An oil dipstick and a control system for the oil dipstick

Abstract

The present invention discloses a control system for an oil gauge, comprising: a DC motor for driving a weight to perform retracting and extending actions under the control of a driving signal; a motor control device for obtaining an input command, and based on the maximum rotation speed threshold of the DC motor, using PWM control technology to generate a driving signal for controlling the motor to operate according to the target requirement corresponding to the input command and / or under the limitation of the maximum rotation speed, wherein the input command is selected from one of forward rotation, reverse rotation, emergency stop, acceleration and deceleration. The present invention reduces the error caused by the manual gauge reading operation, improves the controllability and accuracy of the lowering speed of the gauge, and reduces potential safety hazards.

Description

Technical Field

[0001] The present invention relates to the technical field of oil metering, and in particular to an oil gauge and a control system for the oil gauge. Background Art

[0002] In the technical field of crude oil trade metering at home and abroad, there are two common metering methods, namely static metering and dynamic metering. At present, most of the railway tank cars, automobile tank cars, etc. adopt static metering. Static metering is to determine the container for storing and transporting crude oil through verification, measure the volume of crude oil, obtain a representative crude oil sample from the container, and measure the required mass number of crude oil and the water content of crude oil. Among them, the oil gauge, as the main tool for static metering, has the following requirements: 1) The tape shall not be kinked, bent or spliced; 2) The scale lines and digital lines shall be clear; 3) The tip of the plummet shall not be damaged; 4) The zero point shall be calibrated before using the oil gauge, and it shall be checked whether the plummet is firmly connected to the hook; 5) There is a correction value table within the verification period.

[0003] Static metering is to measure the liquid level height of the crude oil in the container by using an artificial oil gauge, check the capacity table of the container to determine the volume of crude oil corresponding to the liquid level height, and then perform the correction calculation of the temperature and pressure of the crude oil, determine the gross weight and deduct the water content to calculate the net mass of the crude oil.

[0004] In the prior art, for the implementation method of measuring the crude oil liquid level height, an artificial method is mostly used to measure the liquid level height in the tank with an oil gauge. During static metering, the oil gauge selects the plummet according to the oil density. For measuring low-viscosity oils, an oil gauge with a light plummet (0.7 kg) is used, and for measuring high-viscosity oils, an oil gauge with a heavy plummet (1.6 kg) should be used. When measuring with a sounding oil gauge, the lowering speed of the ruler should be controlled within 1.0 m / s. Further, the handover method of the oil products adopts large tank handover. Therefore, the accuracy of the oil gauge measurement is crucial.

[0005] Since the artificial method is used to measure the liquid level depth with an oil gauge, problems such as easy generation of errors in the operation of the personnel for checking the ruler, poor controllability of the lowering speed because it is related to the operation habits of the ruler-checking personnel, and low efficiency due to the need for the operator to take in and let out the oil gauge during lowering and retracting the ruler often occur. Therefore, the prior art needs to design an oil gauge that can quickly and effectively measure the crude oil liquid level and improve the accuracy of traditional manual measurement. Summary of the Invention

[0006] To solve the above technical problems, the present invention provides a control system for an oil gauge, the control system comprising: a DC motor for driving a weight to perform retracting and extending actions under the control of a driving signal; a motor control device for obtaining an input instruction, and based on a maximum rotational speed threshold of the DC motor, using PWM control technology to generate the driving signal for controlling the motor to operate according to a target requirement corresponding to the input instruction and / or under the limitation of the maximum rotational speed, wherein the input instruction is selected from one of forward rotation, reverse rotation, emergency stop, acceleration, and deceleration.

[0007] Preferably, the control system further comprises: a distance measuring device for generating a laser reference signal and vertically emitting the signal to the top surface of the weight, and receiving a reflected laser received signal, and calculating a lower scale distance of the current oil gauge according to a phase difference comparison result between the laser reference signal and the laser received signal.

[0008] Preferably, the motor control device comprises: an input module for obtaining the input instruction; a speed regulation module for receiving and identifying the input instruction, determining a current control requirement, calculating a control rotational speed of the DC motor in the current motor control cycle according to the current control requirement, the rotational speed of the DC motor in the previous motor control cycle, and the maximum rotational speed threshold, and generating a PWM control signal corresponding to the control rotational speed; a driving module for controlling the DC motor to operate at the control rotational speed under the drive of the PWM control signal.

[0009] Preferably, the distance measuring device comprises: a measurement control module for controlling the generation of the laser reference signal, comparing a first square wave signal and a second square wave signal, and calculating a phase difference of the square wave signals using the phase discrimination and counting principle of an RS flip-flop to further obtain the lower scale distance; a reference signal generation module for generating the laser reference signal under the action of the measurement control module and generating a measurement emission signal for emitting to the top plane of the weight based on the laser reference signal; a signal receiving module for conditioning the received laser received signal and converting the laser reference signal and the laser received signal into corresponding first and second square wave signals respectively.

