Pipetting device and liquid level detection method

Abstract

The invention discloses a pipetting device and a liquid level detection method, and belongs to the technical field of equipment control. The device comprises a suction head, a pipetting pump, a target motor and an upper computer, the target motor and the pipetting pump are both in communication connection with the upper computer; the pipetting pump is used for controlling the suction head to suck and discharge liquid and comprises a parameter detection mechanism, and the parameter detection mechanism is in communication connection with the target motor; the upper computer is used for controlling the target motor to drive the suction head to move towards the current to-be-detected liquid level; the parameter detection mechanism is used for obtaining target parameters related to the position of the suction head based on a set time interval in the process that the suction head moves towards the current to-be-detected liquid level, and outputting a first level signal to the target motor to enable the target motor to stop driving the suction head to move under the condition that the target parameters meet the current liquid level detection condition. According to the embodiment of the invention, the operation safety of the pipetting device can be improved.

Description

Technical Field

[0001] This invention relates to the field of equipment control technology, and in particular to a liquid pipetting device and a liquid level detection method. Background Technology

[0002] In existing pipetting equipment, the host computer controls the operation of each component based on the status information fed back by each component. This requires the host computer to maintain good communication with each component. If the communication between the host computer and any component fails, the equipment will malfunction.

[0003] Therefore, existing pipetting equipment suffers from low operational safety. Summary of the Invention

[0004] This invention provides a pipetting device to address the problem of low operational safety in existing pipetting devices.

[0005] According to one aspect of the present invention, a pipetting device is provided, comprising a pipette tip, a pipetting pump, a target motor, and a host computer;

[0006] Both the target motor and the pipette pump are communicatively connected to the host computer.

[0007] The pipette pump is used to control the suction and discharge of liquid by the pipette tip, and includes a parameter detection mechanism, which is communicatively connected to the target motor.

[0008] The host computer is used to control the target motor to drive the suction head to move toward the liquid surface to be measured;

[0009] The parameter detection mechanism is used to acquire target parameters associated with the position of the suction head based on a set time interval during the movement of the suction head toward the current liquid surface to be measured. When the target parameters meet the current liquid surface detection conditions, the mechanism outputs a first level signal to the target motor to stop the target motor from driving the suction head to move. The target parameters can reflect the positional relationship between the suction head and the current liquid surface to be measured.

[0010] According to one aspect of the present invention, a liquid level detection method is provided, the method comprising:

[0011] When the movement of the suction head toward the current liquid surface to be tested is detected, a target parameter associated with the position of the suction head is obtained based on a set time interval, wherein the target parameter is associated with the movement position of the suction head in at least one side of the current liquid surface to be tested;

[0012] If the target parameters meet the current liquid level detection conditions, a first level signal is output to the target motor to stop the target motor from driving the suction head.

[0013] The technical solution provided by this invention involves a parameter detection mechanism sending a first-level signal to the target motor to brake it when the target parameter associated with the pipette tip position meets the current liquid level detection conditions. Based on this first-level signal, the target motor immediately stops moving the pipette tip. Compared to the host computer obtaining a detection position marker from the parameter detection mechanism and outputting a first-level signal to the target motor to stop it, this method avoids situations where the pipette tip touches the bottom due to communication failure between the parameter detection mechanism and the host computer, or where communication delays between the two systems cause the target motor to stop untimely. This significantly improves the timeliness of braking the target motor, reduces the depth of the pipette tip when it stops moving, and enhances the safety of the pipetting device.

[0014] It should be understood that the description in this section is not intended to identify key or essential features of the embodiments of the present invention, nor is it intended to limit the scope of the invention. Other features of the invention will become readily apparent from the following description. Attached Figure Description

[0015] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0016] Figure 1 This is a structural block diagram of a pipetting device provided according to an embodiment of the present invention;

[0017] Figure 2 This is another structural schematic diagram of the pipetting device provided according to an embodiment of the present invention;

[0018] Figure 3 This is a schematic flowchart of a liquid level detection method provided according to an embodiment of the present invention. Detailed Implementation

[0019] To enable those skilled in the art to better understand the present invention, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of the present invention.

[0020] It should be noted that the terms "first," "second," etc., in the specification, claims, and accompanying drawings of this invention are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that the embodiments of the invention described herein can be implemented in orders other than those illustrated or described herein. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover a non-exclusive inclusion; for example, a process, method, system, product, or apparatus that comprises a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or apparatus.

