A fine drip irrigation control system

Abstract

The application discloses a fine drip irrigation control system, which comprises a water source system, a head system, an electrical control system, a programmable controller PLC and an HMI system, and each system cooperatively realizes fine irrigation; the programmable controller PLC is internally provided with an irrigation control program, and the irrigation control program comprises a timing irrigation subprogram, a sensor data acquisition subprogram, a precise fertilizer application control subprogram, a frequency converter communication control subprogram and a data alarm subprogram. The fine drip irrigation control system has the remarkable effects of water saving and fertilizer saving: through the drip irrigation mode and the precise fertilizer application control, the fertilizer utilization rate is increased by more than 50%, and the water consumption is reduced by more than 60%; the automation degree is high: the whole process automation of irrigation, fertilization, monitoring and alarm is realized, manual on-site operation is not needed, the labor intensity is greatly reduced, and the fine drip irrigation control system is suitable for large-scale planting bases; the monitoring is accurate and comprehensive: the key parameters such as soil humidity, nutrients and pH value are monitored in real time, the data acquisition precision is high, and a scientific basis is provided for planting management.

Description

Technical Field

[0001] This invention relates to the technical field of precision drip irrigation control systems, specifically a precision drip irrigation control system. Background Technology

[0002] This invention will use a blueberry plantation in Dandong City as a pilot site to develop a refined drip irrigation system integrating water and fertilizer. Blueberries are shallow-rooted plants with a very developed root system, which makes them particularly sensitive to soil moisture. Excessive dryness leads to water shortage, while excessive moisture reduces soil aeration, potentially causing plant death. Currently, it is known that blueberry greenhouse irrigation requires farmers to visit the greenhouse planting area multiple times a day, using well pumps to irrigate and fertilize the crops.

[0003] Background Technology Deficiencies: Traditional irrigation methods result in significant water and fertilizer waste and are difficult to control precisely. Manual fertilization and irrigation are time-consuming, labor-intensive, and have high management costs. The lack of real-time monitoring of key parameters such as soil nutrients and pH levels leads to uneven crop growth. Traditional methods struggle to provide stable data support. Summary of the Invention

[0004] To address the aforementioned problems, namely those raised in the background section, this invention proposes a refined drip irrigation control system, comprising a water source system, a head system, an electrical control system, a programmable logic controller (PLC), and an HMI system. These systems work together to achieve refined irrigation. The PLC has a built-in irrigation control program, which includes a timed irrigation subroutine, a sensor data acquisition subroutine, a precision fertilization control subroutine, a frequency converter communication control subroutine, and a data alarm subroutine. The HMI system connects to the PLC via a data interaction protocol to achieve parameter setting, data storage, and remote control.

[0005] Preferably, the timed irrigation subroutine can receive irrigation start time, irrigation duration and irrigation cycle parameters set by the HMI system, and automatically output control signals to start the water pump of the head system and the field zone solenoid valves after the set time is reached.

[0006] Preferably, the sensor data acquisition subroutine uses a 4-20mA signal acquisition algorithm to perform analog-to-digital conversion on the analog signals output by the soil moisture sensor, soil nutrient sensor, soil pH sensor and water tank level sensor, and the converted data is stored in the PLC internal register.

[0007] Preferably, the precision fertilization control subroutine acquires real-time irrigation flow data through a flow sensor, combines it with the water-fertilizer ratio parameters set by the HMI system, calculates the required amount of fertilizer, and then outputs a PWM signal to control the fertilization rate of the head system's fertilization equipment.

[0008] Preferably, the inverter communication control subroutine uses the standard MODBUS protocol to establish communication with the inverter, reads the inverter's output frequency, operating current and fault status data in real time, and can send frequency setting commands to the inverter to achieve constant pressure control of the irrigation system.

[0009] Preferably, the data alarm subroutine performs threshold judgment on the collected soil moisture, nutrient, pH value and water tank liquid level data. When the data exceeds the preset range, an alarm signal is generated. The alarm signal is displayed through the HMI system and pushed to the PC and WeChat terminals.

[0010] Preferably, the HMI system has a built-in data management algorithm that can classify and store irrigation records, sensor data records, and alarm records, support data query by time range, and export data to Excel format files.

[0011] Preferably, the constant pressure control of the electrical control system adopts a PID closed-loop control algorithm. The frequency converter dynamically adjusts the output frequency according to the 0-10V feedback signal output by the pressure gauge through the PID algorithm, so that the irrigation system pressure is maintained within the error range of ±0.02MPa.

