Staggered-phase PWM pesticide spraying control device

Abstract

The invention discloses a staggered-phase PWM pesticide spraying control device which comprises a single-chip microcomputer, a touch screen, a pressure sensor, an MOS tube, a CAN drive circuit and an electromagnetic valve, the single-chip microcomputer is used for completing communication, calculation and control work, and the invention relates to the technical field of pesticide spraying control. According to the staggered-phase PWM pesticide spraying control device, the frequency, the duty ratio and the phase can be set and changed at any time, the response time of a controller is smaller than 200 ms, the operation convenience is greatly improved, a certain practical value is achieved, the staggered-phase technology can effectively avoid impact on a circuit caused by simultaneous opening and closing of electromagnetic valves, severe fluctuation of pressure in a pipeline can also be avoided, and the pesticide spraying control device is suitable for large-scale popularization and application. Due to the fact that single-chip microcomputer control and MOS tube driving are adopted, the accuracy rate of generated PWM waves is high, the error is smaller than 0.1%, various circuit protection designs are adopted, and reliable work of the system is guaranteed. In addition, adopted electronic components are low in price, and the cost is low. The system has the advantages of high reliability, high sensitivity and low control power.

Description

Technical Field

[0001] The invention relates to the technical field of spraying control, and in particular to a staggered-phase PWM spraying control device. Background Art

[0002] Field boom sprayers generally have many nozzles, and the control of the nozzles is mostly segmented control rather than independent control; segmented control is to close all the nozzles on this section of the boom through an electric ball valve or manual valve. This method cannot achieve control of a single nozzle and will cause drastic fluctuations in the pressure in the spray pipe, which is not conducive to the requirement of precise spraying of the sprayer.

[0003] In recent years, domestic and foreign researchers have begun to study target spraying technology, which can achieve independent control of a single nozzle. It dynamically changes the frequency and duty cycle of the drive signal of the spray solenoid valve to achieve rapid electromagnetic opening and closing control, thereby quickly changing the flow rate of the nozzle. However, it does not consider the impact of the simultaneous startup or shutdown of each solenoid valve on the circuit and the pressure impact on the pipeline.

[0004] Patent CN203525925U provides a control device for independently driving multiple nozzles, which mainly drives the solid-state relay through PLC, and then drives the multiple nozzles to work independently. This method is costly, the volume of the entire device is relatively large, and it can only change the frequency and duty cycle, but cannot change the phase of the drive signal at any time, and cannot achieve accurate phase mismatch control.

[0005] Patent CN112162513B provides a multi-channel solenoid valve driving device and method, which relates to a solenoid valve control device, which solves the problem of multi-channel solenoid valve driving in the prior art. The PWM duty cycle, constant current excitation and working time of each channel are all calculated and generated in real time inside the ECU, and the problem of continuous control of voltage and current changes of each channel of the solenoid valve under the premise of synchronous action is realized, but the problem of phase adjustment is not solved.

[0006] Intelligent spraying not only needs to control the nozzle flow rate, but also needs to minimize pipeline pressure fluctuations. This device not only controls the opening and closing time of the nozzle, but also adjusts the phase of the driving signal of each nozzle in real time. Summary of the invention

[0007] 1. Technical issues to be resolved

[0008] In view of the shortcomings of the prior art, the present invention provides a staggered phase PWM spray control device to achieve independent drive of each nozzle, so that the spray solenoid valve can be independently controlled, the spray width and spray position can be flexibly adjusted, and the spray can be sprayed where it is needed, and the spray can be stopped where it is not needed. In addition, the spray volume can be adjusted in real time according to the actual spray demand while avoiding large pressure fluctuations as much as possible to achieve target variable spraying. The spraying action of each nozzle is controlled by PWM, and the spray flow rate is controlled by frequency and duty cycle to achieve quantitative spraying; the pressure fluctuation is smoothed by adjusting the phase; this control system can be controlled by either a touch screen or a mobile phone. After the operator sets the frequency, duty cycle and phase, the control device will respond quickly to the output.

