Underwater anti-interference electrochemical water quality sensor

Abstract

The invention relates to the technical field of electronic information engineering, and discloses an underwater anti-interference electrochemical water quality sensor which comprises a signal conditioning module and a control module which are arranged in a waterproof shell, the signal conditioning module is electrically connected with a sensing electrode arranged at the bottom of the waterproof shell, and the control module is electrically connected with an external upper computer. The wireless power supply assembly comprises a transmitting coil and a receiving coil which are arranged in parallel, the transmitting coil is electrically connected with the control module, and the receiving coil is electrically connected with the signal conditioning module; the optoelectronic isolation assembly comprises a primary transceiver module, a secondary transceiver module and a light guide structure. Structural power supply isolation and digital signal isolation are adopted, short-distance simultaneous power supply measurement of a plurality of underwater anti-interference electrochemical water quality sensors can be achieved, the problem that mutual crosstalk is prone to occurring during detection of a plurality of water quality sensors carrying different electrochemical electrodes is solved, and meanwhile time and space limitation is avoided.

Description

Technical Field

[0001] The invention relates to the technical field of electronic information engineering, in particular to an underwater anti-interference electrochemical water quality sensor. Background Art

[0002] The electrochemical water quality sensor mainly consists of two parts: the sensing electrode and the measuring circuit. Among them, the sensing electrode is the core component of the sensor, and different sensing electrodes can detect different substances. When the sensing electrode comes into contact with the substance to be detected, an electrode reaction will occur and generate a certain electrochemical signal. This electrochemical signal is measured and analyzed by the signal conditioning module in the measuring circuit, and converted into an electrical signal related to the substance to be detected and transmitted for convenient monitoring.

[0003] When testing water quality through electrochemical water quality sensors, due to the different substances that need to be detected, multiple water quality sensors carrying different detection electrodes are usually placed in water for detection. However, different detection electrodes (such as electrochemical dissolved oxygen, pH, ammonium ion, potassium ion and conductivity electrodes, etc.) are immersed in the test liquid at the same time for measurement, and interference may occur between circuits and signal transmission. The degree of interference depends on many factors, such as which electrode combination is used, which interface is used, whether the power interface is powered by batteries or AC power, whether the communication interface is connected to a computer or operates as an independent device, how far the electrodes are in the water, the conductivity of the water, etc.

[0004] In order to avoid crosstalk when multiple electrochemical water quality sensors with different electrodes are tested, there are currently two methods used. One is asynchronous power supply acquisition, that is, to control the power supply to each electrochemical water quality sensor for detection in turn. When one electrochemical water quality sensor is finished, the next electrochemical water quality sensor is controlled for detection; the other is to arrange multiple electrochemical sensors at a long distance for measurement. However, the above two methods each have some problems. The first method requires step-by-step control of each sensor for detection, which has cumbersome detection steps and low detection efficiency. The second method is that the distance between each electrochemical water quality sensor is far, resulting in certain differences between the detection positions, and it is difficult to achieve uniformity in water quality detection in space and time scales, which greatly affects the analysis of spatiotemporal laws and prediction accuracy of water quality in monitored waters. Summary of the invention

[0005] The purpose of the present invention is to provide an underwater anti-interference electrochemical water quality sensor to solve the problem of mutual crosstalk that is prone to occur when the current electrochemical sensors work simultaneously, while being unrestricted by time and space, ensuring relatively accurate prediction accuracy.

[0006] The technical solution of the present invention is:

