Anti-interference method and system for photodiode sensor

Abstract

The application belongs to the technical field of measurement and detection, and discloses an anti-interference method and system for a pair of photoelectric sensors. The method is applied to at least two pairs of adjacent pair of photoelectric sensors, and comprises: each receiving end converts a received composite light signal into an electric signal and performs gain amplification to obtain a detection electric signal, the composite light signal comprising a pulse light signal from a corresponding transmitting end and a pulse light signal from an adjacent transmitting end; the peak voltage of the detection electric signal is compared with a preset threshold voltage, if the peak voltage is less than the threshold voltage, a first result is output, and if the peak voltage is greater than the threshold voltage, a second result is output, the first result indicating that there is an obstruction between the transmitting end and the corresponding receiving end, and the second result indicating that there is no obstruction between the transmitting end and the corresponding receiving end. The application ensures the signal detection stability under different obstruction states by dynamically setting the threshold voltage, and effectively solves the problem of mutual interference when the pair of photoelectric sensors are installed side by side.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of measurement and detection technology, in particular to an anti-interference method and system for a reflection type photoelectric sensor. BACKGROUND

[0002] As the core component of automation detection and intelligent control, sensors are widely used in various industries, especially the demand for small, high-precision and cost-effective sensors is particularly significant. In actual deployment, such sensors often need to face side-by-side installation applications, which leads to mutual interference between sensors. To address this challenge, diffuse reflection type sensors can use their built-in synchronous communication function to avoid such interference. However, for reflection type photoelectric sensors, since the transmitting end and the receiving end are designed independently of each other, they cannot solve the interference problem in the same way.

[0003] To solve the above interference problem, one existing solution is to add a synchronization line between the transmitting end and the receiving end to achieve synchronous operation, which reduces interference to some extent. However, this method increases wiring complexity and cost. Another method is to reduce the size of the light spot of the transmitting end light source, such as using a point light source to reduce the interference range, but this increases the alignment accuracy requirement and installation difficulty.

[0004] Although the existing solutions can alleviate interference, they also increase system complexity and installation difficulty. Therefore, a new method is needed that can reduce interference and is easy to install. SUMMARY

[0005] In view of the above problems, the present application provides an anti-interference method and system for a reflection type photoelectric sensor to solve the above technical problems.

[0006] In a first aspect, the present application provides an anti-interference method for a reflection type photoelectric sensor, applied to at least two pairs of adjacent reflection type photoelectric sensors. Each pair of reflection type photoelectric sensors transmits pulsed light signals from the transmitting end to the corresponding receiving end, and the light spots of adjacent transmitting ends overlap at least part of the photosensitive area of a non-corresponding receiving end. The anti-interference method for the reflection type photoelectric sensor comprises:

[0007] Each receiving end converts the received composite light signal into an electrical signal and performs gain amplification to obtain a detection electrical signal, wherein the composite light signal contains pulsed light signals from the corresponding transmitting end and pulsed light signals from the adjacent transmitting end.

[0008] comparing the peak voltage of the detection electrical signal with a preset threshold voltage, if the peak voltage is less than the threshold voltage, outputting a first result, if the peak voltage is greater than the threshold voltage, outputting a second result, the first result indicating that there is an obstruction between the transmitting end and the corresponding receiving end, and the second result indicating that there is no obstruction between the transmitting end and the corresponding receiving end;

[0009] The threshold voltage is dynamically set according to the first peak voltage and the second peak voltage, and satisfies: the threshold voltage is less than the first peak voltage and greater than the second peak voltage, the first peak voltage is the peak voltage of the electrical signal obtained by converting the pulsed optical signal of the corresponding transmitting end into an electrical signal and gain amplification by the receiving end in the non-obstruction state, and the second peak voltage is the peak voltage of the electrical signal obtained by converting the pulsed optical signal of the adjacent transmitting end into an electrical signal and gain amplification by the receiving end in the non-obstruction state.