[0012] Preferably, the system also includes a cloud data platform, which is connected to the HMI system via a wireless network, can receive and store system operation data, and generate crop growth trend reports and irrigation optimization suggestions through big data analysis algorithms.

[0013] Preferably, the precision fertilization control subroutine also has an automatic compensation function. When the flow sensor detects flow fluctuations, it automatically adjusts the fertilization rate to ensure that the deviation between the actual water-fertilizer ratio and the set ratio does not exceed 5%.

[0014] The beneficial technical effects of this invention are as follows: 1. Significant water and fertilizer saving effect: Through drip irrigation and precise fertilizer control, fertilizer utilization rate is increased by more than 50%, water consumption is reduced by more than 60%, and water and fertilizer costs can be saved by 800-1200 yuan per mu per year; 2. High degree of automation: It realizes full automation of irrigation, fertilization, monitoring and alarm, eliminating the need for manual on-site operation, greatly reducing labor intensity, and is suitable for large-scale planting bases; 3. Precise and comprehensive monitoring: Real-time monitoring of key parameters such as soil moisture, nutrients, and pH value, with high data collection accuracy, providing a scientific basis for planting management and avoiding the blindness of experience-based planting; 4. Convenient remote management: Supports remote monitoring and control from multiple terminals. Attached Figure Description

[0015] Figure 1 A flowchart of a refined drip irrigation control system is shown.

[0016] Figure 2 The module connection diagram of the precision drip irrigation control system is shown.

[0017] Figure 3 The parameter interaction logic diagram of the precision drip irrigation control system is shown.

[0018] Figure 4 A diagram illustrating the time-determination mechanism of a refined drip irrigation control system is shown.

[0019] Figure 5 The diagram shows the sensor data acquisition of the precision drip irrigation control system.

[0020] Figure 6 The diagram shows the frequency converter communication control subroutine of the precision drip irrigation control system.

[0021] Figure 7 The diagram shows the data alarm subroutine of the precision drip irrigation control system. Detailed Implementation

[0022] Preferred embodiments of the present invention will now be described with reference to the accompanying drawings. Those skilled in the art should understand that these embodiments are merely illustrative of the technical principles of the present invention and are not intended to limit the scope of protection of the present invention.

[0023] Example

[0024] This invention proposes a refined drip irrigation control system, characterized by comprising a water source system, a head system, an electrical control system, a programmable logic controller (PLC), and an HMI system, with each system working together to achieve refined irrigation; the PLC has a built-in irrigation control program, which includes a timed irrigation subroutine, a sensor data acquisition subroutine, a precision fertilization control subroutine, a frequency converter communication control subroutine, and a data alarm subroutine; the HMI system connects to the PLC via a data interaction protocol to realize parameter setting, data storage, and remote control. Specifically, the water supply system includes a deep well pump (5.5kW power, 15m³ / h flow rate), a water storage tank (100m³ capacity), a water intake pipeline (De63PE pipe), and a distribution box (including a leakage current protector and an air switch). The main system is equipped with a variable frequency centrifugal pump (7.5kW power, 50m head), a sand filter (300mm diameter), a disc filter (6 sets), a pressure sensor (0-1MPa), an electromagnetic flow meter (0-50m³ / h), a pressure safety valve (0.4MPa), a water-fertilizer mixing tank (200L), a metering pump (0-5L / h flow rate), and a PLC control box (Siemens S7-200SMART). Electrical control system: Equipped with a stainless steel control cabinet (1200×800×400mm), a 10-inch industrial touch screen, 20 soil moisture sensors (1 per greenhouse), 10 soil nutrient sensors (1 per 2 greenhouses), 10 soil pH sensors (1 per 2 greenhouses), 1 liquid level sensor (installed in the water tank), a frequency converter (7.5kW, Mitsubishi FR-D740 series), and low-voltage electrical components (Schneider Electric brand). HMI system: The touch screen interface is developed using WinCC software, a 4G module is configured to enable remote communication, and a web management platform and WeChat official account are developed. Field water distribution network: The main pipe uses De63PE pipe (500m in length), the branch pipe uses De32PE pipe (50m per greenhouse, 1000m in total), the capillary pipe uses inlaid drip irrigation tape (300m per greenhouse, 6000m in total), and there are 20 solenoid valves (DC24V).