[0010] Preferably, the reference signal generation module includes: a first signal generation unit connected to the measurement control module for generating a first sine signal containing first frequency information under the control of the measurement control module; a second signal generation unit connected to the measurement control module for generating a second sine signal containing second frequency information under the control of the measurement control module, wherein the absolute value of the difference between the first frequency and the second frequency is less than a preset first threshold; a modulation and transmission unit connected to the output end of the first signal generation unit for amplitude-modulating the first sine signal to obtain the measurement transmission signal.

[0011] Preferably, the signal reception module includes: a signal conditioning unit having a reflected signal receiver, an optoelectronic converter, and a filter amplification circuit, the signal conditioning unit being configured to sequentially perform electrical signal conversion and filter amplification processing on the received laser reception signal to obtain a received conditioning signal; a first square wave generation unit having a first mixing circuit and a first shaping circuit, the first mixing circuit being configured to perform down-conversion mixing processing on the first sine signal and the second sine signal to obtain a first signal to be shaped, the first shaping circuit being configured to perform zero-crossing shaping processing on the first signal to be shaped to obtain the first square wave signal; a second square wave generation unit having a second mixing circuit and a second shaping circuit, the second mixing circuit being configured to perform down-conversion mixing processing on the second sine signal and the received conditioning signal to obtain a second signal to be shaped, the second shaping circuit being configured to perform zero-crossing shaping processing on the second signal to be shaped to obtain the second square wave signal.

[0012] Preferably, the control system further includes: a display device for displaying the lower scale distance and the retracting and extending speed. Further, the distance measurement device is installed above the scale weight, and the laser emitted by the laser emission surface of the distance measurement device is perpendicularly projected onto the upper surface of the scale weight; the DC motor is disposed inside an explosion-proof protective housing, and the explosion-proof protective housing is disposed at the side end of the oil gauge bracket.

[0013] Preferably, the reflected signal receiver in the signal reception module is a convex lens, and a λ / 4 film is coated on the receiving surface of the convex lens, where λ represents the wavelength of the laser signal; a linear voltage regulator is provided at the power input end of the control system.

[0014] Preferably, during the retracting and extending control process of the oil gauge, the newly input input instruction has the highest response priority.

[0015] On the other hand, the present invention also proposes an oil gauge, and the oil gauge includes the control system as described above to measure the height of the crude oil liquid level in the container.

[0016] Compared with the prior art, one or more embodiments of the above solution may have the following advantages or beneficial effects:

[0017] The present invention provides an oil dipstick and a control system for the oil dipstick. The control system and the oil dipstick can be applied to relevant occasions that require dynamic metering and handover. By setting a DC motor for controlling the retraction and extension of the weight and the tape in the oil dipstick, a motor control device for controllably adjusting the motor speed, and a distance measuring device for measuring the actual distance of the tape being lowered. The present invention reduces the errors caused by manual tape measurement operations, improves the controllability and accuracy of the tape lowering speed, realizes the automatic retraction and extension of the tape by controlling the tape lowering speed of the oil dipstick, thereby reducing the labor intensity of the operating personnel, improving the accuracy, measuring more accurately, avoiding the generation of static electricity and reducing potential safety hazards.

[0018] Other features and advantages of the present invention will be described in the following specification, and in part, will be apparent from the specification, or can be understood by implementing the present invention. The objectives and other advantages of the present invention can be realized and obtained by the structures specifically pointed out in the specification, claims, and drawings. Description of the Drawings

[0019] The drawings are used to provide a further understanding of the present invention, and constitute a part of the specification. They are used together with the embodiments of the present invention to explain the present invention, and do not constitute a limitation to the present invention. In the drawings:

[0020] Figure 1 is a schematic diagram of the overall structure of the control system for the oil dipstick according to an embodiment of the present application.

[0021] Figure 2 is a flowchart of the operation of the control system for the oil dipstick according to an embodiment of the present application.

[0022] Figure 3 is a schematic diagram of the structure of the motor control device in the control system for the oil dipstick according to an embodiment of the present application.

[0023] Figure 4 is a schematic diagram of the overall structure of the distance measuring device in the control system for the oil dipstick according to an embodiment of the present application.

[0024] Figure 5 is a schematic diagram of the working principle of the signal conditioning unit in the distance measuring device of the control system for the oil dipstick according to an embodiment of the present application.

[0025] Figure 6 is a schematic diagram of the principle of the modulation and transmission unit in the control system for the oil dipstick according to an embodiment of the present application.

[0026] Figure 7It is a schematic diagram of the phase discrimination function principle of the measurement control module in the distance measurement device within the control system for the dipstick in the embodiments of the present application.

[0027] In the present application, all the drawings are schematic drawings, only used to illustrate the principle of the present invention and not drawn according to the actual ratio.