[0010] In a second aspect, the present application provides an anti-interference system of a pair of photoelectric sensors, comprising:

[0011] At least two pairs of adjacent pair of photoelectric sensors, the transmitting end of each pair of the pair of photoelectric sensors emits a pulsed optical signal to the corresponding receiving end, and the light spots of the adjacent transmitting ends cross cover at least part of the photosensitive area of the non-corresponding receiving end;

[0012] The receiving end of each pair of the pair of photoelectric sensors comprises:

[0013] A power conversion module is configured to connect a power supply and convert the power supply voltage into a working voltage to power the receiving end of the pair of photoelectric sensors.

[0014] An optoelectronic conversion module is configured to convert the received composite optical signal into an electrical signal and perform gain amplification to obtain a detection electrical signal, wherein the composite optical signal contains a pulsed optical signal from the corresponding transmitting end and a pulsed optical signal from the adjacent transmitting end.

[0015] A main control module is configured to compare the peak voltage of the detection electrical signal with a preset threshold voltage, if the peak voltage is less than the threshold voltage, output a first signal, if the peak voltage is greater than the threshold voltage, output a second signal, the threshold voltage is dynamically set according to the first peak voltage and the second peak voltage, and satisfies: the threshold voltage is less than the first peak voltage and greater than the second peak voltage, the first peak voltage is the peak voltage of the electrical signal obtained by converting the pulsed optical signal of the corresponding transmitting end into an electrical signal and gain amplification by the receiving end in the non-obstruction state, and the second peak voltage is the peak voltage of the electrical signal obtained by converting the pulsed optical signal of the adjacent transmitting end into an electrical signal and gain amplification by the receiving end in the non-obstruction state.

[0016] an indication module configured to receive the first signal to show a first result, and receive the second signal to show a second result, the first result indicating that there is an obstruction between the transmitting end and the corresponding receiving end, and the second result indicating that there is no obstruction between the transmitting end and the corresponding receiving end.

[0017] The application provides an anti-interference method and system for a pair of light sensors. The received composite light signal is converted into an electrical signal and amplified in gain at the receiving end. Then, the peak voltage of the detection electrical signal is compared with a preset threshold voltage to determine whether there is an obstruction between the transmitting end and the corresponding receiving end. The threshold voltage is dynamically set according to the first peak voltage and the second peak voltage, and the threshold voltage is less than the first peak voltage and greater than the second peak voltage. Specifically, in the no-obstruction state, the voltage peaks of the light signals from the corresponding transmitting end and the adjacent transmitting end are different at the same receiving end. Therefore, the application dynamically sets the threshold voltage to ensure the signal detection stability in different obstruction states, effectively solves the mutual interference problem of the pair of light sensors installed side by side, and reduces the installation difficulty and wiring difficulty of the pair of light sensors while solving the mutual interference problem of the pair of light sensors installed side by side.

[0018] These aspects or other aspects of the application will be more apparent in the following description of the embodiments. BRIEF DESCRIPTION OF DRAWINGS

[0019] In order to more clearly illustrate the technical solutions of the embodiments of the application or the prior art, the following will briefly introduce the drawings needed to be used in the embodiment description. Obviously, the drawings in the following description are only some embodiments of the application, and for those skilled in the art, other drawings can also be obtained without creative labor.

[0020] Figure 1 An application schematic diagram of the anti-interference method for the pair of light sensors provided by the embodiments of the application is shown.

[0021] Figure 2 A flowchart of the anti-interference method for the pair of light sensors provided by the embodiments of the application is shown.

[0022] Figure 3 A waveform schematic diagram of the composite electrical signal received by the receiving end of the pair of light sensors in the no-obstruction state is shown.

[0023] Figure 4 Another flowchart of the anti-interference method for the pair of light sensors provided by the embodiments of the application is shown.

[0024] Figure 5 A schematic diagram of a receiving end of a reflection type photoelectric sensor is shown. DETAILED DESCRIPTION

[0025] In order to make the persons skilled in the art better understand the scheme of the present application, the technical scheme in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are only some of the embodiments of the present application, not all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by the persons skilled in the art without creative labor fall within the scope of protection of the present application.

