Digital proportional valve controller

Abstract

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

Description

Technical Field

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

[0002] The full name of proportional valve is electro-hydraulic proportional valve. It is a hydraulic valve that converts the input electrical signal into force or displacement in proportion, thereby continuously controlling parameters such as pressure and flow. The proportional valve consists of two parts: a DC proportional solenoid and a hydraulic valve. The hydraulic valve part is not much different from the general hydraulic valve, but the DC proportional solenoid is different from the solenoid used in the general solenoid valve. The proportional solenoid can obtain the displacement output and suction output proportional to the 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 uses a digital processor and can set parameters through a PC, but the human-computer interaction is only a 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 over-current protection, or the over-current 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 a current feedback signal. If multiple controllers are used in the system, the main control system requires more resources.

[0007] Therefore, a digital proportional valve controller is proposed. It uses a digital control circuit, sets parameters online through software, and is equipped with a liquid crystal display to display the controller 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, a liquid crystal display is installed on the top of the guide rail housing;

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

[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, storing 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, which is linearly corresponding to the solenoid valve current;

[0018] The U / I solenoid valve drive circuit outputs a current signal according to a 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 operating status of the controller and providing fault information prompts.

[0026] Preferably, the power devices Q1 and Q2 use devices of the same type, 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 ADC to feedback information to the main control unit, the software controls the output to be disconnected, and outputs 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, and can output a DC signal, a triangular 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 beneficial effects achieved by the present invention are:

[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 adjustment 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 1This is a schematic diagram of the appearance structure of the present invention;

[0040] Figure 2 This is a hardware circuit block diagram of the present invention;

[0041] Figure 3 The schematic diagram of the electromagnet driving circuit and the protection circuit of the present invention;

[0042] Figure 4 Schematic diagram of the flutter control principle of the present invention.

[0043] Including: 1. Guide rail housing; 2. Liquid crystal display controller. DETAILED DESCRIPTION

[0044] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0045] See also Figure 1-4 :

[0046] like Figure 1 As shown, a digital proportional valve controller includes a guide rail housing 1, which 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;

[0047] like Figure 2 As shown, a main control unit is arranged inside the guide rail housing 1. The main control unit adopts a high-performance 32-bit microprocessor, and the microprocessor is connected to the liquid crystal display 2 circuit; it can realize the independent control and linkage control of the 2-way proportional valve control;

[0048] The microprocessor includes functions such as A / D conversion, digital input, LCD display, communication interface, PWM output, analog output module, etc.

[0049] The main control unit control circuit includes:

[0050] 1. Large capacity EEPROM memory to store parameter data and different control strategies;

[0051] 2. U / U, I / U conversion circuit, receiving external input command signal and external valve core displacement sensor signal;

[0052] 3. Industrial bus (one of RS485, CAN or a combination) to communicate with external control systems, or connect to a PC to set parameters through control software

[0053] 4. Wireless communication (one of BT, Wifi, 4G or a combination of them), wireless connection with external devices to achieve remote monitoring, or set parameters through mobile phone APP;

[0054] 5. The LCD display has a human-computer interaction interface, which is used to output the operating status of the controller and provide 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, the proportional valve drive circuit uses a dedicated gate driver U1 to drive power devices Q1 and Q2, which can increase the switching speed of the power devices, reduce the loss of the power devices at the moment of switching, 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 type, which can reduce the synchronization error at the moment of switching, 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. 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, and V1>V2 can be maintained. Q1 and Q2 remain in the disconnected state. By adjusting the C3 and R8 parameters, the delay conduction 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 short-circuited continuously or the temperature rise 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 the error alarm information is output through the LCD screen.

[0062] like Figure 4As shown, the high-performance microprocessor greatly shortens the program's operating cycle and provides conditions for effective vibration control. According to the set vibration frequency, vibration amplitude and input command voltage, the current required to be output on different time axes within a cycle is calculated in advance, and 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-way 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] Although 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 the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present 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 wiring 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 arranged inside the guide rail housing (1), and 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 two-way proportional valves; 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, storing 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, which is linearly corresponding to the solenoid valve current; The U / I solenoid valve drive circuit outputs a current signal according to a 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 wiring 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 interaction interface, which is used for outputting the operating status of the controller and prompting fault information.

5. A digital proportional valve controller according to claim 1, characterized in that: Using the same type of power devices Q1 and Q2 can reduce the synchronization error at the switching moment, 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 error alarm information through the LCD screen.

8. A digital proportional valve controller according to claim 1, characterized in that: 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.

9. A 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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