A universal vibrating wire sensor readout system and readout method

Abstract

The present invention discloses a universal vibrating string sensor readout system and readout method, which relates to a vibrating string sensor, wherein the readout system comprises: an excitation unit, a vibration pickup unit, a temperature unit and a main control unit; the readout method comprises the following steps: S1: the MCU control module receives an external measurement request, obtains a measurement channel number, and distinguishes between two branches of vibrating string measurement and temperature measurement; S2: vibrating string measurement; S3: temperature measurement; S4: the signal communication module transmits the frequency signal and the temperature signal respectively measured by the two branches to the MCU control module, and the MCU control module comprehensively analyzes the frequency value and the temperature value, calculates the stress on the rigid string, and feeds back the output measurement result to complete this measurement. In the present invention, the system adopts an autonomous and controllable solution, gets rid of the limitation of the purchased product module, adopts a two-stage BOOST boost module to realize a large span voltage excitation, and solves the problem that the vibrating string sensor with a large resistance value and a long cable is difficult to vibrate normally.

Description

Technical Field

[0001] The present invention relates to the technical field of vibrating string sensors, and in particular to a universal vibrating string sensor readout system and a readout method. Background Art

[0002] Most of the vibrating string sensor readout devices currently used in the market use purchased modules or self-built discrete modules. They have the following defects:

[0003] 1. Purchased modules are expensive, vendor support is weak, and supply is easily affected;

[0004] 2. Due to the diversity and uncertainty of the data collection site, the connected vibrating string sensor has the problem of large coil resistance span and long cable length, which makes it inconvenient to reuse the self-built discrete module and difficult to excite and oscillate normally. Summary of the invention

[0005] The object of the present invention is to provide a general vibrating-wire sensor readout system and a readout method which are simple and practical and support normal vibration of vibrating-wire sensors with large resistance and long cables.

[0006] In order to solve the above technical problems, the present invention adopts the following technical solution: a universal vibrating string sensor readout system, involving a vibrating string sensor, comprising:

[0007] An excitation unit, used to generate an excitation voltage signal to drive the vibrating-wire sensor coil, includes an excitation generation module and an excitation output gating module, wherein the excitation generation module includes a two-stage BOOST boost module for realizing a large-span voltage excitation;

[0008] A vibration pickup unit, used for capturing frequency signals, the excitation unit is connected to the vibration pickup unit, and the vibration pickup unit comprises a vibration pickup gating input module and a vibration pickup acquisition module;

[0009] A temperature unit, used to measure the ambient temperature, comprising a temperature gating module and a temperature acquisition module;

[0010] The main control unit is used to transmit and process signals. The vibration pickup unit and the temperature unit are respectively connected to the main control unit. The main control unit includes an MCU control module and a signal communication module.

[0011] Furthermore, the two-stage BOOST boost module includes a primary BOOST and a secondary BOOST, the primary BOOST is controlled by an integrated chip, the secondary BOOST is controlled by an MCU, the input end of the secondary BOOST is connected to the output end of the primary BOOST, and both the primary BOOST and the secondary BOOST have the function of raising the dynamic change of the output voltage by utilizing the induced electromotive force of the inductor when the ground loop is closed.

[0012] Furthermore, the secondary BOOST includes a voltage sampling circuit, a current sampling circuit and a MOS tube driving circuit;

[0013] The voltage sampling circuit constitutes an output voltage closed-loop control for stabilizing the output voltage value. The current sampling circuit constructs a current closed-loop control for cooperating with the voltage closed-loop control to determine the resistance of the vibrating-string sensor coil and perform short-circuit detection. The opening and closing of the MOS tube in the MOS tube driving circuit is controlled by the MCU.

[0014] Furthermore, the excitation generation module also includes an excitation power supply module, which is connected to an external voltage source via an external interface. When the external voltage source adopts high-voltage pulse excitation, the excitation power supply module acts as a pump pressure source, which is manifested as a high-voltage pulse, and the pulse peak value is raised to 180V at most. When the external voltage source adopts low-voltage sweep frequency excitation, the excitation power supply module acts as a sweep frequency voltage, which is manifested as a low-voltage sweep frequency, and the sweep frequency voltage is stabilized at 12V.

