A system and method for monitoring the liquid level of an infusion bag, and a method for fabricating a flexible leaky optical fiber.

Abstract

This invention discloses an infusion bag level monitoring system, method, and flexible leaky optical fiber fabrication method, relating to the field of optical fiber sensing technology. The system includes: a light-emitting diode (LED), an infusion bag, a flexible leaky optical fiber level sensor, an optical signal acquisition unit, and a data processing unit. The flexible leaky optical fiber level sensor is disposed inside the infusion bag, with the LED and optical signal acquisition unit respectively located at its two ends. The LED provides an optical signal to the flexible leaky optical fiber level sensor. The flexible leaky optical fiber level sensor detects the change in the optical signal output due to variations in the refractive index of the medium on the surface of the optical fiber inside the infusion bag. The optical signal acquisition unit converts the output optical signal into a digital signal and transmits it to the digital processing unit. The data processing unit analyzes and processes the digital signal to obtain the liquid level height information. The above-mentioned solution in this invention can achieve high-precision measurement and is unaffected by environmental interference.

Description

Technical Field

[0001] This invention relates to the field of fiber optic sensing technology, and in particular to a flexible leaky fiber optic liquid level sensor, its preparation method, and a liquid level monitoring method. Background Technology

[0002] Intravenous infusion is a common auxiliary medical treatment in clinical medicine. Traditional infusion monitoring relies on manual monitoring. However, due to the long infusion process, busy medical staff, patients' drowsiness due to their condition, and fatigue and distraction of caregivers during extended periods, these manual monitoring methods can lead to delayed medical intervention when abnormalities occur in the infusion system. Especially at the end of the infusion, failure to remove the needle promptly can result in consequences such as blood backflow, blood clotting, and air embolism, which can delay treatment or even lead to medical accidents. Improving the safety and reliability of intravenous infusion therapy has always been a problem for the medical industry. Timely and accurate infusion monitoring can effectively improve the safety of intravenous infusions. Currently, the most widely used level monitoring devices are mostly based on capacitive sensors, ultrasonic sensors, and weighing sensors. However, capacitive level sensors are prone to false continuity when the conductive electrodes are splashed by liquid, making calibration difficult and reducing the reliability of level detection. Ultrasonic level measurement suffers from significant errors in the presence of air bubbles in the liquid, requiring complex correction algorithms to compensate for the detected signal. Weighing sensor-based liquid level monitoring devices are bulky, expensive, and susceptible to interference from external forces during intravenous infusion. For these reasons, the application of these sensors is often limited, failing to meet the medical environment requirements for intravenous infusion in patients. Flexible fiber optic sensors, with their advantages of small size, high flexibility, high security, high stability, and resistance to electromagnetic interference, are an effective means to solve these problems.

[0003] By comparing the shortcomings and defects of traditional sensors in measuring liquid level, a liquid level monitoring sensor for infusion bags based on polymer near-infrared flexible leaky optical fiber was designed. Flexible optical fiber offers advantages such as high sensitivity, fast transmission speed, good stability in harsh environments, and strong resistance to electromagnetic interference. Therefore, replacing traditional electronic sensing elements with fiber optic sensing technology is an ideal way to improve performance. Furthermore, combining image processing technology enables accurate liquid level measurement.

[0004] Fiber optic sensing technology can be applied to various fields, including medical and biochemical, power, petrochemical, aerospace, environmental protection, and national defense.

[0005] Existing infusion bag level monitoring based on fiber optic sensing technology mainly falls into the following two categories:

[0006] Pressure-type fiber optic liquid level sensors: These sensors utilize the pressure exerted by the liquid height on a fiber optic sensing probe, and calculate the liquid level from the signal from the probe. In recent years, two types of pressure-type fiber optic liquid level sensors have been extensively researched: fiber optic Fabry-Perot cavity (FBC) level sensors and fiber Bragg grating (FBG) level sensors. FBC level sensors cannot perform absolute liquid level measurement, while FBG level sensors face challenges in wavelength demodulation technology, and demodulators are expensive. Furthermore, the accuracy of liquid pressure conversion is difficult to guarantee in both methods, thus affecting measurement accuracy.

