WO2023030357A1 - 一种抗高频光干扰的光电传感器 - Google Patents

一种抗高频光干扰的光电传感器 Download PDF

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WO2023030357A1
WO2023030357A1 PCT/CN2022/116035 CN2022116035W WO2023030357A1 WO 2023030357 A1 WO2023030357 A1 WO 2023030357A1 CN 2022116035 W CN2022116035 W CN 2022116035W WO 2023030357 A1 WO2023030357 A1 WO 2023030357A1
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signal
interference
control module
signals
photoelectric sensor
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PCT/CN2022/116035
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English (en)
French (fr)
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许永童
谢勇
赵都桂
韦红光
姜星兴
唐佳
周成松
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上海兰宝传感科技股份有限公司
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Priority claimed from CN202111009222.6A external-priority patent/CN113721517A/zh
Priority claimed from CN202111009224.5A external-priority patent/CN113726982A/zh
Application filed by 上海兰宝传感科技股份有限公司 filed Critical 上海兰宝传感科技股份有限公司
Publication of WO2023030357A1 publication Critical patent/WO2023030357A1/zh

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    • G—PHYSICS
    • G05—CONTROLLING; REGULATING
    • G05B—CONTROL OR REGULATING SYSTEMS IN GENERAL; FUNCTIONAL ELEMENTS OF SUCH SYSTEMS; MONITORING OR TESTING ARRANGEMENTS FOR SUCH SYSTEMS OR ELEMENTS
    • G05B19/00—Programme-control systems
    • G05B19/02—Programme-control systems electric
    • G05B19/04—Programme control other than numerical control, i.e. in sequence controllers or logic controllers
    • G05B19/042—Programme control other than numerical control, i.e. in sequence controllers or logic controllers using digital processors
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
    • H04N5/00—Details of television systems
    • H04N5/14—Picture signal circuitry for video frequency region
    • H04N5/21—Circuitry for suppressing or minimising disturbance, e.g. moiré or halo

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  • the invention relates to a photoelectric sensor, in particular to a photoelectric sensor resistant to high-frequency light interference.
  • the photoelectric sensor can realize the collection, detection and processing of the signal through the emission and reception of the optical signal and the photoelectric conversion.
  • ambient light shines on the receiving end of the photoelectric sensor, especially high-frequency interference light, useful signals and interference signals are superimposed, and the amplitude may increase or decrease. Therefore, conventional photoelectric sensor receivers cannot correctly identify useful signals, resulting in abnormal phenomena such as sensor misjudgment.
  • a capacitor is usually added behind the receiving tube, which can effectively attenuate the interference of low-frequency light sources such as sunlight and incandescent lamps.
  • low-frequency light sources such as sunlight and incandescent lamps.
  • the main frequency of these light sources is generally 20K-100KHz, or even 1M-2MHz. Therefore, even if the DC blocking capacitor is added, it is impossible to remove the interference of high-frequency light sources, let alone the interference of the interference signal and the frequency of the useful signal.
  • Proximity switch sensor products can significantly improve anti-interference and avoid product output jitter after adding the hysteresis value. If there is no hysteresis value, when the object to be detected is at the sensing position, the output of the proximity switch may jitter and affect the use.
  • the proximity switch usually set a fixed and compromised hysteresis value at the rated distance, taking into account the hysteresis requirements of small range and large range.
  • the demand for proximity switch sensors in industrial automation is increasing day by day, the detection distance is getting farther and farther, and the detection sensitivity is getting higher and higher. Setting a fixed hysteresis value according to the previous method cannot meet the needs of large-range products.
  • the purpose of the present invention is to provide a photoelectric sensor with high resistance to high-frequency light interference, which has a high ability to resist ambient light interference, can avoid output misjudgment, works stably and reliably, and has a wider application range; it can set different hysteresis in different ranges and meet a large number of applications.
  • the hysteresis requirements of range products in different ranges make the use of sensors more stable and reliable.
  • a photoelectric sensor against high-frequency light interference including a transmitting tube for emitting a laser light source as a modulated optical signal, a double receiving tube for receiving an optical signal, a filter installed at the front end of the dual receiving tube to filter the optical signal, a coupling A band-pass filter circuit connected to the dual receiver tubes, a differential amplifier coupled to the band-pass filter circuit, and a control module for controlling the dual receiver tubes to receive optical signals synchronously with the transmitter tube;
  • the control module also collects and acquires ambient light interference signals, and sets an interference signal threshold. When it is detected that the amplitude of the collected ambient light interference signals is greater than the set interference signal threshold, the control module discards the superimposed interference signal Optical signal below the noise threshold.
  • a photoelectric sensor for resisting high-frequency light interference includes a transmitting tube for emitting laser light sources to modulate optical signals, double receiving tubes for receiving optical signals, and a belt for filtering optical signals installed at the front ends of the dual receiving tubes.
