AD self-adaptive calibration method for sampling probe of biochemical analyzer

Abstract

The invention discloses an AD self-adaptive calibration method for a sampling needle of a biochemical analyzer, and relates to the technical field of medical instruments, in order to solve the problem of deviation of a liquid level detection module and realize automatic deviation calibration of the sampling needle, sampling is calibrated by comparing real-time V-Data and VLiquid of sampling, and the AD self-adaptive calibration method has the beneficial effects that 1, a self-calibration mode of starting each time is adopted, so that the sampling accuracy is improved; inaccurate liquid level detection caused by needle point aging or dirt staining is avoided; 2, each liquid level detection module does not need to be detected and calibrated manually during batch production, so that manpower and time cost are saved; 3, environment temperature detection is added in the method, so that inaccurate detection of the liquid level of the sampling needle due to environment temperature change is avoided.

Description

Technical Field

[0001] This application relates to the technical field of medical devices, and particularly to an AD adaptive calibration method for a sampling needle of a biochemical analyzer. Background Art

[0002] During the process of project testing by the sampling needle of a fully automatic biochemical analyzer, it is necessary to aspirate reagents and the reagent and sample solution in the sample cup. This requires the sampling needle movement unit to detect the liquid level during the vertical descent to the reagent and the sample cup. After detecting the liquid level, the sampling needle movement unit stops the vertical movement and aspirates the sample. Since the capacitance value changes when the sampling needle touches the liquid level, the capacitance signal can be differentially amplified by a hardware circuit to obtain the required electrical signal, and then the microcontroller unit detects the change in the magnitude of the electrical signal value to determine whether it touches the liquid level.

[0003] During the mass production of biochemical analyzers, affected by the circuit board and the deviation of the incoming sampling needle, it is necessary to perform AD calibration on each liquid level detection module. It is necessary to measure and store the AD values of each module in air and in the liquid level as the judgment condition for software liquid level detection. This method will detect the liquid level incorrectly due to the deviation of the AD reference value when the environmental temperature of the sampling needle changes, ages, or gets stained. Each time the sampling needle is repaired and replaced, it is also necessary to recalibrate, and more cumbersome production processes need to be added, consuming more labor and time costs. Summary of the Invention

[0004] The purpose of the present invention is to provide an AD adaptive calibration method for a sampling needle of a biochemical analyzer, solve the problem of deviation of the liquid level detection module, realize automatic calibration of the deviation of the sampling needle, and reduce the costs of development, production, and maintenance.

[0005] The present invention realizes the purpose of the invention through the following technical solutions: An AD adaptive calibration method for a sampling needle of a biochemical analyzer, the calibration method includes the following steps: 1) Obtain a stable air capacitance value V _Air : Turn on the biochemical analyzer. After startup, the AD value detection module collects n AD values, and sends the collected AD values to the processor. The processor uses the bubble sort algorithm to sort them in size: V(0), V(1), V(2)...V(n - 1). After removing the maximum and minimum values, calculate the average V _Air = / (n - 2); 2) Each time a sample is taken, collect the real-time AD value of the sample in real time, and send the real-time AD value of the sample to the processor to obtain V -Data , 3) Obtain the capacitance difference between the tip of the needle in air and in the liquid level as △V t: The temperature sensor samples the real-time ambient temperature T, and then sends the sampled real-time ambient temperature T to the processor. The processor calculates △V according to △V t = -0.1271*T² + 8.0588*T + 208.33 t ; 4) The processor calculates the liquid level capacitance value V according to the liquid level detection formula _Liquid = V _Air + △Vt to obtain V _Liquid ; 5) The processor compares V -Data and V _Liquid : If V -Data is greater than V _Liquid , it means that the liquid level is detected, and the sampling operation is directly performed. If V -Data is less than V _Liquid , it means that the liquid level is not detected. If the liquid level is detected, steps 2)-5) are restarted until the sampling operation can be performed.

[0006] The present invention also provides a biochemical analyzer sampling needle AD adaptive calibration system, including a processor and a biochemical analyzer sampling needle that receives the sampling signal of the processor for sampling. The calibration system further includes an AD value detection module and a temperature sensor connected to the processor. The AD value detection module is used to collect n AD values and the current AD value V -Data after the biochemical analyzer is powered on. The temperature sensor is used to detect the current ambient temperature T. The processor first sorts the obtained AD values in ascending order using the bubble sort algorithm: V(0), V(1), V(2)...V(n - 1), removes the maximum and minimum values, and then calculates the average V _Air = / (n - 2). Then, according to the formula △V t = -0.1271*T² + 8.0588*T + 208.33, △V is calculated t . Furthermore, according to V _Liquid = V _Air + △Vt, the liquid level judgment formula is obtained. Finally, V -Data and V _Liquid are compared to determine whether the sampling is completed. If the sampling is not completed, the sampling operation is restarted.

[0007] The beneficial effects of the present invention are as follows: 1. By adopting the method of self-calibration at each startup, the liquid level detection will not be inaccurate due to the aging of the needle tip or dirt contamination; 2. When mass-producing, there is no need for manual detection and calibration of each liquid level detection module, saving labor and time costs; 3. This method adds environmental temperature detection, and the liquid level detection of the sampling needle will not be inaccurate due to environmental temperature changes, which can greatly improve the adaptability of the liquid level detection module; 4. Each time the sampling needle is repaired and replaced, there is no need for re-calibration, and self-calibration using this method can improve the work efficiency of maintenance engineers; 5. Through this algorithm, the sampling needle module of this biochemical analyzer is more stable and durable than similar products. Brief Description of the Drawings

[0008] Figure 1 It is a flowchart of the adaptive calibration method of the present invention; Figure 2 It is a line graph between environmental temperature and capacitance deviation. Detailed Embodiment

[0009] The following further explains and illustrates the present invention in combination with the detailed embodiment.