[0007] Reflective fiber optic liquid level sensor: The reflective fiber optic sensor uses the liquid level to be measured as a reflective plane. The light output from the optical fiber is perpendicular to the liquid surface. After being reflected by the liquid surface, the light intensity enters the optical fiber perpendicular to the liquid surface. The height of the liquid level can be measured by detecting the change in light intensity in the optical fiber. Therefore, it is a type of intensity modulation fiber optic liquid level sensor. Summary of the Invention

[0008] The purpose of this invention is to provide a flexible leaky fiber liquid level sensor, its preparation method, and a liquid level monitoring method. By utilizing the excellent properties of the flexible fiber itself, high-precision measurement can be achieved without being affected by environmental interference.

[0009] To achieve the above objectives, the present invention provides the following solution:

[0010] In a first aspect, the present invention provides an infusion bag level monitoring system, comprising:

[0011] Light-emitting diode, infusion bag, flexible leak-proof fiber optic liquid level sensor, optical signal acquisition unit, and data processing unit;

[0012] The flexible leaky fiber optic liquid level sensor is installed inside the infusion bag, and the light-emitting diode and the optical signal acquisition unit are respectively installed at both ends of the flexible leaky fiber optic liquid level sensor.

[0013] The light-emitting diode is used to provide an optical signal for the flexible leaky fiber optic liquid level sensor;

[0014] The flexible leaky fiber optic liquid level sensor is used to detect the optical signal output after the optical signal changes due to the change in the refractive index of the medium on the surface of the optical fiber inside the infusion bag.

[0015] The optical signal acquisition unit is used to convert the output optical signal into a digital signal and transmit the acquired digital signal to the digital processing unit;

[0016] The data processing unit is used to analyze and process the digital signal to obtain the liquid level height information.

[0017] Optional, also includes:

[0018] A filter is used to filter out interference signals from natural light.

[0019] Optionally, the flexible leaky fiber optic level sensor includes a fully clad reference fiber and a leaky fiber, wherein the fully clad reference fiber and the leaky fiber are bonded together.

[0020] Optionally, the proportional changes in the fully clad reference fiber and the leaky fiber due to deformation can be corrected using a modified grayscale formula, as follows:

[0021]

[0022] Where L is the initial light intensity of the measuring fiber, l is the real-time light intensity of the measuring fiber, and l0 is the initial light intensity of the reference fiber. r The real-time light intensity of the reference fiber.

[0023] Optionally, the reference fiber size for the full cladding is 5mm*5mm, the core size is 3mm*3mm, and the cladding thickness is 1mm.

[0024] Optionally, the leaky optical fiber has a size of 5mm*4mm, a core size of 3mm*3mm, and a cladding thickness of 1mm.

[0025] Optionally, the analysis and processing of the digital signal specifically includes:

[0026] The grayscale values ​​corresponding to the reference fiber core and the leaked fiber core are extracted from the digital signal. Then, the corresponding grayscale values ​​are calculated using the corrected grayscale formula, and finally, the height information of the corresponding liquid level is obtained.

[0027] Secondly, the present invention provides a method for monitoring the liquid level of an infusion bag, the monitoring method comprising:

[0028] Turn on the LED to emit a light signal;

[0029] An optical signal acquisition unit installed at the output end of a flexible fiber optic liquid level sensor converts optical signals into digital signals;

[0030] The optical signal acquisition unit acquires digital signals and transmits them to the data processing unit.

[0031] The data processing unit processes the acquired digital signals to calculate the liquid level height information and finally provides feedback.

[0032] Thirdly, the present invention provides a method for fabricating flexible leaky optical fiber, the method comprising:

[0033] Fabrication of a fully clad reference fiber;

[0034] Fabrication of leaky optical fibers.

[0035] Optionally, the fabrication of the fully clad reference fiber includes:

[0036] Step 1: Creating the cladding: Select a stainless steel concave groove, a stainless steel strip, and two stainless steel concave gaskets as molds. Inject the cladding PDMS solution into the space between the stainless steel strip and the concave groove until the silicone rubber solution fills the concave groove. After injection, place it in a constant temperature oven at 70°C until it solidifies. Remove the stainless steel strip to obtain the hollow tube cladding.