[0009] (II) Technical solution

[0010] To achieve the above objectives, the present invention is implemented through the following technical solutions: a phase-shifted PWM spray control device, including a single-chip microcomputer (MCU), a touch screen, a pressure sensor, a MOS tube, a CAN drive circuit and a solenoid valve, Figure 1 The structure diagram of the device is shown in FIG. The single chip microcomputer is used to complete communication, calculation and control work, and a touch screen is used as a human-computer interaction interface to realize data exchange with the controller, which can facilitate input of setting data and display various data information in real time. The MOS tube, solenoid valve and nozzle together constitute the spraying actuator;

[0011] After power-on, the MCU obtains the set values ​​of each solenoid valve drive circuit, that is, the input frequency, duty cycle and phase. After obtaining the data, the MCU calculates the corresponding time value, and opens and closes the solenoid valve in sequence according to the generated PWM wave. The MCU obtains the frequency f, duty cycle δ and phase φ set by the operator through the touch screen or the host computer, and checks whether the set value in the register changes in each scanning cycle to ensure a quick response to the change of the set value;

[0012] The timer uses the GPIO pin for pulse output. When configured as comparison output and PWM output function, the comparison register is used as the comparison function, and the pulse counter TIMx_CNT is configured to count up, and the reload register TIMx_ARR is configured to N, that is, the current count value of TIMx_CNT is continuously accumulated under the drive of the TIMxCLK clock source. When the value of TIMx_CNT is greater than N, the TIMx_CNT value will be reset to 0 and count again. While TIMxCNT is counting, the count value of TIMxCNT will be compared with the value pre-stored in the comparison register TIMx_CCR. When the value of the pulse counter TIMx_CNT is less than the value of the comparison register TIMx_CCR, a high level (or low level) is output. On the contrary, when the value X of the pulse counter is greater than or equal to the value A of the comparison register, a low level (or high level) is output.

[0013] In this way, the output pulse period is the value (N+1) stored in the reload register TIMx_ARR multiplied by the clock period of the trigger pulse, and the pulse width is the value A of the comparison register TIMx_CCR multiplied by the clock period of the trigger pulse, that is, the duty cycle of the output PWM is A / (N+1).

[0014] Preferably, the single chip microcomputer adopts a 16-bit timer, which has 4 timers inside, and each timer maps 4 IO ports, so that the single chip microcomputer can output 16 PWM drive signals.

[0015] Preferably, to ensure that the accuracy of the single-chip microcomputer output drive signal is 0.1%, the program automatically adjusts the pre-scaling value PSC and the ARR automatic reload value. When the set frequency is high, the PSC value is set to be small to ensure the accuracy of the output waveform. When the set frequency is low, the PSC value is set to be large, and a longer timing interval can be obtained, thereby ensuring that the waveform covers different period ranges. The required period is calculated using the following formula:

[0016] T=1 / f=(PSC+1)*(ARR+1)*F;

[0017] Among them, f is the frequency of the generated waveform, T is the period of the generated waveform, and F is the main frequency of the microcontroller.

[0018] Preferably, after the single-chip microcomputer collects the data change, it calculates the on-off time of the MOS tube. The single-chip microcomputer uses a timer overflow interrupt, internally calculates the duty cycle δ to set the unit count, and uses the following formula to obtain the on-time t of the relay: on and closing time t off ;

[0019] t on =0

[0020] t off =T*δ.

[0021] Preferably, the PWM waveform output by the single chip microcomputer is divided into three different situations under different phase conditions, one is a pulse signal with no phase difference, one is a pulse (high level) within the cycle, and the other is a pulse (high level) spanning adjacent cycles. The PWM output waveform is as follows: Figure 2 shown.

[0022] Preferably, the phase-shifted PWM spray control device defaults the phase of the first channel to 0, that is, the level of the pulse is high when the cycle begins, then the level rising edge time of the first channel is t1, the level falling edge time is t2, and the output signals of other channels are all relative to the phase of the first channel.

[0023] Preferably, after setting the phase of the pulse signal, the single chip microcomputer determines whether the pulse is still within the current cycle after translation through calculation. If it is still within the current cycle, the following formula is used for calculation:

[0024]

[0025] If the shifted pulse exceeds the range of this cycle, it is necessary to compensate for the excess range when this cycle is turned on, using the following formula:

[0026] t on1 =0

[0027]

[0028] t off2 =T;

[0029] After each timer overflows, it automatically starts calculating from the beginning without software intervention.