[0015] The output end of the excitation power supply module is connected to the input end of the two-stage BOOST boost module. When the excitation power supply module exhibits a high-voltage pulse, the first-stage BOOST is enabled, the output voltage is 36V, the second-stage BOOST works, and the output voltage is 36-180V. When the excitation power supply module exhibits a low-voltage sweep frequency, the first-stage BOOST is turned off, the output voltage is consistent with the voltage of the excitation power supply module, the second-stage BOOST works, and the output voltage is fixed at 12V.

[0016] Furthermore, the excitation output gating module includes a four-to-one time-division multiplexing circuit group, which is used to excite only a single vibrating-wire sensor channel at a time, and the switch of the four-to-one time-division multiplexing circuit group is a high-side switch of an NMOS plus a high-side gate driver IC;

[0017] The output end of the excitation power supply module is connected to the input end of the excitation output selection module. When the excitation power supply module exhibits a high-voltage pulse, the high-side switch of the four-to-one time-sharing multiplexing circuit group has a single opening or closing action and can release a high-voltage pulse to the vibrating string sensor. When the excitation power supply module exhibits a low-voltage sweep frequency, the high-side switch of the four-to-one time-sharing multiplexing circuit group has a periodic opening or closing action and can send gradually increasing periodic low-voltage pulses to the vibrating string sensor.

[0018] Furthermore, the vibration pickup enable input module is connected to the excitation output enable module and the coil node of the vibrating string sensor, and the vibration pickup enable input module includes a vibration pickup enable input circuit group connected one by one to the four-to-one time-sharing multiplexing circuit group, which is used to conduct the feedback signal of the autonomous vibrating vibrating string sensor, and the switch of the vibration pickup enable input circuit group uses a high-side switch of a BJT-driven solid-state relay IC.

[0019] Furthermore, the vibration collection module includes a vibration collection circuit group, which is used to shape the return signal of the vibrating string sensor into a frequency signal that can be measured by the MCU control module;

[0020] The vibration pickup circuit group includes a voltage dividing resistor for voltage division to prevent overshoot, a second-order filter for filtering out clutter and raising the signal, and a comparator for comparing with an expected value and filtering out weak signals with low amplitude.

[0021] Furthermore, the temperature gating module comprises a four-to-one channel multiplexing circuit group connected one by one to the four-to-one time-division multiplexing circuit group, and is used to conduct the ambient temperature signal of the vibrating string sensor;

[0022] The temperature acquisition module includes a two-choice switch selection circuit group, which is used to determine the type of the connected temperature sensor and measure and read the temperature signal.

[0023] Furthermore, the MCU control module includes an AD terminal for reading analog values ​​of an analog temperature sensor and analog values ​​of current and voltage of the secondary BOOST, a timer for capturing the vibration string frequency and reading the value of a digital temperature sensor, a PWM terminal for controlling the boost ratio of the secondary BOOST, and a GPIO terminal for controlling various enabling and multiplexing selections;

[0024] The signal communication module includes a TTL serial port for external communication and an external interface for indicating the module operation status and receiving an external reset request.

[0025] A universal vibrating string sensor readout method, using a universal vibrating string sensor readout system, the method comprising the following steps:

[0026] S1: The MCU control module receives an external measurement request, obtains a measurement channel number, and divides it into two branches: vibrating string measurement and temperature measurement;

[0027] S2: When measuring the vibrating string, first determine whether the vibrating string sensor is connected and measure the coil resistance of the vibrating string sensor, then select the excitation mode and excitation voltage of the excitation generation module according to the coil resistance, then turn on the switch of the excitation output selection module to start the vibrating string sensor, delay and wait for the vibrating string sensor to start vibrating, then turn on the switch of the vibration pickup selection input module to process and conduct the return signal of the vibrating string sensor, and finally the vibration pickup acquisition module captures the return signal and shapes the measurable frequency signal;

[0028] S3: When measuring temperature, first determine the type of temperature sensor connected, then select the corresponding measurement circuit, and finally measure or read the ambient temperature value of the temperature sensor;

[0029] S4: The signal communication module transmits the frequency signals and temperature signals measured by the two branches to the MCU control module respectively. The MCU control module comprehensively analyzes the frequency value and the temperature value, calculates the stress on the rigid string, and feeds back the output measurement results to complete this measurement.