  • the control module also collects and acquires ambient light interference signals, and sets an interference signal threshold. When it is detected that the amplitude of the collected ambient light interference signals is greater than the set interference signal threshold, the control module discards the superimposed interference signal Optical signals below the threshold of interfering signals;
  • the sensor hysteresis setting system includes an amplifier one that receives an input signal and performs one-stage amplification, a positioner coupled to the output terminal of the amplifier one for adjusting the range of the proximity switch, and a positioner coupled to the output terminal of the potentiometer for adjustment.
  • Amplifier 2 for secondary amplification of the received signal, a high-impedance follower connected in parallel to amplifier 2, and an MCU coupled to the output of amplifier 2 and the follower for controlling and setting the return difference;
  • the potentiometer adjusts the output voltage division ratio according to the range of the proximity switch, and the MCU calculates the output return difference value according to the range signal output by the follower.
  • the transmitting tube and the dual receiving tubes are coupled to the control module; the control module responds to the driving signal driving the transmitting tube, and the control module sends a collection signal to control the synchronization of the dual receiving tubes
  • the optical signal acquisition is performed in time division of the driving signal.
  • control module samples the ambient light interference signal cycle by cycle, and the sampling position is located between intervals of collecting useful light signals.
  • the emission tube is a laser light source, and the emission front end of the emission tube is provided with an optical lens I for converging the transmitted modulated light signal.
  • an optical lens 2 is further arranged between the receiving front end of the double receiving tube and the filter.
  • the filter is a band-pass filter corresponding to the same wavelength band as the emitted modulated optical signal.
  • the MCU calculates the output return difference as follows:
  • x is the range signal variable transmitted by the follower
  • y is the return difference
  • m and n are fixed coefficients
  • k is the intercept.
  • the MCU reads the signals output by the amplifier 2 and the follower in a time-sharing manner, and reads them cycle by cycle.
  • a method for setting the hysteresis of a photoelectric sensor against high-frequency light interference including a transmitting tube used to emit a laser light source as a modulated optical signal, a double receiving tube used to receive the optical signal, and installed at the front end of the double receiving tube to filter the optical signal
  • the filter, the band-pass filter circuit coupled to the dual receiver tubes, the differential amplifier coupled to the band-pass filter circuit, the control module for controlling the dual receiver tubes to receive optical signals synchronously with the transmitter tube, and the anti-interference for the sensor Improved sensor hysteresis setting system;
  • the control module also collects and acquires ambient light interference signals, and sets an interference signal threshold. When it is detected that the amplitude of the collected ambient light interference signals is greater than the set interference signal threshold, the control module discards the superimposed interference signal Optical signals below the threshold of interfering signals;
  • the input signal is amplified and divided, it is amplified by the amplifier and then the detection signal is output to the MCU, and the range signal is output to the MCU through the follower;
  • the MCU receives the range signal and calculates and sets the return difference value according to the set algorithm
  • the present invention has the following beneficial effects:
  • the photoelectric sensor adopts dual receiving tubes in hardware, and cooperates with the band-pass filter circuit and differential amplifier, which can distinguish the ambient light signal uniformly irradiated on the dual receiving tubes from the signal of the laser as a modulated optical signal. Most of the ambient light signals It can be judged as a common mode signal and then filtered out, which can effectively filter out the interfering low-frequency and high-frequency signals, and retain useful signals; the control module controls the dual receiving tubes to synchronize with the driving signals of the transmitting tubes for signal acquisition, and at the same time the ambient light interference signal To collect, when the interference signal is close to the wavelength of the modulated optical signal, it can be judged whether there is interference to avoid product misoperation;
  • the range signal is regarded as a variable, and a hysteresis value is output after calculation and processing. Requirements for hysteresis settings in different ranges for large-range products.
  • Figure 1 is a schematic diagram of the return difference of the proximity switch
  • Fig. 2 is a relation diagram of signal strength and distance
  • Fig. 3 is the structural representation of present embodiment
  • Fig. 4 is a partial sectional view of the present embodiment shown in Fig. 1;
  • FIG. 5 is a schematic diagram of an ambient light interference receiver
  • Figure 6 is a schematic diagram of the system
  • Fig. 7 is a schematic diagram of different return difference values corresponding to different measuring ranges.
  • Photoelectric sensors are generally composed of a transmitter and a receiver.
  • the transmitter mainly modulates red light and infrared light sources to emit.
  • the modulated optical signal is reflected back to the receiver, and the receiver outputs an action signal after amplifying and comparing the signal.