[0025] Furthermore, the control cabinet consists of: control cabinet housing, PLC programmable controller, IoT HMI, low-voltage electrical components, contactors, intermediate relays, circuit breakers, frequency converters, terminals, wires, cable trays, etc.

[0026] First, select a suitable number of PLC controllers and the quantity and power of low-voltage components according to customer needs. Then, use drawing software to draw the electrical schematic diagram and component layout diagram to facilitate the later assembly of the control cabinet. Finally, assemble and wire the components according to the original electrical diagram.

[0027] The principle involves using the programmable memory of a programmable logic controller (PLC) to store and execute operational instructions for logic operations, sequential control, timing / counting, and arithmetic operations. Digital input / output interfaces control the on / off states of contactors and intermediate relays, as well as the start / stop, operation, and fault feedback of the frequency converter. Analog input / output interfaces collect data on liquid level, soil temperature and humidity, pH value, etc. The PLC analyzes the collected data to effectively adjust irrigation and fertilization, and provides corresponding alarms. Communication between the PLC and the frequency converter via a MODBUS-RTU interface (nine-pin interface) allows for setting and feedback of irrigation pipeline pressure. Under constant pressure, the impact on the irrigation pipeline is significantly reduced, extending its lifespan and improving the accuracy of irrigation and fertilization. Communication with an IoT touchscreen via Ethernet enables control over timed irrigation, pump start / stop, valve switching, data acquisition, and parameter settings. Data is uploaded to an IoT cloud platform via 4G, mapping the touchscreen display to mobile apps, computers, and WeChat mini-programs for convenient on-site control and data monitoring.

[0028] The timed irrigation subroutine can receive irrigation start time, irrigation duration and irrigation cycle parameters set by the HMI system. After the set time is reached, it will automatically output control signals to start the water pump of the head system and the field zone solenoid valve.

[0029] Specifically, the timed irrigation subroutine The timed irrigation subroutine is the core of automated irrigation scheduling, possessing functions such as parameter reception, time judgment, equipment control, and anomaly handling. Its operating mechanism is as follows: Parameter interaction logic: The subroutine establishes real-time data interaction with the HMI system through the PLC's communication port. It can receive three types of core parameters from the HMI system: irrigation start time (accurate to the minute, supporting 24-hour settings, such as "08:30" and "16:45"), irrigation duration (range 5-180 minutes, minimum adjustment unit 1 minute), and irrigation cycle (supporting single-day, multiple-day, and multi-day cycle modes, such as "twice a day" and "once every three days"). After receiving the parameters, the subroutine automatically verifies their validity (e.g., start time does not exceed the 24-hour range, duration is not less than 5 minutes). If the parameters are abnormal, an error signal is sent to the HMI system, prompting the user to reset.

[0030] Time determination mechanism: The subroutine has a built-in real-time clock module (accuracy ±1 second / day), which reads the current time every 100 milliseconds and compares it with the preset irrigation start time. When the current time matches the set start time, the subroutine starts the timing logic and generates a device control signal. If the system clock becomes disordered due to power failure or other reasons, the subroutine can synchronize the time with the cloud data platform through the HMI system to ensure the accuracy of time determination.

[0031] Equipment control process: Upon reaching the set time, the subroutine first outputs a low-level signal to start the water pump control relay of the main system. After the water pump runs for 3 seconds (completing the start-up buffer), it outputs a high-level signal to open the corresponding field zone solenoid valves according to the preset irrigation sequence (e.g., "Greenhouse 1 → Greenhouse 2 → ... → Greenhouse 20"). After each zone solenoid valve is opened, the subroutine monitors the irrigation duration in real time. When the set duration is reached, it first closes the current zone solenoid valve, delays for 2 seconds, and then closes the next zone solenoid valve to avoid sudden pressure changes in the pipeline. After all zones are irrigated, the water pump is turned off after a 5-second delay to ensure that residual water in the pipeline is drained.

[0032] Anomaly Handling Function: During irrigation, if the subroutine receives abnormal signals such as "soil moisture too high" or "water level too low" from the sensor data acquisition subroutine, it will immediately pause the current irrigation process, shut down the running solenoid valve and water pump, and send a pause command to the HMI system. After the anomaly is resolved, irrigation can be resumed from the paused zone or the entire irrigation process can be restarted.

