Liquid level detection anomaly detection method and pipetting method

Abstract

The invention relates to the technical field of medical apparatus and instruments, and provides a liquid level detection anomaly detection method and a pipetting method, and the liquid level detection anomaly detection method is applied to a liquid level detection system. The liquid level detection system comprises a pipetting arm, a first sensor used for detecting the air pressure of a liquid injection needle on the pipetting arm and a second sensor installed on the pipetting arm and outputting a capacitance detection result, and is characterized in that the method comprises the steps that a first detection stage is executed, and a first liquid level detection height is obtained; executing a second detection stage to obtain a second liquid level detection height; according to the difference value between the second liquid level detection height and the first liquid level detection height, the liquid level detection abnormal condition of the target container is obtained; wherein the first liquid level detection height is obtained according to the air pressure value change in the first detection stage, and the second liquid level detection height is obtained according to the capacitance detection value change in the second detection stage. According to the invention, misjudgment caused by abnormal influence is avoided, and accuracy and reliability of liquid level detection are realized.

Description

Technical Field

[0001] This invention relates to the field of medical device technology, and in particular to a method for detecting abnormal liquid levels and a liquid transfer method. Background Technology

[0002] Liquid level detection is a commonly used technique in medical devices, especially in the process of fluid transfer. To achieve precise fluid volume control, it is necessary to detect the liquid level in the container before performing overall pipetting control. Currently, the mainstream liquid level detection methods mainly include pressure detection and capacitance detection. Pressure detection uses changes in pressure within the pipetting arm needle to determine whether a liquid level has been detected, while capacitance detection monitors changes in capacitance on the pipetting arm needle to detect the liquid level. Due to its high sensitivity and fast response, capacitance liquid level detection technology is widely used in in vitro diagnostic instruments.

[0003] Existing capacitive liquid level detection technology is easily affected by external environmental interference during use, especially when abnormal situations occur, such as the presence of air bubbles on the liquid surface. In such cases, the capacitive probe cannot accurately identify the liquid level position, resulting in incorrect identification results or excessive identification errors, making it difficult to accurately determine whether the identified result is abnormal. Summary of the Invention

[0004] In order to overcome the shortcomings of the prior art, the present invention aims to provide a liquid level detection anomaly detection method and a liquid transfer method, which can avoid complete dependence on capacitance detection value, realize the accuracy and reliability of liquid level detection, improve the liquid level detection accuracy, and avoid misjudgment caused by anomalies.

[0005] In a first aspect, the present invention provides a method for detecting abnormalities in liquid level detection, applied to a liquid level detection system, the liquid level detection system comprising a pipette arm, a first sensor for detecting the air pressure of the injection needle on the pipette arm, and a second sensor mounted on the pipette arm and outputting a capacitance detection result, the method comprising: The first detection phase was executed to obtain the first liquid level detection height; The second detection phase was executed to obtain the second liquid level detection height. Based on the difference between the second liquid level detection height and the first liquid level detection height, information about abnormal liquid level detection in the target container is obtained; The first detection phase includes: Control the injection needle to move along the height direction from a first initial position toward the liquid surface of the target container, and simultaneously control the injection needle to perform an aspiration action; The air pressure value in the needle channel of the injection needle is obtained in real time by the first sensor; The first liquid level detection point is obtained based on the change in the air pressure value. When the injection needle reaches the first liquid level detection point, the first liquid level detection height is obtained based on the current moving height of the injection needle. The second detection phase includes: Control the injection needle to move along the height direction from the second initial position toward the liquid surface of the target container; The capacitance detection value output by the second sensor is acquired in real time; The second liquid level detection point is obtained based on the change in the capacitance detection value. When the injection needle reaches the second liquid level detection point, the second liquid level detection height is obtained based on the current moving height of the injection needle. The step of obtaining information about abnormal liquid level detection in the target container based on the difference between the second liquid level detection height and the first liquid level detection height includes: When the second liquid level detection height is not less than the first liquid level detection height, it is determined whether the difference falls within the first range. Within the first range, the first liquid level detection height output by the first sensor and the second liquid level detection height output by the second sensor are normal. When the second liquid level detection height is less than the first liquid level detection height, the liquid level detection system is determined to be in an abnormal state.

[0006] The liquid level detection anomaly detection method provided by the first aspect of the present invention combines the characteristics of air pressure detection and capacitance detection methods, and links the air pressure detection result with the capacitance detection result. This allows the first liquid level detection height obtained by the first sensor to be used as a comparison benchmark to confirm whether the second liquid level detection height obtained by the current capacitance detection method is true and valid. Compared with the prior art, it can more accurately obtain the liquid level detection height, reduce external interference during the detection process, enhance the capacitance detection sensitivity of the second sensor, and further improve the capacitance detection accuracy. At the same time, it utilizes the difference in the detection principle between the two detection methods. Since the air pressure detection value is lower than the capacitance detection value under normal detection conditions, if the first liquid level detection height is higher than the second liquid level detection height, it indicates that the liquid level detection system has an abnormal condition, avoiding misjudgment caused by abnormal influences, and realizing the accuracy and reliability of liquid level detection.

[0007] In a preferred embodiment of the present invention, if the difference falls into at least one abnormal range other than the first range, a verification phase is performed, the verification phase including: Adjust the sensitivity and / or detection threshold of the first or second sensor according to the abnormal range it falls into; Verify the detection effectiveness of the first liquid level detection height and the second liquid level detection height and output the verification results; If the difference between the first liquid level detection height and the second liquid level detection height in the verification result falls within the abnormal range again, an anomaly identification result falling within the abnormal range will be output.

[0008] In a preferred embodiment of the present invention, the at least one abnormal range includes a second range and a third range when the second liquid level detection height is not less than the first liquid level detection height, wherein the first range, the second range, and the third range are consecutive and arranged in ascending order. Within the second range, adjusting the sensitivity and / or detection threshold of the first sensor or the second sensor includes reducing the sensitivity of the second sensor from a first sensitivity to a second sensitivity lower than the first sensitivity and reducing the detection threshold of the second sensor from a first threshold to a second threshold lower than the first threshold. The abnormal identification result includes determining that there is an abnormality of bubble interference in the second liquid level detection height. Within the third range, adjusting the sensitivity and / or detection threshold of the first sensor or the second sensor includes reducing the sensitivity of the second sensor from a first sensitivity to a third sensitivity lower than the first sensitivity and reducing the detection threshold of the second sensor from a first threshold to a third threshold lower than the first threshold. The anomaly identification result includes determining that there is an external interference anomaly in the second liquid level detection height.

[0009] In a preferred embodiment of the present invention, the at least one abnormal range includes a fourth range and a fifth range that are consecutive in size when the second liquid level detection height is less than the first liquid level detection height. Within the fourth range, adjusting the sensitivity and / or detection threshold of the first sensor or the second sensor includes increasing the sensitivity of the second sensor from a first sensitivity to a fourth sensitivity higher than the first sensitivity and increasing the detection threshold of the second sensor from a first threshold to a fourth threshold higher than the first threshold. The abnormal identification result includes determining that there is a sensitivity abnormality in the second liquid level detection height. Within the fifth range, the anomaly identification result includes determining that the second sensor is damaged.

[0010] In a preferred embodiment of the present invention, the method further includes a calibration phase prior to performing the first detection phase and the second detection phase, the calibration phase including: Control the injection needle to move to the first target position, and read the chip temperature information and capacitance detection value of the second sensor; Based on the chip temperature information and the capacitance detection value, initialize and calibrate the capacitance reference of the second sensor and obtain the reference value; Determine whether the reference value is greater than the detection limit value. If it is, determine that the capacitance detection of the second sensor is abnormal.

[0011] In a preferred embodiment of the present invention, obtaining the first liquid level detection point based on the change in the gas pressure value includes: When the rate of change of the air pressure value is greater than the first preset threshold, the injection needle reaches the first liquid level detection point; The step of obtaining the second liquid level detection point based on the change in the capacitance detection value includes: When the rate of change of the capacitance detection value is greater than the second preset threshold, the injection needle reaches the second liquid level detection point; The second detection phase is executed after the first detection phase, and the first detection phase further includes: When the rate of change of the air pressure value is greater than the first preset threshold, the injection needle is controlled to stop at the current position; The injection needle is reset to the second initial position of the second detection phase based on the first liquid level detection height and the change preset value.

[0012] In a preferred embodiment of the present invention, the method further includes: Based on the obtained information regarding abnormal liquid level detection in the target container, output the confirmed liquid level detection height; Within the abnormal range, the liquid level detection confirmation height is the first liquid level detection height; Within the first range, the liquid level detection confirmation height is the second liquid level detection height.