[0030] The beneficial effects of the present invention are embodied in:

[0031] In the present invention, in order to cope with the diverse working conditions of the diversity of resistance values ​​of vibrating-string sensors and the uncertainty of on-site wiring length, a universal vibrating-string sensor readout system is developed: on the one hand, the system adopts an autonomous and controllable solution with a simple structure and is easy to implement. It is not only suitable for common types of vibrating-string sensors used in construction projects, but also gets rid of the limitations of purchased modules; on the other hand, a two-stage BOOST boost module is used to achieve large-span voltage excitation, which solves the problem that vibrating-string sensors with large resistance values ​​and long cables are difficult to oscillate normally. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 It is a first-level BOOST circuit diagram of an embodiment of the present invention.

[0033] Figure 2 is another circuit diagram of a first-stage BOOST according to an embodiment of the present invention.

[0034] Figure 3 It is a two-stage BOOST circuit diagram of an embodiment of the present invention.

[0035] Figure 4 It is another circuit diagram of the two-stage BOOST according to an embodiment of the present invention.

[0036] Figure 5 It is another circuit diagram of the two-stage BOOST according to an embodiment of the present invention.

[0037] Figure 6 It is another circuit diagram of the two-stage BOOST according to an embodiment of the present invention.

[0038] Figure 7 It is a circuit diagram of an excitation output gating module according to an embodiment of the present invention.

[0039] Figure 8 It is a circuit diagram of a vibration pickup and gating input module according to an embodiment of the present invention.

[0040] Fig. 9 4 is a circuit diagram of a temperature gating module according to an embodiment of the present invention.

[0041] Fig.10 It is an overall flow chart of an embodiment of the present invention. DETAILED DESCRIPTION

[0042] The technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all of the embodiments. In the absence of conflict, the embodiments in this application and the features in the embodiments can be combined with each other. Based on the embodiments in the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention. It should be noted that the electrical components and components involved in this application are standard parts that can be purchased in the prior art.

[0043] See also Fig.10 , a universal vibrating string sensor readout system, involving a vibrating string sensor, comprising:

[0044] An excitation unit, used to generate an excitation voltage signal to drive the vibrating-wire sensor coil, includes an excitation generation module and an excitation output gating module, wherein the excitation generation module includes a two-stage BOOST boost module for realizing a large-span voltage excitation;

[0045] A vibration pickup unit, used for capturing frequency signals, the excitation unit is connected to the vibration pickup unit, and the vibration pickup unit comprises a vibration pickup gating input module and a vibration pickup acquisition module;

[0046] A temperature unit, used to measure the ambient temperature, comprising a temperature gating module and a temperature acquisition module;

[0047] The main control unit is used to transmit and process signals. The vibration pickup unit and the temperature unit are respectively connected to the main control unit. The main control unit includes an MCU control module and a signal communication module.

[0048] In the present invention, in order to cope with the diverse working conditions of the diversity of resistance values ​​of vibrating-string sensors and the uncertainty of on-site wiring length, a universal vibrating-string sensor readout system is developed: on the one hand, the system adopts an autonomous and controllable solution with a simple structure and is easy to implement. It is not only suitable for common types of vibrating-string sensors used in construction projects, but also gets rid of the limitations of purchased modules; on the other hand, a two-stage BOOST boost module is used to achieve large-span voltage excitation, which solves the problem that vibrating-string sensors with large resistance values ​​and long cables are difficult to oscillate normally.

[0049] See also Figure 1-6 In one embodiment, the two-stage BOOST boost module includes a primary BOOST and a secondary BOOST, the primary BOOST is controlled by an integrated chip, the secondary BOOST is controlled by an MCU, the input end of the secondary BOOST is connected to the output end of the primary BOOST, and both the primary BOOST and the secondary BOOST have the function of raising the output voltage dynamically by utilizing the induced electromotive force of the inductor when the ground loop is closed.