[0030] Preferably, the pressure sensor is used to detect the pressure in the pipeline. The pressure sensor outputs a 0-5V voltage signal. The single-chip microcomputer opens the analog signal channel, collects analog data, and quickly converts it into a digital signal through an internal circuit. The single-chip microcomputer can obtain the actual pressure value through calculation. The single-chip microcomputer continuously collects the conversion value, senses the real-time changes in pressure, and sends the pressure value to the display through the CAN bus.

[0031] Preferably, the single chip microcomputer increases IO ports through module expansion, thereby expanding the number of ways to drive the solenoid valve, and connects the modules together through the CAN bus.

[0032] (III) Beneficial effects

[0033] The present invention provides a staggered phase PWM spray control device. Compared with the prior art, it has the following beneficial effects: the staggered phase PWM spray control device can be set and changed at any time through the frequency, duty cycle, and phase, the reaction time of the controller is less than 200ms, the convenience of operation is greatly improved, and it has certain practical value. The staggered phase technology can effectively avoid the impact of the electromagnetic valve opening and closing at the same time on the circuit, and can also avoid the violent fluctuation of the pressure in the pipeline. Due to the use of single-chip microcomputer control and MOS tube drive, the generated PWM wave has a relatively high accuracy, and the error is less than 0.1%. Various circuit protection designs are used to ensure the reliable operation of the system. In addition, the electronic components used in the present invention are inexpensive and the cost is relatively low. It has high reliability, high sensitivity, and low control power. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Figure 1 It is a structural block diagram of the present invention;

[0035] Figure 2 This is the PWM output waveform diagram of the present invention;

[0036] Figure 3 This is the first CAN communication circuit diagram of the present invention;

[0037] Figure 4 This is the second CAN communication circuit diagram of the present invention;

[0038] Figure 5 This is the software interface diagram of the present invention. DETAILED DESCRIPTION

[0039] 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.

[0040] See also Figure 1-5 The embodiment of the present invention provides three technical solutions: a staggered phase PWM spray control device, specifically including the following embodiments:

[0041] Embodiment 1: A phase-shifted PWM spray control device, comprising a single-chip microcomputer (MCU), a touch screen, a pressure sensor, a MOS tube, a CAN drive circuit and a solenoid valve, Figure 1 The structure diagram of the device is shown in FIG. The single chip microcomputer is used to complete communication, calculation and control work, and a touch screen is used as a human-computer interaction interface to realize data exchange with the controller, which can facilitate input of setting data and display various data information in real time. The MOS tube, solenoid valve and nozzle together constitute the spraying actuator;

[0042] After power-on, the MCU obtains the set values ​​of each solenoid valve drive circuit, that is, the input frequency, duty cycle and phase. After obtaining the data, the MCU calculates the corresponding time value, and opens and closes the solenoid valve in sequence according to the generated PWM wave. The MCU obtains the frequency f, duty cycle δ and phase φ set by the operator through the touch screen or the host computer, and checks whether the set value in the register changes in each scanning cycle to ensure a quick response to the change of the set value;

[0043] The timer uses the GPIO pin for pulse output. When configured as comparison output and PWM output function, the comparison register is used as the comparison function, and the pulse counter TIMx_CNT is configured to count up, and the reload register TIMx_ARR is configured to N, that is, the current count value of TIMx_CNT is continuously accumulated under the drive of the TIMxCLK clock source. When the value of TIMx_CNT is greater than N, the TIMx_CNT value will be reset to 0 and count again. While TIMxCNT is counting, the count value of TIMxCNT will be compared with the value pre-stored in the comparison register TIMx_CCR. When the value of the pulse counter TIMx_CNT is less than the value of the comparison register TIMx_CCR, a high level (or low level) is output. On the contrary, when the value X of the pulse counter is greater than or equal to the value A of the comparison register, a low level (or high level) is output.

[0044] In this way, the output pulse period is the value (N+1) stored in the reload register TIMx_ARR multiplied by the clock period of the trigger pulse, and the pulse width is the value A of the comparison register TIMx_CCR multiplied by the clock period of the trigger pulse, that is, the duty cycle of the output PWM is A / (N+1).

