CN213714491U - Intelligent water meter measuring device with self-calibration function - Google Patents
Intelligent water meter measuring device with self-calibration function Download PDFInfo
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- CN213714491U CN213714491U CN202023252239.8U CN202023252239U CN213714491U CN 213714491 U CN213714491 U CN 213714491U CN 202023252239 U CN202023252239 U CN 202023252239U CN 213714491 U CN213714491 U CN 213714491U
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Abstract
The utility model discloses an intelligence water gauge measuring device with self calibration function. The utility model discloses a base table, magnetoresistive sensor, difference amplification unit, low pass filter unit, single chip unit, LCD display element, UART communication unit and memory cell. Magnetic steel is arranged on a transmission gear of the base meter, the magnetic resistance sensor is arranged right above the magnetic steel, and the magnetic resistance sensor is used for sensing the change of a magnetic field and outputting two paths of orthogonal voltage signals to obtain the movement angle and the angular speed of the transmission gear; the two paths of orthogonal voltage signals are connected with the input end of a differential amplification unit, and the output end of the differential amplification unit is connected with the positive input end of a low-pass filtering unit; and the output end of the low-pass filtering unit is connected with an I/O port of the singlechip. The utility model provides the high degree of accuracy of mechanical sensing formula water gauge when the low discharge is measured has improved the range ratio of water gauge.
Description
Technical Field
The utility model belongs to the technical field of the water yield measurement, a intelligence water gauge measuring device with self calibration function is related to.
Background
At present, the water meter mainly adopts a mechanical type as a main metering mode, and mechanical signals are converted into electric signals through sensors such as a reed switch and a Wiegand, so that remote meter reading is realized. Along with the implementation of national energy-saving and emission-reducing policies, the requirement on the accuracy of water meter metering is higher and higher, and the traditional reed switch and Wiegand type sensor do not solve the problems of low metering precision, small initial flow, bidirectional metering, mechanical vibration error metering and the like of a mechanical water meter. Based on the mechanical water meter of magnetic resistance formula, its sensor internal integration two way quadrature wheatstone bridge, the magnetic resistance on every way changes by external magnetic field change, and when base table impeller drove the magnet steel and rotates, the magnetic resistance sensor experienced external magnetic field angle change, produced and output two way differential voltage signal. Compared with the traditional mechanical water meter, the magnetic resistance water meter has the characteristics of high response frequency, high sensitivity, good reliability and the like. However, the magnetoresistive water meter has a small measuring range and low accuracy of small flow, and does not have the functions of self-calibration and bidirectional metering, and does not solve the measurement problem of the traditional mechanical sensing water meter.
Disclosure of Invention
The utility model discloses to the not enough of magnetoresistive sensor water gauge existence, provided an intelligent water gauge measuring device of self calibration function.
The utility model discloses the technical scheme who takes does:
an intelligent water meter measuring device with a self-calibration function comprises a base meter, a magnetic resistance sensor, a differential amplification unit, a low-pass filtering unit, a single chip microcomputer unit, an LCD display unit, a UART communication unit and a storage unit.
Magnetic steel is arranged on a transmission gear of the base meter, the magnetic resistance sensor is arranged right above the magnetic steel, and the magnetic resistance sensor is used for sensing the change of a magnetic field and outputting two paths of orthogonal voltage signals to obtain the movement angle and the angular speed of the transmission gear; the two paths of orthogonal voltage signals are connected with the input end of a differential amplification unit, and the output end of the differential amplification unit is connected with the positive input end of a low-pass filtering unit; the output end of the low-pass filtering unit is connected with an I/O port of the singlechip; the LCD display unit, the UART communication unit and the storage unit are all connected with an I/O port of the single chip microcomputer.
Furthermore, two orthogonal Wheatstone bridges are integrated in the magnetoresistive sensor, and each bridge has four magnetoresistors.
