An ultrasonic level measurement system

Abstract

This invention discloses an ultrasonic level measurement system, including an ultrasonic transducer, a transducer driving circuit, an echo receiving and processing circuit, and an MCU controller. The MCU controller's PWM port alternately generates two different pulse counts of PWM pulses at fixed time intervals, triggering the transducer driving circuit to drive the ultrasonic transducer to alternately emit two types of ultrasonic waves and receive the reflected echo signals of these two ultrasonic waves. The two types of ultrasonic waves include a long pulse train and a short pulse train. This ultrasonic level measurement system, by alternately generating two different pulse counts of PWM pulses, achieves simultaneous measurement of both long and short pulse trains. The combined detection of long and short pulse trains allows for a larger detection range and a wider application range. It combines the advantages of both long and short pulse trains, resolving the inherent contradiction between the small range of short pulse trains and the blind zone of short pulse trains' close-range detection.

Description

Technical Field

[0001] This invention relates to the field of industrial automation testing instruments and meters, and in particular to an ultrasonic level measurement system. Background Technology

[0002] Ultrasonic level gauges calculate the level height by emitting ultrasonic pulses and receiving the echoes reflected from the material surface, based on the speed of sound. Due to their advantages such as non-contact measurement, easy installation, moderate cost, and applicability to both liquid and solid media, they are widely used in liquid and material level measurement in industries such as petrochemicals, water treatment, and grain storage. However, their performance is limited by the inherent contradictions of the emitted waveform: while high-energy long pulse trains can achieve long-distance detection, the transducer's mechanical inertia generates acoustic aftershocks on the order of tens of milliseconds, forming an inertial tail and expanding the near-field blind zone; short pulse trains, while able to compress the blind zone, have insufficient energy, limiting the measurement range and reducing anti-interference capabilities. This "energy-resolution tradeoff" stems from the dual constraints of transducer electromechanical coupling and airborne sound attenuation.

[0003] To address the aforementioned contradictions, most existing commercial instruments are equipped with a manual "short-range / long-range" switching mode, allowing users to select the operating mode based on the estimated measurement distance. This solution is essentially still a single waveform, offering only two preset parameter combinations, requiring manual intervention when operating conditions change, resulting in low levels of intelligence. Current technology fails to fundamentally solve the core problem that a single fixed waveform cannot simultaneously account for blind spots and measurement range, limiting its application in scenarios with rapid liquid level changes and complex media surfaces. Summary of the Invention

[0004] The purpose of this invention is to provide an ultrasonic level measurement system.

[0005] An ultrasonic level measurement system includes an ultrasonic transducer, a transducer driving circuit, an echo receiving and processing circuit, and an MCU controller. The PWM port of the MCU controller, the transducer driving circuit, and the ultrasonic transducer are connected in sequence. The ultrasonic transducer, the echo receiving and processing circuit, and the MCU controller are connected together. During operation, the PWM port of the MCU controller alternately generates two different pulse counts of PWM pulses at fixed time intervals, triggering the transducer drive circuit to drive the ultrasonic transducer to alternately emit two types of ultrasonic waves and receive the reflected echo signals of the two types of ultrasonic waves. The two types of ultrasonic waves include a long pulse train and a short pulse train. The long pulse train is a pulse train containing N1 pulses, and the short pulse train is a pulse train containing N2 pulses. N1 and N2 are both positive integers, and N1 > N2. The two types of reflected echo signals received by the ultrasonic transducer are processed by the echo receiving and processing circuit and then transmitted to the MCU controller. The MCU controller obtains the distance data corresponding to the two types of reflected echo signals. The distance data corresponding to the long pulse train reflected echo signal is A, and the distance data corresponding to the short pulse train reflected echo signal is B. The effective ranging interval of the long pulse train is [A1, A2], and the effective ranging interval of the short pulse train is [B1, B2]. If A1≤A≤A2, then the distance data A corresponding to the long pulse train is used as the final measurement result; If A is not within the effective ranging interval [A1,A2] of the long pulse train, but B1≤B≤B2, then the distance data B corresponding to the reflected echo signal of the short pulse train is used as the final measurement result. If A is not within the effective ranging interval [A1,A2] of the long pulse train, and B is not within the effective ranging interval [B1,B2] of the short pulse train, then the final measurement result is considered invalid.

[0006] Furthermore, N1 can be any value from 8 to 20, and N2 can be any value from 2 to 4. For example, N1 is 15 and N2 is 2.