[0013] In a second aspect, the present invention also provides a liquid pipetting method applied to a liquid level detection system, comprising at least two liquid aspiration processes executed consecutively, the at least two liquid aspiration processes including a first liquid aspiration process and at least one second liquid aspiration process executed after the first liquid aspiration process, the first liquid aspiration process comprising: The liquid level detection anomaly detection method as described in the first aspect embodiment is performed in the first container; Obtain the liquid level detection confirmation height output by the liquid level detection anomaly detection method; The first liquid absorption volume is calculated based on the liquid level detection height, and the liquid absorption action in the first container is performed based on the first liquid absorption volume. The second liquid aspiration process includes a liquid level detection sub-process and a liquid aspiration sub-process, wherein the liquid level detection sub-process includes: Control the injection needle to move along the height direction from the third initial position toward the liquid surface of the second container; The capacitance detection value output by the second sensor is acquired in real time; The third liquid level detection point is obtained based on the change in the capacitance detection value. When the injection needle reaches the third liquid level detection point, the third liquid level detection height is obtained based on the current moving height of the injection needle. Continue to control the injection needle to move downward along the height direction, and at the same time control the injection needle to perform an aspiration action, and record the duration of the aspiration action; The air pressure value in the needle channel of the injection needle is obtained in real time by the first sensor; When the duration is less than a preset time, determine whether the air pressure value has changed; Based on the change in the air pressure value, determine whether the injection needle has reached or is below the liquid surface of the second container. If so, output the third liquid surface detection height as the liquid surface detection confirmation height of the second container. The liquid absorption process includes: The second liquid absorption volume is calculated based on the liquid level detection height in the second container, and the liquid absorption action in the second container is performed based on the second liquid absorption volume.

[0014] According to the second aspect of the present invention, the pipetting method can effectively ensure the effectiveness of the liquid level detection height by utilizing the liquid level detection anomaly detection method of the first aspect embodiment. After obtaining an accurate liquid level detection confirmation height, the pipetting arm is controlled to move towards another target container to continue performing the judgment of whether the capacitance detection of the second sensor is effective by air pressure. Based on this, the liquid volume is accurately collected in at least two container cases, significantly improving the pipetting accuracy for multi-container extraction. Simultaneously, during the initial liquid level detection process, the liquid level detection anomaly detection method is used to determine whether the liquid level detection height obtained by the second sensor is abnormal, ensuring the effectiveness of the capacitance detection value obtained by the second sensor. After confirming that there is no abnormality, the liquid level of other containers is continued to be detected and liquid is aspirated by air pressure changes. This effectively eliminates external environmental interference such as the influence of air bubbles on the liquid surface, achieving precise control of the liquid aspiration volume of each container.

[0015] In a preferred embodiment of the present invention, obtaining the third liquid level detection point based on the change in the capacitance detection value includes: When the rate of change of the capacitance detection value is greater than the third preset threshold, it is determined that the injection needle has reached the third liquid level detection point; The step of determining whether the injection needle has reached or fallen below the liquid surface of the second container based on the change in the air pressure value includes: When the rate of change of the air pressure value is greater than the fourth preset threshold, it is determined that the injection needle has reached or is below the liquid surface of the second container; The second liquid aspiration process also includes: When the rate of change of all the gas pressure values ​​in the liquid level detection subprocess is less than the fourth preset threshold, the injection needle is reset to the third initial position, the capacitance reference of the second sensor is initialized and calibrated, and the reset reference value is obtained. Continue executing the liquid level detection sub-process.

[0016] In a third aspect, the present invention further proposes a liquid level detection and control system, applied to a liquid level detection system, comprising: An execution unit is used to control the movement of the pipette arm; The acquisition unit is used to acquire the air pressure value output by the first sensor and the capacitance detection value output by the second sensor; A recording unit is used to record the height of the injection needle on the pipette arm; A liquid level detection unit is used to determine the liquid level detection height based on the air pressure value and the capacitance detection value; The processing unit is used to control the execution unit, the acquisition unit, the recording unit and the liquid level detection unit to execute the first detection stage and the second detection stage respectively, and to identify the liquid level detection anomaly of the target container and output the liquid level detection confirmation height based on the first liquid level detection height of the first detection stage and the second liquid level detection height of the second detection stage. The first detection phase includes: The execution unit controls the injection needle to move along the height direction from the first initial position toward the liquid surface of the target container, and simultaneously controls the injection needle to perform a suction action; The acquisition unit acquires in real time the air pressure value in the needle channel of the injection needle by the first sensor; The first liquid level detection point is obtained based on the change in the air pressure value. When the injection needle reaches the first liquid level detection point, the liquid level detection unit obtains the first liquid level detection height based on the current moving height of the injection needle. The second detection phase includes: The execution unit controls the injection needle to move along the height direction from the second initial position toward the liquid surface of the target container; The acquisition unit acquires the capacitance detection value output by the second sensor in real time; The second liquid level detection point is obtained based on the change in the capacitance detection value. When the injection needle reaches the second liquid level detection point, the liquid level detection unit obtains the second liquid level detection height based on the current moving height of the injection needle.

[0017] In a fourth aspect, the present invention further provides a computer-readable storage medium storing a computer program, which, when executed by a processor, performs the liquid level detection anomaly detection method as described in the first aspect embodiment or the pipetting method as described in the second aspect embodiment.

[0018] Other features and advantages of the invention will be set forth in the following description, and will be apparent in part from the description, or may be learned by practicing the invention. The objects and other advantages of the invention may be realized and obtained by means of the structures and / or processes particularly pointed out in the description, claims, and drawings. Attached Figure Description

[0019] Figure 1 This is a schematic diagram of the structure of the liquid level detection system provided in an embodiment of the present invention;

[0020] Figure 2 This is a schematic diagram of the structure of the liquid level detection system for detecting the liquid level in the first container during the first detection phase, as provided in an embodiment of the present invention.

[0021] Figure 3 This is a schematic diagram of the liquid level detection system for detecting the liquid level in the second container during the second detection phase, as provided in an embodiment of the present invention.

[0022] Figure 4 A flowchart of the liquid level detection anomaly detection method provided in the embodiments of the present invention;

[0023] Figure 5 A flowchart of the first detection phase provided for embodiments of the present invention;

[0024] Figure 6 A flowchart of the second detection phase provided in an embodiment of the present invention;

[0025] Figure 7 A flowchart illustrating the pipetting method provided in an embodiment of the present invention;

[0026] Figure 8 This is a schematic diagram of the liquid level detection and control system provided in an embodiment of the present invention.

[0027] Explanation of icon numbers: 100 Base, 200 First guide rail, 300 Second guide rail, 400 Slider, 500 Pipette arm, 600 First container, 700 Second container; 800 Liquid level detection and control system, 801 Execution unit, 802 Acquisition unit, 803 Recording unit, 804 Liquid level detection unit, 805 Processing unit. Detailed Implementation

[0028] The following detailed description of the embodiments of the present invention, in conjunction with the accompanying drawings, will provide a thorough understanding of how the present invention uses technical means to solve technical problems and achieve technical effects, enabling its implementation. It should be noted that these specific descriptions are merely intended to facilitate a clearer understanding of the present invention by those skilled in the art, and are not intended to limit the scope of the invention. For example, the terms "first" and "second" mentioned in the embodiments of the present invention are not intended to limit the invention, but are merely used to indicate the sequence numbers of multiple identical or similar devices or mechanisms. Those skilled in the art can readjust these sequence numbers for ease of description or during the organization of technical solutions. Furthermore, alternative solutions are described for some mechanisms in different embodiments, and these alternatives can be applied to other identical or similar devices or mechanisms. As long as there is no conflict, the various embodiments and features in each embodiment of the present invention can be combined with each other, and the resulting technical solutions are all within the protection scope of the present invention.

[0029] The technical solution of the present invention will be described in detail below with reference to the accompanying drawings and specific embodiments.

[0030] Currently, commonly used liquid level detection methods include pressure detection and capacitance detection. Pressure detection uses changes in air pressure to check the liquid level. Liquid is guided into a specific contact pipe connected to a detection device. The liquid forms a surface in the pipe, and the detection device, connected to the pipe, detects changes in gas pressure to determine the liquid level. Capacitance detection uses a capacitance probe. When the probe contacts the liquid surface, the capacitance changes instantaneously, indicating the liquid level. Capacitance detection has advantages over pressure detection, such as higher sensitivity and faster response, and is widely used in in vitro diagnostic instruments. However, capacitance probes are easily affected by the external environment. For example, when air bubbles are present in the liquid, the probe will also collect capacitance information upon contact with the bubbles. This abnormal detection value differs significantly from the true value, severely interfering with subsequent liquid volume calculations. This is especially problematic for precision equipment with strict liquid volume requirements; even small differences in volume can affect the entire reaction process. Therefore, it is necessary to effectively identify anomalies in capacitance detection to prevent them from affecting subsequent processes.