Furthermore, the single chip microcomputer unit adopts a single chip microcomputer FM33L026, and the LCD display unit adopts a liquid crystal display; the 1 st pin of the singlechip is respectively connected with a resistor R1 and a capacitor C1, the other end of the resistor R1 is connected with the 3V voltage of VCC, and the other end of the capacitor C1 is grounded; the pins 52 and 54 of the singlechip are connected with the anode of an electrolytic capacitor CD1 and one end of a capacitor C4 to be connected with 3V voltage of VCC in common, and the cathode of the electrolytic capacitor CD1 and the other end of the capacitor C4 are connected with the ground in common; the 51 st pin and the 53 th pin of the singlechip are grounded; the frequency of the crystal oscillator Y1 is 32.768 KHz; the 48 th pin of the single chip microcomputer is connected with one end of a capacitor C3 and one end of a crystal oscillator Y1, the 49 th pin of the single chip microcomputer is connected with the other ends of the capacitor C2 and the crystal oscillator Y1, and the other ends of the capacitor C3 and the capacitor C2 are grounded together; the 12 th, 16 th and 17 th pins of the single chip are respectively connected with WP, SCL and SDA ports of the memory unit chip; the 55 th pin of the single chip is connected with the VOUTX signal port of the low-pass filtering output port of the X end, the 57 th pin is connected with the VOUTY signal port of the low-pass filtering output port of the Y end, the 5 th, 6 th, 7 th and 8 th pins of the single chip are respectively connected with the 25 th, 26 th, 27 th and 28 th pins of the liquid crystal display, the 13 th, 14 th and 15 th pins of the single chip are connected with the 1 st, 2 th and 3 th pins of the liquid crystal display, the 22 th to 29 th pins of the single chip are connected with the 4 th to 11 th pins of the liquid crystal display, the 31 th and 32 th pins of the single chip are connected with the 12 th and 13 th pins of the liquid crystal display, the 39 th to 46 th pins of the single chip are connected with the 14 th.
The beneficial effects of the utility model reside in that:
1. the utility model provides the high degree of accuracy of mechanical sensing formula water gauge when the low discharge is measured has improved the range ratio of water gauge.
2. The utility model discloses a drive gear angular signal who records in succession judges the water gauge and just reverses the condition to can reject it through setting for the threshold value to the mismeasurement that water gauge mechanical oscillation arouses.
3. The utility model discloses guarantee that the water gauge base table rotates 3 angle values that can sample of a week under all flow to obtain the direction of motion of water gauge under the biggest sampling unit timing time, reduced the consumption of instrument.
Drawings
FIG. 1 is a schematic view of a testing apparatus;
FIG. 2 is a block diagram of the overall flow of a hardware system;
FIG. 3 is a minimal system of a single chip;
FIG. 4 is a differential amplifier circuit diagram;
FIG. 5 is a circuit diagram of a low pass filter;
FIG. 6 is a schematic diagram of the output signal of a magnetoresistive sensor;
fig. 7 is a graph of the meter coefficient characteristic.
Detailed Description
The present invention is described in further detail below with reference to the attached drawings.
Referring to fig. 1, the water meter is installed on the pipeline, when water flow in the pipeline begins to flow, the impeller rotates to drive the magnetic steel installed on the impeller to rotate simultaneously, the magnetic resistance sensor senses the change of a magnetic field, and an output voltage signal is connected to the measuring circuit.
Referring to fig. 2, the available signals in the device are weak, amplification and filtering processing are required to be performed in order to maintain the integrity of the available signals, and then sampling is performed through an ADC inside the single chip microcomputer to process the sampled signals. The whole hardware system work flow is as follows: the magnetic resistance sensor outputs a voltage signal, the signal is amplified through a preamplifier AD620 chip, then the signal is processed through a low-pass filter circuit, finally the signal is input into an ADC inside the single chip microcomputer to be converted, and the signal is processed through the single chip microcomputer FM33L 026.