[0007] Furthermore, the transducer driving circuit includes a connected MOSFET Q1 and a driving pulse transformer T1. The PWM port of the MCU controller, the control terminal of the MOSFET Q1, the first side of the driving pulse transformer T1, the second side of the driving pulse transformer T1, and the ultrasonic transducer are connected in sequence. During operation, the PWM port of the MCU controller outputs PWM pulses to control the switching on and off of the MOSFET Q1, thereby controlling the driving pulse transformer T1 to generate a corresponding excitation signal to excite and drive the ultrasonic transducer, causing the ultrasonic transducer to emit ultrasonic waves corresponding to the excitation signal. The MOSFET Q1, as a high-speed switching device, is controlled by the PWM port of the MCU controller to convert DC into high-frequency pulses; the driving pulse transformer T1 achieves signal isolation and impedance matching, coupling the high-frequency pulses output by the MOSFET Q1 to the transducer terminal, while avoiding ground interference and high-voltage backflow. The transducer drive circuit formed by the combination of MOSFET Q1 and drive pulse transformer T1 not only has high voltage and high current driving capability, but also has precise timing control and excellent electrical isolation characteristics, realizing efficient energy conversion and safe and reliable operation.

[0008] Furthermore, the echo receiving and processing circuit includes a bandpass filter circuit, a logarithmic amplifier circuit, and a comparator connected in sequence. The ultrasonic transducer, the bandpass filter circuit, the logarithmic amplifier circuit, the comparator, and the MCU controller are connected in sequence. During operation, the reflected echo signal received by the ultrasonic transducer is filtered by the bandpass filter circuit, amplified by the logarithmic amplifier circuit, and compared by the comparator. After shaping and conversion into digital pulses, it is sent to the MCU controller. The logarithmic amplifier circuit can be, but is not limited to, an AD8310ARM, to perform logarithmic compression on the filtered reflected echo signal, greatly improving the receiving range of the reflected echo signal and enabling effective detection of both strong and weak reflected echo signals. The comparator can be, but is not limited to, an MCP6001T comparator, to convert the analog reflected echo signal into digital pulses for the MCU controller to capture. With the structure of the above-described echo receiving and processing circuit, signal interference is low, the reflected echo signal detection range is wide, and the detection capability is strong.

[0009] Furthermore, the bandpass filter circuit is a parameter-configurable negative feedback second-order active bandpass filter. The negative feedback second-order active bandpass filter can, but is not limited to, being constructed using multiple operational amplifiers. With this structure, by adjusting the circuit parameters to obtain a high quality factor (Q value), the desired ultrasonic frequency can be accurately selected, while effectively suppressing out-of-band noise and interference, greatly improving the signal-to-noise ratio, and achieving extremely narrow bandwidth and high frequency selectivity. It can also provide significant signal gain at the center frequency, performing pre-amplification while filtering, simplifying system design. In addition, this structure requires only a single operational amplifier and a small number of resistors and capacitors; the circuit is simple and mature, easy to theoretically calculate and simulate, and combines the advantages of high reliability and low cost. In the negative feedback second-order active bandpass filter, when adjusting the circuit parameters, different resistors and capacitors can be selected through jumpers or software parameter settings, such as setting the center frequency of the negative feedback second-order active bandpass filter to 40kHz or 64kHz to match probes of different frequencies.

[0010] Furthermore, a temperature sensor is included, which is connected to the MCU controller. The propagation speed of ultrasound is significantly affected by temperature. By setting up the temperature sensor, the temperature of the propagation medium can be detected in real time, allowing for temperature compensation and ensuring measurement accuracy.

[0011] Furthermore, the system includes a memory and a clock circuit, each connected to the MCU controller. The memory includes FRAM and FLASH memory. FRAM offers high speed and unlimited read / write cycles, while FLASH memory provides large capacity. During system operation, detailed reflected echo signal data, key events, and self-test status are first recorded at high speed in the FRAM memory. When the FRAM memory is full or meets specific conditions, the stored data is batch-transferred to the large-capacity FLASH memory for long-term storage. In addition, the clock circuit provides high-precision timestamps for all stored data. In case of system anomalies, historical data can be retrieved and correlated on a timeline to achieve module-level fault location. For example, by analyzing the morphology and temperature data of the reflected echo signal, it can be determined whether the fault lies in probe scaling, damage, or a temperature sensor malfunction. This collaborative storage scheme combining FRAM and FLASH memory integrates the advantages of both: it possesses the high speed and unlimited read / write cycles of FRAM memory to meet real-time data recording requirements, and the large capacity of FLASH memory for long-term data preservation. Furthermore, combined with the clock circuit settings, the system can achieve multi-dimensional data recording with timestamps, thereby supporting data traceability and fault self-diagnosis, and significantly reducing maintenance costs and time.