[0045] In the embodiment of the present invention, the single chip microcomputer adopts a 16-bit timer, which has 4 timers inside, and each timer maps 4 IO ports, so that the single chip microcomputer can output 16 PWM drive signals.

[0046] Embodiment 2: The technical solution of the embodiment of the present invention is different from that of embodiment 1 in that: to ensure that the accuracy of the single-chip microcomputer output drive signal is 0.1%, the program automatically adjusts the pre-scaling value PSC and the ARR automatic reload value. When the set frequency is high, the PSC value is set to be small to ensure the accuracy of the output waveform. When the set frequency is low, the PSC value is set to be large, and a longer timing interval can be obtained, thereby ensuring that the waveform covers different period ranges. The required period is calculated using the following formula:

[0047] T=1 / f=(PSC+1)*(ARR+1)*F;

[0048] Among them, f is the frequency of the generated waveform, T is the period of the generated waveform, and F is the main frequency of the microcontroller.

[0049] In the embodiment of the present invention, after the single-chip microcomputer collects the data change, it calculates the on-off time of the MOS tube. The single-chip microcomputer uses the timer overflow interrupt, and internally calculates the duty cycle δ with the set unit count. The following formula is used to obtain the on-time t of the relay: on and closing time t off ;

[0050] t on =0

[0051] t off =T*δ.

[0052] In the embodiment of the present invention, the single chip microcomputer outputs a PWM waveform. Under different phase conditions, there are three different conditions: one is a pulse signal with no phase difference, one is a pulse (high level) within the cycle, and the other is a pulse (high level) spanning adjacent cycles. The PWM output waveform is as follows: Figure 2 shown.

[0053] In the embodiment of the present invention, the phase of the staggered PWM spray control device defaults to 0 for the first path, that is, the level of the pulse is high when the cycle starts, then the level rising edge time of the first path is t1, the level falling edge time is t2, and the output signals of other paths are all relative to the phase of the first path.

[0054] In the embodiment of the present invention, after the phase of the pulse signal is set, the single chip microcomputer determines whether the pulse is still within the current cycle after translation through calculation. If it is still within the current cycle, the following formula is used for calculation:

[0055]

[0056] If the shifted pulse exceeds the range of this cycle, it is necessary to compensate for the excess range when this cycle is turned on, using the following formula:

[0057] t on1 =0

[0058]

[0059] t off2 =T;

[0060] After each timer overflows, it automatically starts calculating from the beginning without software intervention.

[0061] Embodiment 3: The technical solution of the embodiment of the present invention is different from that of Embodiment 2 in that: the pressure sensor is used to detect the pressure in the pipeline, the pressure sensor outputs a 0-5V voltage signal, the single-chip microcomputer turns on the analog signal channel, collects analog data, and quickly converts it into a digital signal through the internal circuit. The single-chip microcomputer can obtain the actual pressure value through calculation, the single-chip microcomputer continuously collects the conversion value, senses the real-time change of pressure, and sends the pressure value to the display through the CAN bus.

[0062] In the embodiment of the present invention, the single chip microcomputer increases the IO port through module expansion, thereby expanding the number of ways to drive the solenoid valve, and the modules are connected together through the CAN bus.

[0063] Design of CAN communication circuit: The circuit is as follows Figure 3 As shown in the figure, CAN communication uses TJA1050 driver chip, which is a highly compatible CAN bus transceiver chip that supports CAN bus communication rate up to 1Mbps. Rcan is a 120 ohm bus terminal resistor, which can make the bus quickly enter the recessive state and improve the anti-interference ability.

[0064] Design of MOS tube drive circuit: The response time of MOS tube is ns level, which meets the system requirements. Its drive circuit is as follows: Figure 4 As shown. The IO port of the microcontroller outputs a PWM waveform, which is connected to the base of the NPN transistor N1 through R1. The transistors N1, N2 and resistors R1, R2, R3, and R4 together form an amplifier circuit, which can amplify the signal and enhance its driving ability.