  • photoelectric sensors are used in more and more occasions. Different industrial occasions have various lighting sources, including sunlight, incandescent lamps, fluorescent lamps, LED energy-saving lamps, halogen lamps, and high-pressure sodium lamps. These light sources work at different main frequencies, including DC components, 50Hz-60Hz power frequency signals, high-frequency 20K-100KHz, and even high-frequency light such as 1M-2MHz. These light sources not only have a wide frequency range, but also cover visible light, ultraviolet light, infrared light, etc.
  • the relationship between the signal strength and distance of a general proximity switch, the signal trend change is a nonlinear relationship, similar to a power function.
  • a fixed signal value ⁇ V is set as the hysteresis
  • H1 (S2-S1)/S1*100%
  • a very small H1 may cause the product output to jitter.
  • Large scale H2 (S4-S3)/S3*100%, very large H2 may cause the output of the product to be blocked. From this, it can be seen that there is a large difference in the hysteresis difference between the small range and the large range.
  • the small range product has a risk of output jitter due to the small hysteresis; The risk of output blocking affects the use of large range products.
  • a photoelectric sensor that resists high-frequency light interference including a transmitting tube, a double receiving tube, and a filter set at the receiving front end of the double receiving tube; it also includes There is a band-pass filter circuit coupled to the dual receiver tubes, and a differential amplifier coupled to the band-pass filter circuit, which is used to control the dual receiver tubes to perform receiving actions to synchronize with the transmitter tube to collect modulated optical signals, and to collect ambient light interference according to settings Signal control module.
  • An optical lens 1 is arranged at the emission front end of the emission tube, which is a plano-convex lens. , is also a plano-convex lens, and the plane is located on the side of the receiving front end of the receiving tube.
  • the emission tube uses laser as the VCSEL light source to emit modulated optical signals, and after being concentrated by the optical lens, the light spot is small and the energy is more concentrated.
  • the filter is a band-pass filter with the same band as the modulated optical signal, and it is installed at the receiving front end of the dual receiving tube.
  • the filter has high transmittance to the light of the wavelength of the transmitting tube. It has low permeability, so it can filter out most of the interference signals of different bands of ambient light. The interfering light in the same band needs to be further processed.
  • the ambient light can be equivalent to a surface light source.
  • the ambient light signal is evenly irradiated on the two receiving tubes PD1 and PD2, that is, the signal can be regarded as is a common-mode signal.
  • the band-pass filter circuit can filter out low-frequency signals, such as low-frequency signals such as power-frequency incandescent lamps and sunlight; it can also attenuate signals much higher than the modulated optical frequency, and perform differential amplification on the filtered signals to make excellent circuit differential amplification.
  • the light source with the same wavelength band as the emission tube can pass through the filter. Even after differential amplification, the interference signal of ambient light still exists, but the interference component has dropped a lot. The useful signal will not be completely covered by the interference signal. At this time, the software samples to identify whether there is ambient light. When there is ambient light interference, the software will handle it.
  • the control module responds to the driving signal for driving the transmitting tube, and the control module sends a collection signal to control the dual receiving tubes to synchronize with the driving signal to perform time-sharing optical signal collection.
  • the transmitting tube is a modulated optical signal, and the reading of the modulated signal and the received signal is controlled by an MCU, which can realize the synchronous design of transmission and reception.
  • the transmission conduction signal is narrower, and the window time for collecting useful signals is reduced, which can further improve the anti-interference ability.
  • the ambient light interference signal is sampled cycle by cycle, and the sampling position is located between useful signal intervals. After multiple sampling, the interference signal can be taken. When the amplitude of the sampling interference signal is greater than the set interference signal threshold, the ambient light interference mode will be triggered. At this time, even if some useful signals are lower than the threshold after being superimposed by the interference signal, the signal will be discarded. signal, so as to avoid product output jitter or misjudgment.
  • the photoelectric sensor can work reliably and stably under high-frequency light sources such as fluorescent lamps and LED lamps, and the product can be used in a wider range.
  • the photoelectric sensor also includes a sensor hysteresis setting system for improving the anti-interference performance of the sensor, which includes amplifier 1, potentiometer, amplifier 2, follower and MCU.
  • Amplifier 1 receives the input signal and preliminarily amplifies the input signal.
  • the potentiometer is coupled to the output terminal of amplifier 1 to adjust and set the proximity switch range;
  • amplifier 2 is coupled to the adjustment output terminal of the potentiometer, and the follower is connected in parallel.
  • the amplifier 2 through the voltage division adjustment of the potentiometer, the amplifier 2 outputs the amplified received signal, that is, the signal output A;
  • the follower is high impedance, and is connected in parallel to the amplifier 2 to output the range signal, that is, the signal output B;
  • the MCU is coupled to the amplifier 2 And the output terminal of the follower, in response to the received signal and the range signal, calculates and sets the hysteresis of the control stage.