[0031] Based on this, the present invention first proposes a liquid level detection system in the embodiments, see reference. Figure 1The liquid level detection system includes a base 100, a drive mechanism, and a pipette arm 500. The drive mechanism is mounted on the base 100 and connected to the pipette arm 500. It is used to drive the pipette arm 500 to move within a specific range. This specific range can be a vertical plane, a horizontal plane, or a specified spatial range. In this embodiment, the specific range is a movable space defined by the XYZ axes. The drive mechanism can drive the pipette arm 500 to perform corresponding linear or rotational movements so that it can move to any position within the movable space. Specifically, the driving mechanism may include a rotating body, a first guide rail 200 disposed on the rotating body, a second guide rail 300 disposed on the first guide rail 200, and a slider 400 disposed on the second guide rail 300. The pipette arm 500 is disposed on the slider 400. The movable guide rail can rotate relative to the rotating body around the Z-axis and extend in a direction away from the rotating body. The second guide rail 300 is movably disposed on the first guide rail 200 and moves along the extension direction of the first guide rail 200. The second guide rail 300 extends along the Z-axis. The slider 400 can move along the second guide rail 300 toward the Z-axis. Thus, the pipette arm 500 located on the slider 400 can move relative to the slider 400, the first guide rail 200, and the second guide rail 300 to any position within the movable space under the movement control of the slider 400, the first guide rail 200, and the second guide rail 300. Of course, the drive mechanism can also achieve the movement of the pipette arm 500 within a spatial range through three guide rails set in the corresponding directions of the X, Y, and Z axes, or control the movement range of the pipette arm 500 based on other design needs. These methods have already been implemented in existing technologies and will not be elaborated upon here. In the drive mechanism, the drive source for driving the movement of each guide rail and the slider 400 is usually set as a motor, which can achieve accurate control of the pipette arm 500. Of course, other drive components such as air pumps can also be used to achieve the same drive control effect.

[0032] The pipette arm 500 is equipped with an injection needle and a suction system connected to the injection needle. When the injection needle reaches the liquid surface, the suction system provides suction force to make the injection needle draw liquid, and after the suction is completed, it drives the injection needle to perform the injection action. The liquid surface detection system also includes a first sensor and a second sensor. The first sensor is used to detect the air pressure inside the injection needle on the pipette arm 500. This air pressure value is obtained by the first sensor when the suction system makes the needle channel of the injection needle perform the suction action. The second sensor is used to output the capacitance detection result. It is installed on the pipette arm 500 and has a capacitance detection head. Since the injection needle material is a conductive medium, the injection needle is connected to the capacitance detection head through a wire. When the injection port of the injection needle reaches the liquid surface, the capacitance changes drastically, thereby enabling the second sensor to detect the liquid surface position and output the capacitance detection result. In this embodiment, the first sensor and the aspiration system are mounted on the pipette arm 500. The aspiration system includes an aspiration channel connected to the injection needle and a aspiration pump for generating negative pressure within the aspiration channel. Alternatively, the aspiration system and the first sensor can be mounted in other locations and connected to the injection needle via a pipe, thus enabling the detection of pressure changes within the injection needle. These structures are already implemented in existing technologies and will not be described in detail further.

[0033] According to the liquid level detection system provided in the above embodiments, the present invention provides a liquid level detection anomaly detection method in a first aspect embodiment, which can effectively identify abnormal conditions occurring during liquid level detection and improve the accuracy of liquid level detection. (See also...) Figure 4 The method specifically includes: S1, execute the first detection phase and obtain the first liquid level detection height; The first detection phase is completed based on the movement of the pipette arm and the first sensor, see [link / reference]. Figure 5 This includes the following steps: S11, control the injection needle to move along the height direction from the first initial position toward the liquid surface of the target container, and simultaneously control the injection needle to perform a suction action; exist Figures 1 to 3In the embodiment shown, the height direction is the Z direction, the first container 600 is the target container of the injection needle, and the injection needle is located above the first container 600 at the first initial position O1. The driving component used to control the movement of the injection needle in the Z direction is the first motor. At the start of the first detection phase, the injection needle moves downward along the Z direction under the drive of the first motor. The driving parameters of the first motor are control parameters set internally by the liquid level detection system, such as driving speed V1 and driving acceleration A1. These control parameters can be determined according to the type of liquid (dielectric constant, conductivity, viscosity, etc.). Before contacting the liquid in the first container 600, the first motor accelerates at driving acceleration A1 while driving the pipette arm, and reaches a constant operating speed V1 before the pipette arm reaches the liquid surface. During the driving process of the first motor, the pump motor of the suction system starts to run simultaneously, or runs for a predetermined time before the injection needle reaches the liquid in the target container before or after the start of the first detection phase, so that the injection needle performs a suction action while moving with the pipette arm. The first sensor is responsible for collecting the air pressure value of the needle channel of the injection needle. To ensure the effectiveness of the air pressure value collection, the operating parameters of the pump motor should be constant, such as running at a preset driving speed Z01, so that the suction action remains stable during the movement of the injection needle.

[0034] S12, real-time acquisition of the air pressure value in the needle channel of the injection needle by the first sensor; The first sensor is a pressure sensor, which in this embodiment is electrically connected to the control system within the liquid level detection system. During the first detection phase, it monitors the pressure value in the injection needle channel in real time and continuously outputs this pressure value to the control system. When the injection needle has not reached the liquid surface, the suction action draws in gas from the external environment, and its pressure value is at a stable level. However, when the injection needle contacts the liquid surface, the gas flow is obstructed, and the pressure value decreases sharply, thus determining the height of the injection needle reaching the liquid surface.

[0035] S13, obtain the first liquid level detection point based on the change in air pressure value, and obtain the first liquid level detection height based on the current liquid level detection height when the injection needle reaches the first liquid level detection point.

[0036] Because the pipette arm is controlled by a drive mechanism, the position of the injection needle at various moments as it moves with the pipette arm can be known through the drive mechanism (combined with the control parameters of each motor, control time, etc.), or additionally through a position sensor or other structure to monitor the injection needle position in real time. Therefore, when the pressure change parameters, such as the rate of change or the amount of change, exceed a preset threshold, or when both the rate of change and the amount of change exceed their respective preset thresholds, the injection needle reaches the first liquid level detection point. The liquid level height of the injection needle below the first liquid level detection point can be determined, thus obtaining the first liquid level detection height H1 detected in the first detection stage. For example, in... Figures 1 to 3 In the embodiment shown, the change parameter of the air pressure value adopts the change rate Lp=(Pi-P0) / Δt, where Pi is the currently read air pressure value, P0 is the reference air pressure value at or before the start of the injection needle aspiration action (usually the start time of the first detection stage), and Δt is the time, which is usually a fixed collection time. When Lp is greater than the first preset threshold Kp, it indicates that the injection needle has reached the liquid surface in the target container. The position of the injection port of the injection needle at this time is taken as the first liquid surface detection height H1.

[0037] S2, execute the second detection phase to obtain the second liquid level detection height; The second detection phase is completed based on the movement of the pipette arm and the second sensor. (See [link / reference]). Figure 6 This includes the following steps: S21, control the injection needle to move along the height direction from the second initial position toward the liquid surface of the target container; exist Figures 1 to 3 In the illustrated embodiment, the second initial position O2 is located above the liquid surface in the first container 600, and the height of the second initial position O2 is lower than the height of the first initial position O1. At the start of the second detection phase, the injection needle moves downwards along the Z-direction under the drive of the first motor. The driving parameters of the first motor in this embodiment are the same as those used in the first detection phase; however, different driving parameters can also be used, and this embodiment does not impose specific limitations. Normally, the injection needle's suction action is not activated during the second detection phase; that is, only the first motor operates while the pump motor does not. However, it is also possible to activate the pump motor by ensuring the validity of the capacitance detection value through changes in air pressure, as is done in the prior art, and this is also within the scope of this invention.

[0038] S22, acquire the capacitance detection value output by the second sensor in real time; The second sensor is a capacitance sensor, which is electrically connected to the control system within the liquid level detection system in this embodiment. During the second detection phase, the capacitance value sensed by the second sensor is monitored in real time, and the second sensor continuously outputs the capacitance value to the control system. In this embodiment, because the injection needle material is a conductive medium, it is connected to the capacitance probe of the second sensor on the pipetting arm via a wire. When the injection needle has not reached the liquid surface, the capacitance value output by the second sensor is relatively small. When the injection needle contacts the liquid surface, the dielectric constant changes due to the change of the medium from air to liquid, which usually causes the overall capacitance to increase. However, in special cases, the dielectric constant of the liquid may be less than that of the gas air, causing the capacitance to decrease. Therefore, the change in the capacitance value is used to determine whether the injection needle has reached the liquid level.