[0026] In the embodiments of the present application, it should be noted that, in this document, relational terms such as first and second and the like are used solely to distinguish one entity or action from another entity or action, without necessarily requiring or implying any actual such relationship or order between or among the entities or actions.

[0027] Moreover, the terms "comprising", "comprises", "comprised of" or any other variation thereof are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but can include other elements not expressly listed or inherent to such process, method, article, or apparatus. An element proceeded by "comprises a... " does not, without more constraints, exclude the existence of additional identical elements in the process, method, article, or apparatus that comprises the a stated elements.

[0028] In addition, "a plurality of" in the embodiments of the present application means two or more, and in view of this, "a plurality of" in the embodiments of the present application can also be understood as "at least two". "At least one" can be understood as one or more, for example, as one, two or more. For example, including at least one means including one, two or more, and does not limit which ones are included, for example, including at least one of A, B and C means that A, B, C, A and B, A and C, B and C, or A and B and C can be included.

[0029] The embodiments of the present application provide an anti-interference method for reflection type photoelectric sensors, aiming to solve the signal interference problem between a plurality of reflection type photoelectric sensors arranged adjacent to each other. The embodiments of the present application are applied to at least two pairs of reflection type photoelectric sensors arranged adjacent to each other, each pair of reflection type photoelectric sensors is composed of a sending end and a receiving end, each sending end emits a pulsed light signal to the corresponding receiving end. Due to the side-by-side installation design of the plurality of reflection type photoelectric sensors, the light spots of the adjacent sending ends will cross cover at least part of the photosensitive area of a non-corresponding receiving end, thereby causing signal interference.Figure 1 The application embodiment provides an application schematic diagram of the anti-interference method for the pair of photoelectric sensors, Figure 2 The application embodiment provides a flow chart of the anti-interference method for the pair of photoelectric sensors, referring to Figure 1 The application schematic diagram shows how to arrange the pair of photoelectric sensors, and in Figure 2 The specific process of the anti-interference method is described in detail: as shown in Figure 2 The anti-interference method for the pair of photoelectric sensors includes the following steps:

[0030] The receiving end converts the received composite optical signal into an electrical signal and performs gain amplification to obtain a detection electrical signal, so as to ensure that even a weak optical signal can be accurately recognized and processed by the receiving end. The composite optical signal contains the pulse optical signal from the corresponding transmitting end and the pulse optical signal from the adjacent transmitting end.

[0031] The peak voltage of the detection electrical signal is compared with a preset threshold voltage. If the peak voltage of the detection electrical signal is less than the threshold voltage, a first result is output, and if the peak voltage is greater than the threshold voltage, a second result is output. The first result indicates that there is an obstruction between the transmitting end and the corresponding receiving end, and the second result indicates that there is no obstruction between the transmitting end and the corresponding receiving end.

[0032] The threshold voltage is dynamically set according to the first peak voltage and the second peak voltage. Specifically, the threshold voltage satisfies the condition that the threshold voltage is less than the first peak voltage and greater than the second peak voltage. The first peak voltage is the peak voltage of the electrical signal obtained by converting the pulse optical signal from the corresponding transmitting end into an electrical signal and performing gain amplification by the receiving end in the unobstructed state. The second peak voltage is the peak voltage of the electrical signal obtained by converting the pulse optical signal from the adjacent transmitting end into an electrical signal and performing gain amplification by the receiving end in the unobstructed state.

[0033] Optionally, the threshold voltage of the pair of photoelectric sensors is mainly used to accurately distinguish the signal state, so as to determine whether the receiving end successfully receives the optical signal from the transmitting end, thereby judging whether there is an obstruction between the sensors. In the application embodiment, referring to Figure 3 The waveform diagram of the composite electrical signal received by the receiving end in the unobstructed state is shown in the figure. Obviously, the peak voltage of the electrical signal obtained by converting the pulse optical signal from the corresponding transmitting end into an electrical signal and performing gain amplification by the receiving end in the unobstructed state is obviously greater than the peak voltage of the electrical signal obtained by converting the pulse optical signal from the adjacent transmitting end into an electrical signal and performing gain amplification by the receiving end in the unobstructed state. Therefore, as long as the threshold voltage is set between the two peak voltages, the interference problem of the pair of photoelectric sensors installed side by side can be stably solved.