[0033] The sensor data acquisition subroutine uses a 4-20mA signal acquisition algorithm to perform analog-to-digital conversion on the analog signals output by the soil moisture sensor, soil nutrient sensor, soil pH sensor and water tank level sensor. The converted data is then stored in the PLC's internal register.

[0034] Specifically, the sensor data acquisition subroutine The sensor data acquisition subroutine is responsible for converting the analog signals output by various sensors into processable digital signals, and for completing data storage and preprocessing. Its technical details are as follows: Signal acquisition algorithm: The subroutine uses a 12-bit analog-to-digital converter (ADC) algorithm to process 4-20mA analog signals. The sampling frequency is set to 10Hz (one sample every 0.1 seconds). After each acquisition, a moving average filter is applied to five consecutive sample values ​​to eliminate signal fluctuation interference (such as instantaneous value jumps caused by soil particle loosening in soil moisture sensors). The filtering formula is: Filtered value = (1st sample value + 2nd sample value + ... + 5th sample value) / 5, ensuring data stability.

[0035] Sensor adaptation logic: The subroutine has built-in dedicated calibration parameters for the signal characteristics of different types of sensors. Soil moisture sensor: 4mA corresponds to 0%RH, 20mA corresponds to 100%RH, the calibration coefficient is "(100%RH-0%RH) / (20mA-4mA)=6.25%RH / mA", and the conversion formula is soil moisture = (sampling current value-4mA)×6.25%RH / mA; Soil nutrient sensor: 4mA corresponds to 0mg / kg (nitrogen / phosphorus / potassium), 20mA corresponds to 500mg / kg, the calibration coefficient is "31.25mg / (kg·mA)", and the conversion formula is nutrient content = (sampling current value - 4mA) × 31.25mg / (kg·mA); Soil pH sensor: 4mA corresponds to 4.0 pH, 20mA corresponds to 8.0 pH, calibration coefficient is "0.25pH / mA", conversion formula is pH value = (sampling current value - 4mA) × 0.25pH / mA + 4.0pH; Water level sensor for pool: 4mA corresponds to 0m, 20mA corresponds to 5m, calibration coefficient is "0.3125m / mA", conversion formula is liquid level height = (sampling current value - 4mA) × 0.3125m / mA.

[0036] Data storage and interaction: The converted digital data is stored in the PLC's internal data register (D area). Each sensor has an independent register address (e.g., soil moisture data is stored in D100, soil pH data is stored in D105), and the data update cycle is 1 second. Simultaneously, the subroutine packages all sensor data every 5 seconds and sends it to the HMI system and the data alarm subroutine, providing data support for remote monitoring and anomaly detection. If data transmission fails (e.g., communication interruption), the subroutine automatically stores the data in the PLC's power-off retention register, retransmitting the data after communication is restored to prevent data loss.

[0037] The precision fertilization control subroutine acquires real-time irrigation flow data through a flow sensor, combines it with the water-fertilizer ratio parameters set by the HMI system, calculates the required amount of fertilizer, and then outputs a PWM signal to control the fertilization rate of the head system's fertilization equipment.

[0038] Specifically, the precision fertilization control subroutine The precision fertilization control subroutine achieves precise water and fertilizer mixing through the linkage of flow rate and ratio, and also has a dynamic compensation function. Its implementation details are as follows: Basic control logic: The subroutine receives irrigation flow data (unit: m³ / h, update cycle 0.5 seconds) from the flow sensor in real time and the water-fertilizer ratio parameters set by the HMI system (e.g., "1:200", meaning 1 kg of fertilizer corresponds to 200 m³ of water). It calculates the fertilizer application rate using the formula: Real-time required fertilizer application rate (kg / h) = Real-time irrigation flow rate (m³ / h) / Water-fertilizer ratio. For example, when the real-time flow rate is 10 m³ / h and the ratio is 1:200, the required fertilizer application rate is 0.05 kg / h (i.e., 50 g / h).

[0039] PWM Signal Control: The subroutine outputs a pulse width modulation (PWM) signal to control the fertilizer application equipment (metering pump) of the head system based on the calculated fertilizer application rate. The frequency of the PWM signal is fixed at 1kHz, and the duty cycle (percentage of high-level time) is linearly related to the fertilizer application rate: when the maximum fertilizer application rate of the metering pump is 5kg / h, the corresponding PWM signal duty cycle is 100%; when the fertilizer application rate is 0.05kg / h, the duty cycle is adjusted to 1% (i.e., 1ms high level and 999ms low level). By precisely adjusting the duty cycle, stepless speed regulation of the fertilizer application rate is achieved, ensuring the accuracy of water and fertilizer mixing.