  • the hardware circuit design adopts two-stage amplification. After the signal is input to the amplifier and amplified, the potentiometer is connected to the output of the amplifier, and different voltage divisions are realized through the adjustment of the potentiometer. After voltage division, it is used as the input of amplifier 2 and the input of the follower. Since the follower is high impedance, the influence on the signal is negligible. Among them, different voltage division ratios can be realized by adjusting the potentiometer. As shown in Figure 6, when the potentiometer is adjusted to the top, the voltage division ratio of the amplifier two and the follower is the highest and has the largest range. When the potentiometer is adjusted to the bottom, the voltage division ratio of the amplifier two and the follower is the lowest, and has the smallest range.
  • the range signal is output B to the MCU through the follower, and the MCU performs calculation processing on the signal to set the return difference value. Since the adjustment of the range is realized through the potentiometer, as long as the resistance value of the potentiometer changes, the relative change of the follower signal output B will be caused, and the MCU can read the range signal in real time.
  • the MCU reads signal output A and signal output B in a time-sharing manner, and both signals are read cycle by cycle, which is real-time and highly responsive. As long as the range signal changes, the return difference value changes accordingly. It is guaranteed that the hysteresis value follows the dynamic change of the measuring range.
  • the circuit design can transmit the range signal to the MCU in real time, and the MCU reading the range signal will not affect the signal processing.
  • the MCU internally regards the range signal as a variable, and outputs a hysteresis value after internal processing.
  • the hysteresis value is related to the range, which realizes the requirement of setting different hysteresis for different ranges. To meet the needs of hysteresis settings in different ranges for large-range products. When the product is in different ranges, different hysteresis values can be set. This makes the hysteresis value of the product in the small range, medium range and large range all in an ideal state.