[0034] The anti-interference method for the reflection type photoelectric sensor provided in the embodiments of the present application converts the received composite light signal into an electric signal and performs gain amplification at the receiving end, and then compares the peak voltage of the detection electric signal with the preset threshold voltage to determine whether there is an obstruction between the transmitting end and the corresponding receiving end. The threshold voltage is dynamically set according to the first peak voltage and the second peak voltage, and satisfies that the threshold voltage is less than the first peak voltage and greater than the second peak voltage. Specifically, in the no-obstruction state, the voltage peaks of the light signals from the corresponding transmitting end and the adjacent transmitting end are different at the same receiving end, so the present application dynamically sets the threshold voltage to ensure the signal detection stability in different obstruction states, effectively solves the mutual interference problem of the reflection type photoelectric sensors installed side by side, and compared with the prior art which reduces interference by adding a synchronization line between the transmitting end and the receiving end or reduces interference by reducing the spot size of the light source of the transmitting end, the present application reduces the installation difficulty and wiring difficulty of the reflection type photoelectric sensor, and also solves the mutual interference problem of the reflection type photoelectric sensors installed side by side.

[0035] In some embodiments, Figure 4 Another flowchart of the anti-interference method for the reflection type photoelectric sensor provided in the embodiments of the present application is shown, as shown in Figure 4 In order to further improve the anti-interference ability and detection accuracy of the reflection type photoelectric sensor, the step of comparing the peak voltage of the detection electric signal with the preset threshold voltage in the anti-interference method for the reflection type photoelectric sensor provided in the embodiments of the present application further includes:

[0036] The peak voltage of the detection electric signal is compared with the preset back difference voltage, and if the peak voltage is greater than the back difference voltage, a second result is output, wherein the back difference voltage is dynamically set according to the first peak voltage and the threshold voltage, and satisfies that the back difference voltage is less than the first peak voltage and greater than the threshold voltage. Specifically, if the peak voltage of the detection electric signal is less than the threshold voltage, it indicates that there is an obstruction between the transmitting end and the receiving end, if the peak voltage of the detection electric signal is between the threshold voltage and the back difference voltage, it indicates that the state of the transmitting end and the receiving end is converted from "no obstruction" to "obstruction" or from "obstruction" to "no obstruction", and if the peak voltage of the detection electric signal is greater than the back difference voltage, it indicates that the transmitting end and the receiving end are not obstructed.

[0037] The anti-interference method for the reflection type photoelectric sensor provided in the embodiments of the present application effectively prevents false triggering or frequent state switching caused by small amplitude and instantaneous signal fluctuations by setting the back difference voltage. The signal fluctuation problem caused by environmental changes or slight interference is solved, and the sensor can be more accurate in complex and variable actual application environments.

[0038] In some embodiments, in order to ensure the anti-interference ability and detection stability of the retro-reflective photoelectric sensor, the present application provides a minimum voltage difference between the threshold voltage and the second peak voltage. Specifically, the present application provides an anti-interference method for a retro-reflective photoelectric sensor, wherein the voltage difference between the threshold voltage and the second peak voltage is not less than 50 millivolts.

[0039] In some embodiments, the present application provides an anti-interference method for a retro-reflective photoelectric sensor, wherein the voltage difference between the return difference voltage and the threshold voltage is not less than 30 millivolts, thereby reserving sufficient return difference space to prevent false triggering or frequent state switching due to small amplitude, transient signal fluctuations.

[0040] In some embodiments, in order to optimize the performance of the retro-reflective photoelectric sensor and further reduce interference between adjacent devices, the present application further provides specific spacing requirements between adjacent retro-reflective photoelectric sensors and between the transmitting end and the receiving end of each pair of sensors. The present application provides an anti-interference method for a retro-reflective photoelectric sensor, wherein the spacing between adjacent retro-reflective photoelectric sensors is not less than 45 millimeters, and the spacing between the transmitting end and the receiving end of each pair of retro-reflective photoelectric sensors is not more than 20 centimeters. By setting the spacing, the risk of such cross interference is reduced, thereby improving the reliability and stability of the entire system.