[0040] Automatic compensation function: To cope with flow fluctuations during irrigation (such as changes in water pressure causing the flow rate to drop from 10 m³ / h to 8 m³ / h), the subroutine has a built-in flow fluctuation monitoring and compensation algorithm: Fluctuation monitoring: The difference between the current flow and the flow of the previous cycle is calculated every 0.5 seconds. When the absolute value of the difference exceeds 0.5 m³ / h (i.e., the 5% fluctuation threshold), it is judged as a flow fluctuation and the compensation mechanism is activated. Compensation calculation: The fertilizer application rate is recalculated based on the new real-time flow, and the duty cycle of the PWM signal is adjusted synchronously, with an adjustment response time of less than 0.1 seconds; Accuracy Guarantee: Through a compensation mechanism, the deviation between the actual water-fertilizer ratio and the set ratio is always controlled within 5%. For example, if the set ratio is 1:200, and the flow fluctuation causes the theoretical ratio to become 1:210, the subroutine will correct the actual ratio to 1:203 by increasing the PWM duty cycle, with a deviation of only 1.5%, far below the allowable deviation range of 5%.

[0041] Fault protection: If the flow sensor malfunctions (e.g., no data output or data continuously 0), the subroutine immediately outputs a stop signal, shuts down the metering pump, and sends a "flow sensor malfunction" alarm signal to the data alarm subroutine to prevent fertilizer accumulation caused by continuous fertilization when there is no water flow.

[0042] The inverter communication control subroutine uses the standard MODBUS protocol to establish communication with the inverter, reads the inverter's output frequency, operating current and fault status data in real time, and can send frequency setting commands to the inverter to achieve constant pressure control of the irrigation system.

[0043] Specifically, the inverter communication control subroutine This subroutine achieves bidirectional communication with the frequency converter through the standard MODBUS-RTU protocol, completing data reading and command issuance to ensure constant pressure operation of the irrigation system. The specific design is as follows: Communication parameter configuration: The communication parameters of the subroutine and the inverter are consistent—baud rate 9600bps, data bits 8 bits, stop bits 1 bit, parity mode no parity, communication address set to 1 (can be modified through the HMI system, supporting address range 1-247), communication timeout set to 1 second, if no response is received from the inverter within 1 second, automatically retry 3 times, if the retry fails, it is judged as a communication fault.

[0044] Data read function: The subroutine sends a data read command (MODBUS function code 03) to the inverter every second to read three core parameters of the inverter: Output frequency (register address 40001, data format 16-bit binary, unit Hz, range 0-50Hz). Operating current (register address 40003, data format 16-bit binary, unit A, range 0-10A). Fault status (register address 40010, data format 8-bit binary, 0 indicates normal, non-zero indicates fault, different values ​​correspond to different fault types, such as 1 indicates overcurrent, 2 indicates overload).

[0045] The read data is stored in the PLC register in real time and simultaneously sent to the HMI system for display, making it convenient for users to monitor the inverter's operating status.

[0046] Command issuance function: Based on the constant pressure control requirements of the electrical control system, the subroutine sends a frequency setting command (MODBUS function code 06) to the frequency converter. The command includes the target frequency parameter (calculated by the PID closed-loop control algorithm). For example, when the irrigation system pressure is lower than the set value of 0.3MPa, the PID algorithm calculates that the frequency converter frequency needs to be increased from 30Hz to 35Hz. The subroutine then sends a frequency setting command to the frequency converter, modifying the value of register 40100 (frequency setting register) to 35. After receiving the command, the frequency converter adjusts the output frequency to 35Hz within 0.5 seconds, increasing the pump speed and increasing the system pressure.

[0047] Fault Handling: When the inverter fault status is read as non-zero, the subroutine immediately sends a stop command (setting the frequency to 0Hz), and at the same time converts the fault type (such as overcurrent) into text information and sends it to the data alarm subroutine to trigger an alarm prompt, which helps staff to quickly locate the cause of the fault.

[0048] The data alarm subroutine performs threshold judgments on the collected soil moisture, nutrient, pH value and water tank level data. When the data exceeds the preset range, an alarm signal is generated. The alarm signal is displayed through the HMI system and pushed to the PC and WeChat terminals.