[0021] Figure 1 This is a schematic diagram of the pipetting device provided in an embodiment of the present invention. Figure 1 As shown, the device includes: a pipette tip 11, a pipette pump 12, a target motor 13, and a host computer 14;

[0022] The target motor 13 and the pipette pump 12 are both communicatively connected to the host computer 14.

[0023] The pipette pump 12 is used to control the suction and discharge of liquid by the pipette tip 11, and includes a parameter detection mechanism 1231, which is communicatively connected to the target motor 13;

[0024] The host computer 14 is used to control the target motor 13 to drive the suction head 11 to move toward the current liquid surface to be measured;

[0025] The parameter detection mechanism 1231 is used to acquire target parameters associated with the position of the suction head 11 based on a set time interval during the movement of the suction head 11 toward the current liquid surface to be measured. When the target parameters meet the current liquid surface detection conditions, the mechanism sends a first level signal to the target motor 13 to stop the target motor 13 from driving the suction head 11 to move. The target parameters can reflect the positional relationship between the suction head 11 and the current liquid surface to be measured.

[0026] The pipette pump 12 includes a piston movement chamber and an output chamber located at the end of the movement chamber, with the end of the output chamber used to connect a pipette tip. The pipette pump controls the air pressure in the output chamber by controlling the movement of the piston, thereby controlling the air pressure in the pipette tip connected to the end of the output chamber.

[0027] The pipette tip 11 is used for pipetting. Specifically, it draws the target liquid into the cavity through the pipette tip. After the liquid is moved above the target position, such as another container, reaction cell, reaction chip, etc., the solution inside is discharged to the target position under the control of the pipetting pump.

[0028] The target motor 13 is used to drive the suction head to move along a set axial direction, such as along the Z-axis, where the Z-axis can be understood as the vertical direction. The target motor can be a drive-control integrated motor or a non-drive-control integrated motor.

[0029] To improve the accuracy of liquid aspiration and the safety of pipette tip movement, it is usually necessary to detect the surface position of the liquid to be aspirated when using a pipette tip. In this embodiment, the surface of the liquid to be aspirated is taken as the current test surface, and then the host computer controls the target motor to drive the pipette tip to move towards the current test surface.

[0030] The target motor 13 is configured to drive the suction head to move under the control of a second level signal, and to stop driving the suction head to move under the control of a first level signal. The second level signal can be a low level signal, a high level signal, a rising edge level signal, or a falling edge level signal, etc., and the first level signal is a level signal that is completely opposite to the second level signal.

[0031] It is understandable that if the output cavity is a rigid cavity, the target motor will drive the pipette tip to move while also driving the pipetting pump.

[0032] The host computer 14 is also used to determine the position information of the current liquid surface to be measured based on the position parameters of the target motor 13 when the liquid surface is detected to be in position and the target motor 13 stops operating. Specifically, the position parameters of the target motor can be selected as the current encoded data of the target motor. When the liquid surface is detected to be in position and the target motor stops operating, the current encoded data is parsed to obtain the parsing result. Based on the parsing result, the vertical movement distance of the pipette tip is determined. Based on the movement distance and the set starting position, the position information of the current liquid surface to be measured is determined. The pipetting device can determine the height or volume of the target solution in the target container based on the current position information of the detected liquid surface, and the height or volume of the target solution helps to improve the safety and effectiveness of the pipetting device.

[0033] The time interval can be set based on the descent speed of the pipette tip and the required liquid level detection accuracy. For example, the higher the liquid level detection accuracy, the shorter the time interval; the faster the pipette tip descent speed, the shorter the time interval. In actual use, users can determine the set time interval based on a pre-established correspondence between liquid level detection accuracy, pipette tip descent speed, and time interval.

[0034] The target parameter can be the air pressure in the output chamber of the pipette pump, the air pressure in the pipette tip, the capacitance of the pipette tip, or other parameters, as long as the parameter can reflect the positional relationship between the pipette tip and the liquid surface to be measured.

[0035] Since the parameter detection mechanism 1231 is used to acquire the target parameters, the corresponding parameter detection mechanism can be selected based on the required target parameters. Therefore, the parameter detection mechanism 1231 can be configured as a pressure sensor, a capacitance sensor, or other detection mechanisms associated with the suction head position. The parameter detection mechanism 1231 is configured to output a second-level signal at its control output terminal when the target parameters do not meet the current liquid level detection conditions, and to output a first-level signal when the target parameters meet the current liquid level detection conditions.

