Digital control system based on integrated board and design method of control system

Abstract

The invention relates to a digital control system based on an integrated board and a design method of the control system. The system comprises a PLC board card, a frequency converter board card, a touch screen and a motor. The PLC board card and the frequency converter board card are fixedly installed on the electric fitting board. The PLC board card is provided with a board card interface connected with an external sensor and an instrument; the PLC board card is a PLC board card which is used for collecting external sensors and controlling the starting, stopping and rotating speed of a motor by regulating and controlling each frequency converter in real time so as to realize constant-pressure water supply and some abnormal protection; all external signals need to pass through the PLC board card, and meanwhile, the PLC board card communicates with the frequency converter board through an RS485 bus, reads the working state of the frequency converter board, and controls starting, stopping and debugging of the frequency converter board card so as to control the motor; the touch screen is connected with the PLC board card through a bus, and the touch screen and the control power supply are provided by the PLC board card. The device is low in cost, space-saving, high in wiring efficiency, convenient to overhaul and high in environment adaptability.

Description

Technical Field

[0001] This invention relates to a control system and a design method for the control system, specifically to a low-cost, space-saving, easy-to-maintain, and highly efficient integrated board-based digital control system and a design method for the control system. Background Technology

[0002] The current mainstream variable frequency water supply control system still adopts a hardware approach that combines a PLC controller with a frequency converter in a plastic or metal casing. The PLC controls the frequency converter through hard wiring, and the switch quantity controls the start and stop of the frequency converter, while the analog quantity controls the frequency conversion of the frequency converter to achieve closed-loop constant pressure water supply regulation. The frequency converter parameters can be viewed and set through the frequency converter panel.

[0003] Existing PLCs and frequency converters typically have an IP21 protection rating because the external housing is already integrated by the supplier. However, this results in high housing costs, poor heat dissipation, and a large installation space requirement.

[0004] Cost issues: Existing technologies such as PLCs and frequency converters with metal or plastic casings, PLCs need to be expanded with I / O modules, and frequency converters need to be configured with I / O boards, all of which increase hardware costs.

[0005] Space utilization: In order to effectively improve space utilization, it is necessary to reduce the size and space of major components.

[0006] Wiring convenience: Under current technology, the control circuits of PLC and frequency converter are numerous, prone to errors, and time-consuming.

[0007] Maintenance convenience: Under current technology, if the circuit board of PLC or inverter is burned out or malfunctions, it cannot be completed by visual inspection alone, and the casing must be removed for comprehensive judgment.

[0008] Environmental adaptability: Since water supply pump rooms are generally located in basements, the dark and damp environment makes circuit boards susceptible to moisture damage, and existing circuit boards do not have a protective coating. Summary of the Invention

[0009] To address the aforementioned problems, the main objective of this invention is to provide a low-cost, space-saving, easy-to-maintain, and highly efficient integrated board-based digital control system and its design method.

[0010] The present invention solves the above-mentioned technical problems through the following technical solution: an integrated board-based digital control system, the integrated board-based digital control system comprising: a PLC board, a frequency converter board, a touch screen, and a motor; the PLC board and the frequency converter board are fixedly mounted on the electrical assembly board.

[0011] The PLC board has interfaces for connecting external sensors and instruments. The frequency converter board communicates with the PLC board via RS485. The frequency converter board receives control commands from the PLC and provides feedback on the motor's operating status.

[0012] The PLC board is used to collect data from external sensors and control the start, stop, and speed of motors in real time by regulating various frequency converters, thereby achieving constant pressure water supply and some abnormal protection.

[0013] The PLC board is the core of the entire control system. All external signals must pass through the PLC board. At the same time, the PLC board communicates with the frequency converter board via RS485 bus, reads the working status of the frequency converter board, and controls the start, stop and debugging of the frequency converter board, thereby controlling the motor.

[0014] The touch screen and PLC board are connected via a bus. The touch screen and control power are provided by the PLC board. External sensors and instruments are connected to the board interface.

[0015] In a specific implementation of the present invention, the PLC board and the touch screen use Ethernet TCP communication, and the PLC board and multiple frequency converters use Modbus RTU protocol based on RS485 bus interface to realize the status reading and control of the frequency converters and parameter modification.

[0016] In a specific embodiment of the present invention, the electrical panel is installed inside the inverter cabinet, the inverter housing is installed through the wall, and the heat dissipation aluminum plate and fan are placed outside the cabinet.