[0012] Furthermore, it includes a button and display module, which is connected to the MCU controller. During operation, the user can set parameters or view relevant information through the button and display module.

[0013] Furthermore, an interface unit is included, which is connected to the MCU controller. The interface unit includes a relay output circuit, a 4-20mA transmitter circuit, and a communication interface circuit. The relay output circuit is used to control start / stop, alarm, and other switching signals; the 4-20mA transmitter circuit is used for long-distance industrial transmission of analog signals; and the communication interface circuit is used to exchange data with a host computer or control system, enabling remote parameter reading, setting, and network control. The simultaneous presence of these three circuits ensures backward compatibility with traditional analog equipment (4-20mA and relays) and upward support for modern digital networks (communication interface), providing rich interface options suitable for almost all industrial control scenarios. The relay output circuit can have one, two, or more outputs.

[0014] Furthermore, the relay output circuit includes an optocoupler isolation drive circuit and a relay control output circuit. Through the electrical isolation provided by the optocoupler isolation drive circuit, the path for high voltage, high current surges, or ground loop interference to enter the core control system from the output side is blocked, thereby improving the anti-interference capability and long-term operational stability of the control system.

[0015] Furthermore, the system includes a power input module and a DC-DC power conversion module for power supply, which are connected together. The DC-DC power conversion module is connected to various circuits. During operation, the DC-DC power conversion module converts the voltage input from the power input module into multiple power supplies, such as +5V and +13V, for use by each circuit. The power input module can be equipped with multiple protection structures, including thermistors, TVS diodes, gas discharge tubes, and common-mode inductors, to ensure stable operation of the system in harsh industrial electromagnetic environments.

[0016] Furthermore, the system includes a probe and an instrument. The instrument includes a main control board, and the ultrasonic transducer, the transducer drive circuit, and the echo receiving and processing circuit are all located within the probe. The MCU controller is located on the main control board of the instrument. The instrument may also include an interface board. When the ultrasonic level measurement system includes the temperature sensor, the memory, the clock circuit, the button and display module, the interface unit, the power input module, and the DC-DC power conversion module, the temperature sensor is located on the probe, the memory, the clock circuit, the button and display module, and the DC-DC power conversion module are all located on the main control board, and the interface unit and the power input module are located on the interface board. This arrangement facilitates layout, especially by placing the power input module and the DC-DC power conversion module at a distance, distributed on different sections of the main control board and the interface board, so as to reduce mutual interference through physical space.

[0017] This invention's ultrasonic level measurement system, by having the PWM port of the MCU controller alternately generate two different pulse lengths of PWM pulses at fixed time intervals, triggers the transducer drive circuit, causing the ultrasonic transducer to alternately emit two types of ultrasonic waves, including long pulse trains and short pulse trains, for measurement. In other words, a single operation achieves two measurements simultaneously using both long and short pulse trains. Compared to single long and short pulse train detection, the combined long and short pulse train dual detection allows for a larger detection range and a wider range of applications. It combines the advantages of both long and short pulse trains, physically resolving the inherent contradiction between the small range of short pulse trains and the blind zone of long pulse trains at close range, enabling both short-range and long-range detection. Furthermore, this invention's ultrasonic level measurement system implements a dual-waveform alternating detection mechanism of long and short pulse trains, eliminating the need to judge distance or manually switch between long and short pulse train modes. It possesses scene adaptability, not only simplifying the detection operation but also automatically matching pulse characteristics, fundamentally avoiding the decrease in measurement accuracy caused by improper pulse train type selection.