[0007] An underwater anti-interference electrochemical water quality sensor, comprising a signal conditioning module and a control module arranged in a waterproof housing, wherein the signal conditioning module is electrically connected to a sensing electrode arranged at the bottom of the waterproof housing, and the control module is electrically connected to an external host computer, and further comprising a wireless power supply component and a photoelectric isolation component, wherein the wireless power supply component comprises a transmitting coil and a receiving coil arranged in parallel, wherein the transmitting coil is electrically connected to the control module, and the transmitting coil is used to convert the current transmitted by the control module into an alternating magnetic field, and the receiving coil is electrically connected to the signal conditioning module, and the receiving coil is used to couple with the transmitting coil and generate current to the The signal conditioning module is powered; the optoelectronic isolation component includes a primary transceiver module, a secondary transceiver module and a light-guiding structure, the primary transceiver module includes a primary light transmitter and a primary light receiver, the secondary transceiver module includes a secondary light transmitter and a secondary light receiver, and the light-guiding structure is provided between the primary light transmitter and the secondary light receiver and between the secondary light transmitter and the primary light receiver, the primary light transmitter and the primary light receiver are electrically connected to the control module respectively, the secondary light transmitter and the secondary light receiver are electrically connected to the signal conditioning module respectively, and the optoelectronic isolation component is used to realize signal isolation.

[0008] Preferably, as a further improvement of the present invention, the surface distance between the transmitting coil and the receiving coil is 1 mm to 2 mm.

[0009] Preferably, as a further improvement of the present invention, the primary light emitter and the secondary light emitter are both LED emitters, the primary light receiver and the secondary light receiver are both photoelectric receiving tubes, the primary light receiver and the secondary light receiver are both photoelectric receiving tubes, and the primary light emitter and the secondary light receiver are coaxial and collinear, and the secondary light emitter and the primary light receiver are coaxial and collinear.

[0010] Preferably, as a further improvement of the present invention, the light-guiding structure arranged between the primary light emitter and the secondary light receiver includes a first light-guiding column and a second light-guiding column arranged coaxially and collinearly, the light-guiding structure arranged between the secondary light emitter and the primary light receiver includes a third light-guiding column and a fourth light-guiding column arranged coaxially and collinearly, and the optical coupling end faces of the primary light emitter, the secondary light emitter, the primary light receiver, the secondary light receiver, the first light-guiding column, the second light-guiding column, the third light-guiding column and the fourth light-guiding column are all sealed with transparent optical epoxy glue.

[0011] Preferably, as a further improvement of the present invention, the wavelength of the primary light emitter and the secondary light emitter are the same, and are both selected from any wavelength band between 450nm and 750nm.

[0012] Preferably, as a further improvement of the present invention, when optical communication is used for digital signal isolation, the data transmission rate is less than or equal to 9600 bps.

[0013] Preferably, as a further improvement of the present invention, the signal conditioning module is a signal conditioning board, and the signal conditioning board is provided with an amplifying and filtering circuit, an analog-to-digital conversion module and a microprocessor. The signal conditioning board is electrically connected to the sensing electrode, the receiving coil, the secondary light receiver and the secondary light transmitter, respectively. The signal conditioning board converts the analog electrical signal into a high signal-to-noise ratio DC analog signal through the amplifying and filtering circuit, and converts the DC analog signal into a digital signal by controlling the analog-to-digital conversion module through the microprocessor.

[0014] Preferably, as a further improvement of the present invention, the control module is a control circuit board, a pulse generator module and a power amplifier module are provided on the control circuit board, the pulse generator module and the power amplifier module are electrically connected, and the control circuit board controls the pulse generator module to output an AC signal under the power supply of an external DC power supply, the operating frequency range of the AC signal is 30kHz to 50kHz, the AC signal passes through the power amplifier module to enable the transmitting coil to generate a magnetic field and the rated transmission power is less than or equal to 100mW.

[0015] Preferably, as a further improvement of the present invention, the waterproof shell includes a first shell, a second shell and a third shell arranged in sequence from top to bottom, the first shell and the second shell are detachably connected by threads, and the second shell and the third shell are detachably connected by threads.

[0016] Preferably, as a further improvement of the present invention, the sensing electrode is sealed and installed at the bottom of the third shell, the transmitting coil and the receiving coil are respectively vertically sealed and installed in the high-low coupling docking plug grooves set in the first shell and the second shell, and the LED transmitter and the photoelectric receiving tube are both embedded in the high-low coupling docking plug grooves opened in the first shell and the second shell.