[0065] Optocoupler TLP1 is used to detect whether a short circuit occurs in the drive circuit. R5 is connected in series in the optocoupler input circuit to limit the current. The output of the optocoupler, NPN transistor N3, PNP transistor N1, and resistors R6 and R7 together form a short-circuit protection circuit. When the IO port output is low, the gate of the MOS tube is also low, the MOS tube is not conducting, and the transistor N3 is disconnected, and the P1 tube is also disconnected. At this time, the short-circuit protection circuit does not work; when the IO port output is high, the gate of the MOS tube is also high, the MOS tube is conducting, and the transistor N3 is conducting, which provides a prerequisite for the triggering of the short-circuit protection circuit. If a short circuit occurs on both sides of the solenoid valve at this time, the potentials at both ends of the optocoupler input side tend to be equal, the optocoupler cannot be turned on, and its output end is in a high-resistance state; at this time, since N3 is in the conducting state, the base of the transistor P1 will be at a low level, P1 will quickly conduct, and the gate of the MOS tube will be quickly pulled down to a low potential, and the MOS tube will quickly close. If the output circuit returns to normal at this time, the optocouplers at both ends of the optocoupler input side are turned on, the optocoupler output circuit is rapidly reduced, the potential of the base of the transistor P1 is rapidly pulled up to a high potential, P1 is turned off, and the MOS tube is turned on normally, so that the circuit returns to normal.

[0066] PTC1 is a self-resetting fuse, which is connected in series in the load circuit to protect the MOS tube. When the circuit is working normally, the PTC fuse is in a low-resistance state, allowing the current to pass smoothly. If there is an overcurrent in the circuit, the PTC element will heat up rapidly due to the heat generated by the current, causing its resistance value to increase sharply by several orders of magnitude and enter a high-resistance state, which is equivalent to a "break" in the circuit, thereby limiting the current and protecting other sensitive components in the circuit from damage by overcurrent. When the fault is eliminated and the current in the circuit returns to normal, the PTC fuse will gradually dissipate heat, and the resistance value will decrease accordingly, returning to a low-resistance state, and the circuit will be turned on again, realizing the self-recovery function without the need for manual replacement.

[0067] Host computer software development: In the actual spraying operation, the system operator is often far away from the spraying system. In order to achieve centralized control and make the system easy to use, a set of control software was developed. In the control software, the host computer communicates with the device through the serial port, and the host computer software is developed in C# language.

[0068] The host computer does not have a CAN interface configuration, and uses USB to CAN bus communication, and the communication protocol uses the CANopen protocol. The host computer mainly realizes the input of the frequency, duty cycle and phase of each nozzle, records the opening and closing times of the solenoid valve, and saves the corresponding data in the database for analysis. The software interface is as follows Figure 5 .

[0069] The present invention adopts a single-chip microcomputer to generate multiple PWM waves, and a single module can output up to 16 channels; the frequency, duty cycle and phase of each waveform can be set individually. The system abandons the traditional timing interrupt method and adopts the setting of timer hardware. It can effectively control the on-off time of the output end and control the error to less than one thousandth. It adopts a large-capacity MOS tube to control the connection and closing of the solenoid valve, and designs a short-circuit and over-current protection circuit to protect the MOS tube. It integrates a CAN drive circuit and can form an independent CAN module, which is convenient for networking and expansion and greatly reduces costs.

[0070] Meanwhile, the contents not described in detail in this specification belong to the prior art known to those skilled in the art.

[0071] It should be noted that, in this article, relational terms such as first and second, etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device.