[0028] Among them, the list of reference numerals is as follows:

[0029] 100: Motor control device

[0030] 200: DC motor

[0031] 300: Distance measurement device

[0032] 400: Display device

[0033] 110: Input module

[0034] 120: Speed regulation module

[0035] 130: Driving module

[0036] 140: Speed display module

[0037] 310: Measurement control module

[0038] 320: Reference signal generation module

[0039] 321: First signal generation unit

[0040] 322: Second signal generation unit

[0041] 323: Modulation and transmission unit

[0042] 330: Signal reception module

[0043] 331: Signal conditioning unit

[0044] 3311: Reflection signal receiver

[0045] 3312: Photoelectric converter

[0046] 3313: Filtering and amplifying circuit

[0047] 332: First square wave generation unit

[0048] 3321: First mixing circuit

[0049] 3322: First shaping circuit

[0050] 333: Second square wave generation unit

[0051] 3331: Second mixing circuit

[0052] 3332: Second shaping circuit

[0053] 340: Distance display module Detailed implementation manners

[0054] The following will combine the accompanying drawings and embodiments to elaborate in detail on the implementation manners of the present invention, so as to fully understand how the present invention applies technical means to solve technical problems and the implementation process of achieving technical effects and implement accordingly. It should be noted that as long as there is no conflict, each embodiment in the present invention and each feature in each embodiment can be combined with each other, and the formed technical solutions are all within the protection scope of the present invention.

[0055] Meanwhile, in the following description, for the purpose of explanation, many specific details are elaborated to provide a thorough understanding of the embodiments of the present invention. However, it is obvious to those skilled in the art that the present invention can be implemented without the specific details here or in the specific manner described.

[0056] In the field of crude oil trade metering technology at home and abroad, there are two common metering methods, namely static metering and dynamic metering. Currently, most of the railway tank cars, road tank cars, etc. adopt static metering. Static metering is to determine the container for storing and transporting crude oil through verification, measure the volume of crude oil, obtain a representative crude oil sample from the container, and measure the required mass number of crude oil and the water content of crude oil. Among them, the dipstick is the main tool for static metering and has the following requirements: 1) The tape of the dipstick is not allowed to be kinked, bent or welded; 2) The scale lines and digital lines should be clear; 3) The tip of the plummet is not damaged; 4) Before using the dipstick, the zero point should be calibrated, and it should be checked whether the plummet is firmly connected to the hook; 5) There is a correction value table within the verification period.

[0057] Static metering is to measure the liquid level height of the crude oil in the container by using an artificial dipstick, look up the capacity table of the container to determine the volume of crude oil corresponding to the liquid level height, and then perform temperature and pressure correction calculations for the crude oil, determine the gross weight and deduct the water content to calculate the net mass of the crude oil.

[0058] In the prior art, for the implementation method of measuring the crude oil liquid level height, an artificial method is mostly used to measure the liquid level height in the tank with a dipstick. During static metering, the dipstick selects the plummet according to the oil density. For measuring low-viscosity oils, a dipstick with a light plummet (0.7 kg) is used, and for measuring high-viscosity oils, a dipstick with a heavy plummet (1.6 kg) should be used. When measuring with a sounding dipstick, the lowering speed of the dipstick should be controlled within 1.0 m / s. Further, the handover method of the oil products adopts large tank handover. Therefore, the measurement accuracy of the dipstick is crucial.

[0059] When measuring the liquid level depth with a dipstick manually, problems often occur. For example, errors are easily generated during the operation of the personnel taking the measurement, the controllability of the lowering speed of the dipstick is poor because it is related to the operating habits of the personnel taking the measurement, and the efficiency is low when the operator needs to take in and let out the dipstick during lowering and retracting. Therefore, the prior art needs to design a dipstick that can quickly and effectively measure the crude oil liquid level to improve the accuracy of traditional manual measurement.

[0060] To solve the above technical problems, the present invention proposes a control system for a dipstick. The system is provided with: a DC motor for controlling the retraction and release of the weight and tape in the dipstick, a motor control device for controllably adjusting the motor speed, and a distance measurement device for measuring the actual lowering distance. The present invention uses this control system to achieve the dipstick control for detecting personnel to measure the height of the crude oil liquid level and the adjustable control of the lowering speed, thereby completing the functions of automatically taking in and letting out the dipstick, reducing manual labor, being simple to operate, and having strong practicability.

[0061] Figure 1 It is a schematic diagram of the overall structure of the control system for a dipstick according to an embodiment of the present application. As Figure 1 shown, the control system described in the present invention includes: a motor control device 100, a DC motor 200, and a distance measurement device 300. The motor control device 100 is used to obtain an input instruction, and based on the maximum speed threshold of the DC motor, use PWM control technology to generate a drive signal for controlling the motor to operate according to the target requirement corresponding to the input instruction and / or under the limitation of the maximum speed. Among them, the input instruction is selected from one of forward rotation, reverse rotation, emergency stop, acceleration, and deceleration.