[0041] It can be understood that the anti-interference method for a retro-reflective photoelectric sensor provided by the present application is achieved by programming at the receiving end. Specifically, the specific algorithm and logic judgment of the anti-interference method for a retro-reflective photoelectric sensor are encoded and deployed on the processor or microcontroller of the receiving end for running.

[0042] The present application also provides an anti-interference system for a retro-reflective photoelectric sensor, which comprises:

[0043] At least two pairs of adjacent retro-reflective photoelectric sensors, wherein the transmitting end of each pair of retro-reflective photoelectric sensors emits pulsed light signals to the corresponding receiving end, and the light spots of adjacent transmitting ends cross cover at least part of the photosensitive area of a non-corresponding receiving end.

[0044] Figure 5 A schematic diagram of the receiving end of the retro-reflective photoelectric sensor provided by the present application is shown, as shown in Figure 5 The receiving end of each pair of retro-reflective photoelectric sensors comprises:

[0045] A power conversion module for connecting a power supply and converting the power supply voltage into a working voltage to power the receiving end of the retro-reflective photoelectric sensor. Optionally, the power conversion module is a linear voltage stabilizing circuit for linearly stepping down the input power supply voltage to power the photoelectric conversion module, the main control module and the indication module.

[0046] A photoelectric conversion module is configured to convert a received composite optical signal into an electrical signal and perform gain amplification to obtain a detection electrical signal, wherein the composite optical signal comprises a pulse optical signal from a corresponding transmitting end and a pulse optical signal from an adjacent transmitting end. Optionally, the photoelectric conversion module is a circuit module composed of a photodiode and an operational amplifier circuit, so as to realize conversion of the optical signal into the electrical signal and multi-stage amplification of the electrical signal.

[0047] A main control module is configured to compare a peak voltage of the detection electrical signal with a preset threshold voltage, output a first signal if the peak voltage is less than the threshold voltage, and output a second signal if the peak voltage is greater than the threshold voltage, wherein the threshold voltage is dynamically set according to a first peak voltage and a second peak voltage, and satisfies: the threshold voltage is less than the first peak voltage and greater than the second peak voltage, the first peak voltage is a peak voltage of an electrical signal obtained by converting the pulse optical signal from the corresponding transmitting end into the electrical signal and performing gain amplification on the electrical signal in a non-occlusion state of the receiving end, and the second peak voltage is a peak voltage of an electrical signal obtained by converting the pulse optical signal from the adjacent transmitting end into the electrical signal and performing gain amplification on the electrical signal in the non-occlusion state of the receiving end. Optionally, the main control module is a control chip such as a microcontroller, a single-chip microcomputer or a processor, so as to realize, through programming, comparison of the peak voltage of the detection electrical signal with the preset threshold voltage, output of the first signal if the peak voltage is less than the threshold voltage, and output of the second signal if the peak voltage is greater than the threshold voltage.

[0048] An indication module is configured to receive the first signal to display a first result and receive the second signal to display a second result, wherein the first result indicates that there is an occlusion between the transmitting end and the corresponding receiving end, and the second result indicates that there is no occlusion between the transmitting end and the corresponding receiving end. Optionally, the indication module comprises an indicator light and a corresponding protection circuit, so as to indicate the first result / second result through lighting / extinguishing of the indicator light.

[0049] It can be understood that the purpose of the embodiments of the present application is to provide an effective anti-interference means to improve the interference problem caused by side-by-side installation of the opposite transmitting and receiving photoelectric sensors, and therefore, the specific structures of the modules of the transmitting and receiving photoelectric sensors, such as the power conversion module, the photoelectric conversion module, the main control module and the indication module, are not limited here.