[0036] like Figure 2 As shown, the pipetting device also includes a support structure 15, which supports the target motor 13, the pipetting pump 12, etc. In this figure, the target motor 13 is a lead screw motor, which includes a motor component 131 and a lead screw 132. The pipetting pump 12 includes a first motor 121, a control board 122 connected to the first motor, and an output chamber 123. The control board 122 works in conjunction with the first motor 121 to realize the suction and exhaust functions.

[0037] In one embodiment, such as Figure 2 As shown, the parameter detection mechanism and the pipette pump are an integrated structure; the pipette pump includes an air pump in the output chamber; the parameter detection mechanism 1231 includes a pressure sensor disposed in the output chamber, and the target parameter is the pressure in the output chamber; the control output port of the pipette pump is configured to output a first level signal to the target motor to stop the target motor from driving the pipette tip when the target parameter meets the current liquid level detection conditions.

[0038] Specifically, the parameter detection mechanism shares a processor with the pipette pump; in other words, the processor of the pipette pump controls both the operation of the pipette pump and the operation of the parameter detection mechanism. The control output of the air pump is connected to the target motor 13, and the end of the air pump's output chamber 123 is connected to the pipette tip. A pressure sensor is installed in the output chamber; the target parameter is the air pressure in the output chamber. Since at least one air hole is provided at the end of the output chamber, and the chamber and the pipette tip are connected through this at least one air hole, the air pressure in the output chamber is related to the air pressure in the pipette tip. In other words, if the pipette tip touches the liquid surface, causing a change in its internal air pressure, the air pressure in the output chamber will also change accordingly. Therefore, the air pressure in the output chamber can also reflect the positional relationship between the pipette tip and the liquid surface.

[0039] For example, during the process of the target motor 13 driving the suction head towards the liquid surface to be measured, the air pump is set to draw air in real time, and the air pressure detection mechanism detects in real time whether the air pressure in the output cavity meets the current liquid surface detection conditions. In another example, before the target motor drives the suction head towards the liquid surface to be measured, the host computer controls the air pump to draw air at a set speed for a set time. Then, during the process of the target motor driving the suction head towards the liquid surface to be measured, the air pump exhausts air out in real time through the suction nozzle of the suction head. During the exhaust process, the air pressure sensor obtains in real time whether the air pressure in the output cavity meets the current liquid surface detection conditions. This embodiment has a simple structure and the accuracy of the collected air pressure data is high.

[0040] In one embodiment, the parameter detection mechanism 1231 is a capacitance detection device. The pipette pump includes an output chamber, and a pipette tip adapter is provided at the end of the output chamber. The pipette tip adapter is used to connect the pipette tip to the output chamber. The capacitance detection device is disposed on the pipette tip adapter and is used to detect the capacitance value of the pipette tip through the pipette tip adapter. Accordingly, the target parameter is the capacitance of the pipette tip.

[0041] Specifically, the suction head is made of a conductive material. When the target motor 13 drives the suction head 11 to move in the air, its capacitance remains constant. However, when it reaches the liquid surface and enters the liquid, its capacitance changes. Therefore, the parameter detection mechanism is configured to determine that the liquid surface has been detected when the detected capacitance change is greater than or equal to a set capacitance threshold. Simultaneously, it flips the output signal of its control output terminal from a second-level signal to a first-level signal, causing the target motor to stop driving the suction head under the action of this first-level signal.

[0042] In one embodiment, during the process of the target motor 13 driving the suction head 11 to move towards the liquid surface to be tested, the target parameter detected for the first time by the parameter detection mechanism 1231 is taken as the initial target parameter; the difference between the target parameter subsequently detected by the parameter detection mechanism and the initial target parameter is taken as the corresponding parameter change data.

[0043] In one embodiment, the parameter detection mechanism 1231 uses the difference between the target parameter collected at the next moment and the target parameter collected at the previous moment as parameter change data.

[0044] In one embodiment, during the movement of the suction head toward the current liquid surface to be measured, the parameter detection mechanism is configured to output a second level signal to the target motor.