[0017] Compared with the prior art, the present invention has the following beneficial effects:

[0018] The wireless power supply component can be used for non-contact power supply, power isolation can be achieved, and stable power supply can be achieved in the process of signal conditioning module converting and processing the electrochemical signals collected by the sensing electrodes, thereby avoiding the problem of poor data acquisition accuracy caused by the interference of the mains frequency. The photoelectric isolation component can be used to achieve digital signal isolation by using two sets of optical transceiver modules for modulation and demodulation during signal transmission, and near-field wireless communication is completed between the two sets of optical transceiver modules in the form of optical signals, effectively suppressing the interference of external circuits on sensor signals and noise transmission, so that the mutual crosstalk between electrochemical electrodes is basically eliminated. Therefore, through the coordination between power isolation and digital signal isolation measures, multiple underwater anti-interference electrochemical water quality sensors can be powered and measured at close range at the same time. While solving the problem of mutual crosstalk that is prone to occur in the detection of multiple water quality sensors carrying different electrochemical electrodes, it can also ensure that the multiple water quality sensors are not far apart, thereby ensuring that the spatial and temporal scales are as unified as possible, thereby ensuring that the prediction accuracy is relatively accurate. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 The figure is a schematic diagram of the explosion structure of an underwater anti-interference electrochemical water quality sensor according to an embodiment of the present invention.

[0020] Figure 2 The present invention is a schematic diagram of a power supply for an underwater anti-interference electrochemical water quality sensor according to an embodiment of the present invention.

[0021] Figure 3 The present invention is a schematic diagram of a digital communication implementation of an underwater anti-interference electrochemical water quality sensor according to an embodiment of the present invention. DETAILED DESCRIPTION

[0022] The following is combined with Figure 1 To the attached Figure 3 , the specific implementation methods of the present invention are described in detail. In the description of the invention, it should be understood that the terms "center", "upper", "lower", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside" and the like indicate positions or positional relationships based on the positions or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present invention.

[0023] The terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Therefore, features defined as "first" and "second" may explicitly or implicitly include one or more of the features; in the description of the invention, unless otherwise specified, "plurality" means two or more.

[0024] Example

[0025] like Figures 1 to 3 As shown, an embodiment of the present invention provides an underwater anti-interference electrochemical water quality sensor, including a signal conditioning module 2, a control module 3, a wireless power supply component and a photoelectric isolation component arranged in a waterproof housing, the signal conditioning module 2 is electrically connected to a sensing electrode 4 arranged at the bottom of the waterproof housing, and is used to perform analog-to-digital conversion on the electrochemical signal collected by the sensing electrode 4, the control module 3 is electrically connected to the signal conditioning module 2 and an external host computer 307 respectively, and is used to receive the signal converted by the signal conditioning module 2 and transmit it to the external host computer 307; the wireless power supply component includes a transmitting coil 51 and a receiving coil 52 arranged in parallel, the transmitting coil 51 is electrically connected to the control module 3, the transmitting coil 51 is used to convert the current transmitted by the control module 3 into an alternating magnetic field, and the receiving coil 52 It is electrically connected to the signal conditioning module 2, and the receiving coil 52 is used to couple with the transmitting coil 51 and generate current to supply energy to the signal conditioning module 2; the photoelectric isolation component includes a primary transceiver module, a secondary transceiver module and a light-guiding structure, the primary transceiver module includes a primary light transmitter 61 and a primary light receiver 62, the secondary transceiver module includes a secondary light transmitter 71 and a secondary light receiver 72, and a light-guiding structure is provided between the primary light transmitter 61 and the secondary light receiver 72, and between the secondary light transmitter 71 and the primary light receiver 62, the primary light transmitter 61 and the primary light receiver 62 are electrically connected to the control module 3 respectively, the secondary light transmitter 71 and the secondary light receiver 72 are electrically connected to the signal conditioning module 2 respectively, and the photoelectric isolation component is used to realize the isolation and transmission of the signal.