Referring to fig. 3, the single chip microcomputer unit adopts FM33L026, and the LCD display unit adopts a liquid crystal display. The 1 st pin of the singlechip is respectively connected with a resistor R1 and a capacitor C1, the other end of the resistor R1 is connected with the 3V voltage of VCC, and the other end of the capacitor C1 is grounded. The pins 52 and 54 are connected with the anode of the electrolytic capacitor CD1 and one end of the capacitor C4 which are connected with VCC voltage of 3V, and the cathode of the electrolytic capacitor CD1 and the other end of the capacitor C4 are connected with ground. The 51 st and 53 th pins are grounded. The frequency of the crystal oscillator Y1 is 32.768 KHz. The 48 th pin of the singlechip is connected with one ends of a capacitor C3 and a crystal oscillator Y1, the 49 th pin is connected with the other ends of the capacitor C2 and the crystal oscillator Y1, and the other ends of the capacitor C3 and the capacitor C2 are grounded together. The 12 th, 16 th and 17 th pins of the single chip are respectively connected with WP, SCL and SDA ports of the memory unit chip. The 55 th pin of the single chip is connected with the VOUTX signal port of the X-end low-pass filtering output port, the 57 th pin of the single chip is connected with the VOUTY signal port of the Y-end low-pass filtering output port, the 5 th, 6 th, 7 th and 8 th pins of the single chip are respectively connected with the 25 th, 26 th, 27 th and 28 th pins of the LCD, the 13 th, 14 th and 15 th pins of the single chip are connected with the 1 st, 2 th and 3 rd pins of the LCD, the 22 th to 29 th pins of the single chip are connected with the 4 th to 11 th pins of the LCD, the 31 th and 32 th pins of the single chip are connected with the 12 th and 13 th pins of the LCD, the 39 th to 46 th pins of the single chip are. The 37 th and 38 th pins of the singlechip are connected with the RXD1 and TXD1 pins of the UART ports.
Referring to fig. 4, in the actual measurement process, two paths of voltage signals (X +, X-) and (Y +, Y-) output by the magnetoresistive sensor are respectively connected to the same amplifying and filtering circuit, in this embodiment, a single-path measurement circuit is used for illustration, the input Signal of the filtering circuit is represented by (Signal +, Signal-) which is the two paths of signals (X +, X-) and (Y +, Y-), the pre-differential amplifying circuit adopts an instrument amplifier AD620, a resistor R10 is connected between a pin 1 and a pin 8 of an AD620 chip, and a pin 5 is connected to a reference voltage VREFPin 1.5V,6 output VOUT1The other end of the 7 pin is connected with a 3V voltage VCC, the 4 pin is connected with the ground, the 3 pin is connected with a resistor R8, the other end of the R8 is connected with a Signal + port, and the other end of the 2 pin is connected with a resistor R9, the other end of the R9 is connected with a Signal-port.
Referring to fig. 5, the low pass filter circuit designs the cutoff frequency according to the impeller rotation frequency at the actual maximum flow rate. The input end is a 6-pin V of a differential amplifying circuitOUT1，VOUT1The other end of the resistor R11 is connected with one end of a resistor R12 and one end of a capacitor C9, the other end of the capacitor C9 is grounded, the other end of the R12 is an output end which is connected with the ADC, and is also connected with one end of a capacitor C10, and the other end of the C10 is grounded. The signal output end VOUT2 represents two paths of voltage signals output by the magnetic resistance sensor, and the two paths of voltage signals are respectively amplified and filtered to obtain target signals, the output target signal VOUTX corresponding to the X path is connected with a pin 55 of the single chip microcomputer, and the output target signal VOUTY corresponding to the Y path is connected with a pin 57 of the single chip microcomputer.
The utility model discloses only have a drive gear and installation magnet steel on the base table structure of water gauge, rotate and be used toSmall volume and small starting flow. The magnetic resistance sensor is arranged right above the magnetic steel, senses the change of a magnetic field caused by the rotation of the magnetic steel driven by the transmission gear, and calculates the movement angle and the angular speed of the transmission gear of the base meter according to two orthogonal voltage signals output by the magnetic resistance sensor. All angle values theta of the base table rotating for one circle are obtained through an AD sampling unit of the single chip microcomputer unit1,θ2,……θn]And storing the angular speed as an angle sequence, and calculating the average value of the angular speed of one rotation
Obtaining meter coefficients corresponding to the rotation speed
And calculating the flow of the water meter by using the product of the instrument coefficients and the angle differences corresponding to different angular velocities, and further calculating the water consumption Q. And the water consumption Q is used for correcting the accumulated value Q of the water consumption under each sampling angle of one circle of rotation of the base meter1Thus, the self-calibration of the water meter is realized.
