Multi-functional, high-precision and multi-mode liquid collection system controlled by PLC (Programmable Logic Controller) and programmed algorithm thereof

Abstract

The invention discloses a multi-functional, high-precision and multi-mode liquid collection system controlled by a PLC (Programmable Logic Controller) and a programmed algorithm thereof. Key components comprise the PLC, an upper computer system, an executing mechanism and an auxiliary mechanism, the PLC is composed of a PLC; the upper computer system comprises an HMI (Human Machine Interface) and a central control system; the executing mechanism mainly comprises a stepping motor controller, a stepping motor and a flow signal-pulse device; the auxiliary mechanism is provided with a sampling pump control system. According to the requirements of discontinuous flowing water samples and timing and quantitative sampling, a user sets sampling time nodes and interval time, a PLC carries out algorithm decision making, controls a stepping motor and carries out precise sampling in combination with signals, and the system comprises multiple correction modes, so that the system adapts to various sampling scenes, and the sampling efficiency and speed are different due to precision. In terms of economic cost, mature mechanical and electrical products are used as basic components, optional auxiliary components are used for improving the sampling precision, and the use cost is further reduced by using an original upper computer and a database.

Description

Technical Field

[0001] This invention relates to the fields of control technology, motor control and sensors, and in particular to a device and PLC algorithm system that can control peripheral devices and achieve precise sampling using a PLC at low cost. Background Technology

[0002] The finished products with more precise sampling in the existing market have several limitations in their use:

[0003] (i) Due to the high requirements for the objective environment of the sampling site, such as stable water volume and the ability of the raw water to maintain a continuous liquid level, but in most cases, objective reasons cannot meet these requirements;

[0004] (ii) To achieve more precise sampling, existing systems mostly use servo motors in conjunction with liquid sensors, which are costly, have large equipment size, and are expensive to maintain.

[0005] (iii) Most devices only use liquid sensors for timed sampling, that is, they rely on instantaneous liquid sensing signals to enter timed sampling. This causes the liquid sensor to fail to accurately measure the amount of sampled in some scenarios due to the discontinuous and unstable water flow, and the sampled amount is sometimes too low.

[0006] (iv) In order to meet the requirements of servo motors and various complex functions, some equipment requires the independent manufacture of special precision motherboards, which further increases the cost and maintenance costs. Moreover, the equipment is an independent system and has low integration with the field.

[0007] In practical applications, some situations are complex, the sampling of raw water cannot be continuous, and the maintenance personnel have limited energy and cannot keep track of the sampling equipment at all times. Therefore, there is a need for a device that meets the sampling accuracy requirements, has a simple structure, basic functions, is easy to maintain, allows for direct replacement of inexpensive parts in case of failure, has an independent communication control interface, and can be connected to the existing field system. Summary of the Invention

[0008] This invention provides a PLC-controlled liquid acquisition system with multiple functions, high precision, and multiple modes, as well as its program algorithm. It can effectively solve the problems pointed out in the background art, reduce the cost of component composition, and has room for functional expansion according to the requirements of use.

[0009] PLC control enables a multi-functional, high-precision, and multi-mode liquid acquisition system, and its program algorithms include hardware and software algorithms. The hardware includes a PLC controller, a host computer system, actuators, and auxiliary mechanisms. The algorithms include correction algorithms, single-sample logic algorithms, and timed sampling decision-making.

[0010] The PLC controller is mainly the control core, used for logic operations and control of the motion system, as well as communication and information exchange with the host system.

[0011] The host computer is mainly used for on-site HMI human-machine interface and central control room system, for human-machine interaction and information history storage. Optional components include historical information database and MQTT IoT gateway device.

[0012] The actuator mainly includes a stepper motor controller, a stepper motor, and a flow signal-pulse device, which is the core mechanical structure for on-site sampling. Optional components include a check valve, a terminal solenoid valve, and a raw water sampling signal sensor.

[0013] The stepper motor controller in the actuator controls the direction and speed of the stepper motor. When the stepper motor rotates in reverse, it cleans the residual wastewater in the sampling tube. When the stepper motor rotates in the forward direction, it performs sampling. The flow signal-pulse device is the sampling quantitative feedback signal, which can control the sampling quantity.