[0049] Specific data alarm subroutine The data alarm subroutine is responsible for threshold judgment of system operation data, generating alarm signals and pushing them to each terminal. Its workflow and functions are as follows: Threshold setting and storage: The subroutine receives alarm thresholds for various parameters from the HMI system (which can be modified via the HMI) and stores them in the power-down retention register, including: Soil moisture: lower limit 18%RH, upper limit 25%RH (below the lower limit, alarm "soil drought"; above the upper limit, alarm "soil over-wet"); Soil nutrients (nitrogen): Lower limit 50 mg / kg, upper limit 300 mg / kg (below the lower limit, alarm "nitrogen content insufficient"; above the upper limit, alarm "nitrogen content exceeds the standard"); Soil pH value: lower limit 5.0, upper limit 5.5 (below the lower limit, alarm "soil too acidic"; above the upper limit, alarm "soil too alkaline"); Water tank level: lower limit 0.5m (if the level is below the lower limit, an alarm "water tank level is too low" will be triggered). System pressure: lower limit 0.2MPa, upper limit 0.4MPa (if it is below the lower limit, an alarm will sound "insufficient system pressure"; if it is above the upper limit, an alarm will sound "excessive system pressure".

[0050] Threshold judgment logic: The subroutine obtains real-time data from the sensor data acquisition subroutine and the inverter communication control subroutine every second and compares it with the corresponding threshold. Single parameter judgment: If a parameter exceeds the threshold range, an alarm signal for that parameter is immediately generated (e.g., if the soil moisture is 17%RH, a "soil drought" alarm is generated). Combined judgment: When multiple parameters are abnormal at the same time (such as "soil too wet" + "system pressure too high"), the subroutine will prioritize pushing equipment fault alarms according to the principle of "equipment fault alarms (such as pressure too high) take precedence over environmental parameter alarms (such as soil too wet)" to avoid alarm information congestion.

[0051] Alarm signal push: After an alarm signal is generated, it is pushed through three paths: HMI System: Send an alarm code and text description to the HMI system. A red alarm pop-up window will appear on the HMI interface, and the buzzer (sounding frequency 1Hz) and red alarm light (flashing frequency 1Hz) in the control cabinet will be triggered at the same time. PC: Alarm information is sent to the web management platform via Ethernet. The platform homepage displays alarm prompts and stores information such as alarm time, type, and parameter values ​​in the "Alarm Records" module. On WeChat: The alarm information is pushed to the user's WeChat via the 4G module (in the form of a public account template message). The message includes "Alarm time: 2025-XX-XX 09:30", "Alarm type: Soil over-wet", "Current humidity: 27%RH" and "Handling suggestion: Suspend irrigation and check the drainage system", to ensure that the user is informed in a timely manner.

[0052] Alarm cancellation and recording: When the abnormal parameters return to the normal range, the subroutine automatically generates an "alarm cancellation" signal and pushes it to each terminal, while stopping the buzzer and alarm light; all alarm information (including alarm time, cancellation time, parameter change curve) is stored in the PLC register and retained for no less than 1 year, and can be queried and exported through the HMI system or PC.

[0053] The HMI system has a built-in data management algorithm that can classify and store irrigation records, sensor data records, and alarm records. It supports data querying by time range and can export data to Excel format files.

[0054] The constant pressure control of the electrical control system adopts a PID closed-loop control algorithm. The frequency converter dynamically adjusts the output frequency according to the 0-10V feedback signal output by the pressure gauge, so that the irrigation system pressure is maintained within the error range of ±0.02MPa.

[0055] Specifically, the HMI system (algorithm and function expansion) In addition to basic parameter setting and status display functions, the HMI system's built-in data management algorithms and interaction logic further enhance system usability and data value, as detailed below: (1) Data management algorithm The HMI system employs a hierarchical storage and index management algorithm to achieve efficient management of various types of data: Data is stored in a hierarchical manner: Data is divided into three categories: real-time data (such as current soil moisture and inverter frequency), historical data (such as sensor data stored every 5 minutes and records of each irrigation), and alarm data, each stored in a different database table. Real-time data table: Data update cycle is 1 second, only the latest data is retained for real-time display on the interface; Historical data table: stored in time partitions, with a new data partition generated every 24 hours (e.g., "2025-XX-XX Historical Data Table"). Each partition contains sensor data (one record every 5 minutes) and irrigation records (one record for each irrigation). The data retention period is 1 year. Alarm data table: Each record contains alarm time, alarm type, parameter value, release time, and processing status (unprocessed / processed), and is permanently retained for easy traceability.