[0010] To solve the problem of capacitance deviation caused by dirty needle tips, the present invention no longer adopts the method of storing a fixed air capacitance value of the needle tip during production, avoiding deviation after aging or stain contamination; instead, it automatically collects and calibrates the air capacitance value V at each startup. _Air Perform acquisition and calibration, continuously take n-point AD values through the bubble sort algorithm and sort them by size to obtain: V(0), V(1), V(2)...V(n - 1); then according to the mean filtering algorithm, remove the maximum and minimum values and calculate the average V. _Air Obtain: V _Air = / (n - 2); Using the above formula, a real-time and stable V can be obtained at each startup. _Air .

[0011] To solve the problem of capacitance deviation caused by environmental temperature; hardware-wise, a temperature sensor is used to measure the current environmental temperature T of the sampling. Let the capacitance difference between the needle tip in air and liquid be △V. t , according to the relationship between the temperature T and the capacitance difference △V. t , calibrate it: △V t = -0.1271*T² + 8.0588*T + 208.33; This formula is obtained by fitting after collecting the changes in environmental temperature data of multiple sampling needles, as shown in Figure 2 . Based on the above parameters, the liquid level detection judgment formula is obtained as: V _Liquid = V _Air + △Vt; Please refer to Figure 1 , for the AD adaptive calibration method of the sampling needle of the biochemical analyzer provided by the present invention, the calibration method includes the following steps: 1) Obtain the stable air capacitance value V _Air : Turn on the biochemical analyzer. After startup, the AD value detection module collects n AD values, and sends the collected AD values to the processor. The processor uses the bubble sort algorithm to sort them by size: V(0), V(1), V(2)...V(n - 1). After removing the maximum and minimum values, calculate the average: V _Air = / (n - 2); 2) Each time a sample is taken, the real-time AD value of the sample is collected in real time, and the real-time AD value of the sample is sent to the processor to obtain V -Data ; 3) Obtain the capacitance difference △V between the tip of the needle in air and the liquid surface t : The temperature sensor collects the real-time ambient temperature T of the sample, and then sends the real-time ambient temperature T of the sample to the processor. The processor calculates △V according to △V t =-0.1271*T² + 8.0588*T + 208.33 t ; 4) The processor calculates V according to the liquid surface detection formula V _Liquid = V _Air + △Vt _Liquid ; 5) The processor compares V -Data and V _Liquid : If V -Data is greater than V _Liquid , it means that the liquid surface has been detected, and the sampling operation can be directly performed. If V -Data is less than V _Liquid , it means that the liquid surface has not been detected. If the liquid surface is detected, restart steps 2)-5) until the sampling operation can be performed. Since the sampling operation is calibrated, the detection result will not be affected by the capacitance deviation problem caused by the dirty tip of the needle and the capacitance deviation problem caused by the ambient temperature.

[0012] Therefore, the present invention only needs to update the software algorithm of the sampling needle liquid surface detection module in the original system to realize the self-calibration of the deviation value of the sampling needle. When this method is implanted into a 200-speed biochemical analyzer, its detection parameters and results are shown in Table 1, and repeated tests are carried out at different ambient temperatures: Table 1

[0013] After correction, it can accurately detect the liquid level; and simulate the state of the needle tip aging and being stained, and conduct the test repeatedly again, without any abnormal detection problems occurring.

Claims

1. An AD self - adaptive calibration method for the sampling needle of a biochemical analyzer, characterized in that, The calibration method described above includes the following steps: 1) Obtain the stable air capacitance value V _Air : Turn on the biochemical analyzer. After startup, the AD value detection module collects n AD values and sends the collected AD values to the processor. The processor uses the bubble sort algorithm to sort them by size: V(0), V(1), V(2)...V(n - 1). After removing the maximum and minimum values, calculate the average V _Air = / (n - 2); 2) During each sampling, the real-time AD value of the sampling is collected in real time, and the real-time AD value of the sampling is sent to the processor to obtain V -Data ; 3) Obtain the capacitance difference ΔV between the tip of the needle in air and the liquid surface t : The temperature sensor collects and samples the real-time ambient temperature T, and then sends the sampled real-time ambient temperature T to the processor. The processor calculates ΔV according to ΔV t = -0.1271*T² + 8.0588*T + 208.33 t ; 4) The processor calculates the liquid level capacitance value V according to the liquid level detection formula _Liquid = V _Air + △Vt to calculate and obtain V _Liquid ; 5) The processor compares V -Data with V _Liquid : If V -Data is greater than V _Liquid , it means the liquid level has been detected, and the sampling operation is directly carried out. If V -Data is less than V _Liquid , it means the liquid level has not been detected. If the liquid level is detected, steps 2)-5) are restarted until the sampling operation can be carried out.

2. A biochemical analyzer sampling needle AD adaptive calibration system, comprising a processor and a biochemical analyzer sampling needle that receives the sampling signal of the processor for sampling, characterized in that, The calibration system further includes an AD value detection module and a temperature sensor connected to the processor. The AD value detection module is used to collect n AD values and the current AD value V after the biochemical analyzer is powered on. -Data The temperature sensor is used to detect the current ambient temperature T. The processor first sorts the obtained AD values in ascending order using the bubble sort algorithm: V(0), V(1), V(2)...V(n - 1). After removing the maximum and minimum values, the average value V _Air = / (n - 2). Then, according to the formula △V t = -0.1271*T² + 8.0588*T + 208.33, the value of △V is calculated. t Furthermore, based on V _Liquid = V _Air + △Vt, the liquid level judgment formula is obtained. Finally, V -Data and V _Liquid are compared to determine whether the sampling is completed. If the sampling is not completed, the sampling operation is repeated.

Images