[0014] The above are all relatively mature products on the market, which can reduce product costs and improve equipment economy.

[0015] The auxiliary components include the sampling pump control system, pipelines, sampling collection containers, power supply, buttons, and indicator lights. These are auxiliary accessories to enable the functions. Among them, the pipelines are vulnerable parts that maintenance personnel need to frequently inspect and replace regularly.

[0016] The main algorithms include a correction algorithm, a single sampling logic algorithm, and a timed sampling decision. The correction algorithm is used by maintenance personnel to periodically check for anomalies. The single sampling logic algorithm is the logic program for PLC control of single sampling. The timed sampling decision is the sampling decision logic of the PLC automatic program.

[0017] Furthermore, in the calibration decision-making process, after the system selects to enter the calibration mode and enters the calibration program, the PLC begins to run the calibration algorithm, which specifically includes the following steps:

[0018] S1, The user sets the fluid volume to be calibrated on the touchscreen. ;

[0019] S2, place the sampling scale container to be calibrated, start the sampling pump in continuous working mode to ensure that the external liquid level remains normal during the calibration period;

[0020] S3, press and hold the button provided by the PLC. The stepper motor moves to sample the liquid, which can be paused for observation or continued until the liquid reaches the set physical fluid volume in the graduated container. ;

[0021] S4. Check the touchscreen to see if there are any abnormal data during the operation.

[0022] S5, the PLC obtains the flow pulse count based on the above operation. From the formula Calculate the number of pulses required per unit volume;

[0023] S6. In practical applications, the above method has been found to sometimes result in a small absolute value for mL / pulse count, leading to a large cumulative error and decreased accuracy. Improving accuracy requires increasing the precision of the flow signal-pulse device, thus increasing costs. Furthermore, this method does not align with commonly used sampling quantities. Therefore, a more reliable formula is used in practice, calculating in units of 100 mL / pulse count.

[0024] The number of pulses per unit volume is obtained. .

[0025] Furthermore, for greater accuracy in daily use, when each sampling is quantitative, a fine-tuning formula can be set in the PLC after the system selects the cut-in correction mode.

[0026] ,in Volume number set by the user. Detailed offset based on total sample size, obtained by the user based on experience.

[0027] Furthermore, the sampling logic algorithm specifically includes the following steps:

[0028] S 21 When sampling begins, the PLC controls the stepper motor to reverse through the stepper motor controller, clearing the sampling tube;

[0029] S 22 After the stepper motor reverses for the set time, wait for the motor to stop.

[0030] S 23 When forward sampling begins, the PLC controls the stepper motor to rotate forward while simultaneously detecting the flow signal - the signal from the pulse device;

[0031] S 24 When the PLC receives the flow signal - the pulse device's signal pulses reach the specified number, it stops sampling;

[0032] When adding optional components, the above steps require corresponding device actions. For example, when adding check valves or terminal solenoid valve accessories, S... 21 An action to open the terminal solenoid valve needs to be added, S 24 An action to close the terminal solenoid valve needs to be added;

[0033] Furthermore, the timed sampling decision algorithm is based on user settings and automatically performs a sampling at the designated time. To improve the sampling success rate, the following three decision-making methods are available:

[0034] Choose decision method 1 (denoted as...) When the time arrives, sampling is not performed immediately; instead, a pre-sampling signal is set. The signal from the water flow sensor in the detection pipeline. , If a signal is present, a motor sampling procedure will be executed.

[0035] Choose decision method 2 (denoted as...) When the time arrives, sampling is not performed immediately; instead, a pre-sampling signal is set. The signal from the water flow sensor in the detection pipeline. Rising edge, if a signal exists The rising edge triggers the execution of a motor sampling program, which can avoid the sampling pump stopping during the sampling process.

[0036] Choose decision method 3 (denoted as...) The PLC times the data according to the user-defined time intervals. When the time is up, sampling is not performed immediately; instead, a pre-sampling signal is set. The remaining end time of the detection sampling pump in this cycle ,like > , If the last sampling time is the timer value in the PLC from start to finish, then a motor sampling program will be triggered to execute. This mode is more reliable and can prevent sampling failure due to the sampling pump stopping during the sampling process within a tight time interval.