[0062] Furthermore, in order to achieve the portability, low cost, and power supply limitation of the product, a full-digital DC motor speed control device is used to achieve speed adjustment. Since DC motors have excellent speed regulation characteristics, the speed regulation is smooth, convenient, and the speed regulation range is wide; the overload capacity is large, and it can withstand frequent impact loads and can achieve frequent stepless rapid start, emergency stop, and reverse; the switching frequency of the PWM speed control system is relatively high, and a stable DC power supply can be obtained only by the filtering action of the electric drive inductance, and the low-speed characteristics are good; due to the high switching frequency, the fast response characteristics are good, the dynamic anti-interference ability is strong, and a very wide frequency band can be obtained; the switching device only works in the switching state, the main circuit loss is small, and the device efficiency is high.

[0063] In an embodiment of the present invention, the DC motor 200 is connected to the motor control device 100 and is arranged in an explosion-proof protective housing (not shown), where the explosion-proof protective housing is arranged at the side end position of the dipstick bracket. The DC motor 200 is used to drive the retraction and release of the lowering mechanism formed by the tape and weight in the dipstick under the control of the drive signal.

[0064] Figure 3 This is a schematic structural diagram of the motor control device in the control system for the dipstick of the present application embodiment. As Figure 3 shown, the motor control device 100 includes: an input module 110, a speed regulation module 120, a driving module 130, and a speed display module 140. Among them, the input module 110 is used to obtain the input instruction (input command) (input by the operator). Preferably, this module 110 is implemented by an independent keyboard with interrupts and can input new input instruction types at any time.

[0065] The speed regulation module 120 is the core part of the control circuit of the entire motor control device, and is connected with the corresponding speed display module 140 and driving module 130 to achieve real-time adjustable control of the rotational speed parameters of the motor. The speed regulation module 120 is used to receive and identify the input instruction obtained from the input module 110, determine the current control requirement, and calculate the control rotational speed of the DC motor in the current motor control cycle and the duty ratio of the PWM signal corresponding to the current control rotational speed according to the current control requirement, the rotational speed of the DC motor in the previous motor control cycle, and the maximum rotational speed threshold, so as to generate a PWM control signal corresponding to the current control rotational speed. Preferably, the speed regulation module 120 uses an AT89C51 single-chip microcomputer.

[0066] Furthermore, the DC motor PWM control part of the speed regulation module 120 mainly consists of circuits such as the I / O ports, timer counters, and external interrupt extensions of the AT89C51 single-chip microcomputer to control the acceleration, deceleration, forward rotation, and reverse rotation of the DC motor 200, and can adjust the rotational speed of the motor. In addition, the speed regulation module 120 is also used to collect the actual rotational speed (true rotational speed, including magnitude and direction) of the DC motor 200, so as to conveniently achieve intelligent speed control of the motor in each control cycle. It should be noted that in the process of controlling the retraction and extension of the dipstick, in the embodiment of the present invention, for the input module 110, the newly input input instruction has the highest response priority.

[0067] In addition, the speed regulation module 120 is also used to collect the actual rotational speed of the DC motor 200 in each motor control cycle in real time, and convert the obtained actual rotational speed data into the linear speed of the tape being lowered or retracted in real time, that is, the retraction and extension speed. The speed display module 140 is connected to the speed regulation module 120 and is used to display the actual rotational speed and / or the retraction and extension speed in each motor control cycle.

[0068] The driving module 130 is used to control the DC motor 200 to operate at the control rotational speed of the DC motor in the current motor control cycle under the drive of the PWM control signal output by the speed regulation module 120. Preferably, the driving module 130 uses an L298N chip.

[0069] Figure 2This is the working flowchart of the control system for the dipstick in the embodiments of the present application. As Figure 2 shown, in the operation of lowering and retracting the dipstick, first, an input command containing the current control requirements of the operator is input using the input module 100. Then, the motor control device 200 obtains the current input command and determines the current target requirement. Among them, the target requirements are selected from: forward rotation (for example: lowering the dipstick operation), reverse rotation (for example: retracting the dipstick operation), acceleration (for example: lowering the dipstick acceleration or retracting the dipstick acceleration operation), deceleration (for example: lowering the dipstick deceleration or retracting the dipstick deceleration operation), stopping (for example: pausing), etc.

[0070] Then, the motor control device 200 calculates the motor control speed that meets the current requirement according to the current control requirement, the actual speed of the DC motor in the previous motor control cycle collected (that is, the control speed generated in the previous motor control cycle, so that the motor responds to this speed and the actual speed acting on the DC motor), and the threshold value of the motor speed corresponding to the preset maximum lowering speed. Next, the motor control device 200 converts the motor control speed in the current motor control cycle into the duty cycle data for controlling the motor to operate at this speed, and generates the corresponding PWM control signal. Finally, the motor control device 200 sends the PWM control signal in the current motor control cycle to the drive module 140, and the drive module 140 converts the current PWM control signal into the corresponding motor drive signal, so that the DC motor 200 operates at the specified speed under the control of the drive signal containing the current motor control speed information.

