Magnetostrictive liquid level meter

Abstract

The magnetostriction liquid level meter comprises a control module, a sensing module, a signal processing module and a signal port, the control module is used for generating an initial signal, and the sensing module is connected with the control module to conduct induction based on control of the initial signal and generate an induction signal. The signal processing module is connected with the sensing module to shape the sensing signal and generate a termination signal, the control module is connected with the signal processing module to calculate a liquid level value based on the time difference between the starting signal and the termination signal, and the control module is connected with the signal port to output the liquid level value. According to the magnetostrictive liquid level meter, the induction signals are shaped through the signal processing module, the induction signals with a plurality of pulses can be integrated into the termination signal with only one pulse, and therefore subsequent modules can receive and calculate the termination signal conveniently.

Description

Technical Field

[0001] The utility model belongs to the technical field of magnetostriction, in particular to a magnetostrictive liquid level gauge. Background Art

[0002] The magnetostrictive level gauge is a new type of measuring device. During measurement, a current pulse is first applied to the waveguide wire. This current pulse is accompanied by a circular magnetic field that propagates downward along the waveguide wire at the speed of light. When this circular magnetic field encounters the magnetic field formed by the permanent magnet in the float, the waveguide wire deforms under the influence of the two magnetic fields, generating a torsional wave pulse. This torsional wave pulse propagates along the waveguide wire toward both ends. The detection mechanism in the magnetostrictive level gauge detects this torsional wave pulse and converts it into a corresponding induction signal. The current liquid level value can be calculated by calculating the difference between the time the induction signal occurs and the time the torsional wave pulse is received, and then combining this with the product function of the propagation velocity of the torsional wave pulse.

[0003] Existing magnetostrictive level gauges still have shortcomings in detection accuracy and information transmission accuracy, requiring further improvement and optimization. When detecting torsional wave pulses, the detection mechanism often cannot accurately convert the torsional wave into a sensing signal. The sensing signal waveform contains multiple small pulses, which makes it more difficult to calculate the time difference between the signals and cannot accurately obtain liquid level information. This is especially true in level gauges with dual float designs, which are more prone to signal crosstalk and measurement errors.

[0004] The information disclosed in this background technology section is only intended to increase the understanding of the overall background of the present invention, and should not be regarded as an admission or any form of suggestion that the information constitutes the prior art already known to those skilled in the art. Utility Model Content

[0005] The purpose of the utility model is to provide a magnetostrictive liquid level gauge, which can improve measurement precision and accuracy.

[0006] In order to achieve the above-mentioned purpose, the technical solution provided by a specific embodiment of the present invention is as follows:

[0007] A magnetostrictive liquid level gauge includes a control module, a sensing module, a signal processing module, and a signal port. The control module is used to generate a start signal. The sensing module is connected to the control module to perform sensing based on the control of the start signal and generate a sensing signal. The signal processing module is connected to the sensing module to shape the sensing signal and generate a termination signal. The control module is connected to the signal processing module to calculate a liquid level value based on the time difference between the start signal and the termination signal. The control module is connected to the signal port to output the liquid level value.

[0008] In one or more embodiments of the present invention, the signal processing module includes a comparator and a monostable trigger, the first input end of the comparator is connected to the sensing module to receive the sensing signal, the second input end of the comparator is connected to the reference voltage, the comparator is used to compare the sensing signal and the reference voltage and generate a comparison signal, the monostable trigger is connected to the output end of the comparator to receive the comparison signal, and the monostable trigger is used to shape the comparison signal to generate a termination signal.

[0009] In one or more embodiments of the present invention, the control module includes a control unit and an output unit, the control unit is used to generate a start signal, the control unit is connected to the signal processing module to receive a stop signal and calculate the liquid level value based on the time difference between the start signal and the stop signal, the output unit is connected to the control unit to receive the liquid level value, and the output unit is connected to the signal port to output the liquid level value.

[0010] In one or more embodiments of the present invention, the output unit includes a DAC subunit, which is connected to the control unit to receive the liquid level value, and the DAC subunit is connected to the signal port to generate a current signal at the signal port for representing the liquid level value.