[0045] Specifically, the host computer 14 is used to input a movement command to the input port of the target motor 13. The movement command sets the level signal of the target motor 13 control input port to a second level signal. The second level signal causes the target motor 13 to drive the pipette tip towards the current liquid surface to be measured. When the parameter detection mechanism 1231 detects that the target parameters meet the current liquid surface detection conditions, it flips the second level signal to a first level signal, so that the target motor stops driving the pipette tip based on the first level signal. Optionally, the parameter detection mechanism 1231 and the target motor 13 are configured to be directly connected via I / O signals. The second level signal can be a low level signal, and the first level signal can be a high level signal. This embodiment allows the target motor 13 to brake quickly without the host computer 14 participating in the braking process of the target motor 13, improving the braking speed of the target motor 13 and the speed at which the pipette tip stops moving, thereby improving the safety of the pipetting device operation.

[0046] In one embodiment, the absolute value of the difference between the voltage corresponding to the second level signal and the voltage corresponding to the first level signal is greater than or equal to 5V. This embodiment can achieve better target motor control effect.

[0047] In one embodiment, the parameter detection mechanism 1231 can be configured to output a first-level signal to the control input port, emergency stop port, or limit port of the target motor. It is understood that the target motor 13 only needs to be able to immediately perform an emergency stop operation upon detecting the second-level signal. This embodiment provides multiple optional connection methods between the parameter detection mechanism 1231 and the target motor 13, improving the flexibility of target motor port processing.

[0048] For the host computer 14, after detecting that the target motor 13 has stopped rotating, it needs to determine whether it stopped driving the suction head to move when the liquid level was detected. In one embodiment, if the target motor 13 is detected to have stopped driving the suction head to move, and the suction nozzle position of the suction head corresponding to the current target parameter is below the current liquid level to be measured, it is determined that the target motor 13 stopped driving the suction head to move when the liquid level was detected.

[0049] Specifically, after detecting that the target motor 13 has stopped driving the suction head, the host computer 14 acquires the latest target parameters generated by the parameter detection mechanism 1231, as well as the target parameter change data corresponding to the latest target parameters, and determines whether the target parameter change data is greater than or equal to the set parameter threshold. If so, it is determined that the target parameters meet the current liquid level detection conditions, that is, the suction nozzle position of the suction head is at or below the current liquid level to be measured. Therefore, it is determined that the target motor 13 stopped rotating when the liquid level was detected. It can be understood that if the target change data is not less than the set parameter threshold, it means that the target motor did not stop driving the suction head because the detection was complete, but because of other reasons.

[0050] In one embodiment, the host computer is further configured to control the pipette pump to draw liquid when it detects that the target motor 13 has stopped driving the pipette tip and the nozzle position of the pipette tip corresponding to the current target parameter is below the current liquid surface. Drawing liquid after the pipette tip has stopped moving improves the safety of the pipette tip's liquid aspiration.

[0051] In one embodiment, the host computer is further configured to, upon detecting that the target motor 13 has stopped driving the pipette tip, and that the nozzle position of the pipette tip corresponding to the current target parameter is below the current liquid surface to be measured, control the pipette tip to descend to a corresponding depth based on the position information of the current liquid surface to be measured and the solution height corresponding to the current liquid transfer volume, and control the pipette tip to aspirate liquid after descending to the corresponding depth. Controlling the pipette tip to descend to the corresponding depth before aspirating liquid after it stops moving improves the safety and efficiency of liquid aspiration.

[0052] In one embodiment, the parameter detection mechanism 1231 is configured to generate a detection position marker while outputting a first level signal to the target motor 13 to stop the target motor 13 from driving the suction head. The host computer 14 is configured to determine whether the target motor stops driving the suction head when the liquid surface is detected based on whether the detection position marker is detected, and to determine whether the process of determining the position information of the current liquid surface to be measured needs to be executed based on whether the target motor stops driving the suction head when the liquid surface is detected.

[0053] Specifically, before parsing the current encoded data of the target motor 13 encoder to obtain the parsing result, the host computer detects the detection positioning signal. If the detection positioning indicator is detected, it determines that the target motor 13 has stopped driving the suction head when the liquid surface is detected, and then enters the current encoded data parsing process. If the detection positioning indicator is not detected, it waits for a set waiting time and then queries the detection positioning indicator again until the detection positioning indicator is detected. The host computer can be configured to actively obtain the detection positioning indicator from the parameter detection mechanism, or to determine whether a detection positioning indicator sent by the parameter detection mechanism has been received within a set time period. This embodiment allows the host computer 14 to avoid participating in the braking process of the target motor and to quickly obtain the detection positioning indicator indicating that the target motor 13 has stopped driving the suction head, improving the speed of determining the reason for the target motor stopping. This allows the host computer to start parsing the current encoded data of the target motor with less time delay and to determine the current detection liquid surface position information based on the parsing result, which helps to improve the speed and accuracy of determining the current detection liquid surface position.