[0071] Specifically, the motor control device 200 outputs a series of pulses through the control program, which are amplified and then drive the DC motor 200. By changing the duration of the level of the output pulses, the purposes of making the motor rotate forward, reverse, accelerate, decelerate, stop, etc. are achieved. The control program is designed using the delay method. After the single-chip microcomputer is powered on, the system enters the preparation state. When the buttons for different control requirements are pressed, the PWM control signal containing the duty cycle information of high and low levels output by the motor control device 200 is adjusted, so that the high and low levels of the PWM control signal output can be effective values, and then the acceleration of the DC motor 200 can be controlled.

[0072] Among them, the pulse width modulation (PWM) channels generate pulses whose widths and intervals can be programmed. The interval period of the pulses is controlled by a FOR loop to generate different duty cycles. The PWM signal generated by the single-chip microcomputer cannot directly drive the motor and indirectly drives the motor through the drive circuit to enable it to operate normally. The driving of the motor is completed by means of the constant voltage and constant current bridge 2A drive chip L298N. The specific design method is realized through the joint simulation of Keil C programming and Proteus.

[0073] In this way, the adjustable speed control mode of the DC motor 200 is used to replace the manual hand-cranking mode for the retraction and extension operations of the lower ruler mechanism, ensuring the accuracy and stability of the lower ruler and retraction operations.

[0074] Continue to refer to Figure 1 , the distance measuring device 300 is installed directly above the flat end of the weight. Further, the laser emitted by the laser emitting surface of the distance measuring device 300 is vertically projected onto the upper surface of the weight. In this way, the laser in the distance measuring device 300 can be projected onto the upper surface of the weight. The distance measuring device 300 is used to generate a laser reference signal, vertically emit the signal to the top surface of the weight, and receive the reflected laser reception signal. According to the phase difference comparison result between the laser reference signal and the laser reception signal, the lower ruler distance of the current oil gauge is calculated. It should be noted that the lower ruler distance is the distance between the intersection point of the ruler tape in the oil gauge and the laser light-transmitting plate at the bottom of the distance measuring device 300 after the ruler tape naturally sags under the action of the gravity of the weight and the tip of the weight. In the embodiment of the present invention, the first distance between the intersection point and the top plane of the weight will be calculated in real time through the distance measuring device 300, and then the lower ruler distance can be obtained according to the vertical dimension of the weight.

[0075] In this way, the distance measuring device 300 emits a laser beam to the top plane of the weight, and the beam is perpendicular to the top plane of the weight. Further, the distance measuring device 300 uses the laser ranging principle to measure the phase change of the laser beam whose light intensity is modulated after being emitted to the target (the top plane of the weight) and reflected back, so as to measure the above first distance, and thus calculate the lower ruler distance in real time.

[0076] Figure 4 It is the overall structural schematic diagram of the distance measuring device in the control system for the oil gauge in the embodiment of the present application. As Figure 4 shown, the distance measuring device 300 includes: a measurement control module 310, a reference signal generation module 320, a signal reception module 330, and a distance display module 340.

[0077] Specifically, the measurement control module 310 is used to control the generation of the laser reference signal. Then, the reference signal generation module 320 is used to generate the laser reference signal under the control of the measurement control module 310, and generate a measurement transmission signal for effectively measuring the first distance and used for transmitting to the top plane of the above-mentioned bob weight based on the generated laser reference signal. Next, the signal receiving module 330 is used to condition the received laser receiving signal (reflection signal), and convert the generated laser reference signal and the reflected laser receiving signal into corresponding first square wave signal and second square wave signal respectively. Finally, the measurement control module 310 is further used to compare the first square wave signal and the second square wave signal conditioned by the signal receiving module 330, and calculate the phase difference between these two square wave signals using the phase discrimination counting principle of the RS flip-flop to obtain the above-mentioned first distance, and further obtain the current lower scale distance.

[0078] At this time, the distance display module 340 is connected to the measurement control module 310 and is used to display the real-time generated first distance and / or lower scale distance.

[0079] In this way, the distance measuring device 300 in the embodiment of the present invention obtains the lower scale distance that continuously changes with the operations of lowering and retracting the scale by continuously emitting laser signals to the top plane of the bob weight.

