amplitude of the voltage signal of the resonance unit changes greatly, and the sampling and the calculation of the central processing unit are not facilitated. The resistance value of the signal exciting resistor is reasonably set, so that the voltage value of the resonance unit can be sampled more easily.

In an optional embodiment, the measurement circuit further comprises: at least one filter capacitor; and one filter capacitor is arranged between the first end of at least one resonance unit and the sampling end of the central processing unit.

The filter capacitor that the resonance unit links can filter the voltage signal on the resonance unit, otherwise, the voltage signal on the resonance unit will contain more interference signal, through setting up filter capacitor for the voltage signal on the resonance unit is closer to the sine wave, makes the sampling more accurate.

In an alternative embodiment, the number of the plurality of resonance units is 3 or more than 3, and the rotation information includes a rotation direction and a rotation angle measurement of the rotating plate assembly between the current sampling and the last sampling; or, the number of the plurality of resonance units is 2, and the rotation information includes a rotation angle measurement of the rotating plate assembly between the current sampling and the last sampling.

In this embodiment, the number of the induction coils may not be limited to 2, 3, 4 or more, and if 2 coils are provided, it is difficult to determine the rotation direction of the rotating plate assembly, and the determination of the rotation direction of the rotating plate assembly can be achieved by setting 3 coils or more.

In a second aspect, an embodiment of the present application provides a method for calculating rotation information of a rotating plate assembly, where the nonmagnetic induction measuring device according to any one of the optional embodiments of the first aspect and the first aspect is used, and the method includes: acquiring a plurality of voltage values of a plurality of resonance units sampled by a central processing unit at this time, wherein each resonance unit corresponds to one voltage value; calculating a plurality of corresponding signal intensity values according to the plurality of voltage values, wherein each voltage value corresponds to one signal intensity value; determining whether the sampling is effective or not according to the signal intensity values; if the signal intensity value is valid, acquiring a first metering state value corresponding to each resonance unit according to each signal intensity value to obtain a plurality of first metering state values; and obtaining a plurality of second metering state values obtained by the last sampling, and calculating the rotation information of the rotating plate assembly between the current sampling and the last sampling according to the plurality of first metering state values and the plurality of second metering state values.

In this application, based on the nonmagnetic induction measuring device of the first aspect, the first metering state value corresponding to each induction coil is determined through an internal program, whether a metal layer exists below each induction coil is obtained, and the rotation direction of the rotating plate assembly can be obtained through analysis of the plurality of first metering state values. The scheme has the advantages of shorter detection period, stronger magnetic interference resistance and more accurate obtained measurement result.

In an optional implementation, the obtaining a first metrology state value corresponding to each of the resonant units according to each of the signal strength values includes: comparing each signal strength value with a first judgment threshold value respectively, wherein the first judgment threshold value is determined according to the maximum signal strength value in the plurality of signal strength values; and determining a first metering state value corresponding to each resonance unit according to each comparison result.

In an optional embodiment, the number of the resonant units in the nonmagnetic induction measuring device is 3 or more than 3, and the calculating of the rotation information of the rotating plate assembly between the current sampling and the last sampling according to the first metering state values and the second metering state values includes: and identifying the rotating direction of the rotating plate assembly between the current sampling and the last sampling according to the change relationship between the first metering state values and the second metering state values and a preset metering state change sequence, wherein the preset metering state change sequence comprises a plurality of groups of reference metering state values obtained when the rotating plate assembly rotates along a preset direction.

A change of the metering state value when the rotation plate assembly rotates one turn in a preset direction is set in a preset metering state change sequence, the rotation angle amount is recognized based on the metering state change sequence, and the rotation direction is recognized based on the change sequence of the reference metering state value.

In an optional implementation, the determining whether the current sample is valid according to the plurality of signal strength values includes: determining whether a maximum signal strength value of the plurality of signal strength values is greater than a second determination threshold; and if so, determining that the sampling is effective.

When a metal sheet is inserted between the metal layer and the induction coil, the detected voltage values of the plurality of coils are synchronously reduced, in this case, the obtained four signal intensity values are synchronously reduced, and the maximum signal intensity value cannot be larger than a second judgment threshold value, so that the sampled signal can be judged to be invalid, and meanwhile, the central processing unit can output an interference alarm of external metal insertion.

In an optional embodiment, the method further comprises: and generating an alarm signal when a group of reference metering state values identical to the plurality of first metering state values does not exist in the preset metering state change sequence and/or when the maximum signal strength value in the plurality of signal strength values is not greater than a second judgment threshold value.

Drawings

In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings that are required to be used in the embodiments of the present application will be briefly described below, it should be understood that the following drawings only illustrate some embodiments of the present application and therefore should not be considered as limiting the scope, and that those skilled in the art can also obtain other related drawings based on the drawings without inventive efforts.