[0050] In some embodiments, in order to further improve the anti-interference ability and detection accuracy of the active optical sensor, the anti-interference system for the active optical sensor provided by the embodiments of the present application is used to compare the peak voltage of the detection electric signal with the preset back difference voltage, and output the second signal if the peak voltage is greater than the back difference voltage. The back difference voltage is dynamically set according to the first peak voltage and the threshold voltage, and satisfies: the back difference voltage is less than the first peak voltage and greater than the threshold voltage. Thus, the false triggering or frequent state switching caused by small amplitude and instantaneous signal fluctuation is effectively prevented by setting the back difference voltage, and the signal fluctuation problem caused by environmental changes or slight interference is solved.

[0051] In some embodiments, the voltage difference between the threshold voltage and the second peak voltage in the anti-interference system for the active optical sensor provided by the embodiments of the present application is not less than 50 millivolts.

[0052] In some embodiments, the voltage difference between the back difference voltage and the threshold voltage in the anti-interference system for the active optical sensor provided by the embodiments of the present application is not less than 30 millivolts.

[0053] In some embodiments, the distance between the adjacent active optical sensors in the anti-interference system for the active optical sensor provided by the embodiments of the present application is not less than 45 millimeters, and the distance between the emitting end and the receiving end of each pair of active optical sensors is not more than 20 centimeters.

[0054] The anti-interference system for the active optical sensor provided by the embodiments of the present application is used to convert the received composite light signal into an electric signal and perform gain amplification at the receiving end, and then compare the peak voltage of the detection electric signal with the preset threshold voltage to determine whether there is an obstruction between the emitting end and the corresponding receiving end. The threshold voltage is dynamically set according to the first peak voltage and the second peak voltage, and satisfies: the threshold voltage is less than the first peak voltage and greater than the second peak voltage. Specifically, in the unobstructed state, the voltage peaks of the light signals from the corresponding emitting end and the adjacent emitting end are different, so the embodiments of the present application dynamically set the threshold voltage to ensure the signal detection stability in different obstruction states, effectively solve the mutual interference problem of the active optical sensors installed side by side, and reduce the installation difficulty and wiring difficulty of the active optical sensors compared with the prior art which adds a synchronization line between the emitting end and the receiving end to reduce interference or reduces the spot size of the light source of the emitting end to reduce interference.

[0055] The above description is further detailed in combination with specific embodiments of the present application, and cannot be deemed as limiting the specific implementation of the present application to these descriptions. For those skilled in the art to which the present application belongs, without departing from the concept of the present application, a number of simple deductions or replacements can be made, and all should be considered as the protection scope of the present application.

Claims

1. A method of making a photodiode sensor immune to interference, comprising: The application is applied to at least two pairs of adjacent arranged pair-type photoelectric sensors, the emitting end of each pair of the pair-type photoelectric sensors emits pulse light signals to the corresponding receiving end, and the light spots of adjacent emitting ends cross cover at least part of the photosensitive area of a non-corresponding receiving end. The anti-interference method of the pair-type photoelectric sensor comprises the following steps: Each receiving end converts the received composite light signal into an electric signal and performs gain amplification to obtain a detection electric signal, wherein the composite light signal comprises the pulse light signal from the corresponding emitting end and the pulse light signal from the adjacent emitting end; The peak voltage of the detection electric signal is compared with a preset threshold voltage, if the peak voltage is less than the threshold voltage, a first result is output, if the peak voltage is greater than the threshold voltage, a second result is output, wherein the first result indicates that there is an obstruction between the emitting end and the corresponding receiving end, and the second result indicates that there is no obstruction between the emitting end and the corresponding receiving end; The threshold voltage is dynamically set according to a first peak voltage and a second peak voltage, and satisfies that the threshold voltage is less than the first peak voltage and greater than the second peak voltage, the first peak voltage is the peak voltage of the electric signal obtained by converting the pulse light signal from the corresponding emitting end into an electric signal and performing gain amplification on the receiving end in the non-obstruction state, and the second peak voltage is the peak voltage of the electric signal obtained by converting the pulse light signal from the adjacent emitting end into an electric signal and performing gain amplification on the receiving end in the non-obstruction state.