[0080] Preferably, the measurement control module 310 uses TMS320F2812 to complete the control of generating the laser reference signal through the SPI control method. Figure 7 It is a schematic diagram of the phase discrimination function principle of the measurement control module in the distance measuring device within the control system for the dipstick in the embodiment of the present application. During the process of comparing the first square wave signal and the second square wave signal generated after conditioning the received laser reflection signal by the measurement control module 310, the comparison result of the two square wave signals is processed by pulse filling counting using the phase discrimination counting principle of the RS flip-flop (as Figure 7 shown), to obtain the corresponding phase difference time data, and further obtain the above-mentioned first distance according to the propagation speed of the laser signal.

[0081] Further, refer to Figure 4, the reference signal generation module 320 includes: a first signal generation unit 321, a second signal generation unit 322, and a modulation and transmission unit 323. Specifically, the first signal generation unit 321 is connected to the measurement control module 310 and is configured to generate a first sine signal containing first frequency information under the control of the measurement control module 310. The second signal generation unit 322 is connected to the measurement control module 310 and is configured to generate a second sine signal containing second frequency information under the control of the measurement control module 310. Wherein, the absolute value of the difference between the first frequency and the second frequency is less than a preset first threshold. Further, the first threshold tends to zero, that is, the first threshold is close to but not equal to (approximately equal to) zero. In this way, by using the two generated sine signals with approximate frequencies, spectral leakage can be reduced to a certain extent, and requirements such as small computational load, fast tracking speed, and high computational accuracy can be met.

[0082] The modulation and transmission unit 323 is connected to the output end of the first signal generation unit 321. The modulation and transmission unit 323 is configured to amplitude-modulate the first sine signal to obtain a measurement transmission signal for effective measurement. Figure 6 It is a schematic diagram of the working principle of the modulation and transmission unit in the distance measurement device within the control system for the dipstick in the embodiment of the present application. The laser emitter in the modulation and transmission unit 323 uses a laser diode with a wavelength of 650 nm, and the circuit structure of the laser emitter is as Figure 6 shown. The modulation amplitude of the measurement transmission signal amplitude-modulated by the modulation and transmission unit 323 is between a preset minimum threshold current and a maximum threshold current. Among them, the minimum threshold current is preferably 16 mA, and the maximum threshold current is preferably 22 mA.

[0083] In the embodiment of the present invention, in order to generate a measurement transmission signal for effective measurement, it is necessary to amplitude-modulate the laser emitter so that the laser beam emitted by the laser has a periodic change in amplitude with the DDS sine signal (the first sine signal). The laser emitter selects a semiconductor laser diode HLD650005N4C (wavelength 650 nm, output optical power 5 mW). 650 nm is red visible light. While being eye-catching in color, taking advantage of the strong penetration of red light in visible light, it is beneficial for long-distance measurement. When the first sine signal modulates the laser diode to emit a sine optical signal, the modulation current amplitude must be between the threshold current of 16 mA and the maximum operating current of 22 mA, and fluctuate near the operating current of 18 mA. If it is closer to the maximum operating current, the temperature of the laser diode is more likely to increase, and the temperature change will have an adverse effect on the performance of the laser diode, resulting in a reduction in measurement accuracy.

[0084] Furthermore, the first signal generating unit 321 includes a first DDS sine signal generator and a first filter. More specifically, during the process of the first signal generating unit 321, the first DDS sine signal generator generates a first sine signal with a first frequency characteristic under the control of the measurement control module 310. The DDS sine signal (the first sine signal) after being filtered by the first filter is used in two ways: one way is to stay in the circuit as a reference signal, and the other way is to perform amplitude modulation on the laser emitter.

[0085] Furthermore, the second signal generating unit 321 includes a second DDS sine signal generator and a second filter. More specifically, during the process of the second signal generating unit 322, the second DDS sine signal generator generates a second sine signal with a second frequency characteristic under the control of the measurement control module 310. The DDS sine signal (the second sine signal) after being filtered by the second filter serves as a standard signal for down-conversion processing of the reference signal remaining in the circuit.

[0086] Furthermore, referring to Figure 4 , the signal receiving module 330 includes: a signal conditioning unit 331, a first square wave generating unit 332, and a second square wave generating unit 333. The signal conditioning unit 331 is configured to sequentially perform electrical signal conversion and filter amplification processing on the received laser reception signal, thereby obtaining a received conditioning signal. Figure 5 is a schematic diagram of the working principle of the signal conditioning unit in the distance measurement device within the control system for the dipstick in the embodiment of the present application. As Figure 5 shown, the signal conditioning unit 331 includes: a reflection signal receiver 3311, a photoelectric converter 3312, and a filter amplification circuit 3313.

[0087] Preferably, the reflection signal receiver 3311 is a convex lens, and the photoelectric converter 3312 is a photodiode. When receiving the optical signal, the optical signal reception principle is adopted. Since the reflected optical measurement signal is accompanied by many stray interference signals during propagation, therefore, referring to Figure 5 , in the embodiment of the present invention, a λ / 4 film can be coated on the receiving surface of the convex lens 3311, where λ represents the wavelength of the laser signal (λ = 650 nm). This film has an antireflection effect on the measurement optical signal (the laser reception signal), and also has a certain filtering effect on light of other wavelengths. The convex lens converges the measurement optical signal onto the photodiode 3312 at the focal point. After the photoelectric conversion by the photodiode 3312, a sine current signal with a frequency equal to the frequency of the dipstick signal is obtained, that is, the received conditioning signal.