[0011] In one or more embodiments of the present invention, the output unit also includes a HART signal subunit, which is connected to the control unit to receive the liquid level value and generate a HART modulation signal based on the liquid level value, and the DAC subunit is connected to the HART signal subunit to receive the HART modulation signal and adjust the current signal based on the HART modulation signal.

[0012] In one or more embodiments of the present invention, the DAC subunit includes a DAC chip, a transistor and an adjustment resistor. The DAC chip is connected to the control unit to receive the liquid level value and generate an adjustment signal based on the liquid level value. The control end of the transistor is connected to the DAC chip to receive the adjustment signal. The first end of the transistor is connected to the first end of the adjustment resistor, the second end of the adjustment resistor is connected to the ground voltage, and the second end of the transistor is connected to the power supply voltage and the signal port.

[0013] In one or more embodiments of the present invention, the DAC subunit includes a DAC chip, a transistor and an adjustment resistor, the DAC chip is connected to the control unit to receive the liquid level value, the DAC chip is connected to the HART signal subunit to receive the HART modulation signal, the DAC chip is used to generate an adjustment signal based on the liquid level value and the HART modulation signal, the control end of the transistor is connected to the DAC chip to receive the adjustment signal, the first end of the transistor is connected to the first end of the adjustment resistor, the second end of the adjustment resistor is connected to the ground voltage, and the second end of the transistor is connected to the power supply voltage and the signal port.

[0014] In one or more embodiments of the present invention, the DAC chip is DAC161S997RGHR.

[0015] In one or more embodiments of the present invention, the resistance range of the adjustment resistor is [20, 100)Ω.

[0016] In one or more embodiments of the present invention, the resistance of the regulating resistor is 75Ω.

[0017] Compared to existing technologies, the magnetostrictive level gauge of this utility model shapes the induced signal through a signal processing module, integrating a multi-pulse induced signal into a single-pulse termination signal, thereby facilitating the reception and calculation of the termination signal by subsequent modules. Simultaneously, the signal output section is optimized to ensure effective communication, significantly improving measurement accuracy and reliability. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments recorded in the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0019] Figure 1 This is a system structure diagram of a magnetostrictive liquid level gauge in one embodiment of the present invention.

[0020] Figure 2 This is a circuit diagram of a power module in one embodiment of the present invention.

[0021] Figure 3 This is a circuit schematic diagram of a signal processing module in one embodiment of the present invention.

[0022] Figure 4 2 is a system structure diagram of a control module in one embodiment of the present invention.

[0023] Figure 5 2 is a circuit diagram of a timing subunit in one embodiment of the present invention.

[0024] Figure 6 This is a circuit schematic diagram of a HART signal subunit in one embodiment of the present invention.

[0025] Figure 7 1 is a circuit diagram of a DAC subunit in one embodiment of the present invention.

[0026] Figure 8 Schematic diagram of waveforms of various signals in one embodiment of the present invention. DETAILED DESCRIPTION

[0027] In order to enable those skilled in the art to better understand the technical solutions of the present invention, the following will be combined with the drawings of the embodiments of the present invention to clearly and completely describe the technical solutions of the embodiments of the present invention. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts should fall within the scope of protection of the present invention.

[0028] The terms "coupled," "connected," or "connected" as used in this specification encompass both direct and indirect connections. An indirect connection is a connection made through an intermediate medium, such as an electrically conductive medium, which may have parasitic inductance or capacitance. An indirect connection may also include a connection through other active or passive devices, such as switches, follower circuits, or other circuits or components, to achieve the same or similar functional objectives. Furthermore, in the invention, terms such as "first" and "second" are primarily used to distinguish one technical feature from another and do not necessarily require or imply a specific relationship, quantity, or order between these technical features.

[0029] In the detailed description of the specification, reference is made to the accompanying drawings forming a part thereof, wherein like reference numerals designate like parts throughout, and wherein exemplary embodiments that may be implemented are shown by way of example. It should be understood that other embodiments may be utilized and structural or logical changes may be made without departing from the scope of the present disclosure. Therefore, the following detailed description should not be construed in a limiting sense.

[0030] The various operations in the specification may be described as multiple discrete actions or operations in a manner that is most helpful in understanding the claimed subject matter. However, the order of description should not be interpreted as implying that these operations must be sequentially related. Specifically, these operations may not be performed in the order presented. The described operations may be performed in an order different from the described embodiments. Various additional operations may be performed and / or the described operations may be omitted in additional embodiments.