[0050] This design uses a BOOST boost solution to meet large-span voltage excitation and solve the problem that vibrating string sensors with large resistance and long cables are difficult to vibrate. The reason for using a two-stage boost solution is that the voltage increase ratio is too high. If only one-stage BOOST is used, the duty cycle is as high as 95%, and the current stress applied to the MOS tube and power inductor is too large, which can easily cause the circuit to burn out.

[0051] See also Figure 3-6 In one embodiment, the secondary BOOST includes a voltage sampling circuit, a current sampling circuit and a MOS tube driving circuit;

[0052] The voltage sampling circuit constitutes an output voltage closed-loop control for stabilizing the output voltage value. The current sampling circuit constructs a current closed-loop control for cooperating with the voltage closed-loop control to determine the resistance of the vibrating-string sensor coil and perform short-circuit detection. The opening and closing of the MOS tube in the MOS tube driving circuit is controlled by the MCU.

[0053] In this design, the voltage sampling circuit adopts a resistor voltage division method, proportionally reduces the voltage to be sampled to the range that can be sampled, and then inputs it into the voltage follower, thereby increasing the driving force of the reduced voltage, and then passes through an RC low-pass filter to the built-in AD of the MCU control module for sampling, amplification and restoration. Here, since the voltage span to be sampled is large, the voltage reduction ratio of the resistor voltage division is changed by a solid-state relay, and the drive of the solid-state relay is realized by the MCU control module controlling the BJT;

[0054] The current sampling circuit converts the current into a voltage signal through low-side sampling by a precision resistor, and then amplifies it through a common-mode amplifier and passes through a first-order RC low-pass filter to the built-in AD of the MCU control module for sampling, reduction and restoration. Since the current is extremely large during a short circuit, a TVS tube needs to be added after the current signal is converted into a voltage signal to prevent overshoot from affecting the subsequent circuit.

[0055] Since the driving capability of the MCU control module is limited, the control of the MOS tube driving circuit is implemented by a low-side gate driving chip, which has a pull and sink current peak of 4A and an extremely low rise and fall time of 6ns.

[0056] In one embodiment, the excitation generation module further includes an excitation power supply module, which is connected to an external voltage source via an external interface. When the external voltage source adopts high-voltage pulse excitation, the excitation power supply module acts as a pump pressure source, which is expressed as a high-voltage pulse, and the pulse peak value is raised to 180V at most. When the external voltage source adopts low-voltage sweep frequency excitation, the excitation power supply module acts as a sweep frequency voltage, which is expressed as a low-voltage sweep frequency, and the sweep frequency voltage is stable at 12V.

[0057] The output end of the excitation power supply module is connected to the input end of the two-stage BOOST boost module. When the excitation power supply module exhibits a high-voltage pulse, the first-stage BOOST is enabled, the output voltage is 36V, the second-stage BOOST works, and the output voltage is 36-180V. When the excitation power supply module exhibits a low-voltage sweep frequency, the first-stage BOOST is turned off, the output voltage is consistent with the voltage of the excitation power supply module, the second-stage BOOST works, and the output voltage is fixed at 12V.

[0058] In this design, when the first-level BOOST is enabled, the MCU control module controls the network 1ST_BOOST_CTL to a logic high level, the transistor conducts to pull the 1ST_BOOST_EN network to a high level, and the chip XL6019E1 works, controlling the SW point to GND to be continuously turned on and off at a frequency of 220kHZ. During the on-time, the inductor current rises, and the electromotive force at both ends of the inductor is VSEN; during the off-time, due to the sharp decrease in the inductor current, an induced electromotive force of negative on the left and positive on the right is generated at both ends of the inductor according to the Lenz effect. This electromotive force is superimposed on VSEN to produce an increased voltage. After this voltage passes through a low-voltage drop fast recovery Schottky diode to prevent backflow, it is the actual output voltage of the first-level BOOST. Then, the actual output voltage of the first-level BOOST is compared with the set value through a sampling feedback loop, and the on-time of the SW point to GND within a cycle is dynamically adjusted in real time: when the actual value is higher than the set value, the on-time of the SW point to GND is reduced, and vice versa.