FIG. 1 is a schematic diagram of a measurement circuit in a magnetic induction free measurement apparatus provided by an embodiment of the present application;

FIG. 2 shows a detailed schematic diagram of a measurement circuit in an embodiment of the present application;

fig. 3 shows a schematic diagram of a coil layer of an induction circuit board in an embodiment of the present application;

FIG. 4 is an exploded schematic diagram of a one-way resonant cell in an embodiment of the present application;

fig. 5 shows a schematic diagram of a resonance curve of a resonance unit in an embodiment of the present application;

FIG. 6 shows another detailed schematic diagram of a measurement circuit in an embodiment of the present application;

fig. 7 is a flowchart illustrating a method for calculating rotation information of a rotating plate assembly according to an embodiment of the present application.

Detailed Description

The technical solutions in the embodiments of the present application will be described below with reference to the drawings in the embodiments of the present application. It should be noted that: like reference numbers and letters refer to like items in the following figures, and thus, once an item is defined in one figure, it need not be further defined and explained in subsequent figures. The terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising an … …" does not exclude the presence of other identical elements in a process, method, article, or apparatus that comprises the element. The terms "first," "second," "third," and the like are used solely to distinguish one from another and are not to be construed as indicating or implying relative importance.

In order to solve the technical problems in the prior art, the embodiment of the application provides a non-magnetic induction measuring device.

The induction principle used in the non-magnetic induction measuring device is electromagnetic induction. Electromagnetic induction is a low cost and powerful solution that can be used to detect the presence of metal or conductive objects. Electromagnetic induction is based on the principle of electromagnetic coupling between a coil and a metal target to be inspected, and when the metal target enters an electromagnetic field induced by the coil, some of the electromagnetic energy is transferred into the metal target, the transferred energy generating a circulating current called eddy current, the eddy current flowing in the metal target inducing a reverse electromagnetic field on the coil, resulting in a reduction of the effective inductance of the coil.

In this embodiment, a coil is placed in parallel with a capacitor to constitute an LC resonance unit. The reduction of the effective inductance of the coil will result in a shift of the resonance frequency of the resonance unit, which will change the amplitude of the voltage signal across the coil, and the central processing unit detects the presence of a metal target within the sensing distance by measuring the change in the amplitude of the voltage signal of the coil.

Specifically, the nonmagnetic induction measuring device in this embodiment includes: rotating plate subassembly and induction circuit board. The rotating plate assembly is used for rotating under the pushing of fluid to be measured, a metal layer is arranged in a preset area on the rotating plate assembly, and the rotating plate assembly is used as a metering pointer of the water meter. The induction circuit board and the rotating plate assembly are oppositely arranged at intervals, and the induction circuit board is provided with a measuring circuit. Fig. 1 shows a schematic diagram of a measuring circuit in the present embodiment. Referring to fig. 1, the measurement circuit includes: the pulse generator 110, the plurality of resonance units 120 and the central processing unit 130, wherein a first end of each resonance unit 120 is connected to a sampling end of the pulse generator 110 and the central processing unit 130, a second end of each resonance unit 120 is grounded, each resonance unit 120 comprises an induction coil and a resonance capacitor which are connected in parallel, and the induction coils are distributed along the rotation axis of the rotating plate assembly.

In one embodiment, the number of the induction coils is four, and the four induction coils are uniformly distributed around the rotation axis of the rotation plate assembly, and at this time, one half area on the rotation plate assembly is provided with the metal layer, and the other half area is a non-metal layer. The rotating plate assembly in this embodiment may be a circular plate, a square plate, or another shape. In another embodiment, the number of the induction coils is three, and the three induction coils are uniformly distributed around the rotation axis of the rotation plate assembly, in this case, one third of the area on the rotation plate assembly is provided with the metal layer, and the other two thirds of the area is provided with the non-metal layer. In other embodiments, the number of the induction coils is two, and in this case, one half of the area on the rotating plate assembly is provided with the metal layer, and the other half of the area is a non-metal layer. If a greater number of induction coils are used, at least half of the area on the rotating plate assembly is provided with a metal layer. Of course, too many coil numbers will affect the coil size, resulting in a reduction in the inductance of a single induction coil, and therefore the coil numbers should be set reasonably.

Optionally, the metal material on the metal layer may be an aluminum alloy material with a thickness of about 0.75mm, or may be a 304 stainless steel material with a thickness of about 0.2-0.8 mm.