[0018] In this invention's ultrasonic level measurement system, after the MCU controller obtains distance data corresponding to two types of reflected echo signals, if the distance data A corresponding to the long pulse train is within the effective ranging interval [A1, A2] of the long pulse train and is valid, then regardless of whether the distance data corresponding to the short pulse train is valid, the distance data A corresponding to the long pulse train is used as the final measurement result. That is, for the same distance, when both long and short pulse trains can be used for measurement, the distance data A corresponding to the long pulse train is selected as the final measurement result. Compared to short pulse trains, long pulse trains contain signals with more cycles, have greater energy, and produce stronger reflected echoes. Strong echo signals are easier to identify and receive, especially when the surface of the object being measured is tilted, rough (sound-absorbing), or small in size. Long pulse trains can effectively avoid "missed detections" or "false triggers" caused by weak echoes, exhibiting better stability and reliability, and the measurement results are often more accurate. Attached Figure Description

[0019] Figure 1 This is a schematic diagram of the module structure of the ultrasonic level measurement system of the present invention; Figure 2 This is a circuit diagram of the transducer drive circuit of the ultrasonic level measurement system of the present invention. Figure 3 This is a circuit diagram of the bandpass filter circuit of the ultrasonic level measurement system of the present invention; Figure 4 This is a schematic diagram of the ultrasonic level measurement system of the present invention. Detailed Implementation

[0020] The preferred embodiments of the ultrasonic level measurement system of the present invention will be described in detail below with reference to the accompanying drawings.

[0021] like Figure 1 As shown, an ultrasonic level measurement system includes an ultrasonic transducer 11, a transducer driving circuit 12, an echo receiving and processing circuit 13, and an MCU controller 21. The PWM port of the MCU controller 21, the transducer driving circuit 12, and the ultrasonic transducer 11 are connected in sequence. The ultrasonic transducer 11, the echo receiving and processing circuit 13, and the MCU controller 21 are connected. During operation, the PWM port of the MCU controller 21 alternately generates two different pulse counts of PWM pulses at fixed time intervals, triggering the transducer drive circuit 12 to drive the ultrasonic transducer 11 to alternately emit two types of ultrasonic waves and receive the reflected echo signals of the two types of ultrasonic waves. The two types of ultrasonic waves include a long pulse train and a short pulse train. The long pulse train is a pulse train containing N1 pulses, and the short pulse train is a pulse train containing N2 pulses. N1 and N2 are both positive integers, and N1 > N2. The two types of reflected echo signals received by the ultrasonic transducer 11 are processed by the echo receiving and processing circuit 13 and then transmitted to the MCU controller 21. The MCU controller 21 obtains the distance data corresponding to the two types of reflected echo signals. The distance data corresponding to the long pulse train reflected echo signal is A, and the distance data corresponding to the short pulse train reflected echo signal is B. The effective ranging interval for a long pulse train is [A1, A2], and the effective ranging interval for a short pulse train is [B1, B2]. If A1≤A≤A2, then the distance data A corresponding to the long pulse train is used as the final measurement result; If A is not within the effective ranging interval [A1,A2] of the long pulse train, but B1≤B≤B2, then the distance data B corresponding to the reflected echo signal of the short pulse train is used as the final measurement result. If A is not within the effective ranging interval [A1,A2] of the long pulse train, and B is not within the effective ranging interval [B1,B2] of the short pulse train, then the final measurement result is considered invalid.

[0022] The ultrasonic level measurement system of the present invention includes an ultrasonic transducer 11, a transducer driving circuit 12, an echo receiving and processing circuit 13, and an MCU controller 21, wherein the MCU controller 21 is the control center; the transducer driving circuit 12 is used to excite and drive the ultrasonic transducer 11 to emit ultrasonic waves; the ultrasonic transducer 11 is used to convert electrical energy, emit ultrasonic waves, and receive reflected echo signals of ultrasonic waves; the echo receiving and processing circuit 13 is used to process the reflected echo signals of ultrasonic waves received by the ultrasonic transducer 11 and transmit them to the MCU controller 21.

[0023] In the ultrasonic level measurement system of the present invention, during operation, the MCU controller 21 controls the transducer drive circuit 12, which excites and drives the ultrasonic transducer 11 to emit ultrasonic waves. When the emitted ultrasonic waves encounter the object to be measured, they are reflected to form a reflected echo. The ultrasonic transducer 11 receives the reflected echo signal and sends it to the echo receiving and processing circuit 13 for processing. The processed signal is then transmitted to the MCU controller 21, which analyzes it to obtain the final measurement result.