[0059] When the first-stage BOOST is turned off, the 1ST_BOOST_EN network is set at a logic low level by the pull-down resistor, the chip XL6019E1 does not work, the SW node is always disconnected from GND, and the output of the first-stage BOOST is slightly lower than VSEN, which is manifested in a lower voltage drop on the power inductor and the Schottky diode.

[0060] The input of the secondary BOOST is the output of the primary BOOST. Similarly, the output voltage is raised by utilizing the induced electromotive force of the inductor when the ground loop is closed. The difference is that the output closed-loop control of the secondary BOOST is completed by the MCU control module.

[0061] See also Figure 7 In one embodiment, the excitation output gating module includes a four-to-one time-division multiplexing circuit group for exciting only a single vibrating-wire sensor channel at a time, and the switch of the four-to-one time-division multiplexing circuit group uses a high-side switch of an NMOS plus a high-side gate driver IC;

[0062] The output end of the excitation power supply module is connected to the input end of the excitation output selection module. When the excitation power supply module exhibits a high-voltage pulse, the high-side switch of the four-to-one time-sharing multiplexing circuit group has a single opening or closing action and can release a high-voltage pulse to the vibrating string sensor. When the excitation power supply module exhibits a low-voltage sweep frequency, the high-side switch of the four-to-one time-sharing multiplexing circuit group has a periodic opening or closing action and can send gradually increasing periodic low-voltage pulses to the vibrating string sensor.

[0063] Designed in this way, the excitation output selection module adopts NMOS plus high-side gate driver IC as the high-side switch, and outputs the stabilized voltage of the secondary BOOST circuit to the vibrating string sensor in the form of high and low level square waves. Due to the limitation of input power, the four-to-one time-sharing multiplexing circuit group can only excite one vibrating string sensor channel at a time, and performs the above-mentioned different actions according to the different high and low voltage pulse signals output by the excitation power supply module.

[0064] See also Figure 8 In one embodiment, the vibration pickup enable input module is connected to the excitation output enable module and the coil node of the vibrating string sensor. The vibration pickup enable input module includes a vibration pickup enable input circuit group that is connected one by one to the four-to-one time-sharing multiplexing circuit group, and is used to conduct the feedback signal of the autonomous vibrating vibrating string sensor. The switch of the vibration pickup enable input circuit group uses a high-side switch of a BJT-driven solid-state relay IC.

[0065] In this design, after the excitation is generated and the output is selected, the vibrating string sensor on the corresponding channel is excited to vibrate, enters autonomous vibration, closes the excitation output selection module, and opens the vibration pickup selection input module on the corresponding channel, and hands the frequency signal to the vibration pickup acquisition module;

[0066] The switch of the vibration pickup selection input circuit group is also a high-side switch, but has no high requirements for carrying current and on-resistance, so a BJT driving solid-state relay IC solution is adopted.

[0067] In one embodiment, the vibration pickup and collection module includes a vibration pickup and collection circuit group, which is used to shape the return signal of the vibrating string sensor into a frequency signal that can be measured by the MCU control module;

[0068] The vibration pickup circuit group includes a voltage dividing resistor for voltage division to prevent overshoot, a second-order filter for filtering out clutter and raising the signal, and a comparator for comparing with an expected value and filtering out weak signals with low amplitude.