In the measuring circuit, the pulse generating unit 110 is configured to sequentially output a pulse signal to each of the resonant units 120, the central processing unit 130 is configured to sample a voltage value of a first end of each of the resonant units 120 when each of the resonant units 120 receives the pulse signal, for example, the pulse generating unit 110 outputs the pulse signal to a certain resonant unit 120, the resonant unit 120 receives the pulse signal and generates a corresponding voltage signal at the first end, the central processing unit 130 samples the voltage value of the voltage signal, then the pulse generating unit 110 outputs the pulse signal to a next resonant unit 120, and the central processing unit 130 repeats the sampling step. After sampling, rotation information of the rotating plate assembly between the current sampling and the last sampling is calculated according to the voltage values of the plurality of resonant units 120. The pulse signal generated by the pulse generating unit 110 may be only 1 pulse, so as to minimize the induction time, reduce the interference of the external slowly changing static magnetic field, and reduce the sampling time difference between the induction coils.

When the number of the resonance units is three or more, that is, the number of the induction coils is three or more, the rotation information of the rotation plate assembly includes: measuring the rotation direction and the rotation angle of the rotating plate assembly between the current sampling and the last sampling; when the quantity of resonance unit is two, when induction coil's quantity is two promptly, because can't judge the direction of rotation of rotating plate subassembly, consequently, the rotation information of rotating plate subassembly includes: and measuring the rotation angle of the rotation plate assembly between the current sampling and the last sampling.

The induction circuit board includes: the measuring circuit comprises an element layer and a coil layer, wherein each circuit component in the measuring circuit is packaged on the element layer, a plurality of induction coils are arranged on the coil layer, and the induction coils in the embodiment are PCB coils.

In the present embodiment, the meter applicable to the non-magnetic induction measuring device includes, but is not limited to, a water meter, a gas meter, and the like. Taking a water meter as an example, the rotating plate assembly is arranged above the impeller of the water meter, the water wheel is positioned in a rotating flow formed by the lower-layer hole of the sleeve, water flow impacts the blades on the periphery of the wheel to generate torque, so that the impeller rotates, and the faster the water flow is, the faster the impeller rotates. The water flow drives the impeller to rotate, and the impeller pushes the rotating plate assembly to rotate, so that the rotating plate assembly rotates under the action of the water flow. In the gas meter, the flow of the gas can also push the rotating plate component to rotate.

Further, the measurement circuit further includes: the plurality of signals actuates the resistor. At least one signal excitation resistor is arranged between the pulse generating unit and the first end of at least one resonance unit and used for adjusting the amplitude-frequency characteristic of the connected resonance unit. FIG. 2 shows a detailed schematic diagram of the measurement circuit, where L1-Ln are PCB induction coils, C1-Cn are resonance capacitors, and R1-Rn are signal exciting resistors. In fig. 2, the pulse generating unit includes a plurality of pulse generators, which are respectively pulse generator 1 to pulse generator n, the first end of each resonant unit is connected to the corresponding pulse generator through a signal exciting resistor, pulse generator 1 outputs a pulse signal to the resonant unit composed of L1 and C1 through resistor R1, pulse generator 2 outputs a pulse signal to the resonant unit composed of L2 and C2 through resistor R2, and so on.

In this embodiment, the central processing unit may be a Microprocessor (MCU), the pulse generating unit is disposed inside the MCU, the GPIO of the MCU serves as a pulse signal output pin, and each pulse generator outputs a pulse signal through one GPIO of the MCU, so that the MCU can sequentially control the corresponding GPIO pin to output the pulse signal and obtain the voltage value of the resonant unit through sampling at the corresponding sampling terminal.

Fig. 3 shows a schematic diagram of the coil layer of the induction circuit board in this embodiment, on which four induction coils L1, L2, L3 and L4 are drawn, wherein a central point in each induction coil is a first end of the induction coil and is used for connecting the resonant capacitor, the pulse generation unit and a sampling end of the central processing unit, and a cross intersection of the four induction coils is a common ground point and is connected to a system ground.

Further, the measurement circuit further includes: at least one filter capacitor. A filter capacitor is arranged between the first end of the at least one resonance unit and the sampling end of the central processing unit, the first end of the filter capacitor is connected with the first end of the resonance unit, and the second end of the filter capacitor is connected with the sampling end of the central processing unit. IN fig. 2, the cpu includes a plurality of sampling terminals (IN1, IN2, …, INn), Cc 1-Ccn are filter capacitors, and the first terminal of each resonant unit is connected to the corresponding sampling terminal of the cpu through a filter capacitor. And the signal sampled by the sampling end is converted into digital quantity through the AD converter so as to facilitate the MCU to carry out subsequent calculation. Illustratively, the pulse signal output by the pulse generator 1 is discharged to the system ground after passing through the resonant unit (L1, C1), and the sampling terminal IN1 of the MCU samples the amplitude of the voltage signal generated by the pulse signal on the resonant unit (L1, C1) through the filter capacitor Cc1, and determines whether there is a metal layer below the PCB coil L1.