[0039] S23, obtain the second liquid level detection point based on the change of the capacitance detection value, and when the injection needle reaches the second liquid level detection point, obtain the second liquid level detection height based on the current movement height of the injection needle.

[0040] The change parameter of the capacitance detection value used by the second liquid level detection point can be set as the change amount or the change rate, or the change rate and the change amount. Figures 1 to 3 In the embodiment shown, the change parameter of the capacitance detection value adopts the change rate R=|Ci-C0| / Δt, where Ci is the currently read capacitance detection value, C0 is the capacitance reference value at the beginning of the second detection stage, which can be the capacitance detection value obtained by the second sensor at the beginning of the second detection stage, or the reference value obtained during the initialization calibration process performed before the start of the second detection stage, and Δt is time, which is usually a fixed acquisition time. When R is greater than the second preset threshold Kc, it indicates that the injection needle has reached the liquid surface in the target container. The position of the injection port of the injection needle at this time is taken as the second liquid surface detection height H2.

[0041] S3. Based on the difference between the second liquid level detection height and the first liquid level detection height, obtain information about the liquid level detection of the target container.

[0042] After completing the first and second detection stages, the difference between the second and first liquid level detection heights can be used as a parameter to determine the validity of both heights. This difference is derived from the difference between the detection values ​​obtained by pressure detection and capacitance detection. During pressure detection, when the pressure sensor detects a sudden change in pressure, the injection needle must first draw in liquid before it can stop the continued intake of gas, resulting in a rapid change in pressure. However, there is a certain detection time required from the injection needle reaching the liquid surface to the liquid entering the needle channel and being detected by the pressure sensor. This leads to the detection height measured by the pressure sensor being lower than the actual liquid level. In contrast, during capacitance detection, the capacitance value changes significantly the instant the injection needle contacts the liquid surface. Therefore, it has higher sensitivity and faster response compared to pressure detection, and its detection height is closer to the actual liquid level. Combining the characteristics of the two detection methods mentioned above, there may be a certain detection difference between them. Under this detection difference, the detection height of the second liquid surface should be greater than that of the first liquid surface. At the same time, when the difference between the two is within a reasonable error range, it means that the liquid surface detection heights obtained in the first and second detection stages are both valid values, which can significantly improve the accuracy of liquid surface detection and ensure the reliability of the liquid surface detection results.

[0043] Therefore, step S3, which involves obtaining the liquid surface anomaly detection information based on the difference between the two liquid surface detection heights, specifically includes: S31, when the second liquid level detection height is not less than the first liquid level detection height, determine whether the difference falls within the first range. Within the first range, the first liquid level detection height output by the first sensor and the second liquid level detection height output by the second sensor are normal. S32, when the second liquid level detection height is less than the first liquid level detection height, the liquid level detection system is determined to be in an abnormal state.

[0044] Continue with Figures 1 to 3 Taking the illustrated embodiment as an example, the first liquid level detection height obtained in the first detection stage and the second detection stage are H1 and H2, respectively. When H2 < H1, it indicates that there is an anomaly in the liquid level detection, meaning that at least one of the liquid level detection heights is invalid (in this embodiment, this is usually the invalid detection height of the second sensor). This may be due to external interference or detection errors caused by defects in the sensor itself. When H2 ≥ H1, that is, if the difference ΔH = H2 - H1 ≥ 0, the difference between the first liquid level detection height and the second liquid level detection height should fall within a certain reasonable error range. In this embodiment, this reasonable error range is represented by the first range. This confirms that both the first and second liquid level detection heights are valid and accurate, and the second liquid level detection height with relatively higher accuracy is taken as the liquid level detection confirmation height for output.

[0045] The liquid level detection anomaly detection method of the first aspect of the present invention, by comparing the height of the liquid level detection with that of the capacitive liquid level detection, can prevent over-reliance on the capacitive detection results, more accurately identify abnormal situations, reduce interference from external factors affecting the capacitive detection, and improve the sensitivity and accuracy of the capacitive detection.

[0046] Next, based on the difference obtained in step S3, a detailed analysis can be conducted on any abnormal situations that occur during the liquid level detection process, as follows.

[0047] In S31, if the difference falls into at least one abnormal range that is not in the first range, a verification phase is executed to verify whether the abnormality is an occasional anomaly and to exclude erroneous detection results caused by human interference or accidental events.

[0048] This verification phase includes: S301, adjust the sensitivity and / or detection threshold of the first or second sensor according to the abnormal range it falls into; S302, verify the detection effectiveness of the first liquid level detection height and the second liquid level detection height and output the verification result; S303, if the difference between the first liquid level detection height and the second liquid level detection height in the verification result falls within the abnormal range, output the abnormal identification result that falls within the abnormal range.

[0049] When an anomaly occurs, there may be issues with the sensitivity or detection threshold setting. Therefore, in step S301, the sensitivity or detection threshold of the first or second sensor is readjusted based on the detected anomaly range. Since the anomaly determined by the difference may vary, the sensitivity or detection threshold may be too high or too low under different anomaly conditions. For example, in this embodiment, the first liquid level detection height is used as a calibration height, and the first sensor has higher detection stability than the second sensor. If the second liquid level detection height is significantly higher than the first liquid level detection height, the sensitivity and detection threshold of the second sensor may be set too high. Therefore, the sensitivity and detection threshold of the second sensor are lowered to match the current liquid level height to be identified. Conversely, if the second liquid level detection height is lower than the first liquid level detection height, the sensitivity and detection threshold of the second sensor may be set too low. Therefore, the sensitivity and detection threshold of the second sensor are increased to match the current liquid level height to be identified.

[0050] In the process of processing the collected air pressure or capacitance values, the setting of the number of data points selected and the setting of the number of judgments to determine whether the change in the detected liquid level height or the rate of change is greater than the preset threshold directly affect the accuracy of liquid level detection. Therefore, the setting of the number of data points and the setting of the number of judgments determine the sensitivity of the sensor output value.

[0051] After adjusting the sensor sensitivity and detection threshold in the aforementioned steps, the detection effectiveness is verified again to eliminate the influence of sensor parameter adjustment factors. Therefore, the detection effectiveness in step S302 includes the effectiveness of the first liquid level detection height and the effectiveness of the second liquid level detection height. In one embodiment, if a problem is identified in the first liquid level detection height based on the abnormal range of the difference, the effectiveness verification of the first liquid level detection height continues, the first detection stage is repeated, and the first liquid level detection height is obtained again. Similarly, if a problem is identified in the second liquid level detection height based on the abnormal range of the difference, the effectiveness verification of the second liquid level detection height continues, the second detection stage is repeated, and the second liquid level detection height is obtained again. When both liquid level detection heights have problems, the first and second detection stages are also repeated. The first and second liquid level detection heights obtained in the above process are one of the detection effectiveness verification methods in this embodiment. Of course, other effectiveness verification methods can also be used, which are also within the scope of this invention. It should be noted that, when repeatedly executing the first and second detection phases, the first and second sensors are initialized and calibrated accordingly in this embodiment. For example, if there is a problem with the second liquid level detection height obtained in the second detection phase, the pump motor is reversed and the liquid sucked into the injection needle is emptied, so that the injection needle rises to a height of H1+Δh, which is the second initial position O2, and Δh is a variable preset value. Step S301 is executed, and the reference value of the second sensor is re-initialized, so that the injection needle is reset to the second initial position O2 and the second detection phase is executed again.

[0052] Step S302 further verifies the verification result in S301, taking the difference between the updated first liquid level detection height and the second liquid level detection height. If this difference falls into the aforementioned abnormal range again, it excludes occasional cases and identification anomalies caused by improper benchmark setting, confirms the corresponding abnormal situation, and outputs the anomaly identification result. Taking the existence of an abnormal range m1,...,mn as an example, if the difference before the verification stage falls into the range m1, and the validity of the second liquid level detection height needs to be verified in the case of m1, then the second detection stage is repeated, the second liquid level detection height H2' of the repeated second detection stage is obtained and output, and the second liquid level detection height H2' is compared with the original first liquid level detection height H1 to obtain the difference between them. It is then verified whether the difference falls into m1 again. If so, it is confirmed that there is an abnormal situation corresponding to the abnormal range m1 in the liquid level detection system, and the anomaly identification result is output. It should be noted that, in the updated first liquid level detection height and second liquid level detection height, if the first detection stage is repeated, the first liquid level detection height H1' is updated while the original second liquid level detection height H2 is retained; or if the second detection stage is repeated, the second liquid level detection height H2' is updated while the original first liquid level detection height H1 is retained. Similarly, when both detection stages need to be executed, this corresponds to updating to the latest liquid level detection height.