[0024] In the ultrasonic level measurement system of the present invention, when the MCU controller 21 triggers the transducer drive circuit 12, the PWM port of the MCU controller 21 alternately generates two different pulse counts of PWM pulses at a fixed time interval. Under the triggering of the two different pulse counts of PWM pulses, the transducer drive circuit 12 drives the ultrasonic transducer 11 to alternately emit two types of ultrasonic waves, including long pulse trains and short pulse trains, and receives the reflected echo signals of the two types of ultrasonic waves. Correspondingly, the MCU controller 21 obtains the distance data corresponding to the two reflected echo signals.

[0025] In the ultrasonic level measurement system of the present invention, when there are distance data corresponding to two types of reflected echo signals, the distance data A corresponding to the long pulse train is preferentially used as the final measurement result. Specifically, as long as the distance data A corresponding to the long pulse train reflected echo signal is within the effective ranging interval [A1, A2] of the long pulse train, and the distance data A corresponding to the long pulse train reflected echo signal is valid, regardless of the distance data corresponding to the short pulse train reflected echo signal, the distance data A corresponding to the long pulse train is used as the final measurement result.

[0026] The ultrasonic level measurement system of this invention triggers the transducer drive circuit 12 by having the PWM port of the MCU controller 21 alternately generate two different pulse quantities of PWM pulses at fixed time intervals. This causes the ultrasonic transducer 11 to alternately emit two types of ultrasonic waves, including long pulse trains and short pulse trains, for measurement. In other words, a single operation achieves two measurements simultaneously, one long pulse train and one short pulse train. Compared to single long pulse train or short pulse train detection, the dual detection of long and short pulse trains allows for a larger detection range and a wider range of applications. It combines the advantages of both long and short pulse trains and physically resolves the inherent contradiction between the small range of short pulse trains and the blind zone of close-range detection of long pulse trains, enabling both close-range and long-range detection. Furthermore, the ultrasonic level measurement system of this invention implements a dual-waveform alternating detection mechanism of long pulse trains and short pulse trains, eliminating the need to judge the distance or manually switch between long and short pulse train settings. It has scene adaptive capability, which not only makes the detection operation simpler, but also automatically matches the pulse characteristics, fundamentally avoiding the decrease in measurement accuracy caused by improper selection of pulse train type.

[0027] After obtaining the distance data corresponding to the two reflected echo signals, the distance data can be fused. For example, the average value can be used as the final measurement result. Alternatively, as in the ultrasonic level measurement system of this invention, the distance data A corresponding to the long pulse train can be preferentially used as the final measurement result. In the ultrasonic level measurement system of this invention, if the distance data A corresponding to the long pulse train is within the effective ranging interval [A1, A2] of the long pulse train, and the distance data A corresponding to the long pulse train is valid, regardless of whether the distance data corresponding to the short pulse train is valid, the distance data A corresponding to the long pulse train is used as the final measurement result. That is, for the same distance, when both the long and short pulse trains can be measured, the distance data A corresponding to the long pulse train is also selected as the final measurement result. Compared to short pulse trains, long pulse trains contain signals with more cycles. Long pulse trains have greater energy and stronger reflected echoes. Strong echo signals are easier to identify and receive. In particular, when the surface of the object being measured is tilted, rough (sound-absorbing), or small in size, long pulse trains can effectively avoid "missed detection" or "false triggering" caused by weak echoes. They have better stability and reliability, and the measurement results are often more accurate.

[0028] The effective ranging intervals [A1, A2] of the long pulse train and [B1, B2] of the short pulse train in the ultrasonic level measurement system of this invention can be determined separately by conducting detection calibration experiments at multiple different distances. Specifically, within the range of 0 to 20 m, detection is performed point by point at 1 decimeter intervals, and the distance range in which stable and accurate ranging can be achieved for both the long and short pulse trains is recorded, thereby determining their respective effective ranging intervals.

[0029] In this ultrasonic level measurement system, N1 is preferably any value between 8 and 20, and N2 is any value between 2 and 4. For example, N1 is 15 and N2 is 2. The specific values ​​of N1 and N2 can be determined based on the transducer specifications and differences in hardware circuitry, as well as actual testing. A pulse train of 8 to 20 pulses belongs to the "medium-to-long distance effective region," while a pulse train of 2 to 4 pulses belongs to the "ultra-short distance effective region." The combination of these two types covers more than 90% of the measurement range in industrial applications (from 0.1m to more than 10m), demonstrating strong industrial applicability.