The utility model discloses a concrete theory of operation: two orthogonal Wheatstone bridges integrated in the magnetoresistive sensor are an X bridge and a Y bridge respectively, each bridge is provided with 4 magnetic resistances, the resistance value of each magnetic resistance changes along with the change of an external magnetic field, when the impeller drives the magnetic steel to rotate, the magnetic field generated by the magnetic steel and the X bridge form an included angle phi, as shown in figure 6, the X bridge generates a cosine signal Vcos phi, the Y bridge generates a sine signal Vsin phi, V is the amplitude of two signals, the base table rotates for a circle, and the two output signals complete a period change. The magnetoresistive sensor outputs a differential voltage signal to a measurement circuit. Common mode noise is removed through differential amplification to the voltage signal, obtains the target signal through low pass filtering again, and data processing is carried out after the singlechip accomplishes signal sampling, calculates current impeller turned angle and rotation angular velocity according to formula (1):
wherein, theta is a rotation angle value of the impeller; omega is the rotation angular speed of the impeller; and T is the timing time of the AD sampling unit. The single chip microcomputer obtains the vector angle of the water meter operation and stores the vector angle in the array. V (X) and V (Y) are respectively the output voltage values of the sensor differential signals sampled by the X bridge and the Y bridge; as the value range theta of the tangent function belongs to [ 0-pi ] and V (X) ≠ 0, in order to ensure the validity of the angle calculation, the following formula is adopted to calculate within the range of 0-2 pi:
the timing time T of the AD sampling unit is based on 1/3 of the time required by one rotation of a base table under the maximum instantaneous flow Q4:3150L/H in the standard measuring range of the DN15 water meter, and the calculation formula is as follows:
qmax＝k(ωmax)*ωmax (3)
in the formula, qmaxThe maximum instantaneous flow Q4 is 3150L/H; omegamaxIs the angular velocity, k (ω), of the impeller rotation at maximum instantaneous flowmax) The coefficient of the instrument, T, corresponding to the maximum angular velocitymaxThe time required by one rotation of the base meter under the maximum flow is T, and the time is the timing time of the AD sampling unit. Under ideal conditions and within a specified detection range, the instrument coefficient k and the angular velocity omega are in a nonlinear relation, the values of the instrument coefficient k and the angular velocity omega are calibrated by a flow standard device, and a characteristic curve is shown in FIG. 7.
Judging whether the base table is in accordance with the stored angle sequence of the single chip microcomputerWhen the angle signal is periodically changed after one rotation, the angle value theta obtained by the nth samplingnIs less than the angle value theta obtained by sampling at the n-1 th timen-1When the base table rotates for one circle, all the angle values theta sampled by the single chip microcomputer under one circle of rotation of the base table can be obtained1,θ2,……θn]. Because the rotation speed of the impeller is related to the flow velocity of water flow, the rotation speed of the impeller is different under different flow velocities, and particularly under the condition of small flow, the rotation angle value theta measured by the single chip microcomputer through one-time sampling is far smaller than 360 degrees. From the angular velocity average of one week:
in the formula (I), the compound is shown in the specification,
is the angular velocity average value, and n is the number of samples.
Obtaining corresponding meter coefficients
This gives the cumulative amount Q of actual water used for one revolution:
according to the actual water consumption Q of one rotation, each angle value theta of one rotation of the water meter is corrected to be [ theta ]1,θ2,……θn]Cumulative value Q of water consumption1，
Qi＝k(ωi)*(θi+1-θi) (8)
Correction value DeltaQ
ΔQ＝Q-Q1 (10)
When delta Q is larger than 0, the corrected accumulated flow Q1′＝Q1+ Δ Q; when Δ Q is less than 0, Q1′＝Q1- Δ Q. By the method, the self-calibration of the water meter is realized, and the accuracy of the water meter in small-flow measurement is improved.