[0017] In a specific implementation of the present invention, the PLC on the PLC board is equipped with at least three sets of extended RJ45 ports, including one RS485 communication port, for communication with the frequency converter.

[0018] In a specific embodiment of the present invention, after the PLC board and the frequency converter board are combined, a transparent acrylic plate is placed on the outside for easy observation and protection.

[0019] In a specific embodiment of the present invention, the electrical panel is sprayed with a conformal coating.

[0020] In a specific implementation of this invention, the PLC is equipped with 5 NTC temperature measurement channels.

[0021] A design method for a digital control system based on an integrated board, comprising the following steps: Step 1: Inverter integrated board design: The independent I / O board and handheld device of the traditional inverter are eliminated, and only the bus interface for data interaction is retained. The inverter integrated board is used to receive PLC commands to control the start, stop and speed of the motor, and to provide feedback on the motor's operating status and data. Step 2: PLC integrated board design: Integrate all the I / O functions required by the control system into the PLC integrated board. The I / O functions include external sensor signal acquisition, instrument connection, abnormal protection signal processing, and control signal output of the actuator. The PLC integrated board does not require additional configuration of expansion I / O modules. Step 3: Communication Architecture Construction: The PLC integrated board and the frequency converter integrated board establish a communication connection through a data bus to realize the transmission of control commands, feedback of operating status, and interaction of parameter data; Step 4: Hardware integration and installation: The PLC integration board and the frequency converter integration board both adopt a bare board structure without a shell and are fixedly installed on the electrical assembly board. The electrical assembly board and the integration board are coated with a three-proof coating. Step 5: Human-machine interaction configuration: Communicate with the PLC integrated board via the touch screen to realize parameter setting and operation status display of the control system and frequency converter, without the need for an additional frequency converter operation panel.

[0022] The positive and progressive effects of this invention are as follows: The integrated board-based digital control system and its design method provided by this invention have the following advantages: 1. Reduced cost: The PLC and frequency converter are bare circuit board structures, eliminating the need for a casing and frequency converter I / O board, as well as PLC expansion modules, resulting in lower costs.

[0023] 2. Saves space: Reducing the size of components makes the cabinet more compact.

[0024] 3. Improved wiring efficiency: Only one network cable is needed between the frequency converter and the PLC, which improves wiring efficiency and reduces the error rate.

[0025] 4. Convenience of maintenance: The circuit board is covered with a transparent acrylic sheet. If any electronic components inside are burned out or malfunction, the outer shell can be removed without removing the outer shell. The damage can be observed directly with the naked eye, making it easy to observe and protect.

[0026] 5. Environmental adaptability: The absence of a casing improves heat dissipation, and the circuit board is coated with a three-proof coating to cope with the dark and humid environment of the pump room.

[0027] 6. Eliminate the inverter operation panel: Modify the inverter's routine parameters via PLC and display some routine parameters on the touch screen.

[0028] 7. The PLC board integrates modular functions, reducing costs and space requirements. Attached Figure Description

[0029] Figure 1 This is a schematic diagram of the overall structure of the present invention.

[0030] The following are the names corresponding to the reference numerals in this invention: In the diagram: 1. PLC board; 2. Inverter board; 3. Touch screen; 4. Motor; 5. RS485 communication bus; 6. RJ45 interface; 7. External sensor. Detailed Implementation

[0031] The preferred embodiments of the present invention are given below with reference to the accompanying drawings to illustrate the technical solution of the present invention in detail.

[0032] Figure 1 This is a schematic diagram of the overall structure of the present invention, as shown below. Figure 1 As shown: This invention proposes a digital control system based on an integrated board and a design method for the control system. The control system includes: a PLC board 1, a frequency converter board 2, a touch screen 3, and a motor 4; the PLC board 1 and the frequency converter board 2 are fixedly mounted on the electrical assembly board.

[0033] The PLC board 1 is equipped with an external sensor 7 and a signal switch. The inverter board 2 communicates with the PLC board via RS485 (the RS485 communication network cable in the figure). The inverter board 2 is a frequency converter board that receives control commands from the PLC and provides feedback on the motor's operating status.

[0034] PLC board 1 collects information from external sensor 7 and controls the start / stop and speed of the motor in real time by regulating each frequency converter, thereby achieving constant pressure water supply and some abnormal protection.