[0037] Compared to the three decision-making methods above, this one offers advantages in terms of reliability and priority. > > However, in terms of sampling timeliness, it is compared to > > .

[0038] Compared with existing technologies and products on the market, the present invention has the following features and advantages:

[0039] (i) Since basic components such as PLC and stepper motor systems are all mature products widely used in the market, they are cheaper, have simple mechanical structures, can be mass-produced, and do not require special customization;

[0040] (ii) The scalability of the entire system's functions: to improve accuracy, additional components can be added; to balance cost, basic functions can be used, which makes maintenance easier.

[0041] (iii) The system has three sampling modes, which can easily adapt to various environments and has been tested in harsh environments;

[0042] (iv) For users who need to trace historical information, devices such as historical information databases and MQTT IoT gateways can be added, which is quite flexible; Attached Figure Description

[0043] Figure 1 This is a schematic diagram of the overall system environment structure according to an embodiment of the present invention;

[0044] Figure 2 This is a physical connection diagram of the sampling device in this embodiment of the invention;

[0045] Figure 3 This is a schematic diagram of the expandable components of the overall sampling device according to an embodiment of the present invention;

[0046] Figure 4 This is a flowchart of the timing sampling logic in an embodiment of the present invention;

[0047] Figure 5 This is a schematic diagram illustrating the classification of timing sampling algorithms in an embodiment of the present invention;

[0048] Figure 6 This is a schematic diagram of the single sampling algorithm of an embodiment of the present invention.

[0049] Figure 7 This is a flowchart illustrating the correction operation logic of an embodiment of the present invention;

[0050] Figure Label Explanation: 1-Grey water collection system, 2-Detection instrument, 3-Sampling device, 4-Pipeline flow sensor, 5-Field control touch screen, 6-Sampling collection container, 21-PLC controller, 22-Network switch, 23-Field control touch screen, 24-Control data flow from PLC to stepper controller, 25-Flow signal - pulse signal of pulse device, 26-Stepper motor controller, 27-Grey water collection container, 28-Flow signal - pulse device, 29-Sampling pipeline, 210-Personnel sampling status indicator light, 211-Personnel sampling start switch, 212-PLC control logic framework, 31-Central control room system, 32-Upper computer system, 33-Historical information data 34-MQTT IoT gateway device, 35-Check valve, 36-Terminal solenoid valve, 41-Logic decision arithmetic unit, 42-Water sampling flow sensing signal, 43-Sampling decision selection control, 44-Sampling timeout signal, 45-Logic program framework in PLC, 46-Personnel sampling entry switch signal, 47-Sampling count comparator, 48-First sampling confirmation execution signal, 49-Sampling execution result confirmation, 51-Timed sampling timing algorithm, 52-Water sampling flow sensing signal, 53 and 55-Regular flow sensing signal, 54-Flow sensing pulse signal, 56-How much time is left for the sampling pump to run at this stage, 57-Sampling decision selection controller.

[0051] The objectives, features, and advantages of this invention will be further explained in conjunction with the embodiments and with reference to the accompanying drawings. Detailed Implementation

[0052] It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.

[0053] Embodiments of the present invention:

[0054] I. Overall System Environment Structure

[0055] In an embodiment of a wastewater treatment plant, the sampling structure of its online effluent monitoring system is as follows: Figure 1 The whole system is divided into a greywater collection system 1, a detection instrument 2, and this sampling device 3;

[0056] The greywater collection system is designed to collect greywater from wastewater treatment plants before it is discharged. It uses an external device to collect the greywater at regular intervals and store it in a container for use by the online effluent monitoring system and the sampling device of this invention.

[0057] Furthermore, due to the limited volume of the collection container and the need to provide pre-samples for other testing instruments, the sampler also requires a continuous water flow. Therefore, the collection container must remain flowing continuously during the sampling period triggered by this sampler. For this reason, if the collection container is continuously flowing with water, it needs to be... The signal is transmitted to the PLC of this sampler to assist in decision-making.