[0056] Combined queries can be performed using data types such as "irrigation records only" and "soil pH data only". The query response time is less than 3 seconds. When the number of data records exceeds 1,000, the data will be automatically paginated (50 records per page), and the "export current page" or "export all" functions are supported.

[0057] Excel export format: The exported Excel file adopts a standardized format. Taking the export of irrigation records as an example, the table contains 10 columns of data: "Irrigation number, start time, end time, irrigation zone, irrigation duration (minutes), irrigation water volume (m³), fertilizer application (kg), water-fertilizer ratio, operator, and remarks". The sensor data export table contains 6 columns of data: "collection time, soil moisture (%RH), soil nitrogen content (mg / kg), soil pH value, water tank level (m), and system pressure (MPa)". The data format is standardized, which is convenient for subsequent analysis (such as importing into Excel to create trend charts).

[0058] (2) Multi-terminal interaction optimization The HMI system improves the consistency and convenience of multi-terminal (on-site touchscreen, PC, WeChat) interaction by optimizing communication protocols and interface design: On-site touchscreen: Adopts capacitive touchscreen, supports multi-touch (such as zooming in and out of data charts), and the interface layout is designed according to "functional zones" - the left side is the function menu (parameter setting, status monitoring, data query, alarm handling), the right side is the content display area, and commonly used functions (such as manually starting irrigation, pausing irrigation) are set with shortcut buttons (located at the top of the interface), with a click response time of less than 0.5 seconds; supports automatic screen brightness adjustment (brightness range of 100-500 cd / m² according to the light intensity in the greenhouse) to ensure clear visibility under different lighting conditions.

[0059] PC-based web platform: Based on a B / S architecture (browser / server), it supports access from mainstream browsers such as Chrome and Edge, requiring no client installation. The platform's functionality is consistent with the touchscreen version, and it adds a "data report generation" function—generating data reports by week, month, and quarter (such as the "October Irrigation Data Report"). The reports include statistical data such as irrigation frequency, total irrigation water volume, total fertilizer application, and average soil moisture, and automatically generate trend charts (such as line charts of soil moisture changes and bar charts of irrigation water volume). Reports can be exported to PDF format.

[0060] The system also includes a cloud data platform, which connects to the HMI system via a wireless network. It can receive and store system operation data and generate crop growth trend reports and irrigation optimization suggestions through big data analysis algorithms.

[0061] The precision fertilization control subroutine also has an automatic compensation function. When the flow sensor detects flow fluctuations, it automatically adjusts the fertilization rate to ensure that the deviation between the actual water-fertilizer ratio and the set ratio does not exceed 5%.

[0062] The workflow of this system is as follows: Preset parameters: Users can set the irrigation time period (e.g., 8:00, 16:00), irrigation duration (30 minutes), soil moisture lower limit 18%RH, upper limit 25%RH, fertilizer application rate (5kg per acre), and system pressure 0.3MPa through the HMI system; Start-up and operation: When the set irrigation time is reached, the PLC issues a command to start the water source system pump, the head system pump and the frequency converter. The frequency converter adjusts the frequency to stabilize the system pressure at 0.3MPa. Water-fertilizer mixing: The electromagnetic flow meter collects flow data, the PLC calculates the required amount of fertilizer based on the flow rate, controls the metering pump to start, and injects the fertilizer solution into the pipeline to mix with water; Zoned irrigation: The PLC controls the opening of the solenoid valves of the branch pipes of each greenhouse in a preset sequence. First, the solenoid valve of greenhouse No. 1 is opened, and after 30 minutes of irrigation, it is closed. Then, the solenoid valve of greenhouse No. 2 is opened, and the rotation irrigation is completed in sequence. Real-time monitoring: Sensors collect soil moisture, nutrient, and pH data in real time and transmit them to the PLC. If the soil moisture reaches 25%RH, the PLC will stop irrigation in advance. Data recording and alarm: The system automatically records the amount of water, fertilizer, and irrigation time for this irrigation. If the soil pH value is lower than 5.0, the PLC will trigger an alarm, the HMI interface will display the alarm information and push it to the user's mobile phone. Remote monitoring: Users can view irrigation progress and sensor data in real time via WeChat. If parameters need to be adjusted, the irrigation duration or fertilizer application amount can be modified remotely.