[0088] Further, the first square wave generating unit 332 includes: a first mixing circuit 3321 and a first shaping circuit 3322. Specifically, the input end of the first mixing circuit 3321 is connected to both the first signal generating unit 321 and the second signal generating unit 322, and is configured to perform down-conversion mixing processing on the first sine signal and the second sine signal, and after filtering processing, obtain a first signal to be shaped (obtain a first low-frequency sine signal). The first shaping circuit 3322 is configured to perform zero-crossing shaping processing on the received first signal to be shaped, and obtain the first (low-frequency) square wave signal.

[0089] Further, the second square wave generating unit 333 includes: a second mixing circuit 3331 and a second shaping circuit 3332. Specifically, the input end of the second mixing circuit 3331 is connected to both the second signal generating unit 322 and the signal conditioning unit 331, and is configured to perform down-conversion mixing processing on the second sine signal and the received conditioning signal, and after filtering processing, obtain a second signal to be shaped (obtain a second low-frequency sine signal). The second shaping circuit 3332 is configured to perform zero-crossing shaping processing on the received second signal to be shaped, and obtain the second square wave signal.

[0090] Continue to refer to Figure 1 , the above-mentioned speed display module 140 and the above-mentioned distance display module 340 are integrated in the display device 400. In the embodiment of the present invention, the display device 400 adopts a combined structure of a liquid crystal display screen and / or a four-digit common-anode digital tube SM410564. The display device 400 is configured to dynamically display the above-mentioned first distance and / or the lower scale distance, as well as the actual speed and / or the retracting and extending speed of the motor. Preferably, the liquid crystal display screen adopts a graphic dot matrix liquid crystal display module I2864I-1. I2864I-1 is powered by a 5V voltage, integrates an ST7920 driving chip inside the module, and has a Chinese character library, and can conveniently display Chinese characters through a program. The liquid crystal display screen selects a liquid crystal module with a smaller size to meet the requirements of miniaturized design.

[0091] Further, since the oil dipstick control system needs to have a portable function, in order to ensure the stability of the power supply voltage of the system, at the same time, it is required that the power supply has the characteristics of no ripple and no noise, so as not to affect the normal operation of the entire control system. Therefore, in the embodiment of the present invention, a linear voltage regulator needs to be added at the power input end of the oil dipstick control system. Preferably, the linear voltage regulator adopts a low dropout (LDO) linear voltage regulator LT3024. LT3024 has the characteristics of low noise, low static current, and low dropout voltage, and at the same time has an internal protection circuit with reverse battery protection, current limiting, thermal limiting, and reverse current protection. The voltage input range of LT3024 is 1.8V to 20V, and it has two output modules, which can output two voltages in the range of 1.22V to 20V, and is suitable for the application occasion of the oil dipstick control system.

[0092] In addition, the present invention also provides an oil gauge, which includes the control system described above. The oil gauge of the present invention can automatically measure the height of the crude oil liquid level in the container.

[0093] The present invention designs an oil gauge and a control system for the oil gauge. The control system and the oil gauge can be applied to relevant occasions that require dynamic metering and handover. By setting a DC motor for controlling the retraction and extension of the weight and the tape in the oil gauge, a motor control device for controllably adjusting the motor speed, and a distance measuring device for measuring the actual lowering distance of the tape. The present invention reduces the errors caused by manual tape measurement operations, improves the controllability and accuracy of the lowering speed of the tape, realizes the function of automatically retracting and extending the tape by controlling the lowering speed of the oil gauge, thereby reducing the labor intensity of the operation personnel, improving the accuracy, measuring more accurately, avoiding the generation of static electricity and reducing potential safety hazards.

[0094] Although the embodiments disclosed in the present invention are as above, the content described is only an embodiment adopted for the convenience of understanding the present invention and is not intended to limit the present invention. Any person skilled in the art within the technical field to which the present invention pertains, without departing from the spirit and scope disclosed by the present invention, can make any modifications and changes in the form and details of the implementation, but the scope of patent protection of the present invention shall still be subject to the scope defined by the appended claims.

[0095] It should be understood that the embodiments disclosed in the present invention are not limited to the specific structures disclosed herein, but should extend to equivalent alternatives of these features understood by those of ordinary skill in the relevant art. It should also be understood that the terms used herein are only for the purpose of describing specific embodiments and do not mean to limit.