[0030] The ultrasonic level measurement system of the present invention, such as Figure 2As shown, preferably, the transducer drive circuit 12 includes a connected MOSFET Q1 and a drive pulse transformer T1. The PWM port of the MCU controller 21, the control terminal of the MOSFET Q1, the first side of the drive pulse transformer T1, the second side of the drive pulse transformer T1, and the ultrasonic transducer 11 are connected in sequence. During operation, the PWM port of the MCU controller 21 outputs PWM pulses to control the switching on and off of the MOSFET Q1, thereby controlling the drive pulse transformer T1 to generate a corresponding excitation signal to excite and drive the ultrasonic transducer 11, causing the ultrasonic transducer 11 to emit ultrasonic waves corresponding to the excitation signal. The MOSFET Q1, as a high-speed switching device, is controlled to turn on and off by the PWM port of the MCU controller 21, converting DC into high-frequency pulses; the drive pulse transformer T1 achieves signal isolation and impedance matching, coupling the high-frequency pulses output by the MOSFET Q1 to the connection terminal with the ultrasonic transducer 11, while avoiding ground interference and high-voltage backflow. The transducer drive circuit 12, formed by the combination of MOSFET Q1 and drive pulse transformer T1, not only has high voltage and high current driving capability, but also precise timing control and excellent electrical isolation characteristics, realizing efficient energy conversion and safe and reliable operation.

[0031] In a preferred embodiment of the ultrasonic level measurement system of the present invention, the echo receiving and processing circuit 13 includes a bandpass filter circuit 131, a logarithmic amplifier circuit 132, and a comparator 133 connected in sequence. The ultrasonic transducer 11, the bandpass filter circuit 131, the logarithmic amplifier circuit 132, the comparator 133, and the MCU controller 21 are connected in sequence. During operation, the reflected echo signal received by the ultrasonic transducer 11 is sequentially filtered by the bandpass filter circuit 131, amplified by the logarithmic amplifier circuit 132, and compared by the comparator 133. After shaping and conversion into digital pulses, the signal is sent to the MCU controller 21. The logarithmic amplifier circuit 132, which may, but is not limited to, the AD8310ARM, performs logarithmic compression on the filtered reflected echo signal, greatly improving the receiving range of the reflected echo signal and enabling effective detection of both strong and weak reflected echo signals. The comparator 133, which may, but is not limited to, the MCP6001T comparator, converts the analog reflected echo signal into digital pulses for capture by the MCU controller 21. With the aforementioned structure of the echo receiving and processing circuit 13, signal interference is low, the reflected echo signal detection range is wide, and the detection capability is strong.

[0032] The ultrasonic level measurement system of the present invention, such as Figure 3As shown, preferably, the bandpass filter circuit 131 is a parameter-configurable negative feedback second-order active bandpass filter. The negative feedback second-order active bandpass filter can, but is not limited to, being constructed using multiple operational amplifiers (such as AD8052AR). With the structure of the negative feedback second-order active bandpass filter, a high quality factor (Q value) can be obtained by adjusting the circuit parameters, allowing for precise selection of the desired ultrasonic frequency while efficiently suppressing out-of-band noise and interference, greatly improving the signal-to-noise ratio, and achieving extremely narrow bandwidth and high frequency selectivity. Furthermore, it can simultaneously provide significant signal gain at the center frequency, completing pre-amplification while filtering, simplifying system design. In addition, this structure requires only a single operational amplifier and a small number of resistors and capacitors; the circuit is simple and mature, easy to theoretically calculate and simulate, and possesses the advantages of high reliability and low cost. In the negative feedback second-order active bandpass filter, when adjusting the circuit parameters, different resistors can be selected through jumper settings or software parameter changes. Figure 3 Resistors R39, R43, R40, R45 and capacitors ( Figure 3 Capacitors C45, C48, C46, ​​and C50 are used. For example, the center frequency of the negative feedback second-order active bandpass filter can be set to 40kHz or 64kHz to match probes of different frequencies, giving it strong environmental adaptability.

[0033] The ultrasonic level measurement system of the present invention preferably includes a temperature sensor 14, which is connected to the MCU controller 21. The propagation speed of ultrasonic waves is significantly affected by temperature. By setting the temperature sensor 14, the temperature of the propagation medium can be detected in real time, allowing for temperature compensation and ensuring measurement accuracy.