[0058] The testing instrument is an online effluent monitoring system, which detects environmental indicators such as SS, COD, and TNP in the effluent.

[0059] The sampling device is an example of the present invention. It is used to collect water samples at regular intervals and in quantitative quantities and to refrigerate them for use in the laboratory. The sampling data is sent to the touch screen and the central control room for monitoring and processing.

[0060] II. Specific physical connections of this sampling device

[0061] like Figure 2 As shown, the overall sampling device includes a PLC controller 21, a host computer system, an actuator, and an auxiliary mechanism.

[0062] The PLC controller can be a small or micro PLC that is economical and widely used in the market. It can be equipped with a high-speed counter and a high-speed pulse, and can communicate with the touch screen via Ethernet or RS485 serial port. 16 I / O points are sufficient. All of the above are mature products widely available in the market. This example uses a PLC that is similar to Mitsubishi FX-3U-16MT for illustration.

[0063] The host computer system includes at least a field control touch screen 23, taking Weintek touch screen connected to PLC as an example in this case;

[0064] The actuator includes at least a stepper motor controller 26, a stepper motor, and a flow signal-pulse device 25. In this example, the stepper motor controller is a Leadshine DM556, the stepper motor is a 23HS8442, and the flow signal-pulse device is a turbine Hall flow meter.

[0065] The auxiliary mechanism includes a sampling pump control system 1, pipeline 29, sampling collection container 6, power supply, button 211, indicator light 210 and other related accessories.

[0066] III. Schematic diagram of expandable components for this overall sampling device

[0067] like Figure 3 As shown, the overall sampling device can be expanded to include a central control room system 31, a host computer system 32, a historical information database 33, an MQTT IoT gateway device 34, a check valve 35, and a terminal solenoid valve 36.

[0068] The central control room system includes a host computer system, a historical information database, and an MQTT IoT gateway device;

[0069] Furthermore, the host computer system can utilize the existing control system to reduce costs and increase efficiency. It mainly only needs to have a channel that can communicate with the PLC or touch screen. For example, in this case, the iFix configuration system in the control room can perform real-time monitoring.

[0070] Furthermore, the historical information database can use a relational database, such as SQL Server 2018 in this example, which can be used in conjunction with Excel and the central control room configuration system iFix to process historical messages;

[0071] Furthermore, MQTT IoT gateway devices are IoT devices that can achieve remote monitoring and control.

[0072] The aforementioned check valve is an accessory installed at the end of a pipeline;

[0073] The aforementioned terminal solenoid valve is an accessory installed at the end of the pipeline to prevent liquid from flowing into the sampling bottle when sampling is not in use.

[0074] The aforementioned check valve and terminal solenoid valve are devices installed closest to the sampling bottle, from which sampled water exits at the end of the sampling tube;

[0075] Further check valves and terminal solenoid valves are independent devices that can be added together or independently. If added, they can prevent residual liquid in the pipeline from flowing into the sampling bottle and contaminating the sampling bottle when the motor is not working, thus effectively increasing the sampling accuracy.

[0076] IV. Timed Sampling Logic Algorithm

[0077] In this embodiment, settings are made via a touchscreen, and algorithm decisions are made by a PLC. Figure 4 In automatic mode, the logic decision processor 41 performs decision calculations based on the collected signals.

[0078] Furthermore, in the automatic mode, the cycle timer program sets the sampling flag when the cycle timer expires and begins the next round of timing;

[0079] Furthermore, the sampling water flow sensing signal 42, the sampling time expiration signal 44, the sampling decision selection control 43, and the sampling number comparator 47 are combined to determine the sampling start timing and trigger a sampling.

[0080] Furthermore, after the personnel sampling switch signal 46 is set, the logic decision processor receives the signal, stops the sampling triggering operation, and resets the sampling count on the falling edge;

[0081] Furthermore, pressing the panel button indicates that the staff has removed the mixed sample, and the sampling count is reset.