[0031] For the purposes of this disclosure, the phrase "A and / or B" means (A), (B), or (A and B). For the purposes of this disclosure, the phrase "A, B and / or C" means (A), (B), (C), (A and B), (A and C), (B and C), or (A, B and C).

[0032] Various components and devices may be referred to or shown in the singular form in this document (for example, "MOS tube", "transistor", "switch", etc.), but this is only for convenience of discussion, and any element referred to in the singular form may include multiple such elements according to the teachings of this document.

[0033] The specification uses the phrases "in one embodiment," "in other embodiments," or "in some embodiments," which can each refer to one or more of the same or different embodiments. In addition, the terms "including," "comprising," "having," etc. used with respect to the embodiments of the present disclosure are synonymous.

[0034] like Figure 1 As shown, the magnetostrictive liquid level gauge in one embodiment of the present invention includes a power module 10, a control module 20, a sensor module 30, a signal processing module 40 and a signal port.

[0035] The power module 10 is used to convert the power supply voltage into the power supply voltage required by each module. The control module 20 is used to generate a start signal START. The sensor module 30 is connected to the control module 20 to sense and generate a sensing signal based on the control of the start signal START. The signal processing module 40 is connected to the sensor module 30 to shape the sensing signal and generate a stop signal STOP. The control module 20 is connected to the signal processing module 40 to calculate the liquid level value based on the time difference between the start signal START and the stop signal STOP. The control module 20 is connected to the signal port J1 to output the liquid level value.

[0036] In one embodiment, the magnetostrictive level gauge is a two-wire instrument with a 4-20mA analog output. Signal port J1 is used for both power supply and signal transmission. Pin 2 of signal port J1 is connected to the positive terminal of the power supply (+24V), and pin 1 of signal port J1 is connected to the negative terminal of the power supply (-24V).

[0037] like Figure 2 As shown, the power module 10 may include a protection circuit, a current limiting unit, and a voltage conversion unit. The protection circuit is connected to the power supply voltage via the signal port J1, and the current limiting unit is connected to the protection circuit and the voltage conversion unit. The voltage conversion unit is used to convert the power supply voltage into the operating voltage of each module.

[0038] The protection circuit includes diode D1, diode D2, diode D3, and inductor L1. The anode of diode D1 is connected to pin 2 of the signal port, the cathode of diode D1 is connected to the first end of diode D2 and the first end of inductor L1, the second end of inductor L1 is connected to the current limiting unit, and the second end of diode D2 and the cathode of diode D3 are connected to pin 1 of the signal port.

[0039] Diode D2 is a TVS diode, and diode D3 is a Schottky diode. The protection circuit prevents backflow and stabilizes voltage. The second end of the inductor forms the positive end of the current loop, LOOP_P, while the anode of diode D3 forms the negative end of the current loop, LOOP_M.

[0040] It is understandable that the protection circuit may not be provided, and the positive end LOOP_P of the current loop is formed by the pin 2 of the signal port J1 , and the negative end LOOP_M of the current loop is formed by the pin 1 of the signal port J1 .

[0041] The current limiting unit includes an LDO chip U1 and a current-limiting resistor R1. Pin 3 of the LDO chip U1 is connected to the second end of the inductor, pins 2 and 4 of the LDO chip U1 are connected to the first end of the current-limiting resistor R1, and pin 1 of the LDO chip U1 and the second end of the current-limiting resistor R1 are connected to the voltage conversion unit.

[0042] The LDO chip U1 is preferably LM317C, a low-power LDO chip. LDO chip U1 controls the voltage drop across current-limiting resistor R1. When the resistance of current-limiting resistor R1 is 330Ω, the voltage drop across current-limiting resistor R1 is controlled to 1.25V, which controls the current flowing through current-limiting resistor R1 to approximately 3.8mA. This limits the power consumption of the subsequent circuitry and ensures that the power consumption of the voltage conversion unit does not exceed the required power consumption of the entire sensor system. Due to the voltage drop across LDO chip U1 and current-limiting resistor R1, the voltage at the second terminal of current-limiting resistor R1 becomes 22V.