[0053] Specifically, at least one abnormal range includes a second range and a third range when the second liquid level detection height is not less than the first liquid level detection height. The first range, the second range, and the third range are consecutive and arranged in order of size. For example, the first range, the second range, and the third range are n1[0,Hx), m1[Hx,Hy), and m2[Hy,+∞), respectively. If the difference satisfies 0≤ΔH<Hx and falls within the first range n1, it indicates that the liquid level detection height is normal. If the difference falls within the second range m1, Hx≤ΔH<Hy, and if it falls within the third range m2, ΔH≥Hy.

[0054] Within different anomaly ranges, the anomaly identification results based on the difference also differ. For example, within the second range m1, the anomaly identification result includes determining that the second liquid level detection height is affected by bubble interference. Since this second range m2 is adjacent to the first range n1, it indicates that the second sensor was slightly interfered with during liquid level detection, and bubbles were present in the liquid surface. These bubbles affected the second detection stage, causing the second detection height in the second detection stage to be higher than the true value. However, the first detection stage was not affected, so the difference would be correspondingly larger. Within the third range m2, the anomaly identification result also includes determining that the second liquid level detection height is affected by external interference. This range is far from the first range n1 where the value is normally taken. Furthermore, if the first liquid level detection height in the first detection stage is less than the second liquid level detection height, it can be determined as a valid liquid level detection height, which is more reliable than capacitive detection. Therefore, it is determined that the second sensor is being interfered with by external factors, causing false detections.

[0055] Extendably, the abnormal range also includes a fourth and a fifth range where the second liquid level detection height is less than the first liquid level detection height and the ranges are continuous in size. For example, the fourth and fifth ranges are m3[-Hz,0) and m4(-∞,-Hz), respectively. If the difference satisfies -Hz≤ΔH<0 and falls into the fourth range m3, it indicates that the second sensor has an abnormal sensitivity problem during the liquid level detection process. When the sensitivity is low, the time taken for the rate of change of the capacitance detection value detected by the capacitance probe of the second sensor to exceed the second threshold is longer, resulting in the second liquid level detection height being lower than the first liquid level detection height obtained in the first detection stage. If the difference satisfies ΔH<-Hz and falls into the fifth range m4, it indicates that the second sensor is damaged and the obtained second liquid level detection height is far from the actual liquid level height.

[0056] In conjunction with the aforementioned step S301, which involves adjusting the first or second sensor according to different anomaly ranges, the specific implementation within the five anomaly ranges in this embodiment is as follows: Within the second range, adjusting the sensitivity and / or detection threshold of the first or second sensor includes reducing the sensitivity of the second sensor from a first sensitivity to a second sensitivity lower than the first sensitivity and reducing the detection threshold of the second sensor (refer to the second preset threshold and third preset threshold described below) from the first threshold to a second threshold lower than the first threshold. The first sensitivity and the second threshold can be adjusted based on the abnormal value range of the second range according to the parameter adjustment experience of the second sensor. Accordingly, a preset reduction adjustment value can be used to adjust the second sensor within this range, or the relevant parameters of the second sensor can be adjusted according to the originally set sensitivity and detection threshold. Within the third range, adjusting the sensitivity and / or detection threshold of the first or second sensor includes reducing the sensitivity of the second sensor from the first sensitivity to a third sensitivity lower than the first sensitivity and reducing the detection threshold of the second sensor from the first threshold to a third threshold lower than the first threshold. The third sensitivity and the third threshold can be adjusted based on the abnormal value range of the third range according to the parameter adjustment experience of the second sensor. Accordingly, a preset reduction adjustment value can be used to adjust the second sensor within this range, or the relevant parameters of the second sensor can be adjusted according to the originally set sensitivity and detection threshold. The third sensitivity and the third threshold can be set to be the same as the second sensitivity and the second threshold respectively according to the actual design needs. Of course, they can also be set to other different parameters, all of which are within the feasible range. Within the fourth range, adjusting the sensitivity and / or detection threshold of the first or second sensor includes increasing the sensitivity of the second sensor from the first sensitivity to a fourth sensitivity higher than the first sensitivity and increasing the detection threshold of the second sensor from the first threshold to a fourth threshold higher than the first threshold. The fourth sensitivity and the fourth threshold can be adjusted based on the abnormal value range of the fourth range according to the parameter adjustment experience of the second sensor. Accordingly, the adjustment value can be preset to adjust the second sensor within this range, or the relevant parameters of the second sensor can be adjusted according to the originally set sensitivity and detection threshold. Within the fifth range, since the detection value of the second sensor has clearly exceeded the limit value, it can be determined that the second sensor is damaged and there is no need to adjust its parameters to continue the verification process of detection effectiveness.

[0057] In the above five abnormal ranges, the initial value of the detection threshold of the second sensor is equal to the second preset threshold. When an abnormality is detected for the first time, the first threshold is equal to the second preset threshold. The threshold is then increased or decreased to the second, third, or fourth threshold based on the first threshold. When the second detection is still within the abnormal range, the first threshold is updated to the second, third, or fourth threshold of the previous abnormality detection, and so on.

[0058] Among the five abnormal ranges mentioned above, the adjustment of sensitivity is manifested in adjusting the number of data points collected by the selected sensor, or adjusting the number of judgments made to determine whether the change in the detected liquid level height or the rate of change is greater than a preset threshold. The more data points and the more judgments are made, the lower the sensitivity.

[0059] In this embodiment, the first liquid level detection height is used as the calibration liquid level height. Based on the aforementioned description of step S301, if the second liquid level detection height in the second and third ranges is significantly higher than the first liquid level detection height, the sensitivity of the second sensor may be too high. Therefore, during the verification of detection effectiveness, the sensitivity is lowered to adapt to the current liquid level height. In this embodiment, if the sensitivity in the third range is higher than the sensitivity in the second range in the case of mismatch, the sensitivity adjustment for the third range is greater than the adjustment for the second range. That is, the difference between the first and third sensitivities and the difference between the first and third thresholds are lower than the difference between the first and second sensitivities and the difference between the first and second thresholds, respectively. If the second liquid level detection height in the fourth range is lower than the first liquid level detection height, the sensitivity of the second sensor may be low. Therefore, during the verification of detection effectiveness, the sensitivity is increased to adapt to the current liquid level height.

[0060] Therefore, while using capacitance detection as the primary detection method, a more reliable air pressure detection sensor is introduced. The liquid level detection anomaly detection method in this embodiment can effectively identify various abnormal conditions based on the magnitude of the difference, providing important assistance for after-sales maintenance and problem diagnosis of the liquid level detection system. Multiple judgment conditions are established to avoid misjudgment caused by abnormal influences, while retaining the high detection accuracy of capacitance detection, thus achieving accuracy and reliability of liquid level detection.

[0061] In addition, considering the different anomaly detection scenarios in the aforementioned embodiments, this method also includes: S4. Based on the abnormal liquid level detection information of the target container obtained in the aforementioned embodiments, output the liquid level detection confirmation height.

[0062] The output liquid level detection confirmation height includes different liquid level detection heights output within the first range and the abnormal range. Within the first range, the second liquid level detection height is valid and is output as the liquid level detection confirmation height. Within the abnormal range, the first liquid level detection height is valid because the second liquid level detection height is invalid, and is output as the liquid level detection confirmation height.

[0063] Based on the analysis of different anomaly detection scenarios in the foregoing embodiments, and for ease of understanding, a detailed description is further provided in conjunction with specific embodiments.

[0064] Taking the first liquid level detection height H1 and the second liquid level detection height H2 as examples, there are the following five cases.

[0065] 1) 0≤ΔH<Hx, the liquid level detection height is normal within the first range n1, and the second liquid level detection height is output as the liquid level detection confirmation height for subsequent liquid transfer calculation; 2) Hx≤ΔH<Hy, within the second range m1, there is an abnormality of bubble interference at the second liquid level detection height, indicating that there may be bubbles on the liquid level. The first liquid level detection height is output as the liquid level detection confirmation height. 3) ΔH≥Hy, within the third range m2, the second liquid level detection height is abnormal due to external interference, indicating that the current capacitance detection value is too high, which may be falsely detected in the air or generate an incorrect signal due to interference from the outside air. The first liquid level detection height is output as the liquid level detection confirmation height. 4) -Hz≤ΔH<0, within the fourth range m3, the second liquid level detection height has an abnormal sensitivity, indicating that the current capacitive detection sensitivity is too low, and the first liquid level detection height is output as the liquid level detection confirmation height; 5) ΔH < -Hz, within the fifth range of m4, indicates that the second sensor may be damaged, and the first liquid level detection height is output as the liquid level detection confirmation height.