[0054] In one embodiment, after the parsing result of the current encoded data of the target motor 13 encoder is determined, the position of the suction nozzle corresponding to the parsing result is determined according to the pre-created correspondence between the parsing result and the nozzle position. This nozzle position is used as the position information of the current liquid surface to be measured, wherein the suction nozzle is the port where the solution enters the suction head. This embodiment can quickly determine the position information of the current liquid surface to be measured based on the parsing result.

[0055] In one embodiment, after the position of the suction head is determined, the current target parameters and the target parameter change data corresponding to the current target parameters are acquired; based on the pre-created correspondence between the parameter change data and the suction head insertion depth, the suction head insertion depth corresponding to the target parameter change data is determined; and the position information of the liquid surface to be measured is determined based on the suction head position and the suction head insertion depth. Specifically, the sum of the suction head position and the suction head insertion depth is used as the position information of the liquid surface to be measured. The suction head insertion depth is the depth to which the suction head is submerged in the liquid corresponding to the liquid surface to be measured. Introducing the suction head insertion depth reduces errors caused by excessively large time interval settings or the inability of the target motor to brake instantly, thereby improving the accuracy of the position information of the liquid surface to be measured.

[0056] Since the target parameters associated with the suction head 11 meet the current liquid level detection conditions, it means that the suction head has touched the current liquid surface to be measured. The position information of the current liquid surface to be measured is determined based on the position of the suction nozzle. The position of the suction nozzle is determined based on the parsing result of the current encoded data of the target motor. The current encoded data of the target motor is determined based on the stopping time of the target motor. Therefore, the more timely the braking of the target motor, the smaller the distance between the suction nozzle position corresponding to the parsing result of its encoded data and the current liquid surface to be measured. Thus, the accuracy of the position information of the current liquid surface to be measured determined based on the position of the suction nozzle is higher.

[0057] In one embodiment, the host computer is further configured to: determine whether there is another liquid surface to be tested in the target liquid; if there is another liquid surface to be tested, then take the next liquid surface to be tested as the current liquid surface to be tested, and obtain the current liquid surface detection conditions corresponding to the current liquid surface to be tested, control the target motor 13 to drive the suction head 11 to move towards the current liquid surface to be tested; and after the position information of the current liquid surface to be tested is determined, take the position information of the current liquid surface to be tested as the position information of the next liquid surface to be tested. In this embodiment, the current liquid surface detection conditions are determined based on the difference in parameter change data when the suction head moves in the liquid on both sides of the current liquid surface to be tested. This embodiment achieves the technical effect of automatically determining the position information of different detection liquid surfaces in the target liquid.

[0058] A pipetting device can be assembled from components of different combinations. While the process of moving the pipetting tip towards the liquid surface using the target motor until the position of the liquid surface is determined is the same or similar for each component combination, there are slight differences in the processing flow before the target motor moves the pipetting tip towards the liquid surface. Taking a pressure sensor as an example, the specific differences are as follows:

[0059] In one embodiment, the pipetting device includes a pipette tip 11, a pipetting pump 12, a target motor 13, a host computer 14, and other motion axes. The target motor 13 is a motor with integrated drive and control, and the pipetting pump is an air pump including a parameter detection mechanism. The parameter detection mechanism includes a pressure sensor disposed in the output chamber of the air pump, and the pressure sensor shares a processor with the pipetting pump. Connect and fix the air pump, target motor, host computer, and other motion axes. Connect the air pump to the host computer using the corresponding 485 serial communication method (or 232, Modbus, EtherCAT, CAN bus, etc.). Similarly, connect the target motor (lead screw motor, synchronous belt motor, rack and pinion motor, etc.) to the host computer using the corresponding Modbus (or 232, 485, EtherCAT, CAN bus, etc.) communication method. Configure the air pump's control output port to continuously output a second-level signal (low level signal, high level signal, rising edge, or falling edge) after the pressure change reaches a set threshold. Use debugging software to set the target motor's control input port to enable (or disable, limit, or emergency stop, etc.) port, making the second-level signal (low level signal, high level signal, rising edge, or falling edge) valid. Connect the air pump's control output port and the target motor's control input port using a connecting cable. Attach the suction head to the output port of the air pump's output chamber and reset the air pump's control output port to continuously output the second-level signal. The host computer sends an air intake command to the air pump, causing it to draw in sufficient air. The air pump then activates pressure change detection via a pressure sensor in its output chamber, setting the first acquired pressure value as the initial pressure value. The air pump records the pressure value at regular intervals (10ms, 50ms, or 100ms, etc.). The host computer sends an exhaust command to the air pump, causing it to expel air at a preset speed. Finally, the host computer sends a movement command to the target motor, controlling it to move the air pump and suction head towards the liquid surface at a predetermined speed. In this embodiment, the air pump's processor generates a detection status indicator when it detects that the target parameters meet the current liquid surface detection conditions, and sends this indicator to the host computer. This embodiment combines an air pump with a pressure sensor and a motor with integrated drive and control to perform liquid surface detection and suction head movement braking during the liquid transfer process. The process is simple and highly practical.