[0063] In the description of this invention, terms such as "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," which indicate direction or positional relationships, are based on the directions or positional relationships shown in the accompanying drawings. These are used merely for ease of description and do not indicate or imply that the device or element must have a specific orientation, or be constructed and operated in a specific orientation; therefore, they should not be construed as limitations on the invention. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0064] Furthermore, it should be noted that, in the description of this invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0065] The term "comprising" or any other similar term is intended to cover non-exclusive inclusion, such that a process, article, or apparatus / device that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to those processes, articles, or apparatus / devices.

[0066] The technical solution of the present invention has been described above with reference to the preferred embodiments shown in the accompanying drawings. However, it will be readily understood by those skilled in the art that the scope of protection of the present invention is obviously not limited to these specific embodiments. Without departing from the principles of the present invention, those skilled in the art can make equivalent changes or substitutions to the relevant technical features, and the technical solutions after such changes or substitutions will all fall within the scope of protection of the present invention.

Claims

1. A precision drip irrigation control system, characterized in that, The system includes a water source system, a head system, an electrical control system, a programmable logic controller (PLC), and an HMI system. These systems work together to achieve precision irrigation. The PLC has a built-in irrigation control program, which includes a timed irrigation subroutine, a sensor data acquisition subroutine, a precision fertilization control subroutine, a frequency converter communication control subroutine, and a data alarm subroutine. The HMI system connects to the PLC via a data interaction protocol to enable parameter setting, data storage, and remote control.

2. The precision drip irrigation control system according to claim 1, characterized in that, The timed irrigation subroutine can receive irrigation start time, irrigation duration and irrigation cycle parameters set by the HMI system. After the set time is reached, it automatically outputs control signals to start the water pump of the head system and the field zone solenoid valve.

3. The refined drip irrigation control system according to claim 2, characterized in that, The sensor data acquisition subroutine uses a 4-20mA signal acquisition algorithm to perform analog-to-digital conversion on the analog signals output by the soil moisture sensor, soil nutrient sensor, soil pH sensor and water tank level sensor, and the converted data is stored in the PLC internal register.

4. The refined drip irrigation control system according to claim 3, characterized in that, The precision fertilization control subroutine acquires real-time irrigation flow data through a flow sensor, combines it with the water-fertilizer ratio parameters set by the HMI system, calculates the required amount of fertilizer, and then outputs a PWM signal to control the fertilization rate of the head system's fertilization equipment.

5. The refined drip irrigation control system according to claim 4, characterized in that, The inverter communication control subroutine uses the standard MODBUS protocol to establish communication with the inverter, reads the inverter's output frequency, operating current and fault status data in real time, and can send frequency setting commands to the inverter to achieve constant pressure control of the irrigation system.

6. The refined drip irrigation control system according to claim 5, characterized in that, The data alarm subroutine performs threshold judgments on the collected soil moisture, nutrient, pH value and water tank level data. When the data exceeds the preset range, an alarm signal is generated. The alarm signal is displayed through the HMI system and pushed to the PC and WeChat terminals.

7. The refined drip irrigation control system according to claim 6, characterized in that, The HMI system has a built-in data management algorithm that can classify and store irrigation records, sensor data records, and alarm records. It supports data querying by time range and can export data to Excel format files.

8. The refined drip irrigation control system according to claim 7, characterized in that, The constant pressure control of the electrical control system adopts a PID closed-loop control algorithm. The frequency converter dynamically adjusts the output frequency according to the 0-10V feedback signal output by the pressure gauge through the PID algorithm, so that the irrigation system pressure is maintained within the error range of ±0.02MPa.

9. The refined drip irrigation control system according to claim 8, characterized in that, The system also includes a cloud data platform, which connects to the HMI system via a wireless network. The cloud data platform can receive and store system operation data and generate crop growth trend reports and irrigation optimization suggestions through big data analysis algorithms.

10. The refined drip irrigation control system according to claim 9, characterized in that, The precision fertilization control subroutine also has an automatic compensation function. When the flow sensor detects flow fluctuations, it automatically adjusts the fertilization rate to ensure that the deviation between the actual water-fertilizer ratio and the set ratio does not exceed 5%.

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