[0026] In this embodiment, the sensor collects water quality information through the sensing electrode 4 and generates an analog electrical signal 41, and the analog electrical signal 41 is received by the signal conditioning module 2 and subjected to analog-to-digital conversion processing. During the operation of the signal conditioning module 2, the wireless power supply component can be used to stably supply energy in a non-contact manner to achieve power isolation, thereby avoiding the problem of poor data collection accuracy caused by interference from the mains frequency. The optoelectronic isolation component composed of the primary transceiver module, the secondary transceiver module and the light-guiding structure can form a symmetrical optical path in signal transmission, and optical communication can avoid the influence of electrical noise, so It has the function of isolating digital signals, thereby isolating the signal from the input end by means of modulation and demodulation, avoiding signal interference and transmission error, effectively suppressing the interference and noise transmission of the sensor signal by the external circuit, and basically eliminating the mutual crosstalk between the electrochemical electrodes. The converted signal is transmitted to the external host computer 307 through the cable for monitoring and analysis. Therefore, in the process of using multiple underwater anti-interference electrochemical water quality sensors for measurement, multiple underwater anti-interference electrochemical water quality sensors can be powered on and measured at a close distance simultaneously through power isolation and digital signal isolation measures, without the phenomenon of mutual crosstalk between electrodes.

[0027] Specifically, the signal conditioning module 2 is a signal conditioning board, which is provided with an amplifying and filtering circuit 203, an analog-to-digital conversion module 204 and a microprocessor 206. The signal conditioning board is electrically connected to the sensing electrode 4, the receiving coil 52, the secondary light receiver 72 and the secondary light transmitter 71 respectively. The signal conditioning board converts the analog electrical signal 41 into a high signal-to-noise ratio DC analog signal through the amplifying and filtering circuit 203, and controls the analog-to-digital conversion module 75 through the microprocessor 206 to convert the DC analog signal into a digital signal.

[0028] Among them, the analog-to-digital conversion module 204 is an ADC integrated chip, the amplification and filtering circuit 203 is a multi-stage amplification and filtering circuit, the signal conditioning board converts the analog electrical signal 41 into a DC analog signal with a higher signal-to-noise ratio through the multi-stage amplification and filtering circuit, and the microprocessor 206 reads and writes the SPI interface circuit 205 to control the ADC integrated chip with timing logic to convert the DC analog signal into a digital signal.

[0029] Among them, the sensing electrode 4 can be one of the dissolved oxygen, pH, conductivity, ORP, ion-selective electrochemical electrodes, or one of the photoelectric detection electrodes such as turbidity, chlorophyll, optical dissolved oxygen, etc. The sensing electrode 4 is connected to the signal conditioning board through multiple bundles of wires.

[0030] The analog electrical signal 41 may be one or a combination of direct current voltage, direct current, alternating current voltage, and alternating current signals induced by a sensitive element.

[0031] Specifically, the control module 3 is a control circuit board, on which a pulse generator module 302 and a power amplifier module 303 are provided. The control module 3 is a control circuit board, on which a pulse generator module 302 and a power amplifier module 303 are provided. The pulse generator module 302 and the power amplifier module 303 are electrically connected. When the control circuit board is powered by an external DC power supply 301, the control pulse generator module 302 outputs an AC signal, and the operating frequency range of the AC signal is 30kHz to 50kHz. The AC signal passes through the power amplifier module 303 to enable the transmitting coil 51 to generate a magnetic field and the rated transmission The transmission power is less than or equal to 100mW, the surface distance between the transmitting coil 51 and the receiving coil 52 is controlled within 1mm to 2mm, the receiving coil 52 is electrically connected to the signal conditioning board, and when power is supplied, the receiving coil 52 passively generates an induced current under the condition of an alternating electromagnetic field generated in the transmitting coil 51, and a stable DC power supply voltage is formed after rectification and filtering by the rectifier circuit 201 arranged on the signal conditioning board, and the voltage regulation is enabled to adjust the DC voltage to a stable voltage that can be used by the analog front-end circuit. The wireless charging field formed by the transmitting coil 51 and the receiving coil 52 has a different power reference ground source, so it has a power isolation effect.

[0032] The pulse generator module 302 can be constructed by using a dedicated chip, a single-chip microcomputer, or an operational amplifier integrated circuit. The transmission power can be adjusted by controlling the PWM frequency and the duty cycle. The power amplifier is preferably constructed by using a field effect transistor.