  • a photoelectric sensor hysteresis setting method for anti-high-frequency light interference which includes a transmitting tube for emitting a laser light source as a modulated optical signal, a double receiving tube for receiving optical signals, installed in A filter for optical signal filtering at the front end of the dual receiving tubes, a band-pass filter circuit coupled to the dual receiving tubes, a differential amplifier coupled to the band-pass filtering circuit, used to control the dual receiving tubes to receive optical signals synchronously with the transmitting tube
  • the control module of the sensor, the sensor hysteresis setting system for the improvement of the sensor's anti-interference.
  • the control module also collects and acquires ambient light interference signals, and sets an interference signal threshold. When it detects that the amplitude of the collected ambient light interference signal is greater than the set interference signal threshold, the control module discards the superimposed interference signal and is lower than the interference signal. Threshold light signal.
  • the input signal is amplified and divided, it is amplified by the amplifier and then the detection signal is output to the MCU, and the range signal is output to the MCU through the follower;
  • the MCU receives the range signal and calculates and sets the return difference value according to the set algorithm.

Abstract

本发明公开了一种抗高频光干扰的光电传感器，解决了现有方案无法解决高频光源干扰、产品会出现误判断的问题，其技术方案要点是包括有发射管、双接收管、安装于双接收管前端对光信号进行滤光的滤波片、耦接于双接收管的带通滤波电路、耦接于带通滤波电路的差分放大器、用于控制同步接收光信号的控制模块、用于传感器抗干扰性改进的传感器回差设定系统；控制模块还采集获取有环境光干扰信号，且设定有干扰信号阈值，当检测到采集的环境光干扰信号幅值大于设定的干扰信号阈值时，控制模块丢弃叠加干扰信号后低于干扰信号阈值的光信号，本发明的一种抗高频光干扰的光电传感器，具有高抗干扰能力，可避免输出误判断，工作稳定可靠，适用范围更广泛。

Description

一种抗高频光干扰的光电传感器 技术领域
本发明涉及光电传感器，特别涉及一种抗高频光干扰的光电传感器。
背景技术
光电传感器通过光信号的发射和接收并进行光电转换后，可实现对信号的采集、检测处理。当环境光照射至光电传感器的接收端时，特别是高频的干扰光，有用信号和干扰信号叠加，幅值有可能增加，有可能减少。因此，常规光电传感器接收器无法正确识别有用信号，从而导致传感器误判断等异常现象。
现有技术通常在接收管后面增加电容，可以将太阳光、白炽灯等低频光源的干扰有效衰减。但是对于高频光源，如节能灯、LED照明灯，这些光源的工作主频一般在20K～100KHz、甚至1M～2MHz等频率信号。因此，即使增加隔直电容无法去除高频光源干扰、更无法去除干扰信号和有用信号频率接近的干扰。
而其他方式则有通过在传统型的光电传感器增加一个窄缝，即在光电传感器表面增加一个不透光的罩子，只留出一个小孔，将环境光进行遮挡。同样也会遮挡有用信号，导致传感器的检测距离衰减严重，影响传感器的使用。
传统的解决方案均不能有效解决高频光源的干扰。使得光电传感器的应用场合受到限制。
接近开关传感器产品(包括光电传感器)加入了回差值后，可显著的提高抗干扰性，避免产品输出抖动。如果没有回差值，当被检测体位于感应位置时，可能会出现接近开关输出抖动影响使用。以往的 接近开关通常是在额定距离处，设定一个固定的，折中的回差值，兼顾小量程和较大量程的回差要求。然而工业自动化对接近开关传感器的需求日益增长，检测距离越来越远，检测灵敏度越来越高。按照以往的方式设定一个固定的回差值，不能满足大量程产品的需求。特别是那些具有距离调节的，涵盖了小量程和大量程的产品。固定回差不能兼顾最小量程和最大量程的要求。从而影响产品的使用，部分严重的情况，接近开关输出抖动或者闭住现象，危害自动化生产。