Claims (3)
1. The utility model provides an intelligence water gauge measuring device with self calibration function which characterized in that:
the device comprises a base table, a magnetoresistive sensor, a differential amplification unit, a low-pass filtering unit, a single chip microcomputer unit, an LCD display unit, a UART communication unit and a storage unit;
magnetic steel is arranged on a transmission gear of the base meter, the magnetic resistance sensor is arranged right above the magnetic steel, and the magnetic resistance sensor is used for sensing the change of a magnetic field and outputting two paths of orthogonal voltage signals to obtain the movement angle and the angular speed of the transmission gear; the two paths of orthogonal voltage signals are connected with the input end of a differential amplification unit, and the output end of the differential amplification unit is connected with the positive input end of a low-pass filtering unit; the output end of the low-pass filtering unit is connected with an I/O port of the singlechip; the LCD display unit, the UART communication unit and the storage unit are all connected with an I/O port of the single chip microcomputer.
2. The intelligent water meter measuring device of claim 1, wherein:
two orthogonal Wheatstone bridges are integrated in the magnetoresistive sensor, and each bridge is provided with four magnetoresistors.
3. The intelligent water meter measuring device of claim 1, wherein:
the single chip microcomputer unit adopts a single chip microcomputer FM33L026, and the LCD display unit adopts a liquid crystal display; the 1 st pin of the singlechip is respectively connected with a resistor R1 and a capacitor C1, the other end of the resistor R1 is connected with the 3V voltage of VCC, and the other end of the capacitor C1 is grounded; the pins 52 and 54 of the singlechip are connected with the anode of an electrolytic capacitor CD1 and one end of a capacitor C4 to be connected with 3V voltage of VCC in common, and the cathode of the electrolytic capacitor CD1 and the other end of the capacitor C4 are connected with the ground in common; the 51 st pin and the 53 th pin of the singlechip are grounded; the frequency of the crystal oscillator Y1 is 32.768 KHz; the 48 th pin of the single chip microcomputer is connected with one end of a capacitor C3 and one end of a crystal oscillator Y1, the 49 th pin of the single chip microcomputer is connected with the other ends of the capacitor C2 and the crystal oscillator Y1, and the other ends of the capacitor C3 and the capacitor C2 are grounded together; the 12 th, 16 th and 17 th pins of the single chip are respectively connected with WP, SCL and SDA ports of the memory unit chip; the 55 th pin of the single chip is connected with the VOUTX signal port of the low-pass filtering output port of the X end, the 57 th pin is connected with the VOUTY signal port of the low-pass filtering output port of the Y end, the 5 th, 6 th, 7 th and 8 th pins of the single chip are respectively connected with the 25 th, 26 th, 27 th and 28 th pins of the liquid crystal display, the 13 th, 14 th and 15 th pins of the single chip are connected with the 1 st, 2 th and 3 th pins of the liquid crystal display, the 22 th to 29 th pins of the single chip are connected with the 4 th to 11 th pins of the liquid crystal display, the 31 th and 32 th pins of the single chip are connected with the 12 th and 13 th pins of the liquid crystal display, the 39 th to 46 th pins of the single chip are connected with the 14 th.
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| Publication number | Priority date | Publication date | Assignee | Title |
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| CN114413939A (en) * | 2022-01-11 | 2022-04-29 | 浙江东胜物联技术有限公司 | Rotation detection system of low-voltage driving anisotropic magnetoresistive sensor |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
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| CN114413939A (en) * | 2022-01-11 | 2022-04-29 | 浙江东胜物联技术有限公司 | Rotation detection system of low-voltage driving anisotropic magnetoresistive sensor |
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Denomination of utility model: An intelligent water meter measuring device with self calibration function Effective date of registration: 20220928 Granted publication date: 20210716 Pledgee: Bank of Hangzhou Limited by Share Ltd. science and Technology Branch Pledgor: HANGZHOU SECK INTELLIGENT TECHNOLOGY CO.,LTD. Registration number: Y2022980016798 |