[0033] Specifically, the primary light emitter 61 and the secondary light emitter 71 are both LED emitters, the primary light receiver 62 and the secondary light receiver 72 are both photoelectric receiving tubes, and the primary light emitter 61 and the secondary light receiver 72 are coaxial and collinear, and the secondary light emitter 71 and the primary light receiver 62 are coaxial and collinear.

[0034] Furthermore, the light-guiding structure arranged between the primary light emitter 61 and the secondary light receiver 72 includes a first light-guiding column 81 and a second light-guiding column 82 which are coaxially and collinearly arranged, and the light-guiding structure arranged between the secondary light emitter 71 and the primary light receiver 62 includes a third light-guiding column 83 and a fourth light-guiding column 84 which are coaxially and collinearly arranged. The first light-guiding column 81 and the second light-guiding column 82 are used to transmit the response instruction sent by the serial port of the microprocessor 206 arranged in the signal conditioning board to the serial port bus chip 306 arranged on the control circuit board, and the upper computer 307 sends a read instruction through the serial port bus chip 306 on the control circuit board, and then transmits it to the serial port receiving end of the microprocessor 206 in the signal conditioning board through the third light-guiding column 83 and the fourth light-guiding column 84.

[0035] Among them, the optical coupling end faces of the primary light emitter 61, the secondary light emitter 71, the primary light receiver 62, the secondary light receiver 72, the first light guide column 81, the second light guide column 82, the third light guide column 83 and the fourth light guide column 84 are all sealed with transparent optical epoxy glue, specifically, they are sealed with two-component transparent optical epoxy glue OPT8217, and the optical glue OPT8217 has excellent light transmittance.

[0036] Furthermore, the wavelength of the primary light emitter 61 and the secondary light emitter 71 are the same, both are selected from any band between 450nm and 750nm, and can be blue light, green light, yellow light, or near-infrared LED. The corresponding primary light receiver 62 and the secondary light receiver 72 should preferably be a phototransistor with high sensitivity at the main wavelength of the LED.

[0037] Furthermore, a primary LED drive control circuit 305 and a primary photoelectric receiving tube control circuit 304 are provided on the control circuit board, and a secondary LED drive control circuit 207 and a secondary photoelectric receiving tube control circuit 208 are provided on the signal conditioning board, wherein the primary LED drive control circuit 305 and the secondary LED drive control circuit 207 are both controlled by a direct control method in which the LED anode is connected to the pull-up resistor and the cathode is connected to the control signal, the control signal of the primary light emitter 61 is taken from the serial bus chip 306, and the control signal of the secondary light emitter 71 is taken from the serial output port of the microprocessor 206, the primary photoelectric receiving tube control circuit 304 and the secondary photoelectric receiving tube control circuit 208 are both connected by the collector to the pull-up resistor and the emitter to the isolated ground, the collector of the primary photoelectric receiving tube 41 is connected to the serial bus chip 308, and the collector of the secondary photoelectric receiving tube 51 is connected to the serial output port of the microprocessor 206.

[0038] Furthermore, in order to ensure the stability of data transmission, when optical communication is used for digital signal isolation, the data transmission rate is less than or equal to 9600 bps.

[0039] In another embodiment of the present invention, in order to facilitate installation and seal and waterproof the internal devices, the waterproof shell includes a first shell 11, a second shell 12 and a third shell 13 arranged in sequence from top to bottom, and the first shell 11 and the second shell 12 are detachably connected by threads, and the second shell 12 and the third shell 13 are detachably connected by threads.

[0040] The sensing electrode 4 is encapsulated at the bottom of the third housing 13 by epoxy resin glue, and the epoxy resin glue has the advantages of IP68 waterproof grade, strong insulation, aging resistance, strong corrosion resistance, high temperature resistance, etc.

[0041] Among them, the transmitting coil 51 is vertically installed in the first shell 11, and the receiving coil 52 is vertically installed on the second shell 12. Each coil is embedded in a pre-opened high and low coupling plug groove with white silicone, perpendicular to the horizontal plane. The receiving coil 52 is connected to the signal conditioning board through two wires, and the transmitting coil 51 is connected to the control circuit board through two wires.