发明内容
本发明的目的是提供一种抗高频光干扰的光电传感器，具有高抗环境光干扰能力，可避免输出误判断，工作稳定可靠，适用范围更广泛；能实现不同量程设定不同回差，满足大量程产品在不同量程回差的需求，传感器使用更加稳定、可靠。
本发明的上述技术目的是通过以下技术方案得以实现的：
一种抗高频光干扰的光电传感器，包括有用于发射激光光源作为调制光信号的发射管、用于接收光信号的双接收管、安装于双接收管前端对光信号进行滤光的滤波片、耦接于双接收管的带通滤波电路、耦接于带通滤波电路的差分放大器、用于控制双接收管同步于发射管接收光信号的控制模块；
所述控制模块还采集获取有环境光干扰信号，且设定有干扰信号阈值，当检测到采集的环境光干扰信号幅值大于设定的干扰信号阈值时，所述控制模块丢弃叠加干扰信号后低于干扰信号阈值的光信号。
更进一步地，一种抗高频光干扰的光电传感器，包括有用于发射激光光源调制光信号的发射管、用于接收光信号的双接收管、安装于双接收管前端对光信号进行滤光的带通滤波片、耦接于双接收管的带 通滤波电路、耦接于带通滤波电路的差分放大器、用于控制双接收管同步于发射管接收光信号的控制模块、用于传感器抗干扰性改进的传感器回差设定系统；
所述控制模块还采集获取有环境光干扰信号，且设定有干扰信号阈值，当检测到采集的环境光干扰信号幅值大于设定的干扰信号阈值时，所述控制模块丢弃叠加干扰信号后低于干扰信号阈值的光信号；
所述传感器回差设定系统包括有接收输入信号并进行一级放大的放大器一、耦接于放大器一的输出端用于调节接近开关量程的定位器、耦接于电位器的调节输出端用于对接收信号进行二级放大的放大器二、并联于放大器二的高阻抗跟随器、耦接于放大器二及跟随器的输出端用于控制及设定回差值的MCU；
所述电位器根据接近开关量程调节输出分压比，所述MCU根据跟随器输出的量程信号计算输出回差值。
作为优选，所述发射管及双接收管耦接于所述控制模块；所述控制模块响应于驱动所述发射管的驱动信号，且所述控制模块发送采集信号以控制所述双接收管同步于驱动信号分时进行光信号采集。
作为优选，所述控制模块逐周期采样环境光干扰信号，且采样位置位于采集有用光信号的间隔间。
作为优选，所述发射管为激光光源，所述发射管的发射前端设置有对发射的调制光信号进行汇聚的光学透镜一。
作为优选，所述双接收管的接收前端和滤波片之间还设置有光学透镜二。
作为优选，所述滤波片为对应于发射的调制光信号同波段的带通滤波片。
作为优选，所述MCU计算输出回差值具体为：
y＝m*x -n+k；
其中，x为跟随器传输的量程信号变量，y为回差值，m、n为固定系数，k为截距。
作为优选，所述MCU分时读取放大器二与跟随器输出的信号，均逐周期读取。
一种抗高频光干扰的光电传感器回差设定方法，包括有用于发射激光光源作为调制光信号的发射管、用于接收光信号的双接收管、安装于双接收管前端对光信号进行滤光的滤波片、耦接于双接收管的带通滤波电路、耦接于带通滤波电路的差分放大器、用于控制双接收管同步于发射管接收光信号的控制模块、用于传感器抗干扰性改进的传感器回差设定系统；
所述控制模块还采集获取有环境光干扰信号，且设定有干扰信号阈值，当检测到采集的环境光干扰信号幅值大于设定的干扰信号阈值时，所述控制模块丢弃叠加干扰信号后低于干扰信号阈值的光信号；
包括有以下步骤：
通过调节电位器通过分压比对量程进行调节；
输入信号经过放大和分压后，再通过放大器放大后输出检测信号至MCU，并通过跟随器输出量程信号至MCU；
MCU接收量程信号根据设定算法计算并设定回差值
综上所述，本发明具有以下有益效果：
本光电传感器在硬件上采用双接收管，配合于带通滤波电路和差分放大器，可将均匀照射在双接收管上的环境光信号与激光作为调制光信号的信号进行区分，大部分环境光信号可判断为共模信号进而进 行滤除，可以有效滤除干扰的低频和高频信号，保留有用信号；控制模块控制双接收管同步于发射管的驱动信号进行信号采集，同时对环境光干扰信号进行采集，当干扰信号接近调制光信号波长时，可判断是否有干扰存在以避免产品误动作；
通过电位器调节分压比设定量程，并通过高阻抗的跟随器进行量程信号的输出，进而通过MCU可进行回差的实时响应计算与设定，可将量程的信号实时传递到MCU，且MCU读取量程信号不会影响信号的处理，将量程信号作为一个变量，经计算处理后输出一个回差值，回差值与量程相关，实现了不同量程，设定不同回差的需求，满足大量程产品在不同量程回差设定的需求。
附图说明
图1为接近开关的回差值示意图；
图2为信号强度与距离的关系图；
图3为本实施例的结构示意图；
图4为图1所示本实施例的局部剖视图；
图5为环境光干扰接收器的示意图；
图6为本系统示意图；
图7为不同量程对应不同回差值示意图。
具体实施方式
以下结合附图对本发明作进一步详细说明。
光电传感器一般有发射器、接收器等组成，发射器主要是将红光、红外光光源调制后发出。当有检测物时，调制光信号反射回接收器，接收器对信号进行放大、比较等处理后，输出动作信号。随着科技的日益发展，光电传感器用于越来越多的场合。不同的工业场合，照明 光源是各式各样的，有太阳光、白炽灯、荧光灯、LED节能灯、卤素灯、高压钠灯等。这些光源的工作主频不一，包括了直流分量、50Hz～60Hz工频信号、高频20K～100KHz、甚至1M～2MHz等高频频率光。这些光源不仅频率范围宽，而且波段涵盖可见光和紫外线、红外线等。