Optionally, fig. 4 shows an exploded schematic diagram of the single-channel resonant unit, please refer to fig. 4, lx (gpio) is a pulse signal output pin of the MCU, and rx (gpio) is a sampling end pin of the MCU. Rx is signal exciting resistance, L is inductance of the PCB coil, Rs is inherent series resistance of the PCB coil, C is resonance capacitance, and the resonance frequency of the resonance unit is f₀. The resonance curve of the resonance unit is shown in fig. 5, which shows an amplitude-frequency characteristic curve between the voltage value at the first end of the resonance unit and the frequency of the applied signal source (pulse signal output from the pulse generator). As shown in fig. 4, the MCU outputs a single pulse signal with VLx waveform to the resonant unit through a pulse signal output pin lx (gpio), and after passing through an LC resonant unit composed of a PCB coil and a resonant capacitor, an ac signal with VAmp waveform is generated on the resonant unit, and after being filtered by a filter capacitor Cc, the ac signal is sampled by a sampling terminal pin rx (gpio) of the MCU.

When designing the induction circuit board, the parameters of each circuit component are determined in advance, wherein, the calculation formula of the resonant frequency is as follows, and simultaneously, the capacitance value of the resonant capacitor C can be calculated according to the following formula:

in this embodiment, the amplitude-frequency characteristic of the resonance unit, that is, the steepness of the resonance curve in fig. 5, may be adjusted by the signal excitation resistor connected to the resonance unit, and if the resistance value of the signal excitation resistor is extremely small, the resonance curve of the resonance unit is extremely steep, and once the effective inductance of the induction coil changes by one point, the amplitude of the voltage signal of the resonance unit changes greatly, which is not favorable for sampling and calculation of the MCU. The resistance value of the signal exciting resistor is reasonably set, so that the voltage value of the resonance unit can be more easily sampled by the MCU.

The filter capacitor that the resonance unit links can filter the voltage signal on the resonance unit, otherwise, the voltage signal on the resonance unit will contain more interference signal, through setting up filter capacitor for the voltage signal on the resonance unit is closer to the sine wave, makes MCU's sampling more accurate.

When the metal layer on the rotating plate assembly enters the electromagnetic field range of the induction coil, the alternating current in the induction coil generates eddy current in the metal layer, and the eddy current induces a reverse electromagnetic field in the induction coil, so that the effective inductance of the induction coil is reduced.

When the frequency of the pulse signal output by the pulse generating unit is matched with the resonant frequency of the resonant unit, as can be seen from the resonant curve of fig. 5, the voltage value obtained at this time is maximum, and if the effective inductance of the induction coil is reduced, the resonant frequency of the resonant unit will be shifted accordingly, and then the voltage value sampled by the MCU will also be reduced due to the mismatch of the resonant points.

In fig. 2, the MCU sequentially sends single pulse signals to the coils L1-Ln, and detects the change of voltage signals passing through the coils L1-Ln to obtain corresponding voltage values for subsequent calculation.

Optionally, in the measurement circuit of this embodiment, the method further includes: the switch is gated. The gating switch comprises an output end and a plurality of input ends, the input ends are respectively and correspondingly connected with the first ends of the resonance units, the output end of the gating switch is connected with the sampling end of the central processing unit, and the gating switch is used for connecting one input end of the input ends with the output end.

When the sampling end of the MCU has insufficient resources, the sampling of the multi-path voltage signals can be realized by adding a gating switch outside the MCU, and the effect and the amplitude of signal sampling are not influenced.

Fig. 6 shows another detailed schematic diagram of the measurement circuit in the present embodiment. As shown in fig. 6, in this embodiment, each input terminal of the gating switch is connected to the second terminal of the filter capacitor (the first terminal of the filter capacitor is connected to the first terminal of the resonant unit), the output terminal of the gating switch is connected to the sampling terminal of the MCU, and the signal sampled by the sampling terminal is converted into a digital value by the AD converter, so that the MCU can perform subsequent calculation. The gating switch can determine whether to switch the voltage signal of the first input end to enter the AD converter of the MCU or switch the voltage signal of the second input end or the nth input end to enter the AD converter of the MCU.

In this embodiment, the number of the PCB coils may not be limited to 2, 3, 4 or even more, if 2 coils are provided, it is difficult to determine the rotation direction of the rotating plate assembly, and the determination of the rotation direction of the rotating plate assembly can be achieved by providing 3 coils, but the relative fault tolerance is low. In this embodiment preferably 4 coils are used.

In the following description of this embodiment, a method for calculating rotation information of a rotating plate assembly is provided, where when the number of induction coils is 3 or more than 3, the rotation information includes a rotation direction and a rotation angle; when the number of the induction coils is 2, the rotation information includes a rotation angle measurement, and does not include a rotation direction. For convenience of illustration, the present embodiment will be described in detail below by taking four induction coils and a rotating plate assembly as a semi-metallized disk.