[0082] Furthermore, after a sampling is performed, if the sampling result is normal, the sampling count is incremented; if an abnormality occurs during the process, the abnormality code is saved to the corresponding PLC register.

[0083] V. Classification of Timed Sampling Timing Algorithms

[0084] In this example, as Figure 5 As shown, the water flow sensing signal 52 for greywater sampling will set the sampling marker. In automatic mode, it will trigger the logic decision processor to perform sampling. The sampling procedure is based on user settings, such as... Figure 5 There are three methods, which are compared below;

[0085] Decision method 1 (denoted as F1) is selected, and sampling is triggered as soon as the conventional water flow sensing signal 53 is detected to be closed;

[0086] Choosing decision method 2 (denoted as F2) requires the detection of water flow sensing pulse signal 54 to trigger the sampling process;

[0087] Decision method 3 (denoted as F3) is selected. Water flow sensing signal 55 is detected, and the remaining time 55 (sent by the greywater collection system) of the sampling pump in this stage is detected. The sampling work is triggered only if the sampling time is longer than the previous sampling time (the timer value from start to end in the PLC).

[0088] In the above comparison, F1 is simpler and more adaptable, and can be used in most scenarios. However, since it only considers the instantaneous water flow signal, the sampling system is often inaccurate when there are frequent interruptions in the initial stage of reclaimed water sampling.

[0089] F2 is widely used in a variety of scenarios. This example uses this method. Since the sampling work is triggered only when the water flow sensing pulse signal is detected, it can be guaranteed to be parallel and synchronous with the reclaimed water sampling, which more realistically reflects the water sample as the online instrument, and is also more adaptable to various scenarios.

[0090] The F3 is best suited for timely sampling scenarios. It triggers sampling as long as the remaining time of a single sampling in the reclaimed water sampling system is greater than the predicted sampling time. However, its synchronization with online instruments using water samples is somewhat poor.

[0091] VI. Single Sampling Algorithm Flow

[0092] In this example, the logic flow of the algorithm in the PLC for a single sampling step is as follows: Figure 6 The sampling algorithm logic can be summarized as follows:

[0093] S 61 , If the signal is marked as valid, the PLC selects the appropriate method based on the timing sampling algorithm. In this example, we will use method 2 for selection. ;

[0094] S 62 The PLC enters a waiting state to track and monitor the signal from the water flow sensor in the water acquisition system. The arrival of the rising edge, such as a signal When the rising edge arrives, the actual sampling step begins;

[0095] S 63 Upon entering the sampling control action, the PLC sends pulses to control the stepper motor to reverse, and after a set time T... 反 Then, allow it to stand still for a few seconds;

[0096] S 64 The PLC sends pulses to control the stepper motor to rotate forward and reset the pulse counter to control the sampling action. The PLC tracks the pulse count in real time. It stops when the pulse count reaches the set value or the sampling time exceeds the limit. The sampling time is added to the offset as the predicted time for the next sampling. If any abnormality occurs in the process, such as the sampling time exceeding the limit, the process stops and the sampling status is recorded to the PLC.

[0097] VII. Correction Operation Logic Flow

[0098] In this example, during the correction decision, such as Figure 7 As shown in the calibration operation logic flowchart, after the system selects the calibration mode and enters the calibration program, the PLC starts running the calibration algorithm, which specifically includes the following steps:

[0099] S 71 Users set the fluid volume to be calibrated on the touchscreen. ;

[0100] S 72 Place the sampling scale container to be calibrated, start the sampling pump in continuous working mode, and ensure that the external liquid level remains normal during the calibration period.

[0101] S 73 Press and hold the button provided by the PLC The stepper motor moves to sample the liquid, which can be paused for observation or continued until the liquid reaches the set physical fluid volume in the graduated container. ;

[0102] S 74 Check the touchscreen to see if there are any abnormal data during operation;

[0103] S 75 The PLC obtains the number of flow pulses based on the above operations. From the formula Calculate the number of pulses required per unit volume.