如图1及图2所示，一般接近开关的信号强度和距离关系，信号趋势变化是一个非线性关系，类似于幂函数。如设定一个固定信号值△V作为迟滞,可以看出在小量程的产品对应回差H1＝(S2-S1)/S1*100％，H1非常小可能会导致产品输出抖动。大量程H2＝(S4-S3)/S3*100％，H2非常大可能会导致产品输出闭住。由此，可以看出产品在小量程和大量程的回差相差是具有较大的差异，严重者小量程产品因回差过小，有输出抖动风险；大量程产品因回差过大，有输出闭住的风险，影响了大量程产品的使用。
根据一个或多个实施例，公开了一种抗高频光干扰的光电传感器，如图3、图4所示，包括有发射管、双接收管、设置于双接收管接收前端的滤波片；还包括有耦接于双接收管的带通滤波电路，耦接于带通滤波电路的差分放大器，用于控制双接收管进行接受动作以同步于发射管采集调制光信号、根据设定采集环境光干扰信号的控制模块。在发射管的发射前端设置有光学透镜一，为平凸透镜，平面位于发射管发射前端一侧，对调制光信号进行汇聚调整；在双接收管的接收前端和滤波片之间设置有光学透镜二，同样为平凸透镜，平面位于接收管接收前端一侧。
发射管采用激光作为VCSEL光源发射调制光信号经过光学透镜一聚光后，使得光点小，能量更集中。滤波片选用与调制光信号同波 段的带通滤波片，设置于双接收管的接收前端，该滤波片对发射管波长的光具有高透过性，对大于该波段和小于该波段的光，具有低的透过性，因此，可滤除大部分环境光不同波段的干扰信号。同波段的干扰光，还需进一步处理。
正常情况下，光电传感器的发射光斑远远小于环境光的光源面积。因此，环境光可等效为面光源，当环境光源经过带通滤波片、光学透镜二等投射至接收管时，环境光信号均匀的照射在两个接收管PD1、PD2上，即信号可认为是共模信号。带通滤波电路可滤除低频信号，如工频的白炽灯、太阳光等低频信号；也可以衰减远高于调制光频率信号，经滤波后的信号，进行差分放大，制作优良的电路差分放大，可滤除大部分共模干扰源，放大差模信号。因制作工艺的影响，接收管、差分放大器、外围电路不可能做到完全一致，少部分干扰信号会依然被放大，需要其他处理措施。
由于目前光源种类众多，光源的波段丰富，与发射管同波段的光源，是可以透过滤波片的，即使通过差分放大后，环境光的干扰信号依然存在，但是干扰分量已经下降很多。不至于有用信号完全被干扰信号所覆盖。此时通过软件处采样识别是否有环境光。当有环境光干扰时，软件上进行处理。
控制模块响应于驱动发射管的驱动信号，且控制模块发送采集信号以控制双接收管同步于驱动信号分时进行光信号采集。发射管是调制光信号，调制信号和接收信号读取由一个MCU控制，可实现发射与接收同步设计。通过驱动发射管的信号作为标志位，通过分时采集信号，确认有信号的采集时间点，打开由双接收管组成的接收转换电路进行信号采集，为了提高抗干扰能力，打开信号采集的窗口期较小。 发射导通信号更窄，采集有用信号的窗口时间减少，可进一步提高抗干扰能力。
如图5所示，逐周期采样的环境光干扰信号，采样位置位于有用信号的间隔间。经过多次采样，可采取到干扰信号，当采样干扰信号幅值大于设定的干扰信号阈值时，触发环境光干扰模式，此时即使个别有用信号被干扰信号叠加后低于阈值，将丢弃该信号，从而避免产品输出抖动或者误判断。
该光电传感器在荧光灯、LED灯等高频光源时，实现可靠稳定的工作，产品使用的范围更广。
如图6所示，光电传感器还包括有用于传感器抗干扰性改进的传感器回差设定系统，其包括有放大器一、电位器、放大器二、跟随器及MCU。
放大器一接收输入信号，初步对输入信号进行一级放大，电位器耦接于放大器一的输出端，用于调节设定接近开关量程；放大器二耦接于电位器的调节输出端，跟随器并联于放大器二，通过电位器的分压调节，放大器二输出放大后的接收信号，即信号输出A；跟随器为高阻抗，并联于放大器二输出量程信号即信号输出B；MCU耦接于放大器二和跟随器的输出端，响应于接收信号和量程信号，进行控制级回差的计算设定。
硬件电路设计上采用了两级放大，信号输入至放大器一经过放大后，在放大器一输出端接入电位器，经过电位器调节实现不同的分压。分压后作为放大器二的输入和跟随器的输入，由于跟随器是高阻抗的，对信号的影响可忽略不计。其中通过电位器调节可以实现不同的分压比。如图6所示，电位器调至最上方时，放大器二和跟随器的分 压比最高，具有最大量程。电位器调至最下方时，放大器二和跟随器的分压比最低，具有最小量程。量程信号通过跟随器将量程信号输出B至MCU，MCU将信号进行运算处理后，设定回差值。由于量程的调节是通过电位器实现的，只要电位器阻值变化都会引起跟随器信号输出B的相对变化，实现了MCU实时读取量程信号。MCU将跟随器信号输出B作为一个变量x，按公式y＝m*x -n+k进行计算，y为回差值，m、n为固定系数，k为截距。通过该算法可以看出回差值也是幂函数。其中m、n、k 3个系数跟产品特性相关，需要收集样本计算得出。
MCU读取信号输出A、信号输出B是分时进行的，两者信号都是逐周期读取，具有实时性，高响应性。只要量程信号变化，回差值跟随变化。保证回差值跟随量程动态变化。
在量程范围大的接近开关，当调节至小量程时，跟随器的信号输出B跟随电位器相对变化，如图7所示，△V1作为小量程的迟滞，此时的回差为H1＝(S2-S1)/S1*100％。如电位器调节至中间量程时，△V2作为中间量程的迟滞，此时的回差为H2＝(S4-S3)/S3*100％。如电位器调节至大量程时，△V3作为大量程的迟滞，此时的回差为H3＝(S6-S5)/S5*100％。可以看出不同量程的回差值大小不一样，实现不同量程对应不同回差值，满足大量程产品不同回差的设定需求，提高产品的使用范围。