Fig. 7 shows a flow chart of the calculation method, which, as shown in fig. 7, comprises the following steps:

step 200: and acquiring a plurality of voltage values of the plurality of resonance units sampled by the central processing unit at this time.

The central processing unit samples the voltage signals generated on the resonance units through the sampling ends to obtain voltage values, and each resonance unit obtains one corresponding voltage value to obtain a plurality of voltage values. For four induction coils, a total of four voltage values are obtained. The sampling end is connected with an AD converter in the central processing unit, and the sampled voltage signal is converted into digital quantity through the AD converter.

Step 210: and calculating to obtain a plurality of corresponding signal intensity values according to the plurality of voltage values.

Because the rotating plate assembly is designed by adopting a semi-metallized disk, no matter which position the disk rotates to, the lower part of at least one induction coil is completely provided with a metal layer, the corresponding voltage value is the minimum voltage value, the lower part of at least one induction coil is completely provided with a nonmetal layer, and the corresponding voltage value is the maximum voltage value. Therefore, two of the four voltage values obtained are different greatly, namely a maximum voltage value and a minimum voltage value, and the two voltage values are relatively close to each other. Therefore, after converting the voltage values into digital values, the following simple method can be used to compare the voltage values in order: and taking the minimum voltage value of the plurality of voltage values as a background voltage value, and subtracting the background voltage value from each voltage value to obtain a corresponding signal intensity value. Each voltage value corresponds to one signal intensity value, and a plurality of signal intensity values are obtained.

Step 220: determining whether the sampling is effective or not according to the signal intensity values; if so, the jump proceeds to step 230.

And after a plurality of signal strength values are obtained, determining whether the sampling is valid or not according to the plurality of signal strength values, if so, performing the next calculation, and if not, generating an alarm signal. In a specific embodiment, it is determined whether a maximum signal strength value of the plurality of signal strength values is greater than a second determination threshold, and if so, it is determined that the current sampling is valid, and if not, it is determined that the current sampling is invalid. The second judgment threshold is a preset reference value, which may be set according to an empirical value or obtained based on multiple test measurements.

Step 230: and acquiring a first metering state value corresponding to each resonance unit according to each signal intensity value to obtain a plurality of first metering state values.

In step 230, each signal intensity value is compared with the first determination threshold to obtain a plurality of comparison results, and then the first measurement state value corresponding to each resonant unit can be determined according to each comparison result to obtain a plurality of first measurement state values. For a total of four first metrology state values obtained for the four induction coils, the following table one shows the first metrology state values for the four induction coils L1-L4:

L1	L2	L3	L4
					1	0	0	1

watch 1

In the first table, the first measurement state value is represented by simple 0 and 1, for example, a value of 0 indicates that no metal layer is below the induction coil, and a value of 1 indicates that a metal layer is below the induction coil, and it can be understood that, in the case where a partial region below the induction coil is a metal layer and a partial region is a non-metal layer, whether the first measurement state value is specifically 0 or 1 is determined according to a result of comparison with the first determination threshold. Of course, the first metering state value is not limited to being represented in other ways.

In this embodiment, the first determination threshold is a preset reference value, which may be determined according to a maximum signal strength value of a plurality of signal strength values obtained, where the plurality of signal strength values may be a plurality of signal strength values obtained by this sampling, or a plurality of signal strength values obtained according to a certain experimental measurement. The first determination threshold may be half of the maximum signal strength value, and at this time, the first determination threshold is located just in the middle of the maximum signal strength value and the minimum signal strength value, so that the magnitude of each signal strength value is easier to distinguish. After the signal intensity value is compared with the first judgment threshold value, the first metering state value of the induction coil is recorded as 0 for the signal intensity value greater than the first judgment threshold value, and the first metering state value of the induction coil is recorded as 1 for the signal intensity value not greater than the first judgment threshold value.

Step 240: and obtaining a plurality of second metering state values obtained by the last sampling, and calculating the rotation information of the rotating plate assembly between the current sampling and the last sampling according to the plurality of first metering state values and the plurality of second metering state values.

If the number of the resonant units in the nonmagnetic induction measuring device is 3 or more than 3, the step 240 specifically includes: and acquiring a plurality of second metering state values obtained by last sampling, and identifying the rotating direction of the rotating plate assembly between the current sampling and the last sampling according to the change relationship between the plurality of first metering state values and the plurality of second metering state values and a preset metering state change sequence. The preset metering state change sequence comprises a plurality of groups of reference metering state values obtained when the rotating plate assembly rotates along a preset direction. Each group of reference metering state values comprises a plurality of reference metering state values corresponding to the plurality of induction coils.