[0035] The touch screen and PLC board are connected via a bus. The touch screen and control power are provided by the PLC board. External sensors and instruments are connected to the board interface.

[0036] The PLC board and the touch screen use Ethernet TCP communication. The PLC board and multiple frequency converters use the Modbus RTU protocol based on the RJ45 interface to realize the status reading, control and parameter modification of the frequency converters.

[0037] The electrical control panel is installed inside the inverter cabinet, while the inverter housing is installed through the wall, with the heat dissipation aluminum plate and fan placed outside the cabinet.

[0038] In specific implementation, the PLC board of the present invention adds at least three sets of extended RJ45 ports to the PLC with one 485 communication port for communication with the frequency converter.

[0039] In the specific implementation process, after the PLC board and the frequency converter board in this invention are combined, a transparent acrylic plate is placed on the outside for easy observation and protection.

[0040] In the specific implementation process, the electrical assembly board of the present invention is sprayed with a three-proof coating, and the PLC is equipped with 5 NTC temperature measurement channels.

[0041] In the specific implementation process, the PLC and the touch screen in this invention still use Ethernet TCP communication, and the PLC and multiple frequency converters use the Modbus RTU protocol based on the RJ45 interface to realize the status reading and control of the frequency converters, parameter modification, etc.

[0042] The PLC board 1 of this invention is the core of the entire control system. All external signals must pass through the PLC board. At the same time, the PLC on the PLC board controls the frequency converter on the frequency converter board 2. The frequency converter uses RS485 communication to read the status of the frequency converter board and control the motor start, stop and speed adjustment, etc.

[0043] The board interface of this invention includes the ability to collect signals with digital input, such as water source status, outlet overpressure signal, cabinet door emergency stop signal, pump room flooding signal, etc.

[0044] The inverter board of this invention connects to the network cable via a 485 communication board, eliminating the original DI, DO, AI, and AO terminals. The inverter board's product model is KQ-M210-C series, manufactured by Shanghai Kaiquan. The PLC board of this invention has the product model KQ-ZLC5P, also manufactured by Shanghai Kaiquan.

[0045] To improve communication stability and real-time performance, the PLC and frequency converter generally adopt the TCP communication protocol. In order to ensure that the water supply can still be stable when the PLC fails, the frequency converter can communicate with the touch screen via RS485 to complete the control of start-stop and frequency adjustment. The touch screen then communicates with the PLC to receive the PLC's PID frequency adjustment.

[0046] In this invention, the PLC and frequency converter are bare circuit board structures, eliminating the need for a casing and frequency converter I / O board, as well as the PLC expansion module, resulting in lower costs.

[0047] This invention reduces the size of components, making the cabinet more compact.

[0048] This invention improves wiring efficiency, requiring only one network cable between the frequency converter and the PLC, thus reducing wiring efficiency and error rate.

[0049] The present invention makes maintenance more convenient. The circuit board is encased in a transparent acrylic sheet, so if any electronic components inside are burnt out or malfunction, the outer casing can be removed, and the problem can be observed directly with the naked eye. This facilitates observation and protection.

[0050] This invention has better heat dissipation performance without a large outer shell, and the circuit board is coated with a three-proof coating to cope with the dark and humid environment of the pump room.

[0051] This invention eliminates the need for a frequency converter operation panel. Instead, it uses a PLC to modify the frequency converter's conventional parameters and displays these parameters on a touchscreen.

[0052] The PLC board of this invention integrates modular functions, reducing cost and space requirements.

[0053] This invention solves the problem of resource waste by eliminating the independent I / O board for the frequency converter and unifying all I / O functions with a PLC integrated board. This completely solves the problem of redundant I / O function configuration between the frequency converter and the PLC in traditional systems, maximizing resource utilization. Simultaneously, the frequency converter handheld device is eliminated, and its operation and display functions are replaced and designed using a touch screen and the PLC integrated board.

[0054] This invention significantly reduces costs: the integrated board adopts a bare board structure without a shell, eliminating the cost of the shell and mold, and at the same time eliminating the inverter I / O board and PLC expansion module, resulting in a significant reduction in hardware costs.

[0055] This invention saves installation space: the bare board structure reduces the size of components, the equipment cabinet is more compact, and the space utilization rate is significantly improved.