电路设计可将量程的信号实时传递到MCU，且MCU读取量程信号不会影响信号的处理。MCU内部将量程信号作为一个变量，经内部处理后输出一个回差值。该回差值与量程相关，实现了不同量程，设定不同回差的需求。满足大量程产品在不同量程回差设定的需求。 产品在不同量程时，可设定不同的回差值。使得产品在小量程、中量程、大量程的回差值均处于理想状态。
根据一个或多个实施例，公开了一种抗高频光干扰的光电传感器回差设定方法，包括有用于发射激光光源作为调制光信号的发射管、用于接收光信号的双接收管、安装于双接收管前端对光信号进行滤光的滤波片、耦接于双接收管的带通滤波电路、耦接于带通滤波电路的差分放大器、用于控制双接收管同步于发射管接收光信号的控制模块、用于传感器抗干扰性改进的传感器回差设定系统。
控制模块还采集获取有环境光干扰信号，且设定有干扰信号阈值，当检测到采集的环境光干扰信号幅值大于设定的干扰信号阈值时，控制模块丢弃叠加干扰信号后低于干扰信号阈值的光信号。
其包括有以下步骤：
调节电位器通过分压比对量程进行调节；
输入信号经过放大和分压后，再通过放大器放大后输出检测信号至MCU，并通过跟随器输出量程信号至MCU；
MCU接收量程信号根据设定算法计算并设定回差值。
本具体实施例仅仅是对本发明的解释，其并不是对本发明的限制，本领域技术人员在阅读完本说明书后可以根据需要对本实施例做出没有创造性贡献的修改，但只要在本发明的权利要求范围内都受到专利法的保护。

Claims (10)

  1. 一种抗高频光干扰的光电传感器，其特征是：包括有用于发射激光光源作为调制光信号的发射管、用于接收光信号的双接收管、安装于双接收管前端对光信号进行滤光的滤波片、耦接于双接收管的带通滤波电路、耦接于带通滤波电路的差分放大器、用于控制双接收管同步于发射管接收光信号的控制模块；
    所述控制模块还采集获取有环境光干扰信号，且设定有干扰信号阈值，当检测到采集的环境光干扰信号幅值大于设定的干扰信号阈值时，所述控制模块丢弃叠加干扰信号后低于干扰信号阈值的光信号。
  2. 根据权利要求1所述的一种抗高频光干扰的光电传感器，其特征是：包括有用于发射激光光源作为调制光信号的发射管、用于接收光信号的双接收管、安装于双接收管前端对光信号进行滤光的滤波片、耦接于双接收管的带通滤波电路、耦接于带通滤波电路的差分放大器、用于控制双接收管同步于发射管接收光信号的控制模块、用于传感器抗干扰性改进的传感器回差设定系统；
    所述控制模块还采集获取有环境光干扰信号，且设定有干扰信号阈值，当检测到采集的环境光干扰信号幅值大于设定的干扰信号阈值时，所述控制模块丢弃叠加干扰信号后低于干扰信号阈值的光信号；
    所述传感器回差设定系统包括有接收输入信号并进行一级放大的放大器一、耦接于放大器一的输出端用于调节接近开关量程的定位器、耦接于电位器的调节输出端用于对接收信号进行二级放大的放大器二、并联于放大器二的高阻抗跟随器、耦接于放大器二及跟随器的输出端用于控制及设定回差值的MCU；
    所述电位器根据接近开关量程调节输出分压比，所述MCU根据跟随器输出的量程信号计算输出回差值。
  3. 根据权利要求1所述的抗高频光干扰的光电传感器，其特征是：所述发射管及双接收管耦接于所述控制模块；所述控制模块响应于驱动所述发射管的驱动信号，且所述控制模块发送采集信号以控制所述双接收管同步于驱动信号分时进行光信号采集。
  4. 根据权利要求3所述的抗高频光干扰的光电传感器，其特征是：所述控制模块逐周期采样环境光干扰信号，且采样位置位于采集有用光信号的间隔间。
  5. 根据权利要求1所述的抗高频光干扰的光电传感器，其特征是：所述发射管的发射前端设置有对发射的调制光信号进行汇聚的光学透镜一。
  6. 根据权利要求5所述的抗高频光干扰的光电传感器，其特征是：所述双接收管的接收前端和滤波片之间还设置有光学透镜二。
  7. 根据权利要求1所述的抗高频光干扰的光电传感器，其特征是：所述滤波片为对应于发射的调制光信号同波段的带通滤波片。
  8. 根据权利要求2所述的抗高频光干扰的光电传感器，其特征是，所述MCU计算输出回差值具体为：
    y＝m*x -n+k；
    其中，x为跟随器传输的量程信号变量，y为回差值，m、n为固定系数，k为截距。
  9. 根据权利要求2所述的抗高频光干扰的光电传感器，其特征是：所述MCU分时读取放大器二与跟随器输出的信号，均逐周期读取。
  10. 一种抗高频光干扰的光电传感器回差设定方法，其特征是：包括有用于发射激光光源作为调制光信号的发射管、用于接收光信号的双接收管、安装于双接收管前端对光信号进行滤光的滤波片、耦接 于双接收管的带通滤波电路、耦接于带通滤波电路的差分放大器、用于控制双接收管同步于发射管接收光信号的控制模块、用于传感器抗干扰性改进的传感器回差设定系统；
    所述控制模块还采集获取有环境光干扰信号，且设定有干扰信号阈值，当检测到采集的环境光干扰信号幅值大于设定的干扰信号阈值时，所述控制模块丢弃叠加干扰信号后低于干扰信号阈值的光信号；
    包括有以下步骤：
    通过调节电位器通过分压比对量程进行调节；
    输入信号经过放大和分压后，再通过放大器放大后输出检测信号至MCU，并通过跟随器输出量程信号至MCU；
    MCU接收量程信号根据设定算法计算并设定回差值。
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