[0043] The voltage conversion unit includes two power chips, U2 and U3, and their peripheral circuits. Power chip U2 is connected to LDO chip U1 and converts 22V to a 5V operating voltage. Power chip U3 is connected to power chip U2 and converts 5V to a 3.3V operating voltage. The peripheral circuits of power chips U2 and U3 include capacitors C3-C10 and inductors L3-L4 for voltage filtering.

[0044] In one embodiment, the sensor module 30 includes an excitation unit, a signal detection unit, a waveguide, and two permanent magnets. Each of the two permanent magnets is housed in a float, which floats with the surface of the liquid to be tested. The liquids to be tested can be two types, with each float floating on the surface of one type of liquid.

[0045] The excitation unit is connected to the control module 20 to receive the start signal START, and the excitation unit is connected to the first end of the waveguide wire and the second end of the waveguide wire to generate a current pulse signal on the waveguide wire based on the control of the start signal START. The current pulse signal will be accompanied by a circular magnetic field, propagating downward along the waveguide wire at the speed of light. When the circular magnetic field encounters the magnetic field formed by the permanent magnet, the waveguide wire will be deformed under the action of the two magnetic fields, generating a torsional wave pulse. The torsional wave pulse propagates along the waveguide wire to both ends, and the signal detection unit generates an induction pulse after detecting the torsional wave pulse, and amplifies the induction pulse to generate an induction signal. When there are two permanent magnets, two torsional wave pulses will be generated on the waveguide wire in succession, and the signal detection unit will also generate two induction signals in succession.

[0046] In other embodiments, only one float and one permanent magnet may be provided, that is, a single float level gauge design may be adopted. This embodiment does not involve structural improvements to the sensor module 30 and can be implemented using existing technologies, which will not be elaborated here.

[0047] like Figure 3 As shown, the signal processing module 40 includes a comparator U9 and a monostable trigger U10 and peripheral circuits thereof. The first input terminal of the comparator U9 is connected to the signal detection unit to receive the sensing signal. The second input terminal of the comparator U9 is connected to the reference voltage (3.3V) through the resistor R29. The comparator U9 is used to compare the sensing signal with the reference voltage to generate a comparison signal.

[0048] In one embodiment, the first input terminal of the comparator U9 is a positive input terminal, and the second input terminal of the comparator U9 is a negative input terminal. When the sensing signal is greater than the reference voltage, the comparator U9 outputs a high-level comparison signal. When the sensing signal is less than the reference voltage, the comparator U9 outputs a low-level comparison signal.

[0049] Pins 2 and 9 of the monostable trigger U10 are connected to the output end of the comparator U9 to receive the comparison signal. The monostable trigger U10 is used to shape the comparison signal and generate a termination signal STOP through its own pin 13.

[0050] The model of the monostable trigger U10 is preferably SN74AHC123APWR.

[0051] Since the sensing signal generated by the signal detection unit has multiple pulses, the comparator U9 can filter out several pulse signals with higher peak values among these pulses, and then integrate these pulse signals into a square wave through the monostable trigger U10 to facilitate subsequent signal recognition.

[0052] like Figure 4 As shown, the control module 20 includes a control unit 21 and an output unit 22. The control unit 21 is used to generate a start signal START, and the control unit 21 is connected to the signal processing module 40 to receive a stop signal STOP and calculate the liquid level value based on the time difference between the start signal START and the stop signal STOP. The output unit 22 is connected to the control unit 21 to receive the liquid level value, and the output unit 22 is connected to the current loop positive terminal LOOP_P and the current loop negative terminal LOOP_M to output the liquid level value.

[0053] In one embodiment, the control unit 21 includes an MCU subunit 24 and a timing subunit 23. The MCU subunit 24 is used to generate a timing control signal. The timing subunit 23 is connected to the MCU subunit 24 to generate a start signal START based on the timing control signal. The timing subunit 23 is connected to pin 13 of the monostable trigger U10 to receive the stop signal STOP and time the time difference between the start signal START and the stop signal STOP to generate a timing signal. The MCU subunit 24 receives the timing signal and calculates the timing signal to obtain a liquid level value.