[0072] 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 phase-shifted PWM spray control device, characterized in that: It includes a single-chip microcomputer, a touch screen, a pressure sensor, a MOS tube, a CAN drive circuit and a solenoid valve. The single-chip microcomputer is used to complete communication, calculation and control work. The touch screen is used as a human-computer interaction interface to realize data exchange with the controller, which can facilitate the input of setting data and display various data information in real time. The MOS tube, solenoid valve and nozzle together constitute the spraying actuator; After power-on, the MCU obtains the set values ​​of each solenoid valve drive circuit, that is, the input frequency, duty cycle and phase. After obtaining the data, the MCU calculates the corresponding time value, and opens and closes the solenoid valve in sequence according to the generated PWM wave. The MCU obtains the frequency f, duty cycle δ and phase φ set by the operator through the touch screen or the host computer, and checks whether the set value in the register changes in each scanning cycle to ensure a quick response to the change of the set value; The timer uses the GPIO pin for pulse output. When configured as comparison output and PWM output function, the comparison register is used as the comparison function, and the pulse counter TIMx_CNT is configured to count up, and the reload register TIMx_ARR is configured to N, that is, the current count value of TIMx_CNT is continuously accumulated under the drive of the TIMxCLK clock source. When the value of TIMx_CNT is greater than N, the TIMx_CNT value will be reset to 0 and count again. While TIMxCNT is counting, the count value of TIMxCNT will be compared with the value pre-stored in the comparison register TIMx_CCR. When the value of the pulse counter TIMx_CNT is less than the value of the comparison register TIMx_CCR, a high level is output. On the contrary, when the value X of the pulse counter is greater than or equal to the value A of the comparison register, a low level is output; In this way, the output pulse period is the value (N+1) stored in the reload register TIMx_ARR multiplied by the clock period of the trigger pulse, and the pulse width is the value A of the comparison register TIMx_CCR multiplied by the clock period of the trigger pulse, that is, the duty cycle of the output PWM is A / (N+1).

2. The staggered phase PWM spray control device according to claim 1, characterized in that: The single chip microcomputer adopts a 16-bit timer, and has 4 timers inside. Each timer maps 4 IO ports, so that the single chip microcomputer can output 16 PWM drive signals.

3. The staggered phase PWM spray control device according to claim 1, characterized in that: To ensure that the accuracy of the microcontroller output drive signal is 0.1%, the program automatically adjusts the pre-scaling value PSC and the ARR automatic reload value. When the set frequency is high, the PSC value is set to a smaller value to ensure the accuracy of the output waveform. When the set frequency is low, the PSC value is set to a larger value to obtain a longer timing interval, thereby ensuring that the waveform covers different cycle ranges. The required cycle is calculated using the following formula: T=1 / f=(PSC+1)*(ARR+1)*F; Among them, f is the frequency of the generated waveform, T is the period of the generated waveform, and F is the main frequency of the microcontroller.

4. The staggered phase PWM spray control device according to claim 3, characterized in that: After the single-chip microcomputer collects the data change, it calculates the on-off time of the MOS tube. The single-chip microcomputer uses the timer overflow interrupt, and internally calculates the duty cycle δ to set the unit count. The following formula is used to obtain the on-time t of the relay: on and closing time t off ; t on ＝0 t off =T*δ。 5. The staggered phase PWM spray control device according to claim 4, characterized in that: The PWM waveform output by the single chip microcomputer is divided into three different situations under different phase conditions, one is a pulse signal with no phase difference, one is that the pulse is within the cycle, and the other is that the pulse spans adjacent cycles.

6. The staggered phase PWM spray control device according to claim 5, characterized in that: The phase-shifted PWM spray control device defaults the phase of the first channel to 0, that is, the level of the pulse is high when the cycle begins, then the level rising edge time of the first channel is t1, the level falling edge time is t2, and the output signals of other channels are all relative to the phase of the first channel.

7. The staggered phase PWM spray control device according to claim 6, characterized in that: After setting the phase of the pulse signal, the microcontroller calculates whether the pulse is still within the current cycle after translation. If it is still within the current cycle, the following formula is used for calculation: If the shifted pulse exceeds the range of this cycle, it is necessary to compensate for the excess range when this cycle is turned on, using the following formula: t on1 ＝00 t off2 =T; After each timer overflows, it automatically starts calculating from the beginning without software intervention.

8. The staggered phase PWM spray control device according to claim 1, characterized in that: The pressure sensor is used to detect the pressure in the pipeline. The pressure sensor outputs a 0-5V voltage signal. The single-chip microcomputer opens the analog signal channel, collects analog data, and quickly converts it into a digital signal through the internal circuit. The single-chip microcomputer can obtain the actual pressure value through calculation. The single-chip microcomputer continuously collects the conversion value, senses the real-time changes in pressure, and sends the pressure value to the display through the CAN bus.

9. The staggered phase PWM spray control device according to claim 1, characterized in that: The single chip microcomputer increases IO ports through module expansion, thereby expanding the number of ways to drive the electromagnetic valve, and connects the modules together through the CAN bus.

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