[0042] The LED transmitter and the photoelectric receiving tube are both embedded in the high-low coupling butt plug grooves provided in the first shell 11 and the second shell 12 .

[0043] Among them, a waterproof connector 91 and a connector conversion assembly 92 are provided on the top of the first shell 11. The inner wall of the connector conversion assembly 92 is provided with threads, and the waterproof connector 91 is provided with threads. The connector conversion assembly 92 and the waterproof connector 91 are fastened by threaded connection. The outer wall is smooth and is bonded to the inner wall of the first shell 11 by glue. It is used to assemble the waterproof connector 91 and the first shell 11. The waterproof connector 91 prevents external liquid from entering the first shell 11 through the cable gap to damage electronic components. The connector conversion assembly 92 is responsible for assembling the waterproof connector 91 and the first shell 11 together.

[0044] The second housing 12 and the third housing 13 are sealed and connected via a first sealing ring 93 and a second sealing ring 94 , which can prevent water from damaging electronic components after the waterproof housing is assembled.

[0045] In summary, the wireless power supply component set up in the present invention can supply power in a non-contact manner, can realize power isolation, and can realize stable energy supply in the process of the signal conditioning module converting and processing the electrochemical signal collected by the sensing electrode, thereby avoiding the problem of poor data acquisition accuracy caused by the interference of the mains frequency; the photoelectric isolation component set up can realize digital signal isolation by using two groups of optical transceiver modules for modulation and demodulation during signal transmission, and complete near-field wireless communication between the two groups of optical transceiver modules in the form of optical signals, effectively suppressing the interference of external circuits on sensor signals and noise transmission, so that the mutual crosstalk between electrochemical electrodes is basically eliminated; therefore, through the coordination between power isolation and digital signal isolation measures, multiple underwater anti-interference electrochemical water quality sensors can be powered and measured at close range at the same time, while solving the problem of mutual crosstalk that is prone to occur in the detection of multiple water quality sensors carrying different electrochemical electrodes, it can also ensure that the multiple water quality sensors are not far apart, thereby ensuring that the spatial and temporal scales are as unified as possible, thereby ensuring that the prediction accuracy is relatively accurate.

[0046] The above disclosures are only several preferred specific embodiments of the present invention. However, the embodiments of the present invention are not limited thereto. Any changes that can be conceived by those skilled in the art should fall within the protection scope of the present invention.

Claims

1. An underwater anti-interference electrochemical water quality sensor, comprising a signal conditioning module (2) and a control module (3) arranged in a waterproof housing, wherein the signal conditioning module (2) is electrically connected to a sensing electrode (4) arranged at the bottom of the waterproof housing, and is used to perform analog-to-digital conversion on the electrochemical signal collected by the sensing electrode (4); the control module (3) is electrically connected to the signal conditioning module (2) and an external host computer (307), respectively, and is used to receive the signal converted by the signal conditioning module (2) and transmit it to the external host computer (307), characterized in that: Also includes: A wireless power supply component, comprising a transmitting coil (51) and a receiving coil (52) arranged in parallel, wherein the transmitting coil (51) is electrically connected to the control module (3), and is used to convert the current transmitted by the control module (3) into an alternating magnetic field, and the receiving coil (52) is electrically connected to the signal conditioning module (2), and is used to couple with the transmitting coil (51) and generate current to supply energy to the signal conditioning module (2); A photoelectric isolation component comprises a primary transceiver module, a secondary transceiver module and a light guide structure. The primary transceiver module comprises a primary light transmitter (61) and a primary light receiver (62). The secondary transceiver module comprises a secondary light transmitter (71) and a secondary light receiver (72). The light guide structure is provided between the primary light transmitter (61) and the secondary light receiver (72) and between the secondary light transmitter (71) and the primary light receiver (62). The primary light transmitter (61) and the primary light receiver (62) are respectively electrically connected to the control module (3). The secondary light transmitter (71) and the secondary light receiver (72) are respectively electrically connected to the signal conditioning module (2). The photoelectric isolation component is used to achieve signal isolation and transmission.