[0056] This invention improves wiring efficiency: the PLC integrated board and the frequency converter integrated board only need to be connected through a single bus, replacing the traditional multiple sets of hard wiring, improving wiring efficiency by more than 50%, and significantly reducing the error rate.

[0057] This invention makes maintenance more convenient: the external transparent acrylic plate allows direct observation of the internal electronic components, enabling fault diagnosis without removing the outer casing, thus improving maintenance efficiency by more than 30%.

[0058] This invention is adaptable to complex environments: the shell-less design improves heat dissipation performance, the three-proof coating effectively resists harsh environments such as dark and humid conditions and dust, and the stability of the equipment is significantly enhanced.

[0059] This invention simplifies the operation process: parameter setting and status monitoring are uniformly realized through a touch screen, eliminating the need for an inverter operation panel, making operation more convenient and intuitive.

[0060] The foregoing has shown and described the basic principles, main features, and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The embodiments and descriptions in the specification are merely illustrative of the principles of the invention. Various changes and modifications can be made to the invention without departing from its spirit and scope, and all such changes and modifications fall within the scope of the present invention as defined by the appended claims and their equivalents.

Claims

1. A digital control system based on an integrated board, characterized in that: The integrated board-based digital control system includes: a PLC board, a frequency converter board, a touch screen, and a motor; the PLC board and the frequency converter board are fixedly mounted on the electrical assembly board; The PLC board has interfaces for connecting external sensors and instruments, while the frequency converter board is a frequency converter board that receives control commands from the PLC and provides feedback on the motor's operating status. The PLC board is a PLC board that collects data from external sensors and controls the start, stop and speed of motors in real time by regulating various frequency converters, so as to achieve constant pressure water supply and some abnormal protection. The PLC board is the core of the entire control system. All external signals must pass through the PLC board. At the same time, the PLC board communicates with the frequency converter board via RS485 bus, reads the working status of the frequency converter board, and controls the start, stop and debugging of the frequency converter board, thereby controlling the motor. The touch screen and PLC board are connected via a bus, and the power supply for the touch screen and control is provided by the PLC board.

2. The integrated board-based digital control system according to claim 1, characterized in that: The PLC board and the touch screen use Ethernet TCP communication. The PLC board and multiple frequency converters use the Modbus RTU protocol based on the RS485 bus interface to realize the status reading, control and parameter modification of the frequency converters.

3. The integrated board-based digital control system according to claim 1, characterized in that: The electrical control panel is installed inside the inverter cabinet, while the inverter housing is installed through the wall, with the heat dissipation aluminum plate and fan placed outside the cabinet.

4. The integrated board-based digital control system according to claim 1, characterized in that: The PLC board should have at least three additional RJ45 ports, including one RS485 communication port, for communication with the frequency converter.

5. The integrated board-based digital control system according to claim 1, characterized in that: After the PLC board and the frequency converter board are combined, an external transparent acrylic sheet is placed for easy observation and protection.

6. The integrated board-based digital control system according to claim 1, characterized in that: The electrical panel is coated with a conformal coating.

7. The integrated board-based digital control system according to claim 1, characterized in that: The PLC adds 5 NTC temperature measurement channels.

8. A design method for a digital control system based on an integrated board as described in any one of claims 1-7, characterized in that: The design method includes the following steps: Step 1: Inverter integrated board design: The independent I / O board and handheld device of the traditional inverter are eliminated, and only the bus interface for data interaction is retained. The inverter integrated board is used to receive PLC commands to control the start, stop and speed of the motor, and to provide feedback on the motor's operating status and data. Step 2: PLC integrated board design: Integrate all the I / O functions required by the control system into the PLC integrated board. The I / O functions include external sensor signal acquisition, instrument connection, abnormal protection signal processing, and control signal output of the actuator. The PLC integrated board does not require additional configuration of expansion I / O modules. Step 3: Communication Architecture Construction: The PLC integrated board and the frequency converter integrated board establish a communication connection through a data bus to realize the transmission of control commands, feedback of operating status, and interaction of parameter data; Step 4: Hardware integration and installation: The PLC integration board and the frequency converter integration board both adopt a bare board structure without a shell and are fixedly installed on the electrical assembly board. The electrical assembly board and the integration board are coated with a three-proof coating. Step 5: Human-machine interaction configuration: Communicate with the PLC integrated board via the touch screen to realize the setting of control system and inverter parameters and display of operating status, without the need for an additional inverter operation panel.

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