2. The anti-interference method of the pair-type photoelectric sensor according to claim 1, wherein the step of comparing the peak voltage of the detection electric signal with the preset threshold voltage further comprises: The peak voltage of the detection electric signal is compared with a preset back difference voltage, if the peak voltage is greater than the back difference voltage, the second result is output; The back difference voltage is dynamically set according to the first peak voltage and the threshold voltage, and satisfies that the back difference voltage is less than the first peak voltage and greater than the threshold voltage.

3. The method of claim 1, wherein the method is applied to a pair of phototransistors. The voltage difference between the threshold voltage and the second peak voltage is not less than 50 millivolts.

4. The method of claim 2, wherein the method further comprises: determining whether the received signal is a valid signal or an invalid signal; and if the received signal is determined to be an invalid signal, then generating a signal to indicate that the received signal is an invalid signal. The voltage difference between the back difference voltage and the threshold voltage is not less than 30 millivolts.

5. The method of claim 1, wherein the method is applied to a pair of phototransistors. The spacing between the adjacent pair-type photoelectric sensors is not less than 45 millimeters, and the spacing between the emitting end and the receiving end of each pair of the pair-type photoelectric sensors is not more than 20 centimeters.

6. A system for interference rejection in a photodiode sensor, comprising: The application comprises: At least two pairs of adjacent arranged pair-type photoelectric sensors, the emitting end of each pair of the pair-type photoelectric sensors emits pulse light signals to the corresponding receiving end, and the light spots of adjacent emitting ends cross cover at least part of the photosensitive area of a non-corresponding receiving end; The receiving end of each pair of the pair-type photoelectric sensors comprises: A power conversion module is used for connecting a power supply and converting the power supply voltage into a working voltage to power the receiving end of the pair-type photoelectric sensor; A photoelectric conversion module is used for converting the received composite light signal into an electric signal and performing gain amplification to obtain a detection electric signal, wherein the composite light signal comprises the pulse light signal from the corresponding emitting end and the pulse light signal from the adjacent emitting end; The master control module is configured to compare the peak voltage of the detection electrical signal with a preset threshold voltage, output a first signal if the peak voltage is less than the threshold voltage, and output a second signal if the peak voltage is greater than the threshold voltage, wherein the threshold voltage is dynamically set according to a first peak voltage and a second peak voltage, and satisfies that the threshold voltage is less than the first peak voltage and greater than the second peak voltage, the first peak voltage is a peak voltage of an electrical signal obtained by converting a pulse optical signal of a corresponding transmitting end into an electrical signal and performing gain amplification on the electrical signal by the receiving end in a non-occlusion state, and the second peak voltage is a peak voltage of an electrical signal obtained by converting a pulse optical signal of an adjacent transmitting end into an electrical signal and performing gain amplification on the electrical signal by the receiving end in a non-occlusion state. The indication module is configured to display a first result by receiving the first signal, and display a second result by receiving the second signal, wherein the first result indicates that there is an occlusion between the transmitting end and the corresponding receiving end, and the second result indicates that there is no occlusion between the transmitting end and the corresponding receiving end.

7. The anti-interference system of the pair-of-beam photoelectric sensor according to claim 6, wherein the master control module is further configured to compare the peak voltage of the detection electrical signal with a preset return difference voltage, and output the second signal if the peak voltage is greater than the return difference voltage. wherein The return difference voltage is dynamically set according to the first peak voltage and the threshold voltage, and satisfies that the return difference voltage is less than the first peak voltage and greater than the threshold voltage.

8. The anti-tamper system for a photo sensor of claim 7, wherein, The voltage difference between the threshold voltage and the second peak voltage is not less than 50 millivolts.

9. The anti-tamper system for a photo sensor of claim 8, wherein, The voltage difference between the return difference voltage and the threshold voltage is not less than 30 millivolts.

10. The anti-tamper system for a photo sensor of claim 7, wherein, The interval between the pair-of-beam photoelectric sensors arranged adjacently is not less than 45 millimeters, and the interval between the transmitting end and the receiving end of each pair of the pair-of-beam photoelectric sensors is not more than 20 centimeters.

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