[0069] In this design, after the vibration pickup selection input module on the corresponding channel is turned on, the return signal of the vibrating string sensor is shaped by the vibration pickup collection circuit group into a frequency signal that can be measured by the MCU control module, so that the oscillation frequency of the vibrating string sensor can be collected, and then the magnitude of the stress on the steel string can be calculated;

[0070] The return signal of the vibrating string sensor contains overshoot voltage signals, sweep frequency residues and frequency signals of power frequency interference, so the first part of the vibration collection circuit group is to divide the voltage to prevent overshoot, then the second-order filter filters out clutter and raises the signal, and finally the comparator compares it with the expected value to filter out weak signals with low amplitude. The vibration frequency of the current vibrating string sensor is obtained by counting the number of return signals of the vibrating string sensor per unit time. In order to ensure the sampling accuracy of the frequency signal, the MCU control module discards the previous return signal to avoid interference from the excitation signal, and then collects a small amount of return signals to estimate the approximate frequency. If it exceeds the normal range, the current sampling is stopped and the next sampling is performed until the sampling time ends, or until enough return samples are collected. During each collection process, the MCU control module calculates and judges the results and discards some invalid data.

[0071] See also Fig. 9 In one embodiment, the temperature gating module includes a four-to-one channel multiplexing circuit group connected one by one to the four-to-one time-division multiplexing circuit group, and is used to conduct the ambient temperature signal of the vibrating string sensor;

[0072] The temperature acquisition module includes a two-choice switch selection circuit group, which is used to determine the type of the connected temperature sensor and measure and read the temperature signal.

[0073] In this design, each temperature acquisition signal corresponds to a vibrating string sensor channel. Before collecting the vibrating string signal, it is necessary to first collect the ambient temperature signal of the vibrating string sensor to eliminate the influence of the field temperature change on the vibrating string quantity collection result. Among them, the temperature sensor is compatible with the digital DS18B20 sensor and the analog NTC resistance sensor;

[0074] The four-choice-one time-division multiplexing circuit group and the two-choice-one switch selection circuit group use a signal switch IC with low on-resistance. For the sake of protecting the internal part of the module, the input part of the four-choice-one time-division multiplexing circuit group is not turned on by default, and the two-choice-one switch selection circuit group selects an NTC analog temperature sensor by default;

[0075] The NTC analog temperature sensor uses a resistor voltage divider, with a high-precision, low-temperature drift calibration resistor connected in series with the NTC. The voltage across the NTC is collected by a voltage follower, and compared with the injected voltage to obtain the ratio of the NTC resistance to the calibration resistance, and then the NTC resistance is calculated. The temperature value is fed back by table calculation. The injected voltage is generated by a precision regulator, and the current driving capability of this voltage value is improved by a voltage follower.

[0076] When the default analog temperature acquisition determines that the NTC resistor is approximately open-circuited, it is determined that a digital temperature sensor is connected. At this time, the two-to-one switch selection circuit group is switched to select the DS18B20 digital temperature sensor with a two-wire connection method, and then the temperature value is read through the MCU control module.

[0077] In one embodiment, the MCU control module includes an AD terminal for reading analog temperature sensor analog quantity and the secondary BOOST current and voltage analog quantity, a timer for capturing the vibration string frequency and reading the digital temperature sensor value, a PWM terminal for controlling the secondary BOOST boost ratio, and a GPIO terminal for controlling various enable and multiplexing selections;

[0078] The signal communication module includes a TTL serial port for external communication and an external interface for indicating the module operation status and receiving an external reset request.

[0079] In this design, after receiving the measurement request from the outside of the module, the main control unit obtains the measurement channel number and is divided into two branches: temperature measurement and vibrating string measurement: when measuring temperature, first determine the type of temperature sensor connected, then select the corresponding measurement circuit to measure and read the ambient temperature value of the temperature sensor; when measuring vibrating string, first determine the connection and coil resistance of the vibrating string sensor, select the excitation mode and excitation voltage according to the resistance, then turn on the excitation output selection module switch to make the vibrating string sensor vibrate, turn on the vibration pickup selection input module switch after a delay, process the return signal and capture it. The main control unit comprehensively analyzes the temperature value and frequency value, calculates the stress on the rigid string, and outputs the measurement result to complete this measurement.