[0037] Step 2: Injecting the fiber core: Inject the fiber core PDMS solution into the cladding obtained in Step 1, and place it in a constant temperature oven at 70°C until it cures;

[0038] Step 3: Demolding the finished product: After curing, the finished optical fiber is peeled off from the concave groove. At this point, the fully clad reference optical fiber is completed.

[0039] Optionally, the fabrication of the leaky optical fiber includes the following steps:

[0040] Step 1: Use a concave gasket to fix the stainless steel strip in the center of the concave groove. Inject the coating solution into the gap between the stainless steel strip and the concave groove until the surface of the silicone rubber solution is flush with the stainless steel strip. After injection, place it in a constant temperature oven at 70°C until it solidifies. Then, remove the stainless steel strip to obtain the concave coating.

[0041] Step 2: Injecting the fiber core: Inject the fiber core solution into the cladding obtained in Step 1, and place it in a constant temperature oven at 70°C until it solidifies;

[0042] Step 3: Demolding the finished product. After curing, the finished optical fiber is peeled from the concave groove. At this point, the leaky optical fiber is complete.

[0043] According to specific embodiments provided by the present invention, the present invention discloses the following technical effects:

[0044] 1. The polymer near-infrared flexible optical fiber, which is independently designed and manufactured using a molding method, has the characteristics of high flexibility, resistance to corrosion, anti-interference, and ultra-stable near-infrared transmission. Therefore, compared with the traditional infusion bag liquid level measurement method, this sensor has the advantages of strong anti-interference ability and corrosion resistance, and solves the shortcomings of the traditional method.

[0045] 2. Relatively speaking, polymer flexible optical fibers have a wide range of applications and lower manufacturing costs, and it is also relatively easy to build this system. Therefore, compared with traditional methods, this method is more cost-effective.

[0046] 3. At the algorithm level, as long as the algorithm is designed reasonably and has low complexity, the software integration is almost cost-free. Furthermore, based on the obtained digital signals, algorithms can be designed to calculate other indicators of the liquid. Therefore, the algorithm level has strong scalability. Attached Figure Description

[0047] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the 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.

[0048] Figure 1 This is the main view of the assembly diagram of the infusion bag level monitoring system of the present invention;

[0049] Figure 2 This is a front view of the flexible leaking fiber optic liquid level sensor of the present invention;

[0050] Figure 3 shows the fabrication process of the flexible leaky fiber liquid level sensor of the present invention; Figure 3(a) shows the specifications of the mold selected in this example; Figure 3(b) shows a schematic diagram of the fully clad fiber structure; Figure 3(c) shows a schematic diagram of the leaky fiber structure; Figure 3(d) shows the assembled flexible leaky fiber liquid level sensor.

[0051] Figure 4 This is a flowchart of the image processing algorithm for the infusion bag level monitoring system of the present invention;

[0052] Figure 5 This is a schematic diagram showing the sensor brightness information corresponding to different liquid level heights in the infusion bag liquid level monitoring system of the present invention.

[0053] Explanation of reference numerals in the attached figures

[0054] 1. Light-emitting diode; 2. Infusion bag; 3. Flexible leaky fiber optic sensor; 4. Near-infrared camera; 5. Data processing unit; 6. Fully clad fiber; 7. Leaky fiber; 8. Filter; 9. Reference fiber cladding; 10. Reference fiber core; 11. Leaky fiber core; 12. Leaky fiber cladding; 13. Stainless steel concave groove; 14. Stainless steel concave gasket; 15. Stainless steel strip. Detailed Implementation

[0055] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. 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 are within the scope of protection of the present invention.

[0056] The purpose of this invention is to provide a flexible leaky fiber liquid level sensor, its preparation method, and a liquid level monitoring method. By utilizing the excellent properties of the flexible fiber itself, high-precision measurement can be achieved without being affected by environmental interference.

[0057] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0058] Example 1

[0059] See Figures 1-2 This invention provides an infusion bag level monitoring system, comprising:

[0060] 1. Light-emitting diode; 2. Infusion bag; 3. Flexible leak fiber optic liquid level sensor; 4. Optical signal acquisition unit; and 5. Data processing unit.

[0061] The light-emitting diode is a 980nm light-emitting diode; the optical signal acquisition unit is a near-infrared camera 4 (800-1000nm) combined with a 900nm filter 8; and the data processing unit is a PC 5.

