A digital proportional valve controller

Abstract

The application relates to the technical field of proportional valve controllers, and discloses a digital proportional valve controller which comprises a guide rail shell, the top of the guide rail shell is provided with a liquid crystal display, the controller can realize single control or linkage control of two proportional valves; a main control unit is arranged in the guide rail shell, the main control unit adopts a high-performance 32-bit microprocessor, the microprocessor is connected with a liquid crystal display circuit; the microprocessor comprises an A / D conversion, digital input, LCD display, communication interface, PWM output and analog quantity output module; the microprocessor circuit and a peripheral circuit, a proportional valve driving circuit and an overcurrent protection circuit are arranged, digital control is realized, the anti-interference capability is improved, a friendly man-machine interface is arranged, parameter adjustment is facilitated, an industrial bus is arranged, system integration is facilitated, multi-machine linkage debugging and linkage control are realized, wireless connection technology is adopted, remote monitoring is realized, an optimal control algorithm and a control circuit are adopted, product cost is reduced, and product performance is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of proportional valve controllers, in particular to a digital proportional valve controller. Background Art

[0002] A proportional valve, also known as an electro-hydraulic proportional valve, is a hydraulic valve that converts an input electrical signal into force or displacement proportionally, thereby continuously controlling parameters such as pressure and flow. A proportional valve consists of two parts: a DC proportional solenoid and a hydraulic valve. The hydraulic valve portion is similar to a typical hydraulic valve, but the DC proportional solenoid differs from the solenoid used in conventional solenoid valves. Using a proportional solenoid produces displacement output and suction force output proportional to a given current.

[0003] When the proportional valve is working, it needs to be controlled by a controller. The existing proportional valve controllers are divided into the following types:

[0004] One is realized by an analog circuit composed of operational amplifiers and discrete components. The parameter setting is completed by a potentiometer. The parameter setting process is cumbersome and is not conducive to the timely adjustment of different parameters in various working occasions.

[0005] One type uses a digital processor and can set parameters through a PC, but the human-computer interaction is only simple LED display, etc., the human-computer interaction is poor, and the operating status of the controller cannot be observed online;

[0006] At the same time, power drive circuits mostly use modulation circuits to modulate high-frequency carriers and low-frequency dither signals. The circuits require multiple oscillation circuits and modulation circuits. The circuits are complex and costly. Due to the aging of electronic component parameters and temperature drift, the controller performance consistency is poor, the output has no overcurrent protection, or the overcurrent protection response through the software is too slow. When the controller output is short-circuited, it is easy to cause the internal power devices to heat up and burn out, posing a safety hazard. A single proportional valve control requires one command signal and one current feedback signal. If multiple controllers are used in the system, the main control system resource requirements are relatively high.

[0007] Therefore, a digital proportional valve controller is proposed. It uses a digital control circuit, sets parameters online through software, and is equipped with an LCD display to display the controller's operating status and proportional valve current and other parameters in real time. It is equipped with an industrial bus to achieve joint control of multiple controllers. Summary of the Invention

[0008] The object of the present invention is to provide a digital proportional valve controller to solve the problems raised in the above background technology.

[0009] In order to solve the above technical problems, the present invention provides the following technical solutions: a digital proportional valve controller, comprising a guide rail housing, wherein a liquid crystal display is installed on the top of the guide rail housing;

[0010] A main control unit is provided inside the guide rail housing. The main control unit adopts a high-performance 32-bit microprocessor, which is connected to a liquid crystal display (2) circuit. It can realize independent control and linkage control of the two-way proportional valve.