[0080] See also Fig.10 A universal vibrating string sensor readout method, using a universal vibrating string sensor readout system, the method comprising the following steps:

[0081] S1: The MCU control module receives an external measurement request, obtains a measurement channel number, and divides it into two branches: vibrating string measurement and temperature measurement;

[0082] S2: When measuring the vibrating string, first determine whether the vibrating string sensor is connected and measure the coil resistance of the vibrating string sensor, then select the excitation mode and excitation voltage of the excitation generation module according to the coil resistance, then turn on the switch of the excitation output selection module to start the vibrating string sensor, delay and wait for the vibrating string sensor to start vibrating, then turn on the switch of the vibration pickup selection input module to process and conduct the return signal of the vibrating string sensor, and finally the vibration pickup acquisition module captures the return signal and shapes the measurable frequency signal;

[0083] S3: When measuring temperature, first determine the type of temperature sensor connected, then select the corresponding measurement circuit, and finally measure or read the ambient temperature value of the temperature sensor;

[0084] S4: The signal communication module transmits the frequency signals and temperature signals measured by the two branches to the MCU control module respectively. The MCU control module comprehensively analyzes the frequency value and the temperature value, calculates the stress on the rigid string, and feeds back the output measurement results to complete this measurement.

[0085] In the present invention, in order to cope with the diverse working conditions of the diversity of resistance values ​​of vibrating-string sensors and the uncertainty of on-site wiring length, a universal vibrating-string sensor readout system is developed, which adopts a two-stage BOOST boost module to realize large-span voltage excitation, solving the problem that vibrating-string sensors with large resistance values ​​and long cables are difficult to vibrate normally.

[0086] It should be understood that the examples and implementation modes described herein are for illustrative purposes only and are not intended to limit the present invention. Those skilled in the art may make various modifications or changes based on the examples and implementation modes. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A universal vibrating wire sensor readout system, involving a vibrating wire sensor, characterized in that: include: An excitation unit, used to generate an excitation voltage signal to drive the vibrating-wire sensor coil, includes an excitation generation module and an excitation output gating module, wherein the excitation generation module includes a two-stage BOOST boost module for realizing a large-span voltage excitation; A vibration pickup unit, used for capturing frequency signals, the excitation unit is connected to the vibration pickup unit, and the vibration pickup unit comprises a vibration pickup gating input module and a vibration pickup acquisition module; A temperature unit, used to measure the ambient temperature, including a temperature gating module and a temperature acquisition module; A main control unit, used for transmitting and processing signals, the vibration pickup unit and the temperature unit are respectively connected to the main control unit, and the main control unit includes an MCU control module and a signal communication module; The two-stage BOOST boost module includes a primary BOOST and a secondary BOOST, wherein the primary BOOST is controlled by an integrated chip, and the secondary BOOST is controlled by an MCU, wherein the input end of the secondary BOOST is connected to the output end of the primary BOOST, and both the primary BOOST and the secondary BOOST have the function of utilizing the induced electromotive force of the inductor when the ground loop is turned off to raise the dynamic change of the output voltage; The excitation generation module also includes an excitation power supply module, which is connected to an external voltage source via an external interface. When the external voltage source adopts high-voltage pulse excitation, the excitation power supply module acts as a pump pressure source, which is manifested as a high-voltage pulse, and the pulse peak value is raised to 180V at most. When the external voltage source adopts low-voltage sweep frequency excitation, the excitation power supply module acts as a sweep frequency voltage, which is manifested as a low-voltage sweep frequency, and the sweep frequency voltage is stable at 12V. The output end of the excitation power supply module is connected to the input end of the two-stage BOOST boost module. When the excitation power supply module exhibits a high-voltage pulse, the first-stage BOOST is enabled, the output voltage is 36V, the second-stage BOOST works, and the output voltage is 36~180V. When the excitation power supply module exhibits a low-voltage frequency sweep, the first-stage BOOST is turned off, the output voltage is consistent with the voltage of the excitation power supply module, the second-stage BOOST works, and the output voltage is fixed at 12V.

2. The universal vibrating wire sensor readout system of claim 1, wherein: The secondary BOOST includes a voltage sampling circuit, a current sampling circuit and a MOS tube driving circuit; The voltage sampling circuit constitutes an output voltage closed-loop control for stabilizing the output voltage value. The current sampling circuit constructs a current closed-loop control for cooperating with the voltage closed-loop control to determine the resistance of the vibrating-string sensor coil and perform short-circuit detection. The opening and closing of the MOS tube in the MOS tube driving circuit is controlled by the MCU.