[0060] In one embodiment, compared to the previous embodiments, the target motor in this embodiment is not an integrated drive and control motor, but includes a motor controller, a motor driver, and a motor body. The air pump, motor controller, motor driver, motor body, host computer, and other motion axes are hardware-connected and their positions are fixed. Specifically, the air pump is connected to the host computer via a corresponding 485 serial communication (or 232, Modbus, EtherCAT, CAN bus, etc.). Similarly, the motor body (lead screw motor, synchronous belt motor, rack and pinion motor, etc.) is connected to the driver, and the driver is connected to the motor controller. The motor controller is connected according to a set communication method (Modbus, EtherCAT, Ethernet, CAN, CANopen, or Prof). Connect the air pump (e.g., inet) to the host computer; configure the air pump's control output port to continuously output a second-level signal (low-level signal, high-level signal, rising edge, or falling edge) after the pressure change reaches a set threshold; use debugging software to set the motor controller's control input port to enable (or disable, limit, or emergency stop, etc.) port, and the second-level signal (low-level signal, high-level signal, rising edge, or falling edge, etc.) is valid; connect the air pump's control output port and the motor controller's control input port using a connecting cable; install the suction head on the air pump and reset the air pump's control output port to continuously output the second-level signal. During operation, the host computer sends an air intake command to the air pump, causing it to draw in sufficient air. Simultaneously, it controls the pressure sensor to detect pressure changes, setting the first acquired pressure value as the initial pressure. The pressure sensor collects pressure values ​​at regular intervals (10ms, 50ms, or 100ms, etc.). The host computer sends an exhaust command to the air pump, causing it to expel air at a preset speed. Finally, the host computer sends a movement command to the motor controller, instructing the motor to move the air pump and suction head towards the liquid surface at a predetermined speed. This embodiment combines an air pump with a pressure sensor with a non-drive-controlled integrated motor for liquid level detection and suction head braking during the pipetting process, demonstrating strong practicality.

[0061] In one embodiment, the pipette pump includes an output chamber, which is equipped with a parameter detection mechanism. The parameter detection mechanism includes a pressure sensor that extends into the pipette tip. The target motor is an integrated drive and control motor. The parameter detection mechanism is connected to the host computer hardware via a corresponding 485 serial communication (or alternatively, 232, Modbus, EtherCAT, CAN bus, etc.). Similarly, the target motor (lead screw motor, synchronous belt motor, rack and pinion motor, etc.) is connected to the host computer via a corresponding Modbus (or alternatively, 232, 485, EtherCAT, CAN bus, etc.) communication. The control output port of the parameter detection mechanism is configured to continuously output a second-level signal (low-level signal, high-level signal, rising edge, or falling edge signal) after the pressure change reaches a set threshold. The control input port of the target motor is configured using debugging software. The port is set to enable (or disable, limit, or emergency stop, etc.), and the second-level signal (low-level signal, high-level signal, rising edge, or falling edge, etc.) is valid. A connecting cable is used to connect the control output port of the parameter detection device and the control input port of the target motor. The control output port of the parameter detection device is reset to continuously output the second-level signal. The pressure sensor is controlled to start detecting pressure changes, and the first obtained pressure value is set as the initial pressure value. The pressure sensor records a pressure value at regular intervals (10ms, 50ms, or 100ms, etc.). The host computer sends a movement command to the target motor, causing the target motor to drive the air pump and suction head to move towards the liquid surface at a predetermined speed. It is understood that the integrated drive and control motor in this embodiment can be replaced with a non-integrated drive and control motor; the specific implementation method is not described in detail here.