[0011] The microprocessor includes A / D conversion, digital input, LCD display, communication interface, PWM output, and analog output modules;

[0012] The main control unit control circuit includes:

[0013] EEPROM memory, which stores parameter data and different control strategies;

[0014] U / U, I / U conversion circuit, receiving external input command signal and external valve core displacement sensor signal;

[0015] The industrial bus communicates with the external control system or connects to the PC to set parameters through the control software;

[0016] Wireless communication module, wireless connection with external devices, to achieve remote monitoring or parameter setting through mobile phone APP;

[0017] U / U analog output circuit, analog output of solenoid valve current feedback signal, has a linear correspondence with the solenoid valve current;

[0018] The U / I solenoid valve drive circuit outputs current signals according to the preset control strategy to control the proportional valve;

[0019] Overcurrent protection circuit, overcurrent protection of U / I proportional valve drive circuit to ensure the safety of the controller;

[0020] The proportional valve drive circuit uses gate driver U1 to drive power devices Q1 and Q2;

[0021] The overcurrent protection circuit uses the U2-B op amp to form a hysteresis loop comparator. The current feedback voltage charges the C3 capacitor through D3. After the C3 capacitor voltage V1 ≥ the overcurrent protection voltage V2, U2-B outputs a high level to control the power devices Q1 and Q2 to disconnect. At this time, the ADC voltage is 0V, but the C3 capacitor needs to be discharged through the R8 resistor to maintain V1>V2. Q1 and Q2 remain in the disconnected state. By adjusting the C3 and R8 parameters, the delayed on-time of the drive circuit during overcurrent can be effectively controlled.

[0022] Preferably, the guide rail housing is a DIN guide rail housing and is provided with a multi-way terminal block.

[0023] Preferably, the industrial bus is one of RS485 and CAN or a combination thereof;

[0024] The wireless communication module is one of BT, Wifi, and 4G or a combination thereof.

[0025] Preferably, the liquid crystal display controller has a human-computer interaction interface for outputting the controller's operating status and providing fault information prompts.

[0026] Preferably, the power devices Q1 and Q2 use devices of the same model, which can reduce the synchronization error at the switching moment, improve product performance and reduce noise in the driving path.

[0027] Preferably, an NTC temperature sensor is provided in the overcurrent protection circuit to measure the temperature rise of the power device. When the temperature of the power device rises, the resistance value of RT1 decreases, the voltage of V2 decreases, and the upper limit of the overcurrent protection current decreases.

[0028] Preferably, the NTC temperature sensor sets the ADC to feedback information to the main control unit, the software controls the output to be disconnected, and outputs the error alarm information through the LCD screen.

[0029] Preferably, the microprocessor sets the vibration frequency, vibration amplitude and input command voltage, and calculates in advance the current required to be output on different time axes within a cycle. The current feedback of the solenoid valve is compared with the current on the preset time axis. If the feedback current is less than the preset current, the power output is turned on, otherwise it is disconnected.

[0030] Preferably, the industrial bus controls the output of the proportional valve, can output a DC signal, a triangle wave model, a step signal, and a set output waveform, and obtain a feedback signal through the industrial bus.

[0031] Compared with the prior art, the present invention has the following beneficial effects:

[0032] 1. Digital control circuit improves anti-interference ability and facilitates parameter adjustment;

[0033] 2. LCD display, friendly human-computer interaction interface;

[0034] 3. Industrial bus, convenient for system integration, multi-machine joint debugging and control;

[0035] 4. Wireless connection technology to achieve remote monitoring;

[0036] 5. Optimize control algorithms and control circuits to reduce product costs and improve product performance;

[0037] 6. Improved output protection to increase product safety and reliability;

[0038] 7. Optimize control methods, reduce control signal resource requirements, and facilitate system integration. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] Figure 1It is the appearance structure schematic diagram of the present application;

[0040] Figure 2 It is the hardware circuit block diagram of the present application;

[0041] Figure 3 It is the electromagnet driving circuit and protection circuit schematic diagram of the present application;

[0042] Figure 4 It is the tremor control principle schematic diagram of the present application.

[0043] 1, guide rail shell; 2, liquid crystal display controller. DETAILED DESCRIPTION

[0044] The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative work fall within the scope of protection of the present application.