[0062] A flexible leaky fiber optic liquid level sensor 3 is installed inside the infusion bag 2. The light-emitting diode 1 and the optical signal acquisition unit 4 are respectively installed at both ends of the flexible leaky fiber optic liquid level sensor 3. The light-emitting diode and the optical signal acquisition unit need to be facing the input end and the output end of the flexible fiber optic cable.

[0063] The aforementioned components are interconnected as a whole. The 980nm LED 1 provides an optical signal to the flexible leaky fiber optic sensor. The infusion bag 2 holds the liquid to be measured. The flexible leaky fiber optic level sensor 3 detects the change in the light source signal due to the change in the refractive index of the medium on the surface of the fiber optic cable inside the infusion bag, and outputs the corresponding optical signal. The optical signal acquisition unit 4 converts the output near-infrared light signal into a digital signal and then transmits the acquired digital signal to the digital processing unit 5. A filter 8 is located above the optical signal acquisition unit and is used to filter out interference signals from natural light. After detecting the changing optical signal, the flexible leaky fiber optic level sensor 3 converts the optical signal into a digital signal through the optical signal acquisition unit 4 and then transmits it to the data processing unit 5. The image processing module of the data processing unit analyzes and processes the digital signal and finally provides the liquid level height information.

[0064] like Figure 2As shown, the flexible leaky fiber optic liquid level sensor includes a fully clad reference fiber and a leaky fiber, which together form the sensor for detecting optical signals. The fiber is used to detect the output optical signal after the light source signal changes due to the change in the refractive index of the medium on the fiber core surface inside the infusion bag. The principle used to measure liquid level height through light source brightness information is as follows: utilizing the transmission loss characteristics of light, one side of the fiber core is exposed as the measuring fiber. When the liquid level rises (or falls), the refractive index of the external medium of the fiber core changes, and the light transmission loss changes accordingly. By measuring the output light intensity, the amount of light intensity loss can be obtained. Therefore, some indicators, such as liquid level, can be obtained by analyzing the strength of the change in the optical signal.

[0065] The fully clad reference fiber is a self-made polymer flexible fiber. The fully clad fiber 6 has a size of 5mm*5mm, a core size of 3mm*3mm, and a cladding thickness of 1mm. The leaky fiber 7 has a size of 5mm*4mm, a core size of 3mm*3mm, and a cladding thickness of 1mm.

[0066] The reference fiber and the leaked fiber are tightly bonded together with silicone adhesive to ensure that the reference fiber and the measurement fiber undergo any possible deformation synchronously. The cross-sections of the two fibers and the core surface of the leaked fiber are neat and flat.

[0067] In the above situation, the light intensity in the two optical fibers changes proportionally due to deformation. By correcting the grayscale formula, this proportional change caused by deformation is eliminated, and a corrected grayscale value close to the theoretical value is obtained.

[0068] Furthermore, the specific formula for correcting the grayscale is as follows:

[0069]

[0070] Where L is the initial light intensity of the measuring fiber, l is the real-time light intensity of the measuring fiber, and l0 is the initial light intensity of the reference fiber. r The real-time light intensity of the reference fiber.

[0071] As shown in parts (a) to (d) of Figure 3, in this embodiment, the fabrication steps of the polymer flexible optical fiber sensor include fabricating a fully clad reference fiber and fabricating a leaky fiber. The steps for fabricating the fully clad reference fiber are as follows:

[0072] Step 1: Cladding Fabrication. Select a stainless steel concave groove 13 (internal space: 5mm*5mm*200mm), a stainless steel strip 15 (3mm*3mm*200mm), and two stainless steel concave gaskets 14 (outer diameter: 5mm*5mm*200mm, inner diameter: 3mm*3mm*5mm) as the mold. The stainless steel material is smooth and will not affect the transmission and output of the optical signal. If the surface is uneven, the integrity of the collected optical signal cannot be guaranteed. The size of the stainless steel strip determines the inner diameter. Use the concave gaskets to fix the stainless steel strip in the center of the concave groove. Inject the cladding PDMS solution (main agent: crosslinking agent = 20:1, refractive index ≈ 1.41) into the interlayer between the stainless steel strip and the concave groove until the silicone rubber solution fills the concave groove. After injection, place it in a 70℃ constant temperature oven until curing. Remove the stainless steel strip to obtain the hollow tube cladding.