3. The universal vibrating wire sensor readout system of claim 1, wherein: The excitation output gating module includes a four-to-one time-division multiplexing circuit group, which is used to excite only a single vibrating wire sensor channel at a time, and the switch of the four-to-one time-division multiplexing circuit group uses a high-side switch of an NMOS plus a high-side gate driver IC; The output end of the excitation power supply module is connected to the input end of the excitation output selection module. When the excitation power supply module exhibits a high-voltage pulse, the high-side switch of the four-to-one time-sharing multiplexing circuit group has a single opening or closing action and can release a high-voltage pulse to the vibrating string sensor. When the excitation power supply module exhibits a low-voltage sweep frequency, the high-side switch of the four-to-one time-sharing multiplexing circuit group has a periodic opening or closing action and can send gradually increasing periodic low-voltage pulses to the vibrating string sensor.

4. The universal vibrating wire sensor readout system of claim 3, wherein: The vibration pickup enable input module is connected to the excitation output enable module and the coil node of the vibrating string sensor. The vibration pickup enable input module includes a vibration pickup enable input circuit group that is connected one by one to the four-to-one time-sharing multiplexing circuit group, and is used to conduct the feedback signal of the autonomous vibrating vibrating string sensor. The switch of the vibration pickup enable input circuit group uses a high-side switch of a BJT-driven solid-state relay IC.

5. The universal vibrating wire sensor readout system of claim 1, wherein: The vibration collection module includes a vibration collection circuit group, which is used to shape the return signal of the vibrating string sensor into a frequency signal that can be measured by the MCU control module; The vibration pickup circuit group includes a voltage dividing resistor for voltage division to prevent overshoot, a second-order filter for filtering out clutter and raising the signal, and a comparator for comparing with an expected value and filtering out weak signals with low amplitude.

6. The universal vibrating wire sensor readout system of claim 3, wherein: The temperature gating module comprises a four-to-one channel multiplexing circuit group connected one by one to the four-to-one time-division multiplexing circuit group, and is used to conduct the ambient temperature signal of the vibrating string sensor; The temperature acquisition module includes a two-choice switch selection circuit group, which is used to determine the type of the connected temperature sensor and measure and read the temperature signal.

7. The universal vibrating wire sensor readout system of claim 1, wherein: The MCU control module includes an AD terminal for reading the analog value of the analog temperature sensor and the analog value of the current and voltage of the secondary BOOST, a timer for capturing the vibration string frequency and reading the value of the digital temperature sensor, a PWM terminal for controlling the boost ratio of the secondary BOOST, and a GPIO terminal for controlling various enabling and multiplexing selections; The signal communication module includes a TTL serial port for external communication and an external interface for indicating the module operation status and receiving an external reset request.

8. A universal vibrating wire sensor readout method, characterized in that: Using the universal vibrating wire sensor readout system according to any one of claims 1 to 7, the method comprises the following steps: S1: The MCU control module receives an external measurement request, obtains a measurement channel number, and divides it into two branches: vibrating string measurement and temperature measurement; S2: When measuring the vibrating string, first determine whether the vibrating string sensor is connected and measure the coil resistance of the vibrating string sensor, then select the excitation mode and excitation voltage of the excitation generation module according to the coil resistance, then turn on the switch of the excitation output selection module to start the vibrating string sensor, delay and wait for the vibrating string sensor to start vibrating, then turn on the switch of the vibration pickup selection input module to process and conduct the return signal of the vibrating string sensor, and finally the vibration pickup acquisition module captures the return signal and shapes the measurable frequency signal; S3: When measuring temperature, first determine the type of temperature sensor connected, then select the corresponding measurement circuit, and finally measure or read the ambient temperature value of the temperature sensor; S4: The signal communication module transmits the frequency signals and temperature signals measured by the two branches to the MCU control module respectively. The MCU control module comprehensively analyzes the frequency value and the temperature value, calculates the stress on the rigid string, and feeds back the output measurement results to complete this measurement.

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