[0045] Please refer to Figure 1-4 :

[0046] As Figure 1 shown, a digital proportional valve controller comprises a guide rail shell 1, the guide rail shell 1 is a DIN guide rail shell, and is provided with a plurality of wiring terminal rows; a liquid crystal display 2 is mounted on the top of the guide rail shell 1 for displaying the running state of the controller;

[0047] As Figure 2 shown, a main control unit is arranged in the guide rail shell 1, the main control unit adopts a high-performance 32-bit microprocessor, and the microprocessor is electrically connected with the liquid crystal display 2; 2-way proportional valve control can be realized in separate control and linkage control;

[0048] The microprocessor comprises A / D conversion, digital input, LCD display, communication interface, PWM output, analog quantity output module and other functions;

[0049] The main control unit control circuit comprises:

[0050] 1. A large-capacity EEPROM memory for storing parameter data and different control strategies;

[0051] 2. A U / U, I / U conversion circuit for receiving external input instruction signals and external valve core displacement sensor signals;

[0052] 3. An industrial bus (RS485, CAN or a combination thereof) for communicating with an external control system or connecting a PC to set parameters through control software

[0053] 4. Wireless communication (one of BT, Wifi, 4G or a combination of them) to connect to external devices wirelessly for remote monitoring or parameter setting via mobile phone APP;

[0054] 5. The LCD display has a human-computer interaction interface for outputting the controller's operating status and providing fault information prompts;

[0055] 6. U / U analog output circuit, the analog output of the solenoid valve current feedback signal is linearly corresponding to the solenoid valve current;

[0056] 7. U / I solenoid valve drive circuit outputs current signal according to the preset control strategy to control the proportional valve;

[0057] 8. Overcurrent protection circuit, overcurrent protection of U / I proportional valve drive circuit to ensure the safety of the controller;

[0058] like Figure 3 As shown in the figure, the proportional valve drive circuit uses a dedicated gate driver U1 to drive the power devices Q1 and Q2, which can increase the switching speed of the power devices, reduce the loss of the power devices at the switching moment, reduce the heat generation of the power devices, and increase the service life of the product; the power devices Q1 and Q2 use devices of the same model, which can reduce the synchronization error at the switching moment, improve product performance and reduce noise in the drive path.

[0059] like Figure 3 As shown in the overcurrent protection circuit, the U2-B op amp forms a hysteresis loop comparator. The current feedback voltage charges the C3 capacitor through D3. When the C3 capacitor voltage V1 ≥ the overcurrent protection voltage V2, U2-B outputs a high level to control the power devices Q1 and Q2 to be disconnected. At this time, the ADC voltage is 0V, but the C3 capacitor needs to be discharged through the R8 resistor to maintain V1>V2. Q1 and Q2 remain in the disconnected state. By adjusting the parameters of C3 and R8, the delayed on-time of the drive circuit during overcurrent can be effectively controlled.

[0060] Considering the characteristic that the rated current of power devices decreases after the temperature rises, an NTC temperature sensor is used to measure the temperature rise of power devices. When the temperature of power devices rises, the resistance value of RT1 decreases, the voltage of V2 decreases, and the upper limit of overcurrent protection current decreases;

[0061] If the output is continuously short-circuited or the temperature of the power device reaches the preset protection point, the feedback is sent to the main control unit through the ADC, the software controls the output to be disconnected, and an error alarm message is output through the LCD screen.

[0062] like Figure 4As shown in the figure, the high-performance microprocessor greatly shortens the program's operating cycle and provides conditions for effective dither control. According to the set dither frequency, dither amplitude and input command voltage, the current required to be output on different time axes within a cycle is calculated in advance. The current feedback of the solenoid valve is compared with the current on the preset time axis. If the feedback current is less than the preset current, the power output is turned on, otherwise it is disconnected.

[0063] Optimize proportional valve control mode:

[0064] 1. Compatible with existing controllers, using command signal + feedback signal control;

[0065] 2. The proportional valve output can be controlled through the industrial bus, and can output DC signals, triangular wave signals, step signals, and other set output waveforms, etc., and obtain feedback signals through the industrial bus. Multi-channel proportional valve outputs only require one bus to control, which facilitates system integration, reduces the resource requirements of the main control system, and simplifies external wiring.