[0096] The phrase "one embodiment" or "an embodiment" mentioned in the specification means that a specific feature, structure or characteristic described in connection with the embodiment is included in at least one embodiment of the present invention. Therefore, the phrases "one embodiment" or "an embodiment" that appear throughout the specification do not necessarily all refer to the same embodiment.

[0097] Although the above examples are used to illustrate the principles of the present invention in one or more applications, for those skilled in the art, without departing from the principles and ideas of the present invention, various modifications can obviously be made in the form, usage and details of the implementation without creative labor. Therefore, the present invention is defined by the appended claims.

Claims

1. A control system for an oil gauge, characterized in that, The control system includes: A DC motor, which is used to drive the counterweight to perform retracting and extending actions under the control of a drive signal; A motor control device, which is used to obtain an input instruction, and based on the maximum rotation speed threshold of the DC motor, use PWM control technology to generate the drive signal for controlling the motor to operate according to the target requirement corresponding to the input instruction and / or under the limitation of the maximum rotation speed, wherein the input instruction is selected from one of forward rotation, reverse rotation, emergency stop, acceleration, and deceleration; A distance measurement device, which is used to generate a laser reference signal and vertically emit the laser reference signal to the top surface of the counterweight, and receive the reflected laser reception signal, and calculate the measurement results of the lower scale distance of the current oil gauge and the crude oil liquid level height according to the phase difference comparison result between the laser reference signal and the laser reception signal, including: A measurement control module, which is used to control the generation of the laser reference signal, and compare a first square wave signal and a second square wave signal, and calculate the phase difference of the square wave signals by using the phase discrimination and counting principle of an RS flip-flop, and further obtain the lower scale distance; A reference signal generation module, which is used to generate the laser reference signal under the action of the measurement control module, and generate a measurement transmission signal for emitting to the top surface of the counterweight based on the laser reference signal; A signal reception module, which is used to condition the received laser reception signal, and convert the laser reference signal and the laser reception signal into the corresponding first square wave signal and second square wave signal respectively; Wherein, the reference signal generation module includes: A first signal generation unit, which is connected to the measurement control module and is used to generate a first sine signal containing first frequency information under the control of the measurement control module; A second signal generation unit, which is connected to the measurement control module and is used to generate a second sine signal containing second frequency information under the control of the measurement control module, wherein the absolute value of the difference between the first frequency and the second frequency is less than a preset first threshold, and the first threshold is close to and tends to zero; A modulation and transmission unit, which is connected to the output end of the first signal generation unit and is used to amplitude-modulate the first sine signal to obtain the measurement transmission signal.

2. The control system according to claim 1, characterized in that, The motor control device includes: An input module, which is used to obtain the input instruction; A speed regulation module, which is used to receive and identify the input instruction, determine the current control requirement, calculate the control rotation speed of the DC motor in the current motor control cycle according to the current control requirement, the rotation speed of the DC motor in the previous motor control cycle, and the maximum rotation speed threshold, and generate a PWM control signal corresponding to the control rotation speed; A drive module, which is used to control the DC motor to operate at the control rotation speed under the drive of the PWM control signal.

3. The control system according to claim 1, characterized in that, The signal reception module includes: A signal conditioning unit, which includes a reflected signal receiver, an optoelectronic converter, and a filtering and amplifying circuit. The signal conditioning unit is configured to sequentially perform electrical signal conversion and filtering and amplifying processing on the received laser reception signal to obtain a received conditioned signal; A first square wave generating unit, which includes a first mixing circuit and a first shaping circuit. The first mixing circuit is configured to perform down-conversion mixing processing on the first sine signal and the second sine signal to obtain a first signal to be shaped. The first shaping circuit is configured to perform zero-crossing shaping processing on the first signal to be shaped to obtain the first square wave signal; A second square wave generating unit, which includes a second mixing circuit and a second shaping circuit. The second mixing circuit is configured to perform down-conversion mixing processing on the second sine signal and the received conditioned signal to obtain a second signal to be shaped. The second shaping circuit is configured to perform zero-crossing shaping processing on the second signal to be shaped to obtain the second square wave signal.

4. The control system according to claim 1, wherein The control system further includes: A display device, which is configured to display the lower ruler distance and the pay-off and take-up speed. Further, The distance measuring device is installed above the weight. The laser emitted by the laser emitting surface of the distance measuring device is vertically projected onto the upper surface of the weight; The DC motor is disposed within an explosion-proof protective housing, and the explosion-proof protective housing is disposed at a side end of the oil gauge bracket.

5. The control system according to claim 1 or 4, wherein, The reflected signal receiver in the signal receiving module is a convex lens, and a λ / 4 film is coated on the receiving surface of the convex lens, where λ represents the wavelength of the laser signal; A linear voltage regulator is provided at the power input end of the control system.

6. An oil gauge, characterized in that, The oil gauge includes the control system according to any one of claims 1 to 5 to implement the measurement of the height of the crude oil liquid level in the container.

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