[0034] The ultrasonic level measurement system of the present invention preferably includes a memory 22 and a clock circuit 23. The memory 22 and the clock circuit 23 are each connected to the MCU controller 21. The memory 22 includes a FRAM memory and a FLASH memory. The FRAM memory has high-speed, unlimited read / write characteristics, while the FLASH memory has large capacity. During system operation, detailed reflected echo signal data, key events, self-test status, etc., can be recorded at high speed in the FRAM memory. When the FRAM memory is full or meets specific conditions, the data stored therein is transferred in batches to the large-capacity FLASH memory for long-term storage. Furthermore, the clock circuit 23 is also connected, providing high-precision timestamps for all stored data. In case of system malfunction, historical data can be retrieved and correlated on the timeline to achieve module-level fault location. For example, by analyzing the morphology and temperature data of the reflected echo signal, it can be determined whether the problem is probe scaling, damage, or a temperature sensor malfunction. The aforementioned collaborative storage solution combining FRAM and FLASH memory integrates the technological advantages of both: it possesses the high-speed, unlimited read / write capabilities of FRAM memory to meet real-time data recording needs, while also having the large-capacity storage capacity of FLASH memory for long-term data preservation. Furthermore, combined with the clock circuit 23, the system can achieve multi-dimensional data recording with timestamps, thereby supporting data traceability and fault self-diagnosis, significantly reducing maintenance costs and time.

[0035] The ultrasonic level measurement system of the present invention preferably includes a button and display module 24, which is connected to the MCU controller 21. During operation, the user can set parameters or view relevant information through the button and display module 24.

[0036] The ultrasonic level measurement system of the present invention preferably includes an interface unit 3, which is connected to the MCU controller 21. The interface unit 3 includes a relay output circuit 31, a 4-20mA transmitter circuit 32, and a communication interface circuit 33. The relay output circuit 31 is used to control start / stop, alarm, and other switching signals; the 4-20mA transmitter circuit 32 is used for long-distance industrial transmission of analog signals; and the communication interface circuit 33 is used to exchange data with a host computer or control system, enabling remote parameter reading, setting, and network control. The simultaneous existence of these three circuits provides backward compatibility with traditional analog equipment (4-20mA and relays) and upward support for modern digital networks (communication interface), offering rich interface options suitable for almost all industrial control scenarios. The relay output circuit 31 can have one, two, or more outputs.

[0037] In the ultrasonic level measurement system of the present invention, preferably, the relay output circuit 31 includes an optocoupler isolation drive circuit 311 and a relay control output circuit 312. Through the electrical isolation of the optocoupler isolation drive circuit 311, the path of high voltage, high current surges, or ground loop interference from the output side into the core control system is blocked, thereby improving the anti-interference capability and long-term operational stability of the control system.

[0038] The ultrasonic level measurement system of the present invention preferably includes a power input module 41 and a DC-DC power conversion module 42 for power supply, wherein the power input module 41 and the DC-DC power conversion module 42 are connected. The DC-DC power conversion module 42 is connected to various circuits. During operation, the DC-DC power conversion module 42 converts the voltage input from the power input module 41 into multiple power supplies, such as +5V and +13V, for use by various circuits. The power input module 41 can be equipped with multiple protection structures such as a thermistor, TVS diode, gas discharge tube, and common-mode inductor to ensure stable operation of the system in harsh industrial electromagnetic environments.

[0039] The ultrasonic level measurement system of the present invention, such as Figure 4 As shown, preferably, the system includes a probe 10 and an instrument 20. The instrument 20 includes a main control board 201. The ultrasonic transducer 11, the transducer drive circuit 12, and the echo receiving and processing circuit 13 are all located within the probe 10. The MCU controller 21 is located on the main control board 201 of the instrument 20. The instrument 20 may also include an interface board 202. When the ultrasonic level measurement system includes the temperature sensor 14, the memory 22, the clock circuit 23, the button and display module 24, the interface unit 3, the power input module 41, and the DC-DC power conversion module 42, the temperature sensor 14 is located on the probe 10, the memory 22, the clock circuit 23, the button and display module 24, and the DC-DC power conversion module 42 are all located on the main control board 201, and the interface unit 3 and the power input module 41 are located on the interface board 202. Through the above modular and separate design, the core control is kept away from harsh environments. Meanwhile, the power input module 41 and the DC-DC power conversion module 42 are set at a distance and distributed on different boards of the main control board 201 and the interface board 202, so as to reduce mutual interference through the physical distance.

[0040] In the ultrasonic level measurement system of the present invention, the probe 10 and the instrument 20 can be installed as an integral unit or as separate units.