[0104] This embodiment demonstrates a multi-functional, high-precision, and multi-mode liquid sampling system and its program algorithm controlled by a PLC. When budget is limited, it utilizes readily available and economical hardware. Based on basic hardware, it adjusts functionality by adding or removing components, and leverages existing on-site control systems and databases to further reduce costs. Enhanced software design ensures practical applicability and cost savings. This solution, without using high-precision electromechanical hardware, achieves multi-functional, high-precision, and multi-mode liquid sampling through PLC program coordination, addressing issues such as inaccurate sampling due to cost constraints, frequent sampling failures in variable environments, and difficulties in network data processing.

[0105] The above descriptions are merely some embodiments of the present invention. For those skilled in the art, various modifications and improvements can be made without departing from the inventive concept of the present invention, and these all fall within the protection scope of the present invention.

Claims

1. A multi-functional, high-precision, and multi-mode liquid acquisition system controlled by a PLC, and its program algorithm, characterized in that: Key algorithms for PLC controllers, host computer systems, actuators, auxiliary mechanisms, and PLC programs; The PLC controller is used for on-site calculation and decision-making and to control the actuators. It communicates with the host computer system via RS485 and industrial Ethernet to save status data. The host computer system includes a human-machine interface (HMI) and a central control room system. The HMI is used for on-site system settings and provides a human-machine interface. The central control room system is used for system settings and human-machine interface. Optional components of the host computer system include a historical information database and an MQTT IoT gateway device. These optional components can further enhance the system's functionality. The actuator includes a stepper motor controller, a stepper motor, and a flow signal-pulse device. Optional components for the actuator include a check valve and a terminal solenoid valve. These optional components can further enhance sampling accuracy and resistance to abnormal interference. Auxiliary components include the sampling pump control system, pipelines, sampling collection containers, power supply, buttons, indicator lights, etc. The key algorithms of the PLC program include a single sampling logic algorithm, a sampling timing selection algorithm, a fault handling algorithm, a sampling correction algorithm, and a manual control algorithm. The aforementioned single sampling logic algorithm is the operational logic control for daily sampling once. The aforementioned sampling timing selection algorithm is the algorithm logic for automatically sampling at the designated time during daily automatic operation, which can match the sampling pump startup timing to perform a single sampling and avoid sampling failure. The aforementioned fault handling algorithm is the algorithm logic for handling various faults that occur during operation. The aforementioned sampling correction algorithm is the control algorithm for correcting quantitative sampling during maintenance, which can improve the sampling accuracy. The aforementioned manual control algorithm is the control algorithm for debugging various functions of the machine hardware.

2. The PLC-controlled liquid acquisition system and its program algorithm as described in claim 1, characterized in that... The sampling logic algorithm of the PLC program is as follows: First, reverse the stepper motor to clear the residue, then reset the counter, delay the forward rotation sampling, and the flow signal-pulse device will sense the water volume and send out corresponding pulses. When the PLC senses that the number of pulses has reached the target value, it will stop the stepper motor. If a sampling timeout occurs, it will stop running. The sampling time is timed in the PLC from start to finish. After relevant preset calculations, the time T1 is obtained and used as a reference for the maximum timeout value of the next sampling.

3. The PLC-controlled liquid acquisition system and its program algorithm as described in claim 1, characterized in that... The sampling timing of the PLC program can be selected using decision method 1 (denoted as F1) as follows: The PLC times the time interval set by the user. When the time is up, sampling is not performed immediately, and a preparation sampling signal S is set. 准备标记 The signal S from the water flow sensor in the detection pipeline 水流感应 S 水流感应 If a signal is present, a motor sampling procedure will be executed.

4. The PLC-controlled liquid acquisition system and its program algorithm as described in claim 1, characterized in that... The sampling timing of the PLC program can be selected using decision method 2 (denoted as F2) as follows: The PLC times the time interval set by the user, and does not immediately sample when the time arrives, but instead sets a ready sampling signal S. 准备标记 The signal S from the water flow sensor in the detection pipeline 水流感应 Rising edge, if signal S exists 水流感应 A rising edge triggers the execution of a motor sampling program, which avoids the sampling pump stopping during the sampling process.