[0066] While embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions, and variations may be made to these embodiments without departing from the principles and spirit of the invention, and that the scope of the invention is defined by the appended claims and their equivalents.

Claims

1. A digital proportional valve controller, comprising a guide rail housing (1), characterized in that: The guide rail housing (1) is a DIN guide rail housing and is provided with a multi-way terminal block. A liquid crystal display (2) is installed on the top of the guide rail housing (1) for displaying the operating status of the controller; A main control unit is provided inside the guide rail housing (1), and the main control unit adopts a high-performance 32-bit microprocessor, which is connected to the liquid crystal display (2) circuit; it can realize the independent control and linkage control of the two-way proportional valve; The microprocessor includes A / D conversion, digital input, LCD display, communication interface, PWM output, and analog output modules; The main control unit control circuit includes: EEPROM memory, which stores parameter data and different control strategies; U / U, I / U conversion circuit, receiving external input command signal and external valve core displacement sensor signal; The industrial bus communicates with the external control system or connects to the PC to set parameters through the control software; Wireless communication module, wireless connection with external devices, to achieve remote monitoring or parameter setting through mobile phone APP; U / U analog output circuit, analog output of solenoid valve current feedback signal, has a linear correspondence with the solenoid valve current; The U / I solenoid valve drive circuit outputs current signals according to the preset control strategy to control the proportional valve; Overcurrent protection circuit, overcurrent protection of U / I proportional valve drive circuit to ensure the safety of the controller; The proportional valve drive circuit uses gate driver U1 to drive power devices Q1 and Q2; The overcurrent protection circuit uses the U2-B op amp to form a hysteresis loop comparator. The current feedback voltage charges the C3 capacitor through D3. After the C3 capacitor voltage V1 ≥ the overcurrent protection voltage V2, U2-B outputs a high level to control the power devices Q1 and Q2 to disconnect. At this time, the ADC voltage is 0V, but the C3 capacitor needs to be discharged through the R8 resistor to maintain V1>V2. Q1 and Q2 remain in the disconnected state. By adjusting the C3 and R8 parameters, the delayed on-time of the drive circuit during overcurrent can be effectively controlled.

2. A digital proportional valve controller according to claim 1, characterized in that: The guide rail housing is a DIN guide rail housing and is provided with a multi-way terminal block.

3. A digital proportional valve controller according to claim 1, characterized in that: Industrial bus is RS485, CAN or a combination thereof; The wireless communication module is one of BT, Wifi, and 4G or a combination thereof.

4. A digital proportional valve controller according to claim 1, characterized in that: The liquid crystal display (2) has a human-machine interactive interface for outputting the operating status of the controller and prompting fault information.

5. The digital proportional valve controller according to claim 1, characterized in that: Using the same type of power devices Q1 and Q2 can reduce synchronization errors at switching moments, improve product performance, and reduce noise in the drive path.

6. A digital proportional valve controller according to claim 1, characterized in that: An NTC temperature sensor is set in the overcurrent protection circuit to measure the temperature rise of the power device. When the temperature of the power device rises, the resistance of RT1 decreases, the voltage of V2 decreases, and the upper limit of the overcurrent protection current decreases.

7. A digital proportional valve controller according to claim 6, characterized in that: The NTC temperature sensor sets the ADC to feedback information to the main control unit, the software controls the output to be disconnected, and outputs the error alarm information through the LCD screen.

8. The digital proportional valve controller according to claim 1, characterized in that: The microprocessor sets the dither frequency, dither amplitude and input command voltage, and calculates in advance the current that needs to be output on different time axes within a cycle. The current feedback of the solenoid valve is compared with the current on the preset time axis. If the feedback current is less than the preset current, the power output is turned on, otherwise it is disconnected.

9. The digital proportional valve controller according to claim 1, characterized in that: The industrial bus controls the proportional valve output, which can output DC signals, triangle wave signals, step signals, and set output waveforms, and obtain feedback signals through the industrial bus.

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