[0073] Step 2: Inject the fiber core. Inject the fiber core PDMS solution (main agent: crosslinking agent = 5:1, refractive index ≈ 1.43) into the cladding obtained in Step 1, and place it in a constant temperature oven at 70°C until it cures.

[0074] Step 3: Demolding the finished product. After curing, the finished optical fiber is peeled off from the concave groove. At this point, the fully clad flexible optical fiber 6 is completed.

[0075] The steps for fabricating leaky optical fiber are as follows:

[0076] Step 1: Use the concave gasket 14 to fix the stainless steel strip 15 to the center of the concave groove 13. Inject the coating solution into the space between the stainless steel strip and the concave groove until the silicone rubber solution level is flush with the stainless steel strip. After injection, place it in a constant temperature oven at 70℃ until it cures. Then, remove the stainless steel strip to obtain the concave coating.

[0077] Step 2: Inject the fiber core. Inject the fiber core solution into the cladding obtained in Step 1, and place it in a constant temperature oven at 70°C until it solidifies.

[0078] Step 3: Demolding the finished product. After curing, the finished optical fiber is peeled off from the concave groove. At this point, the leaky optical fiber 7 is complete.

[0079] In this system, when the light signal emitted by the light source passes through the flexible leaky fiber optic level sensor in the infusion bag, the refractive index of the medium on the surface of the leaky fiber core changes due to the change in liquid level, and the light signal also changes accordingly. Therefore, some useful indicators can be obtained by analyzing the changes in the light signal before and after the change. Specifically, taking water, saline, and glucose solutions as examples for liquid level measurement, the flexible leaky fiber optic level sensor collects liquid level change data by detecting changes in the light signal, such as... Figure 5 As shown.

[0080] For image processing algorithms on PCs, the programs should ideally be comprehensive, easy to maintain, and robust.

[0081] like Figure 4 As shown, this invention also discloses a method for monitoring the liquid level of an infusion bag based on a flexible leaking fiber optic liquid level sensor, comprising the following steps:

[0082] Step 1: Turn on the 980nm LED. As the liquid level in the infusion bag changes, the refractive index of the medium on the surface of the leaky optical fiber changes, and the transmission mode of the light signal emitted by the LED changes in the leaky optical fiber. Therefore, the intensity of the light signal passing through the leaky optical fiber changes.

[0083] Step 2: The optical signal acquisition unit installed at the output end of the flexible optical fiber liquid level sensor is responsible for converting the optical signal that changes due to the change in the refractive index of the medium on the fiber core surface into a digital signal.

[0084] Step 3: Acquire digital signals through the optical signal acquisition unit and transmit them to the data processing unit.

[0085] Step 4: The data processing unit processes the acquired digital signals, calculates the liquid level height information, and finally provides feedback.

[0086] Specifically, the acquired digital signal is decomposed to obtain the grayscale values ​​corresponding to the reference fiber core and the leaked fiber core. Then, the grayscale values ​​are processed to calculate the liquid level height information and finally provide feedback.

[0087] This measurement method effectively addresses the shortcomings of traditional infusion bag level monitoring methods. Compared to traditional sensors, this sensor not only boasts advantages such as wear resistance, corrosion resistance, high measurement accuracy, small size, and comprehensive functionality, but also exhibits strong resistance to electromagnetic interference and deformation, easy system assembly, and a wide range of applications. The monitoring system can measure the level of any medical intravenous solution, such as physiological saline and glucose solution.

[0088] The various embodiments in this specification are described in a progressive manner, with each embodiment focusing on the differences from other embodiments. The same or similar parts between the various embodiments can be referred to each other.

[0089] This document uses specific examples to illustrate the principles and implementation methods of the present invention. The descriptions of the above embodiments are only for the purpose of helping to understand the method and core ideas of the present invention. Furthermore, those skilled in the art will recognize that, based on the ideas of the present invention, there will be changes in the specific implementation methods and application scope. Therefore, the content of this specification should not be construed as a limitation of the present invention.