[0054] like Figure 5 As shown, timing subunit 23 includes a TDC chip U5 and its peripheral circuits. Pins 8 through 11 of TDC chip U5 are connected to MCU subunit 24 to receive timing control signals. TDC chip U5 is controlled by the timing control signals and generates a start signal START via its own pin 31. Pin 30 of TDC chip U5 is connected to pin 13 of monostable trigger U10 to receive a stop signal STOP. TDC chip U5 calculates the time difference between the start signal START and the stop signal STOP to generate a timing signal, which it transmits to MCU subunit 24 via its own pin 12. MCU subunit 24 accurately calculates the liquid level based on the product function of the propagation velocity of the waveguide wire torsional wave pulse.

[0055] In other embodiments, the MCU sub-unit 24 may generate a start signal START, and the timing sub-unit 23 may receive the start signal START and the stop signal STOP and calculate the time difference between the two signals. This embodiment does not involve structural improvements to the control unit 21 and can be implemented using existing technologies, which will not be further described here.

[0056] like Figure 4As shown, in one embodiment, the output unit 22 includes a HART signal subunit 25, a DAC subunit 26, and a key and display subunit 27. The HART signal subunit 25 is connected to the control unit 21 to receive the liquid level value and generate a HART modulation signal HART_OUTPUT based on the liquid level value. The DAC subunit 26 is connected to the control unit 21 to receive the liquid level value. The DAC subunit 26 is connected to the current loop positive terminal LOOP_P and the current loop negative terminal LOOP_M to generate a current signal representing the liquid level value at the current loop positive terminal LOOP_P and the current loop negative terminal LOOP_M. The DAC subunit 26 is connected to the HART signal subunit 25 to receive the HART modulation signal HART_OUTPUT and adjust the current signal based on the HART modulation signal HART_OUTPUT.

[0057] The button and display subunit 27 is connected to the MCU subunit 24. The MCU subunit 24 controls the button and display subunit 27 to display data such as output current and liquid level value. Control instructions can also be input to the MCU subunit 24 through the button and display subunit 27. It has the function of calibrating the functional relationship between the liquid level value and the output value and switching the display mode.

[0058] Specifically, the MCU sub-unit 24 generates a first output control signal and a second output control signal containing liquid level value information.

[0059] like Figure 6 As shown, the HART signal subunit 25 includes a HART chip U8 and its peripheral circuits. The model of the HART chip U8 is preferably AD5700BCP_RL7, which has functions such as HART modulation and demodulation, and carrier detection.

[0060] Pins 6 through 10 of the HART chip U8 are connected to the MCU subunit 24 to receive a first output control signal. Based on the first output control signal, the HART chip U8 generates and outputs a HART modulation signal HART_OUTPUT through its own pin 14. Pin 17 of the HART chip U8 is connected to the positive terminal LOOP_P of the current loop to receive and demodulate the HART communication signal in the loop. The demodulated signal is then sent to the MCU subunit 24.

[0061] Pins 14 and 17 of the HART chip U8 are connected to a filter circuit comprising resistors R18, R22, R23, R25, capacitors C40, C41, C47, and C52. These capacitors and resistors are high-pass and low-pass filters, respectively. Frequencies below 2300 Hz and above 1100 Hz pass through the filters, allowing the HART chip U8 to receive and output valid HART communication signals.

[0062] In other embodiments, the HART signal subunit 25 may not be provided, and the output unit 22 does not perform HART modulation through the HART signal subunit 25 .

[0063] like Figure 7 As shown, the DAC subunit 26 output module includes a DAC chip U7, a transistor Q5, an adjustment resistor R26, and peripheral circuits. Pins 4 to 8 of the DAC chip U7 are connected to the MCU subunit 24 to receive the second output control signal. Pin 13 of the DAC chip U7 is connected to pin 14 of the HART chip U8 to receive the HART modulation signal HART_OUTPUT. Pin 9 of the DAC chip U7 is connected to the negative terminal LOOP_M of the current loop. The DAC chip U7 is used to generate a regulation signal at its own pin 16 based on the second output control signal and the HART modulation signal HART_OUTPUT.