2. The underwater anti-interference electrochemical water quality sensor according to claim 1, characterized in that: The surface distance between the transmitting coil (51) and the receiving coil (52) is 1 mm to 2 mm.

3. The underwater anti-interference electrochemical water quality sensor according to claim 1, characterized in that: The primary light emitter (61) and the secondary light emitter (71) are both LED emitters, the primary light receiver (62) and the secondary light receiver (72) are both photoelectric receiving tubes, and the primary light emitter (61) and the secondary light receiver (72) are coaxial and collinear, and the secondary light emitter (71) and the primary light receiver (62) are coaxial and collinear.

4. The underwater anti-interference electrochemical water quality sensor according to claim 3 is characterized in that: The light-guiding structure arranged between the primary light emitter (61) and the secondary light receiver (72) comprises a first light-guiding column (81) and a second light-guiding column (82) which are coaxially arranged in a collinear manner, and the light-guiding structure arranged between the secondary light emitter (71) and the primary light receiver (62) comprises a third light-guiding column (83) and a fourth light-guiding column (84) which are coaxially arranged in a collinear manner. The optical coupling end faces of the primary light emitter (61), the secondary light emitter (71), the primary light receiver (62), the secondary light receiver (72), the first light-guiding column (81), the second light-guiding column (82), the third light-guiding column (83) and the fourth light-guiding column (84) are sealed and connected to each other.

5. The underwater anti-interference electrochemical water quality sensor according to claim 4, characterized in that: The wavelength of the primary light emitter (61) and the secondary light emitter (71) is the same, and both are selected from any wavelength band between 450nm and 750nm.

6. The underwater anti-interference electrochemical water quality sensor according to claim 5, characterized in that: When optical communication is used for digital signal isolation, the data transmission rate is less than or equal to 9600bps.

7. The underwater anti-interference electrochemical water quality sensor according to claim 1, characterized in that: The signal conditioning module (2) is a signal conditioning board, on which an amplifying and filtering circuit (203), an analog-to-digital conversion module (204) and a microprocessor (206) are provided. The signal conditioning board is electrically connected to the sensing electrode (4), the receiving coil (52), the secondary light receiver (72) and the secondary light transmitter (71) respectively. The signal conditioning board converts the analog electrical signal (41) into a high signal-to-noise ratio DC analog signal through the amplifying and filtering circuit (203), and controls the analog-to-digital conversion module (75) through the microprocessor (206) to convert the DC analog signal into a digital signal.

8. The underwater anti-interference electrochemical water quality sensor according to claim 1, characterized in that: The control module (3) is a control circuit board, on which a pulse generator module (302) and a power amplifier module (303) are provided, and the pulse generator module (302) and the power amplifier module (303) are electrically connected. When powered by an external DC power supply (301), the control circuit board controls the pulse generator module (302) to output an AC signal, wherein the operating frequency range of the AC signal is a frequency band of 30 kHz to 50 kHz, and the AC signal causes the transmitting coil (51) to generate a magnetic field through the power amplifier module (303), and the rated transmission power is less than or equal to 100 mW.

9. The underwater anti-interference electrochemical water quality sensor according to any one of claims 2 to 8, characterized in that: The waterproof housing comprises a first housing (11), a second housing (12) and a third housing (13) which are arranged in sequence from top to bottom; the first housing (11) and the second housing (12) are detachably connected by threads, and the second housing (12) and the third housing (13) are detachably connected by threads.

10. The underwater anti-interference electrochemical water quality sensor according to claim 9, characterized in that: The sensing electrode (4) is sealed and mounted on the bottom of the third shell (13); the transmitting coil (51) and the receiving coil (52) are respectively vertically and sealed and mounted in high-low coupling butt plug grooves provided in the first shell (11) and the second shell (12); and the LED transmitter and the photoelectric receiving tube are both embedded in the high-low coupling butt plug grooves provided in the first shell (11) and the second shell (12).

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