[0066] Therefore, this method can identify different abnormal situations, providing important assistance for after-sales maintenance and problem diagnosis of equipment; at the same time, in abnormal situations, the first liquid level detection height is output as the liquid level detection confirmation height, and the test equipment can continue to carry out subsequent liquid aspiration steps, etc., without causing test interruption and thus wasting liquid volume.

[0067] To further improve the detection accuracy of this method, in one embodiment, the method further includes a calibration stage before performing steps S1 and S2, in which the first sensor and the second sensor are initialized and calibrated to ensure the accuracy of liquid level detection. The calibration stage specifically includes: S01, control the injection needle to move to the first target position, and read the chip temperature information and capacitance detection value of the second sensor; S02, Based on the chip temperature information and capacitance detection value, initialize and calibrate the capacitance reference of the second sensor and obtain the reference value; S03, determine whether the reference value is greater than the detection limit value. If it is greater, determine that the capacitance detection of the second sensor is abnormal.

[0068] by Figure 1Taking the illustrated embodiment as an example, the drive mechanism moves the injection needle to a position above the target container. After the first motor is initialized, the first motor drives the pipette arm to descend at a drive speed V2 and a drive acceleration A2, thereby moving the injection needle to the first target position H0. The drive speed V2 and drive acceleration A2 can be set to the same values ​​as V1 and A2, or they can be set to different values. At this time, the chip temperature of the second sensor and the current capacitance detection value of the capacitance probe are read. Due to differences in the manufacturing process of the injection needle and the influence of surrounding environmental factors, the reference value for capacitance detection may vary in each second detection stage. Therefore, the capacitance reference of the second sensor is re-initialized and calibrated before the first and second detection stages to obtain the reference value C0 required for this capacitance detection. The first target position H0 can coincide with the first initial position O1, or it can be above O1 or at another position different from O1. Accordingly, if the reference value C0 is greater than the detection limit value Ck, it indicates that the reference value in this calibration stage has exceeded the limit of capacitance detection, and the current capacitance detection value is considered invalid.

[0069] Furthermore, this method also includes replacing the injection needle and re-performing the calibration stage if the output capacitance detection is abnormal during the calibration phase.

[0070] This recalibration phase is used to eliminate erroneous calibrations caused by accidental events. If the capacitance detection problem still occurs after recalibration, it indicates that the injection needle may be damaged, and the needle should be removed and the test repeated.

[0071] In addition, the calibration phase may also include initial calibration of the first and second sensors according to different liquid types (dielectric constant, conductivity, viscosity, etc.), adjusting the calibration coefficient of the second sensor (such as the second preset threshold Kc) and the calibration coefficient of the corresponding air pressure detection of the first sensor (such as the rate of change threshold, i.e. the first preset threshold Kq), as well as motion parameters such as the driving speed and driving acceleration of the first motor and the pump motor, to adjust the detection sensitivity between different liquids and ensure timing.

[0072] Based on the liquid level detection anomaly detection method provided in the first aspect embodiment, the present invention further proposes a liquid transfer method applied to a liquid level detection system in a second aspect embodiment. This liquid transfer method includes at least two consecutively executed liquid aspiration processes, each liquid aspiration process performing an independent liquid suction action. The at least two liquid aspiration processes include a first liquid aspiration process and at least one second liquid aspiration process executed after the first liquid aspiration process. Figure 1 As shown, the injection needle can be moved to the first container 600 and the second container 700 under the control of the liquid level detection system to perform the first liquid aspiration process and the second liquid aspiration process respectively.

[0073] Among them, see Figure 7The first liquid aspiration process includes: S110, the liquid level detection anomaly detection method of the first aspect embodiment is executed in the first container; This liquid level detection anomaly detection method is applied during the first liquid aspiration process of the current injection needle. Its purpose is to initialize and calibrate the detection reference of the first and second sensors, analyze whether there is an abnormal state in the current liquid level detection system, and output an accurate liquid level detection confirmation height.

[0074] S120, Obtain the liquid level detection confirmation height output by the liquid level detection anomaly detection method; S130, calculate the first liquid absorption amount based on the liquid level detection and confirm the height, and perform the liquid absorption action in the first container based on the first liquid absorption amount; After obtaining an accurate liquid level detection and confirmation height, the injection needle is controlled to draw liquid from the first container 600 at the corresponding height position according to the set liquid absorption volume, so as to achieve precise control of the liquid absorption volume in the first container 600.

[0075] If no sensor malfunction occurs during the first liquid aspiration process, the second liquid aspiration process will continue. The second liquid aspiration process includes a liquid level detection subprocess and a liquid aspiration subprocess. The liquid level detection subprocess is used to confirm the liquid level height in the second container 700, and the liquid aspiration subprocess controls the liquid aspiration action based on the liquid level height confirmed by the liquid level detection subprocess.

[0076] Specifically, see Figure 7 The liquid level detection sub-process includes: S211, control the injection needle to move along the height direction from the third initial position toward the liquid surface of the second container; The control process is basically the same as the control process in S21, but the third initial position O3 is a different position from the second initial position O2, so that the injection needle is located above the second container 700 and can move downward to contact the liquid surface and below the liquid surface of the second container 700. Before the injection needle is moved from the third initial position O3, the liquid type of the second container is different from that of the first container, or it can be the same. Based on the current chip temperature and the current capacitance detection value, the air pressure reference and capacitance reference of the second container 700 are re-initialized and calibrated. The reference value can be obtained by averaging all the readings except the maximum and minimum readings by the sensor.

[0077] S212, acquire the capacitance detection value output by the second sensor in real time; S213, obtain the third liquid level detection point based on the change of the capacitance detection value, and obtain the third liquid level detection height based on the current liquid level detection height when the injection needle reaches the third liquid level detection point; Based on steps S212 and S213, the third liquid level detection height obtained by the second sensor is acquired.

[0078] S214, continue to control the injection needle to move downward along the height direction, and at the same time control the injection needle to perform a suction action, and record the duration of the suction action; S215, real-time acquisition of the air pressure value in the needle channel of the injection needle by the first sensor; S216, when the duration is less than the preset time, determine whether the air pressure value changes; S217: Determine whether the injection needle has reached or is below the liquid surface of the second container based on the change in air pressure. If so, output the third liquid surface detection height as the liquid surface detection confirmation height of the second container.

[0079] Combining steps S214 and S215, the air pressure monitoring of the first sensor determines whether the current third liquid level detection height is effective. Under the condition that the second sensor itself is not abnormal during the first liquid suction action, the air pressure change can determine whether there are interfering bubbles in the current liquid level of the second container 700, so as to eliminate the influence of bubbles. In one embodiment, in conjunction with the liquid level detection anomaly detection method for the first container in the aforementioned embodiments, the anomaly of the second sensor in the four ranges other than the fifth range is only a problem with detection accuracy. The second sensor is not damaged. Therefore, the third liquid level detection height performed by the second sensor can still be used in the second liquid aspiration process. Its accuracy may be relatively lower than the actual liquid level height, but it does not affect the aspiration volume or accuracy, and will not cause liquid waste. In the prior art, it is impossible to accurately identify whether the anomaly detected by the capacitive detection sensor will affect the normal operation of the pipetting process. In particular, when the liquid level detection anomaly is detected in the prior art, the current working process of the device will be stopped immediately, but it is impossible to identify and analyze what caused the anomaly and whether the anomaly will further affect the subsequent work, requiring too much manual intervention. The pipetting method in this embodiment can solve this problem to ensure the normal operation of pipetting as much as possible. It can be further described that when an abnormality in liquid level detection other than the fifth range is identified during the first liquid aspiration action, the descent depth of the injection needle can be adaptively adjusted according to the identified abnormality during the second liquid aspiration process to ensure that a sufficient specified amount of liquid is aspirated at that descent depth, thereby achieving uninterrupted testing and avoiding liquid waste.

[0080] In specific implementation, the drive mechanism moves the injection needle downward, while the pump motor operates at a specified drive speed Z02. The drive speed Z02 is adjusted according to the type of liquid, etc., to obtain the parameters of the pump motor. The first sensor collects the air pressure value in the needle channel. When the third liquid level detection point is detected, if the rate of change of air pressure Lp is greater than the preset threshold (where the preset threshold can be different from the first preset threshold in the first liquid aspiration process, and can be reasonably set according to the specific implementation situation such as the type of liquid), the duration t of the suction action, i.e., the operation of the pump motor, is recorded. If the rate of change of air pressure Lp is not greater than the preset threshold within the range of duration t being less than or equal to the preset time T, it indicates that there is an abnormal situation. Otherwise, it indicates that the injection needle is in the liquid and not in the air bubble, and the third liquid level detection height H3 is output as the liquid level detection confirmation height of the second container 700.