[0062] The technical solution provided by this invention involves a parameter detection mechanism sending a first-level signal to the target motor to brake it when the target parameter associated with the pipette tip position meets the current liquid level detection conditions. Based on this first-level signal, the target motor immediately stops driving the pipette tip. Compared to the host computer obtaining a detection position marker from the parameter detection mechanism and then outputting a first-level signal to the target motor to stop the pipette tip movement, this method avoids situations where the pipette tip touches the bottom due to communication failure between the parameter detection mechanism and the host computer, or where communication delays between the parameter detection mechanism and the host computer cause the target motor to stop untimely. This significantly improves the timeliness of the target motor braking, reduces the depth of the pipette tip when it stops moving, and enhances the safety of the pipetting device operation.

[0063] Figure 3 This is a flowchart of a liquid level detection method provided in an embodiment of the present invention. This method is applicable to scenarios where, during liquid transfer using a pipetting device, the parameter detection mechanism detects that the pipette tip has reached the liquid surface, and controls the target motor to stop moving the pipette tip. Figure 3As shown, the method includes:

[0064] S110. When it is detected that the pipette tip is moving towards the current liquid surface to be measured, a target parameter associated with the position of the pipette tip is obtained based on a set time interval. The target parameter can reflect the positional relationship between the pipette tip and the current liquid surface to be measured.

[0065] The target parameter can be the gas pressure in the output chamber of the pipette pump or the capacitance of the pipette tip.

[0066] If the target parameter or the change data of the target parameter is within the corresponding threshold range, it is determined that the pipette tip is above the current liquid surface to be tested; if the target parameter or the change data of the target parameter is not within the corresponding threshold range, it is determined that the pipette tip has at least reached the current liquid surface to be tested.

[0067] In one embodiment, the host computer sends a movement command to the target motor and the parameter detection mechanism. The movement command is a second-level signal input to the control input terminal of the target motor. The second-level signal causes the target motor to drive the suction head to move towards the current liquid surface to be tested. The movement command controls the parameter detection mechanism to start parameter detection to obtain the target parameters associated with the position of the suction head based on a set time interval.

[0068] In one embodiment, the pipette pump is configured to vent air during the pipette tip descent process; upon receiving a movement command from a host computer, the pipette pump performs the venting operation and controls the sensor included in the parameter detection mechanism to collect target parameters associated with the pipette tip position.

[0069] When the parameter detection mechanism detects that the suction head is moving toward the current liquid surface to be measured, it outputs a second level signal to the target motor and obtains the target parameters associated with the position of the suction head through the parameter detection mechanism based on a set time interval.

[0070] For example, consider a scenario where the parameter detection mechanism is integrated with a pipette pump (air pump). Upon receiving a parameter detection command from the pipette pump, the pressure sensor determines that the target motor is driving the pipette tip towards the current liquid surface to be measured. Therefore, it uses the target parameter associated with the pipette tip position at set time intervals and continuously outputs a second-level signal to the target motor. If the detected target parameter matches the current liquid surface detection conditions, the second-level signal is flipped to a first-level signal. In one embodiment, the second-level signal and the first-level signal are two opposite level signals.

[0071] For example, in a scenario where the parameter detection mechanism and the pipette pump are independent, the host computer sends a second-level signal to the target motor, and simultaneously sends agreed-upon signals to the pipette pump and the parameter detection mechanism. This causes the pipette pump to draw in or expel air as the pipette tip moves toward the currently detected liquid surface, and causes the parameter detection mechanism to determine that the pipette tip is moving toward the currently detected liquid surface and activate the parameter detection function.

[0072] S120. If the target parameters meet the current liquid level detection conditions, output a first level signal to the target motor to stop the target motor from driving the suction head.

[0073] If the target parameter or the change in the target parameter is not within the corresponding threshold range, it is determined that the target parameter or the change in the target parameter meets the current liquid level detection conditions, that is, the nozzle has reached the current liquid level, or the current liquid level position has been detected. Therefore, a first level signal is output to the target motor so that the target motor stops driving the nozzle movement under the control of the first level signal.

[0074] In one embodiment, the second level signal and the first level signal are two completely opposite level signals, such as a low level signal and a high level signal.