In one embodiment, the metering state change sequence may include a first sequence and a second sequence, wherein the first sequence represents a plurality of sets of reference metering state values obtained when the rotating plate assembly rotates in the forward direction, and the second sequence represents a plurality of sets of reference metering state values obtained when the rotating plate assembly rotates in the reverse direction, and wherein table two below shows one embodiment of the first sequence and table three shows one embodiment of the second sequence:

L1	L2	L3	L4
				0	0	1	1
1	0	0	1
				1	1	0	0
0	1	1	0

watch two

L1	L2	L3	L4
				0	0	1	1
0	1	1	0
				1	1	0	0
1	0	0	1

Watch III

Illustratively, the central processing unit obtains a plurality of first metering state values (for example, 1, 0) sampled this time and obtains a plurality of second metering state values (for example, 0, 1, 0) sampled last time, and obtains a front-back change sequence between the two groups of metering state values; if two groups of reference metering state values are found in the first sequence, respectively: 1. 1, 0 and 0, 1, 0, and the front-back change sequence of the two groups of reference metering state values is matched with the front-back change sequence corresponding to the previous two times of sampling, so that the rotating direction of the rotating plate assembly between the current sampling and the last sampling is positive rotation; if two groups of reference metering state values are found in the second sequence, respectively: 1. 1, 0 and 0, 1, 0, and the sequence of the front and back change of the two groups of reference metering state values is matched with the sequence of the front and back change corresponding to the previous two times of sampling, so that the rotation direction of the rotating plate assembly between the current sampling and the last sampling is obtained to be reverse.

Prior to step 240, the method further comprises: and judging whether a group of reference metering state values identical to the plurality of first metering state values exist in a preset metering state change sequence, if so, executing the step 240, if not, indicating that the current metering fails, generating an alarm signal, discarding a group of first metering state values obtained by the current sampling, and waiting for the next sampling.

In this step 240, if two groups of reference metering state values matching the sequence of the forward and backward changes corresponding to the two times of sampling are not found in both the first sequence and the second sequence, that is, there is neither forward rotation nor reverse rotation, at this time, it is considered that a fault may occur in this metering, and an alarm signal is generated.

In a preset metering state change sequence, a change of the metering state value when the rotating plate assembly rotates one turn in a preset direction is set, so that a rotation angle measurement of the rotating plate assembly can be determined according to the plurality of first metering state values and the plurality of second metering state values, taking table three as an example, for example, the plurality of first metering state values corresponding to the coils L1-L4 are 1, 0, and the corresponding plurality of second metering state values are 0, 1, 0, so that the rotating plate assembly is inverted 1/4 turns according to table three, that is, the rotation angle measurement is 45 °.

In the water meter, the water flow pushes the rotating plate component to rotate, and the water flow has forward flow and reverse flow, so that the rotating plate component also has forward rotation and reverse rotation, for some water meters, the water flow only flows in one direction, for example, a check valve is arranged in the water meter, the reverse flow of the water flow can be prevented, for the part of the water meter, the rotating direction of the rotating plate component does not need to be determined, and therefore, only 2 induction coils can be arranged at the lowest.

If the number of the resonant units in the nonmagnetic induction measuring device is 2, the step of obtaining the rotation angle of the rotating plate assembly is the same as the above mode, which is not described herein.

In this embodiment, the central processing unit performs a measurement detection once according to a set detection period, and in each detection period, the central processing unit controls the pulse generation unit to sequentially output a pulse signal to each resonance unit, samples a voltage value on the resonance unit, obtains n voltage values for n resonance units, calculates rotation information according to the

above step

200 and 240 after obtaining n voltage values, obtains a rotation direction of the rotation plate assembly, sends a signal of positive rotation +1 to the measurement unit in the central processing unit if the rotation plate assembly is positive rotation, sends a signal of negative rotation +1 to the measurement unit in the central processing unit if the rotation plate assembly is negative rotation, and then enters a sleep state to perform measurement detection when a next detection period arrives. The metering unit performs internal metering calculation according to the signal sent by the central processing unit. In one embodiment, the metering unit is a central processing unit internal register.

Optionally, after each measurement and detection, the central processing unit inputs the total number of turns from the start of measurement to the current rotation of the rotating plate assembly, and the number of turns in the forward rotation and the number of turns in the reverse rotation to the measurement unit.

By the rotation information calculation method provided by the embodiment of the application, the external strong static magnetic field interference can be effectively filtered. The specific principle is as follows:

when the external static magnetic field approaches the induction coil, the time difference between the four coils L1-L4 before and after measurement is only microsecond-level difference, so the influence of the static magnetic field on the induced voltages of the four coils L1-L4 can be considered as synchronous, at the moment, the voltage changes of the 4 coils detected by the central processing unit are also synchronous, the detected minimum voltage value is used as a background voltage value, the voltage values are subtracted from the background voltage value, the influence quantity of the change of the external static magnetic field on the measurement of the 4 coils is subtracted, and therefore the external static magnetic field has no influence on the calculation result.