Claims

1. An infusion bag level monitoring system, characterized in that, include: Light-emitting diode, infusion bag, flexible leak-proof fiber optic liquid level sensor, optical signal acquisition unit, and data processing unit; The flexible leaky fiber optic liquid level sensor is installed inside the infusion bag, and the light-emitting diode and the optical signal acquisition unit are respectively installed at both ends of the flexible leaky fiber optic liquid level sensor. The light-emitting diode is used to provide an optical signal for the flexible leaky fiber optic liquid level sensor; The flexible leaky fiber optic liquid level sensor is used to detect the optical signal output after the optical signal changes due to the change in the refractive index of the medium on the surface of the optical fiber inside the infusion bag. The optical signal acquisition unit is used to convert the output optical signal into a digital signal and transmit the acquired digital signal to the digital processing unit; The data processing unit is used to analyze and process the digital signal to obtain the liquid level height information; The flexible leaky fiber optic level sensor includes: a fully clad reference fiber and a leaky fiber, wherein the fully clad reference fiber and the leaky fiber are bonded together. Fabrication of a fully clad reference fiber includes: Step 1: Creating the cladding: Select a stainless steel concave groove, a stainless steel strip, and two stainless steel concave gaskets as molds. Inject the cladding PDMS solution into the space between the stainless steel strip and the concave groove until the silicone rubber solution fills the concave groove. After injection, place it in a constant temperature oven at 70°C until it solidifies. Remove the stainless steel strip to obtain the hollow tube cladding. Step 2: Injecting the fiber core: Inject the fiber core PDMS solution into the cladding obtained in Step 1, and place it in a constant temperature oven at 70°C until it cures; Step 3: Demolding the finished product: After curing, the finished optical fiber is peeled off from the concave groove. At this point, the fully clad reference optical fiber is completed. The fabrication of the leaky optical fiber includes the following steps: Step 1: Use a concave gasket to fix the stainless steel strip in the center of the concave groove. Inject the coating solution into the gap between the stainless steel strip and the concave groove until the surface of the silicone rubber solution is flush with the stainless steel strip. After injection, place it in a constant temperature oven at 70°C until it solidifies. Then, remove the stainless steel strip to obtain the concave coating. Step 2: Injecting the fiber core: Inject the fiber core solution into the cladding obtained in Step 1, and place it in a constant temperature oven at 70°C until it solidifies; Step 3: Demolding the finished product: After curing, the finished optical fiber is peeled off from the concave groove. At this point, the leaky optical fiber is completed.

2. The infusion bag level monitoring system according to claim 1, characterized in that, Also includes: A filter is used to filter out interference signals from natural light.

3. The infusion bag level monitoring system according to claim 1, characterized in that, The proportional changes in the fully clad reference fiber and the leaky fiber caused by deformation are corrected by a modified grayscale formula, which is as follows: ； in, L To measure the initial light intensity of the optical fiber, l To measure the real-time light intensity of the optical fiber. The initial light intensity of the reference fiber is used as a reference. The real-time light intensity of the reference fiber.

4. The infusion bag level monitoring system according to claim 3, characterized in that, The reference fiber size for the fully clad fiber is 5mm. 5mm, core size is 3mm 3mm, cladding thickness is 1mm; The leaky optical fiber is 5mm in size. 4mm, core size is 3mm 3mm, with a cladding thickness of 1mm.

5. The infusion bag level monitoring system according to claim 3, characterized in that, The analysis and processing of the digital signal specifically includes: The grayscale values ​​corresponding to the reference fiber core and the leaked fiber core are extracted from the digital signal, and then the corresponding grayscale values ​​are calculated using the corrected grayscale formula. Finally, the height information of the corresponding liquid level is obtained.

6. A method for monitoring the liquid level of an infusion bag, characterized in that, The monitoring method employs the infusion bag level monitoring system as described in any one of claims 1-5, and the monitoring method includes: Turn on the LED to emit a light signal; An optical signal acquisition unit installed at the output end of a flexible fiber optic liquid level sensor converts optical signals into digital signals; The optical signal acquisition unit acquires digital signals and transmits them to the data processing unit. The data processing unit processes the acquired digital signals, calculates the liquid level height information, and finally provides feedback.

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