[0075] The technical solution of the liquid level detection method provided in this invention involves a parameter detection mechanism acquiring target parameters associated with the position of the pipette tip based on a set time interval during the movement of the pipette tip toward the liquid surface to be measured. When the target parameters meet the current liquid level detection conditions, the mechanism directly outputs a first-level signal to the target motor to stop the target motor from driving the pipette tip, without having to indirectly brake the target motor through the host computer. This improves the timeliness of the target motor braking, reduces the depth of the pipette tip when it stops moving, and improves the safety of the pipetting device movement.

[0076] It should be noted that for any parts of the present invention not described in detail in the embodiments, please refer to the foregoing embodiments.

[0077] The specific embodiments described above do not constitute a limitation on the scope of protection of this invention. Those skilled in the art should understand that various modifications, combinations, sub-combinations, and substitutions can be made according to design requirements and other factors. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of this invention should be included within the scope of protection of this invention.

Claims

1. A pipetting device, characterized in that, Includes pipette tips, pipette pumps, target motors, and host computers; Both the target motor and the pipette pump are communicatively connected to the host computer. The pipette pump is used to control the suction and discharge of liquid by the pipette tip, and includes a parameter detection mechanism, which is communicatively connected to the target motor. The host computer is used to control the target motor to drive the suction head to move toward the liquid surface to be measured; The parameter detection mechanism is used to acquire target parameters associated with the position of the suction head based on a set time interval during the movement of the suction head toward the current liquid surface to be measured. When the target parameters meet the current liquid surface detection conditions, the mechanism outputs a first level signal to the target motor to stop the target motor from driving the suction head to move. The target parameters can reflect the positional relationship between the suction head and the current liquid surface to be measured.

2. The apparatus according to claim 1, characterized in that, The host computer is also used to determine the position information of the current liquid surface to be measured based on the position parameters of the target motor when the liquid surface is detected to be in place and the target motor stops operating.

3. The apparatus according to claim 1, characterized in that, During the movement of the suction head toward the current liquid surface to be measured, the parameter detection mechanism is configured to output a second level signal to the target motor.

4. The apparatus according to claim 1, characterized in that, The parameter detection mechanism is configured to generate a detection positioning mark while outputting the first level signal to the target motor to stop the target motor from driving the suction head to move. The host computer is configured to determine whether the target motor stops driving the suction head when the liquid surface is detected based on whether the detection mark is detected, and to execute the current liquid surface position information determination process when the target motor stops driving the suction head when the liquid surface is detected.

5. The apparatus according to claim 2, characterized in that, When the liquid level is detected and the target motor stops operating, determining the position information of the current liquid level to be measured based on the position parameters of the target motor includes: When it is detected that the target motor has stopped driving the suction head, and the suction head position corresponding to the current target parameters is below the current liquid surface to be measured, the position information of the current liquid surface to be measured is determined according to the current encoding data of the target motor encoder.

6. The apparatus according to claim 1, characterized in that, The pipette pump includes an output chamber; The parameter detection mechanism includes a pressure sensor disposed in the output cavity, and the target parameter is the pressure in the output cavity; The control output port of the pipette pump is configured to output a first level signal to the target motor to stop the target motor from driving the pipette tip when the target parameters meet the current liquid level detection conditions.

7. The apparatus according to claim 1, characterized in that, The parameter detection mechanism is a capacitance detection device; The end of the pipette pump is provided with a pipette tip adapter, which is used to connect the pipette tip; The capacitance detection device is disposed on the suction head adapter and is used to detect the capacitance value of the suction head through the suction head adapter.

8. A method for detecting liquid levels, characterized in that, A pipetting pump used in any one of the pipetting apparatuses of claims 1-7, comprising: When the movement of the suction tip toward the current liquid surface to be measured is detected, a target parameter associated with the position of the suction tip is obtained based on a set time interval, wherein the target parameter can reflect the positional relationship between the suction tip and the current liquid surface to be measured; If the target parameters meet the current liquid level detection conditions, a first level signal is output to the target motor to stop the target motor from driving the suction head.

9. The method according to claim 8, characterized in that, Also includes: When the suction head is detected to be moving toward the current liquid surface to be measured, a second level signal is output to the target motor, and the target parameters associated with the position of the suction head are obtained by the parameter detection mechanism based on a set time interval.

10. The method according to claim 8, characterized in that, The target parameter is either the gas pressure in the output chamber of the pipette pump or the capacitance of the pipette tip.

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