Meanwhile, by adopting the calculation method, the condition that a metal sheet is inserted between the metal layer and the PCB coil from the outside can be detected, and an alarm signal is generated when the inserted metal sheet interferes with the detection of a normal voltage signal. The specific principle is as follows: in step 220, it is determined that the signal sampled this time is valid only when the maximum signal strength value is greater than the second determination threshold. When a metal sheet is inserted between the metal layer and the induction coil, the detected voltage values of the coils L1-L4 are synchronously reduced, in this case, after the four voltage values are subtracted from the background voltage value, the obtained four signal intensity values are synchronously reduced, the maximum signal intensity value cannot be larger than a second judgment threshold value, and therefore the sampled signal can be judged to be invalid, and meanwhile, the central processing unit can output an interference alarm of external metal insertion.

To sum up, the nonmagnetic induction measuring device and the calculation method of the rotation information of the rotating plate assembly provided by the embodiment of the application have the following technical effects:

1. because the existing inductance type nonmagnetic metering scheme induces the later waveform change of LC oscillation, the detection time of an induction signal is long, the interference of an external slowly-changing strong magnetic field and the actual signal change are difficult to distinguish, and metering errors are easy to occur under the external strong magnetic interference. The technical scheme adopts single-pulse output for the excitation signal applied to the induction coil, and compared with a plurality of LC oscillation waveforms generated by an inductance type non-magnetic metering scheme, the detection period is shorter, and the anti-magnetic interference capability is stronger.

2. The traditional PCB coil non-magnetic metering scheme adopts the technical scheme that large alternating excitation current is input into a primary coil, alternating induced current is generated on a secondary coil, and then the induced voltage value generated by the induced current on a resistor is detected so as to detect the rotating position of a metal disc. In order to generate a sufficiently large induced current in the secondary winding, it is necessary to ensure that the excitation current in the primary winding is sufficiently large, which results in a large overall power consumption. According to the technical scheme, the excitation pulse signal is directly input to the induction coil, so that the size of the excitation current can be controlled, the same signal intensity can be obtained, and the power consumption of the whole machine is effectively reduced.

3. Compared with the traditional PCB coil non-magnetic metering scheme, the technical scheme cancels the modes of the primary coil and the secondary coil, can draw induction coils with larger sizes in a limited space, and has larger coil inductance. And according to the formula of the equivalent impedance Rp of the resonant cell:

it can be seen that the larger the inductance L, the larger the impedance Rp of the entire resonant unit, and the larger the induced current on the metallized disk, the larger the signal induced change on the coil. Thus takingThe primary coil is eliminated, the area and the number of turns of a single induction coil are increased, and the signal strength can be effectively increased.

4. Excitation pulse signals of the induction coils are respectively sent, so that the generation of invalid excitation current is reduced, and the power consumption of the whole machine is reduced.

5. The voltage value is collected through the sampling end of the central processing unit, the actual signal intensity value can be obtained, and the signal margin range of the whole machine after assembly is judged to be large enough in batch production. The existing scheme generally adopts a comparator to judge the rotation direction of a disc, and only 0 and 1 signals can be obtained through comparison, but the actual specific signal intensity value is unknown. For example, when the nonmagnetic induction measuring device is assembled or installed, if the distance between the rotating plate assembly and the induction coil is relatively long, the measured signal intensity value is relatively small, so that if the specific signal intensity value is not known, the signal intensity value is likely to be usable in mass production, but after the signal intensity value is used for a period of time, because the set signal margin is insufficient, and because the device parameters of each resistor and capacitor are attenuated, pulses are lost, and metering cannot be performed. The technical scheme can directly obtain a specific signal intensity value, so that a signal intensity threshold value can be set in the central processing unit to judge whether the assembly is poor, and when the distance between the rotating plate component and the PCB coil on the induction circuit board is far, the signal intensity threshold value can be directly known in a factory.

6. The filter capacitor Cc is arranged at the front end of the sampling end instead of the excitation pulse signal, so that the excitation pulse signal can enter the induction coil more favorably to generate a larger excitation signal.

7. The amplitude changes of the voltage signals among the induction coils are compared through an internal program, and the influence of external strong static magnetic field interference on signal judgment is eliminated through a differential comparison method.

8. And setting a second judgment threshold value through an internal program, effectively judging the interference of the externally inserted metal sheet, and alarming and outputting.

9. The induction coil in this application adopts the PCB coil, and the coil is directly drawn on the PCB board, so can control the number of turns, interval isoparametric of coil more accurately, the wiring of PCB coil is very accurate, can not produce too big error basically. Compared with the existing inductance type non-magnetic metering scheme, the parameters of the inductance coil are influenced by the winding process, the consistency of the inductance is difficult to ensure, the accuracy of the inductance is difficult to ensure, and the error is generally about 20-30%. The induction coil of the scheme has better consistency and is more favorable for batch production.