5. The PLC-controlled liquid acquisition system and its program algorithm as described in claim 1, characterized in that... The sampling timing of the PLC program can be selected using decision method 3 (denoted as F3) as follows: The PLC times the time interval set by the user, and does not immediately sample when the time arrives, but instead sets a ready sampling signal S. 准备标记 The system detects how much time T2 the sampling pump has remaining in operation during this phase. If T1 > T2, it triggers a motor sampling program execution. This mode is more reliable and can prevent sampling failure due to the sampling pump stopping within a tight time interval.

6. The PLC-controlled liquid acquisition system and its program algorithm as described in claim 1, characterized in that... The sampling correction algorithm method of the PLC program is as follows: After entering the correction mode, the user sets the fluid volume V to be corrected. 体积设定 Press and hold the button provided by the PLC Stepper motor sampling allows for pauses and observations until the set physical fluid volume V is reached. 体积设定 And obtain the corresponding flow pulse number N. 脉冲数 From the formula However, in practice, a more reliable formula is used. The number of pulses U per unit volume is obtained. 单位体积脉冲数 .

7. The PLC-controlled liquid acquisition system and its program algorithm as described in claim 1, characterized in that... After calibration, when actual sampling is required, to further increase accuracy, formula U can be used. 总计脉冲数 =U 单位体积脉冲数 ×V 每次采样设定 +U 手工脉冲校正量 V 每次采样设定 Volume number set by the user, U 手工脉冲校正量 Detailed offsets obtained by users based on experience.

8. The PLC-controlled liquid acquisition system and its program algorithm as described in claim 1, characterized in that... The PLC controller is used for on-site calculation and decision-making and to control the actuators. It communicates with the host computer system via RS485 and industrial Ethernet to save status data. The PLC-controlled liquid acquisition system and its program algorithm as described in claim 1 are characterized in that the host computer system includes a human-machine interface (HMI) and a central control room system.

9. The PLC-controlled liquid acquisition system and its program algorithm as described in claim 1, characterized in that, S 水流感应 The reference signal is an important marker for the system sampling time. The signal can be transmitted from the induction signal of the pipeline to the PLC of the sampling device via hard wire, or from the sampling pump control system and then from the field touch screen to the PLC of the sampling device via industrial network.

10. The PLC-controlled liquid acquisition system and its program algorithm as described in claim 1, characterized in that, The optional check valve is a device located near the end of the sampling pipeline in the sampling device. It can effectively prevent residual water in the pipeline from flowing into the collection bottle after a single sampling, thus preventing inaccurate sampling.

11. The PLC-controlled liquid acquisition system and its program algorithm as described in claim 1, characterized in that, The optional terminal solenoid valve is an electronic device located at the end of the sampling pipeline of the sampling device, closest to the collection bottle. It opens when the PLC starts a sampling program and closes when the sampling ends, further preventing residual water in the pipeline from flowing to the collector and causing inaccurate sampling.

12. The PLC-controlled liquid acquisition system and its program algorithm as described in claim 1, characterized in that... The stepper motor controller and stepper motor of the actuator can be mature products on the market with good economic benefits, while general products can achieve the precision of high-value products.

13. The PLC-controlled liquid acquisition system and its program algorithm as described in claim 1, characterized in that... Flow signal-pulse devices are mature products on the market with good economic benefits; the specific model is selected according to the requirements. The PLC-controlled liquid acquisition system and its program algorithm as described in claim 1, characterized in that... Auxiliary components include the sampling pump control system, pipelines, sampling collection containers, power supply, buttons, indicator lights, etc. The PLC-controlled liquid acquisition system and its program algorithm as described in claim 1, characterized in that, The host computer system can be optionally equipped with a historical information database, providing management and historical tracing capabilities; The PLC-controlled liquid acquisition system and its program algorithm as described in claim 1, characterized in that, An optional component is the MQTT IoT gateway device, which provides remote control and monitoring capabilities.

14. The PLC-controlled liquid acquisition system and its program algorithm as described in claim 1, characterized in that, The raw water sampling signal sensor is a device installed on the raw water collection device. It senses whether the raw water collection device is full, prevents sampling from continuing when the raw water level is low, and can record the cause of sampling timeout faults for easy troubleshooting.

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