[0064] The control terminal of transistor Q5 is connected to pin 16 of DAC chip U7. The first terminal of transistor Q5 is connected to the first terminal of adjustment resistor R26. The second terminal of adjustment resistor R26 is connected to the ground voltage. The second terminal of transistor Q5 is connected to the anode of diode D13. The cathode of diode D13 is connected to the positive terminal LOOP_P of the current loop. Diode D13 is used to prevent current backflow.

[0065] In this embodiment, due to the two-wire design, the signal port serves both power supply and signal transmission functions. The second end of transistor Q5 is connected to the positive terminal LOOP_P of the current loop via diode D13, i.e., to the power supply voltage, thus providing a driving power source for the current signal loop. In other embodiments, if other wiring systems are used, such as a four-wire system, the second end of transistor Q5 needs to be connected to the power supply voltage in addition to being connected to the signal port to provide driving power for the current signal loop.

[0066] In one embodiment, the transistor Q5 is an NPN-type BJT tube, the first end of the transistor Q5 is an emitter, the second end of the transistor Q5 is a collector, and the control end of the transistor Q5 is a base.

[0067] DAC chip U7 generates and regulates the current signal by controlling the on and off switching of transistor Q5. Because BJT transistors operate over a wide current range, spanning at least 4mA to 20mA, emitter degradation is required to stabilize the transconductance (gm) of transistor Q5. That is, when transistor Q5 is connected to DAC chip U7, it acts as a switch, controlling whether the current signal passes through DAC chip U7. This reduces the power consumption of DAC chip U7 itself, improves circuit performance and efficiency, enables precise current control, reduces energy loss, and reduces power consumption and heat generation during operation of DAC chip U7.

[0068] The model of DAC chip U7 is preferably DAC161S997RGHR. This chip is a current-type DAC with HART modulation, which is used for 4-20mA analog output. In actual applications, when the detection data exceeds the range, it is also necessary to output a current of more than 20mA (such as 20.5mA).

[0069] The resistance range of the adjustment resistor R26 is preferably [20Ω, 100Ω). Further, the resistance of the adjustment resistor R26 is preferably 75Ω.

[0070] Because a larger value for regulating resistor R26 increases power consumption in the current signal loop, HART communication becomes unstable or even fails when the current signal is 20mA or greater. By limiting the value of regulating resistor R26, the output current limit can be increased, ensuring normal HART communication even when the output current increases to 20.5mA.

[0071] In actual application, when the power supply is powered on, the power module 10 converts the power supply voltage into 5V and 3.3V operating voltages. The MCU subunit 24 generates a timing control signal and controls the timing control signal to generate a start signal START, and the sensing module starts sensing and generates a sensing signal.

[0072] like Figure 8 As shown, after the sensing signal passes through comparator U9, several pulses in the center of its waveform trigger the comparator to generate a comparison signal. By adjusting the reference voltage received by comparator U9, the pulse amplitude threshold that triggers comparator U9 can be adjusted. Because the peaks of the several pulses in the center of the sensing signal are close together, the comparator extracts these pulses to avoid missing the sensing signal. Monostable trigger U10 then responds to the first rising edge of the comparison signal and delays it for a period of time, generating a square wave-shaped termination signal, STOP, which is easily received and calculated by the TDC chip U5. The width of this square wave can also be adjusted by adjusting the parameters of monostable trigger U10.

[0073] The TDC chip U5 calculates the time difference between the start signal START and the end signal STOP. Since two floats are set, two end signals STOP will be generated successively. The TDC chip U5 can calculate the time difference between the two end signals STOP and the start signal START respectively, or it can calculate the time difference between only one end signal STOP and the start signal START. This can be freely set according to needs.

[0074] After the MCU subunit 24 calculates the liquid level value based on the time difference between the two signals, it sends the liquid level value data to the HART chip U8 and the DAC chip U7 respectively. The DAC chip U7 modulates and generates a current signal carrying the HART signal, which is output to the outside through the signal port J1.

[0075] The magnetostrictive liquid level meter of the present application is suitable for a two-wire instrument design, has lower system power consumption, integrates HART communication function, increases flexibility and real-time monitoring functions, and can perform HART communication normally when the output current is 4mA-20.5mA.