The above description is only an example of the present application and is not intended to limit the scope of the present application, and various modifications and changes may be made by those skilled in the art. Any modification, equivalent replacement, improvement and the like made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A non-magnetic induction measuring device, comprising:

the rotating plate assembly is used for rotating under the pushing of the fluid to be measured, and a metal layer is arranged on a preset area on the rotating plate assembly;

the induction circuit board is arranged opposite to the rotating plate assembly at intervals, and a measuring circuit is arranged on the induction circuit board; the measurement circuit includes: the sampling device comprises a pulse generating unit, a plurality of resonance units and a central processing unit, wherein a first end of each resonance unit is respectively connected with the pulse generating unit and a sampling end of the central processing unit, a second end of each resonance unit is grounded, each resonance unit comprises an induction coil and a resonance capacitor which are connected in parallel, and the induction coils are distributed along a rotating shaft of a rotating plate component;

the pulse generating unit is used for outputting pulse signals to each resonance unit in sequence, the central processing unit is used for sampling the voltage value of the first end of each resonance unit when each resonance unit receives the pulse signals, and the rotation information of the rotating plate assembly between the current sampling and the last sampling is calculated according to the voltage values of the resonance units.

2. The measurement device of claim 1, wherein the measurement circuit further comprises: a gating switch; the gating switch comprises an output end and a plurality of input ends, the input ends are respectively correspondingly connected with the first ends of the resonance units, the output end of the gating switch is connected with the sampling end of the central processing unit, and the gating switch is used for connecting one input end of the input ends with the output end.

3. The measurement device of claim 1 or 2, wherein the measurement circuit further comprises: a plurality of signal excitation resistors; at least one signal excitation resistor is arranged between the pulse generating unit and the first end of at least one resonance unit and used for adjusting the amplitude-frequency characteristic of the connected resonance unit.

4. The measurement device of claim 1, wherein the measurement circuit further comprises: at least one filter capacitor; and the filter capacitor is arranged between the first end of at least one resonance unit and the sampling end of the central processing unit.

5. The measurement device of claim 1, wherein:

the number of the plurality of resonance units is 3 or more than 3, and the rotation information comprises the rotation direction and the rotation angle measurement of the rotating plate assembly between the current sampling and the last sampling;

or, the number of the plurality of resonance units is 2, and the rotation information includes a rotation angle measurement of the rotating plate assembly between the current sampling and the last sampling.

6. A method for calculating rotation information of a rotating plate assembly, wherein the magnetically inductionless measuring apparatus according to any one of claims 1 to 5 is used, the method comprising:

acquiring a plurality of voltage values of a plurality of resonance units sampled by a central processing unit at this time, wherein each resonance unit corresponds to one voltage value;

calculating a plurality of corresponding signal intensity values according to the plurality of voltage values, wherein each voltage value corresponds to one signal intensity value;

determining whether the sampling is effective or not according to the signal intensity values;

if the signal intensity value is valid, acquiring a first metering state value corresponding to each resonance unit according to each signal intensity value to obtain a plurality of first metering state values;

and obtaining a plurality of second metering state values obtained by the last sampling, and calculating the rotation information of the rotating plate assembly between the current sampling and the last sampling according to the plurality of first metering state values and the plurality of second metering state values.

7. The method according to claim 6, wherein the obtaining a first metrology state value corresponding to each of the resonant units according to each of the signal strength values comprises:

comparing each signal strength value with a first judgment threshold value respectively, wherein the first judgment threshold value is determined according to the maximum signal strength value in the plurality of signal strength values;

and determining a first metering state value corresponding to each resonance unit according to each comparison result.

8. The method according to claim 6, wherein the number of the resonant units in the non-magnetic induction measuring device is 3 or more than 3, and the calculating of the rotation information of the rotating plate assembly between the current sampling and the last sampling according to the first metering state values and the second metering state values comprises:

and identifying the rotating direction of the rotating plate assembly between the current sampling and the last sampling according to the change relationship between the first metering state values and the second metering state values and a preset metering state change sequence, wherein the preset metering state change sequence comprises a plurality of groups of reference metering state values obtained when the rotating plate assembly rotates along a preset direction.

9. The method of claim 8, wherein determining whether the current sample is valid according to the plurality of signal strength values comprises:

determining whether a maximum signal strength value of the plurality of signal strength values is greater than a second determination threshold;

and if so, determining that the sampling is effective.

10. The computing method of claim 9, wherein the method further comprises:

and generating an alarm signal when a group of reference metering state values identical to the plurality of first metering state values does not exist in the preset metering state change sequence and/or when the maximum signal strength value in the plurality of signal strength values is not greater than a second judgment threshold value.