[0041] The ultrasonic level measurement system of this invention can also pre-store optimized algorithm parameter sets (including but not limited to transmission power, filter center frequency, gain, damping time, and dynamic threshold coefficient) for different "measurement objects" (such as open tanks and waveguides) and "process conditions" (such as calm liquid surfaces and vigorous stirring) in the software. When using it, the user only needs to select the option that matches the actual working conditions on the interface, and the system will automatically call the corresponding hardware configuration and software parameter set to achieve "one-click" optimal debugging.

[0042] The above description is merely an embodiment of the present invention and does not limit the patent scope of the present invention. Any equivalent process transformations made using the content of the present invention specification, or direct or indirect applications in other related technical fields, are similarly included within the patent protection scope of the present invention.

Claims

1. An ultrasonic level measurement system, characterized in that: It includes an ultrasonic transducer, a transducer driving circuit, an echo receiving and processing circuit, and an MCU controller. The PWM port of the MCU controller, the transducer driving circuit, and the ultrasonic transducer are connected in sequence. The ultrasonic transducer, the echo receiving and processing circuit, and the MCU controller are connected together. During operation, the PWM port of the MCU controller alternately generates two different pulse counts of PWM pulses at fixed time intervals, triggering the transducer drive circuit to drive the ultrasonic transducer to alternately emit two types of ultrasonic waves and receive the reflected echo signals of the two types of ultrasonic waves. The two types of ultrasonic waves include a long pulse train and a short pulse train. The long pulse train is a pulse train containing N1 pulses, and the short pulse train is a pulse train containing N2 pulses. N1 and N2 are both positive integers, and N1 > N2. The two types of reflected echo signals received by the ultrasonic transducer are processed by the echo receiving and processing circuit and then transmitted to the MCU controller. The MCU controller obtains the distance data corresponding to the two types of reflected echo signals. The distance data corresponding to the long pulse train reflected echo signal is A, and the distance data corresponding to the short pulse train reflected echo signal is B. The effective ranging interval of the long pulse train is [A1, A2], and the effective ranging interval of the short pulse train is [B1, B2]. If A1≤A≤A2, then the distance data A corresponding to the long pulse train is used as the final measurement result; If A is not within the effective ranging interval [A1,A2] of the long pulse train, but B1≤B≤B2, then the distance data B corresponding to the reflected echo signal of the short pulse train is used as the final measurement result. If A is not within the effective ranging interval [A1,A2] of the long pulse train, and B is not within the effective ranging interval [B1,B2] of the short pulse train, then the final measurement result is considered invalid.

2. The ultrasonic level measurement system according to claim 1, characterized in that: N1 can be any value from 8 to 20, and N2 can be any value from 2 to 4.

3. The ultrasonic level measurement system according to claim 1, characterized in that: The transducer drive circuit includes a connected MOS transistor Q1 and a drive pulse transformer T1.

4. The ultrasonic level measurement system according to claim 1, characterized in that: The echo receiving and processing circuit includes a bandpass filter circuit, a logarithmic amplifier circuit, and a comparator connected in sequence; the bandpass filter circuit is a parameter-configurable negative feedback second-order active bandpass filter.

5. The ultrasonic level measurement system according to claim 1, characterized in that: It includes a temperature sensor, which is connected to the MCU controller.

6. The ultrasonic level measurement system according to claim 1, characterized in that: It includes a memory and a clock circuit, each of which is connected to the MCU controller. The memory includes FRAM memory and FLASH memory.

7. The ultrasonic level measurement system according to claim 1, characterized in that: It includes a button and display module, which is connected to the MCU controller.

8. The ultrasonic level measurement system according to claim 1, characterized in that: The system includes an interface unit connected to the MCU controller. The interface unit includes a relay output circuit, a 4-20 transmitter circuit, and a communication interface circuit. The relay output circuit includes an optocoupler isolation drive circuit and a relay control output circuit.

9. The ultrasonic level measurement system according to claim 1, characterized in that: It includes a power input module for power supply and a DC-DC power conversion module, which are connected to each other.

10. The ultrasonic level measurement system according to claim 1, characterized in that: The device includes a probe and an instrument. The instrument includes a main control board. The ultrasonic transducer, the transducer drive circuit, and the echo receiving and processing circuit are all located inside the probe. The MCU controller is located on the main control board of the instrument.

Images