[0076] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above and that the present invention can be implemented in other specific forms without departing from the spirit or essential characteristics of the present invention. Therefore, the embodiments should be considered in all respects as illustrative and non-restrictive, and the scope of the present invention is defined by the appended claims, not the foregoing description, and all variations within the meaning and range of equivalents of the claims are intended to be encompassed within the present invention. Any reference sign in a claim should not be construed as limiting the claim to which it relates.

[0077] In addition, it should be understood that although this specification is described in terms of implementation methods, not every implementation method contains only one independent technical solution. This narrative method of the specification is only for the sake of clarity. Those skilled in the art should regard the specification as a whole. The technical solutions in each embodiment can also be appropriately combined to form other implementation methods that can be understood by those skilled in the art.

Claims

1. A magnetostrictive liquid level gauge, characterized in that: It includes a control module, a sensing module, a signal processing module and a signal port. The control module is used to generate a start signal. The sensing module is connected to the control module to perform sensing based on the control of the start signal and generate a sensing signal. The signal processing module is connected to the sensing module to shape the sensing signal and generate a termination signal. The control module is connected to the signal processing module to calculate the liquid level value based on the time difference between the start signal and the termination signal. The control module is connected to the signal port to output the liquid level value.

2. The magnetostrictive liquid level gauge according to claim 1, characterized in that: The signal processing module includes a comparator and a monostable trigger. The first input end of the comparator is connected to the sensing module to receive the sensing signal, the second input end of the comparator is connected to the reference voltage, the comparator is used to compare the sensing signal and the reference voltage and generate a comparison signal, the monostable trigger is connected to the output end of the comparator to receive the comparison signal, and the monostable trigger is used to shape the comparison signal to generate a termination signal.

3. The magnetostrictive liquid level gauge according to claim 1, characterized in that: The control module includes a control unit and an output unit, the control unit is used to generate a start signal, the control unit is connected to the signal processing module to receive a stop signal and calculate the liquid level value based on the time difference between the start signal and the stop signal, the output unit is connected to the control unit to receive the liquid level value, and the output unit is connected to the signal port to output the liquid level value.

4. The magnetostrictive liquid level gauge according to claim 3, characterized in that: The output unit includes a DAC subunit, the DAC subunit is connected to the control unit to receive the liquid level value, and the DAC subunit is connected to the signal port to generate a current signal for representing the liquid level value at the signal port.

5. The magnetostrictive liquid level gauge according to claim 4, characterized in that: The output unit also includes a HART signal subunit, which is connected to the control unit to receive the liquid level value and generate a HART modulation signal based on the liquid level value. The DAC subunit is connected to the HART signal subunit to receive the HART modulation signal and adjust the current signal based on the HART modulation signal.

6. The magnetostrictive liquid level gauge according to claim 4, characterized in that: The DAC subunit includes a DAC chip, a transistor and an adjustment resistor. The DAC chip is connected to the control unit to receive the liquid level value and generate an adjustment signal based on the liquid level value. The control end of the transistor is connected to the DAC chip to receive the adjustment signal. The first end of the transistor is connected to the first end of the adjustment resistor, the second end of the adjustment resistor is connected to the ground voltage, and the second end of the transistor is connected to the power supply voltage and the signal port.

7. The magnetostrictive liquid level gauge according to claim 5, characterized in that: The DAC subunit includes a DAC chip, a transistor and an adjustment resistor. The DAC chip is connected to the control unit to receive the liquid level value, the DAC chip is connected to the HART signal subunit to receive the HART modulation signal, and the DAC chip is used to generate an adjustment signal based on the liquid level value and the HART modulation signal. The control end of the transistor is connected to the DAC chip to receive the adjustment signal, the first end of the transistor is connected to the first end of the adjustment resistor, the second end of the adjustment resistor is connected to the ground voltage, and the second end of the transistor is connected to the power supply voltage and the signal port.

8. The magnetostrictive liquid level gauge according to claim 6 or 7, characterized in that: The DAC chip is DAC161S997RGHR.

9. The magnetostrictive liquid level gauge according to claim 6 or 7, characterized in that: The resistance range of the regulating resistor is [20,100)Ω.

10. The magnetostrictive liquid level gauge according to claim 9, characterized in that: The resistance of the regulating resistor is 75Ω.

Images