[0081] Continue reading Figure 7 The liquid aspiration process includes: S221, calculate the second liquid absorption amount based on the liquid level detection and height confirmation of the second container, and perform the liquid absorption action in the second container based on the second liquid absorption amount.

[0082] This step is basically the same as step S130, except that the target container is transferred from the first container 600 to the second container 700, which will not be elaborated on here.

[0083] In step S213, obtaining the third liquid level detection point based on the change in the capacitance detection value includes: S2131, when the rate of change of the capacitance detection value is greater than the third preset threshold, it is determined that the injection needle has reached the third liquid level detection point.

[0084] If the rate of change R of the capacitance detection value Ci relative to the capacitance reference value C0 is greater than the third preset threshold Kc1, it indicates that the medium contacted by the second sensor has changed from air to liquid. At this time, the injection needle reaches the liquid surface of the second container 700, which is the third liquid surface detection point. The third preset threshold Kc1 is set according to the different types of liquids (dielectric constant, conductivity, viscosity, etc.), and can be set to a value that is the same as or different from the second preset threshold Kc, depending on the actual implementation.

[0085] In step S217, determining whether the injection needle has reached or fallen below the liquid surface of the second container based on the change in air pressure includes: S2171, when the rate of change of air pressure is greater than the fourth preset threshold, it is determined that the injection needle has reached or is below the liquid surface of the second container.

[0086] If the rate of change of air pressure Lp is greater than the fourth preset threshold Kq1, it indicates that liquid has been drawn into the needle channel of the injection needle. At this time, the injection needle reaches the liquid surface and below the liquid surface of the second container 700. The fourth preset threshold Kq1 is set according to the different types of liquids (dielectric constant, conductivity, viscosity, etc.), and can be set to a value that is the same as or different from the first preset threshold Kq, depending on the actual implementation.

[0087] In addition, in case of abnormalities in the air pressure detection, the second liquid aspiration process also includes: S218, when the rate of change of all air pressure values ​​in the liquid level detection subprocess is less than the fourth preset threshold, the injection needle is reset to the third initial position, the capacitance reference of the second sensor is initialized and the reset reference value is obtained. S219, continue executing the liquid level detection sub-process.

[0088] In steps S218 and S219, if the rate of change of all air pressure values ​​during step S214 is less than the fourth preset threshold, it indicates an abnormal situation. The pump motor stops, the drive mechanism resets the injection needle to the third initial position O3, resets the reference, and continues to execute steps S211 to S217.

[0089] This pipetting method can be applied to liquid aspiration processes in multiple containers, effectively ensuring the accuracy of liquid level detection and enabling precise control of the pipetting process in each container. It reduces interference from external factors and significantly improves the accuracy of liquid volume aspiration. In the extended content of this embodiment, there can be multiple second containers 700 instead of just one. The second liquid aspiration process used in subsequent second containers 700 is also within the scope of this invention.

[0090] In a third aspect, the present invention also proposes a liquid level detection and control system 800, see reference. Figure 8 Applied to liquid level detection systems, including: Execution unit 801 is used to control the movement of the pipette arm; The acquisition unit 802 is used to acquire the air pressure value output by the first sensor and the capacitance detection value output by the second sensor; Recording unit 803 is used to record the height of the injection needle on the pipette arm; The liquid level detection unit 804 is used to determine the liquid level detection height based on the air pressure value and the capacitance detection value. The processing unit 805 is used to control the execution unit 801, the acquisition unit 802, the recording unit 803 and the liquid level detection unit 804 to execute the first detection stage and the second detection stage respectively, and to identify the abnormal liquid level detection situation of the target container and output the liquid level detection confirmation height based on the first liquid level detection height of the first detection stage and the second liquid level detection height of the second detection stage.

[0091] The first detection stage and the second detection stage are consistent with steps S11 to S12 and steps S21 to S23 of the liquid surface detection anomaly detection method in the first aspect embodiment.

[0092] This liquid level detection control system 800 can implement the liquid level detection anomaly detection method in the first aspect embodiment and obtain the liquid level detection height of the target container.

[0093] In a fourth aspect, the present invention also provides a computer-readable storage medium comprising a stored program, wherein, when the program is executed, the computer-readable storage medium controls the execution within a device of the liquid level detection anomaly detection method of the first aspect embodiment or the liquid transfer method of the second aspect embodiment of the present invention.

[0094] This invention also provides a computer device, which includes a processor, a memory, and a computer program stored in the memory and executable on the processor. When executed by the processor, the computer program implements the liquid level detection anomaly detection method or the liquid transfer method described in the embodiments; to avoid repetition, these will not be described in detail here. Alternatively, when executed by the processor, the computer program implements the functions of each model / unit of the control device in the embodiments; to avoid repetition, these will not be described in detail here.

[0095] Computer devices include, but are not limited to, processors and memory. Those skilled in the art will understand that the above are merely examples of computer devices and do not constitute a limitation on computer devices. A computer device may include more or fewer components than illustrated, or a combination of certain components, or different components. For example, a computer device may also include input / output devices, network access devices, buses, etc.

[0096] The processor referred to can be a Central Processing Unit (CPU), or other general-purpose processors, digital signal processors (DSPs), application-specific integrated circuits (ASICs), field-programmable gate arrays (FPGAs), or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc. A general-purpose processor can be a microprocessor or any conventional processor.

[0097] Memory can be an internal storage unit of a computer device, such as a hard drive or RAM. Memory can also be an external storage device of a computer device, such as a plug-in hard drive, Smart Media Card (SMC), Secure Digital (SD) card, or Flash Card. Furthermore, memory can include both internal and external storage units. Memory is used to store computer programs and other programs and data required by the computer device. Memory can also be used to temporarily store data that has been output or will be output.

[0098] In the above embodiments, implementation can be achieved entirely or partially through software, hardware, firmware, or any combination thereof. When implemented using software, it can be implemented entirely or partially in the form of a computer program product. The computer program product includes one or more computer instructions. When the computer instructions are loaded and executed on a computer, all or part of the processes or functions described in the embodiments of this application are generated. The computer can be a general-purpose computer, a special-purpose computer, a computer network, or other programmable device. The computer instructions can be stored in a computer-readable storage medium or transmitted from one computer-readable storage medium to another. For example, the computer instructions can be transmitted from one website, computer, server, or data center to another website, computer, server, or data center via wired (e.g., coaxial cable, fiber optic, Digital Subscriber Line (DSL)) or wireless (e.g., infrared, wireless, microwave, etc.) means. The computer-readable storage medium can be any available medium accessible to a computer or a data storage device such as a server or data center that integrates one or more available media. The available media may be magnetic media (e.g., floppy disks, hard disks, magnetic tapes), optical media (e.g., high-density digital video discs (DVDs)), or semiconductor media (e.g., solid-state drives (SSDs)).

[0099] While specific embodiments of the invention have been described in detail by way of examples, those skilled in the art should understand that the examples are for illustrative purposes only and not intended to limit the scope of the invention. Those skilled in the art should understand that modifications can be made to the above embodiments without departing from the scope and spirit of the invention. The scope of the invention is defined by the appended claims.

[0100] Finally, it should be noted that the above description is merely the preferred embodiment of the present invention and is not intended to limit the present invention in any way. Any person skilled in the art can make many possible variations and simple substitutions to the technical solutions of the present invention using the disclosed methods and techniques without departing from the scope of the present invention; all of these variations fall within the protection scope of the present invention.

Claims

1. A method for detecting abnormalities in liquid level detection, applied to a liquid level detection system, the liquid level detection system comprising a pipette arm, a first sensor for detecting the air pressure of the injection needle on the pipette arm, and a second sensor mounted on the pipette arm and outputting a capacitance detection result, characterized in that, The method includes: The first detection phase was executed to obtain the first liquid level detection height; The second detection phase was executed to obtain the second liquid level detection height. Based on the difference between the second liquid level detection height and the first liquid level detection height, information about abnormal liquid level detection in the target container is obtained; The first detection phase includes: Control the injection needle to move along the height direction from a first initial position toward the liquid surface of the target container, and simultaneously control the injection needle to perform an aspiration action; The air pressure value in the needle channel of the injection needle is obtained in real time by the first sensor; The first liquid level detection point is obtained based on the change in the air pressure value. When the injection needle reaches the first liquid level detection point, the first liquid level detection height is obtained based on the current moving height of the injection needle. The second detection phase includes: Control the injection needle to move along the height direction from the second initial position toward the liquid surface of the target container; The capacitance detection value output by the second sensor is acquired in real time; The second liquid level detection point is obtained based on the change in the capacitance detection value. When the injection needle reaches the second liquid level detection point, the second liquid level detection height is obtained based on the current moving height of the injection needle. The step of obtaining information about abnormal liquid level detection in the target container based on the difference between the second liquid level detection height and the first liquid level detection height includes: When the second liquid level detection height is not less than the first liquid level detection height, it is determined whether the difference falls within the first range. Within the first range, the first liquid level detection height output by the first sensor and the second liquid level detection height output by the second sensor are normal. When the second liquid level detection height is less than the first liquid level detection height, the liquid level detection system is determined to be in an abnormal state.

2. The method according to claim 1, characterized in that, If the difference falls into at least one abnormal range other than the first range, a verification phase is performed, the verification phase including: Adjust the sensitivity and / or detection threshold of the first or second sensor according to the abnormal range it falls into; Verify the detection effectiveness of the first liquid level detection height and the second liquid level detection height and output the verification results; If the difference between the first liquid level detection height and the second liquid level detection height in the verification result falls within the abnormal range again, an anomaly identification result falling within the abnormal range will be output.

3. The method according to claim 2, characterized in that, The at least one abnormal range includes a second range and a third range when the second liquid level detection height is not less than the first liquid level detection height, wherein the first range, the second range, and the third range are consecutive and arranged in ascending order. Within the second range, adjusting the sensitivity and / or detection threshold of the first sensor or the second sensor includes reducing the sensitivity of the second sensor from a first sensitivity to a second sensitivity lower than the first sensitivity and reducing the detection threshold of the second sensor from a first threshold to a second threshold lower than the first threshold. The abnormal identification result includes determining that there is an abnormality of bubble interference in the second liquid level detection height. Within the third range, adjusting the sensitivity and / or detection threshold of the first sensor or the second sensor includes reducing the sensitivity of the second sensor from a first sensitivity to a third sensitivity lower than the first sensitivity and reducing the detection threshold of the second sensor from a first threshold to a third threshold lower than the first threshold. The anomaly identification result includes determining that there is an external interference anomaly in the second liquid level detection height.

4. The method according to claim 3, characterized in that, The at least one abnormal range includes a fourth range and a fifth range that are consecutive in size when the second liquid level detection height is less than the first liquid level detection height. Within the fourth range, adjusting the sensitivity and / or detection threshold of the first sensor or the second sensor includes increasing the sensitivity of the second sensor from a first sensitivity to a fourth sensitivity higher than the first sensitivity and increasing the detection threshold of the second sensor from a first threshold to a fourth threshold higher than the first threshold. The abnormal identification result includes determining that there is a sensitivity abnormality in the second liquid level detection height. Within the fifth range, the anomaly identification result includes determining that the second sensor is damaged.

5. The method according to any one of claims 1 to 4, characterized in that, The method further includes a calibration phase prior to performing the first detection phase and the second detection phase, the calibration phase comprising: Control the injection needle to move to the first target position, and read the chip temperature information and capacitance detection value of the second sensor; Based on the chip temperature information and the capacitance detection value, initialize and calibrate the capacitance reference of the second sensor and obtain the reference value; Determine whether the reference value is greater than the detection limit value. If it is, determine that the capacitance detection of the second sensor is abnormal.

6. The method according to any one of claims 1 to 4, characterized in that, The step of obtaining the first liquid level detection point based on the change in the air pressure value includes: When the rate of change of the air pressure value is greater than the first preset threshold, the injection needle reaches the first liquid level detection point; The step of obtaining the second liquid level detection point based on the change in the capacitance detection value includes: When the rate of change of the capacitance detection value is greater than the second preset threshold, the injection needle reaches the second liquid level detection point; The second detection phase is executed after the first detection phase, and the first detection phase further includes: When the rate of change of the air pressure value is greater than the first preset threshold, the injection needle is controlled to stop at the current position; The injection needle is reset to the second initial position of the second detection phase based on the first liquid level detection height and the change preset value.

7. The method according to any one of claims 2 to 4, characterized in that, Also includes: Based on the obtained information regarding abnormal liquid level detection in the target container, output the confirmed liquid level detection height; Within the abnormal range, the liquid level detection confirmation height is the first liquid level detection height; Within the first range, the liquid level detection confirmation height is the second liquid level detection height.

8. A pipetting method, characterized in that, This invention relates to a liquid level detection system, which includes a pipette arm, a first sensor for detecting the air pressure of the injection needle on the pipette arm, and a second sensor mounted on the pipette arm and outputting a capacitance detection result. The system comprises at least two consecutive aspiration processes, each including a first aspiration process and at least one second aspiration process performed after the first aspiration process. The first aspiration process includes: The liquid level detection anomaly detection method as described in any one of claims 1 to 7 is performed in the first container; Obtain the liquid level detection confirmation height output by the liquid level detection anomaly detection method; The first liquid absorption volume is calculated based on the liquid level detection height, and the liquid absorption action in the first container is performed based on the first liquid absorption volume. The second liquid aspiration process includes a liquid level detection sub-process and a liquid aspiration sub-process, wherein the liquid level detection sub-process includes: Control the injection needle to move along the height direction from the third initial position toward the liquid surface of the second container; The capacitance detection value output by the second sensor is acquired in real time; The third liquid level detection point is obtained based on the change in the capacitance detection value. When the injection needle reaches the third liquid level detection point, the third liquid level detection height is obtained based on the current moving height of the injection needle. Continue to control the injection needle to move downward along the height direction, and at the same time control the injection needle to perform an aspiration action, and record the duration of the aspiration action; The air pressure value in the needle channel of the injection needle is obtained in real time by the first sensor; When the duration is less than a preset time, determine whether the air pressure value has changed; Based on the change in the air pressure value, determine whether the injection needle has reached or is below the liquid surface of the second container. If so, output the third liquid surface detection height as the liquid surface detection confirmation height of the second container. The liquid absorption process includes: The second liquid absorption volume is calculated based on the liquid level detection height in the second container, and the liquid absorption action in the second container is performed based on the second liquid absorption volume.

9. The method according to claim 8, characterized in that, The step of obtaining the third liquid level detection point based on the change in the capacitance detection value includes: When the rate of change of the capacitance detection value is greater than the third preset threshold, it is determined that the injection needle has reached the third liquid level detection point; The step of determining whether the injection needle has reached or fallen below the liquid surface of the second container based on the change in the air pressure value includes: When the rate of change of the air pressure value is greater than the fourth preset threshold, it is determined that the injection needle has reached or is below the liquid surface of the second container; The second liquid aspiration process also includes: When the rate of change of all the gas pressure values ​​in the liquid level detection subprocess is less than the fourth preset threshold, the injection needle is reset to the third initial position, the capacitance reference of the second sensor is initialized and calibrated, and the reset reference value is obtained. Continue executing the liquid level detection sub-process.

10. A liquid level detection and control system, characterized in that, An application is made in a liquid level detection system, the liquid level detection system including a pipette arm, a first sensor for detecting the air pressure of the injection needle on the pipette arm, and a second sensor mounted on the pipette arm and outputting a capacitance detection result; the liquid level detection control system includes: An execution unit is used to control the movement of the pipette arm; The acquisition unit is used to acquire the air pressure value output by the first sensor and the capacitance detection value output by the second sensor; A recording unit is used to record the height of the injection needle on the pipette arm; A liquid level detection unit is used to determine the liquid level detection height based on the air pressure value and the capacitance detection value; The processing unit is used to control the execution unit, the acquisition unit, the recording unit and the liquid level detection unit to execute the first detection stage and the second detection stage respectively, and to identify the liquid level detection anomaly of the target container and output the liquid level detection confirmation height based on the first liquid level detection height of the first detection stage and the second liquid level detection height of the second detection stage. The first detection phase includes: The execution unit controls the injection needle to move along the height direction from the first initial position toward the liquid surface of the target container, and simultaneously controls the injection needle to perform a suction action; The acquisition unit acquires in real time the air pressure value in the needle channel of the injection needle by the first sensor; The first liquid level detection point is obtained based on the change in the air pressure value. When the injection needle reaches the first liquid level detection point, the liquid level detection unit obtains the first liquid level detection height based on the current moving height of the injection needle. The second detection phase includes: The execution unit controls the injection needle to move along the height direction from the second initial position toward the liquid surface of the target container; The acquisition unit acquires the capacitance detection value output by the second sensor in real time; The second liquid level detection point is obtained based on the change in the capacitance detection value. When the injection needle reaches the second liquid level detection point, the liquid level detection unit obtains the second liquid level detection height based on the current moving height of the injection needle.

11. A computer-readable storage medium, characterized in that, The computer-readable storage medium stores a computer program, which, when executed by a processor, performs the liquid level detection anomaly detection method as described in any one of claims 1 to 7 or the pipetting method as described in any one of claims 8 to 9.

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