Reflection type photoelectric detection device

Abstract

The utility model discloses a reflective photoelectric detection device, relates to the technical field of switch control circuits, and overcomes the defect that passenger safety and obstacle recognition accuracy cannot be considered at the same time in the prior art. According to the utility model, the mirror surface reflective photoelectric sensor which is small in size and stronger in anti-interference capability is matched with the photoresistor, so that tiny objects or transparent and semitransparent objects can be detected. According to the utility model, the emitter is matched with the reflective mirror, so that a light source of the emitter forms multiple paths of light to be identified by the receiver after passing through the reflective mirror, and the receiver changes the self resistance value based on the intensity of the light so as to further control the on-off of the photoelectric switch, further change the input signal of the PLC and further change the opening and closing state of the shielding door. The sensor provided by the utility model can respond to environmental changes more quickly, ensures that the opening and closing operation of the shielding door is more timely, and is helpful for preventing unnecessary waiting or potential safety hazards caused by response lag.

Description

TECHNICAL FIELD

[0001] The utility model belongs to switch control circuit technical field, especially relates to a reflection type photoelectric detection device. BACKGROUND

[0002] The shield door, also known as platform curtain door or safety door, is represented as Platform screen doors (PSD) in English, which refers to the way of surrounding the space above and below the train with glass curtain wall on the platform. When the train arrives, the electric door on the glass curtain wall is opened to allow passengers to get on and off the train. When the subway or train arrives at the station, the opening of the shield door allows passengers to pass through, and when the subway or train starts, the shield door is closed. In this process, there is a risk of objects or people being trapped in the shield door.

[0003] Currently, in order to avoid the risk of the shield door trapping people or objects, light curtain detection method and laser detection method are usually used to identify whether there is an obstacle to control the forced opening of the shield door. Among them, the light curtain detection method is to install infrared emitters and infrared receivers on both sides of the door body of the shield door to form an infrared protective light wave. When an object blocks the light in the light curtain, the receiver cannot receive the complete light signal, thereby judging that there is an object. The main equipment used is infrared light curtain sensor, such as Anjie HR series safety grating light curtain sensor. The laser detection method includes laser beam detection method, laser ranging method and laser radar method. The laser beam detection method is to install a pair of laser emitting and receiving devices on the left and right sides between the shield door and the train door to form a laser light curtain. When an object blocks the laser beam, the receiving end cannot receive the laser signal, and the system judges that there is a foreign object and alarms. The laser ranging method uses an infrared laser ranging sensor placed on the top between the shield door and the train door to project an infrared laser beam downward and form a light spot on the target surface. By obtaining the distance information between the light spot and the detector in real time and making intelligent judgment, it is identified whether a target appears. The detector of the laser radar method is installed on the top of the shield door, which uses ToF ranging scanning technology to effectively detect and identify dynamic obstacles.

[0004] However, for transparent or semi-transparent objects such as thin plastic film, glass fragments, etc., the light curtain detection may fail, and when the object size is small and just between the light spacing, it may not be detected. The laser beam of the laser beam detection method may damage the human eye, which easily causes potential safety threat to passengers and staff. In view of this, the utility model provides a reflection type photoelectric detection device. UTILITY MODEL CONTENT

[0005] The utility model aims at providing a reflection type photoelectric detection device to overcome the defects that passenger safety and obstacle identification accuracy cannot be considered in the prior art. The specific technical scheme is as follows:

[0006] A reflective photoelectric detection device, comprising:

[0007] a transmitter for emitting a light source for a receiver to identify;

[0008] a receiver for receiving the light source emitted by the transmitter and changing the internal resistance based on the light source;

[0009] a photoelectric switch connected to the receiver, the photoelectric switch being composed of at least a triode, and the base of the triode being controlled by the internal resistance value of the receiver to control the on-off of the triode;

[0010] a PLC connected to the photoelectric switch, and the high-low level of the photoelectric switch being obtained to control the high-low level of the output based on the input high-low level, and further to control the switching state of the shielding door;

[0011] The transmitter and the receiver are installed on the same side of the shielding door intersection, and the other side is provided with a reflector for reflecting the light source emitted by the transmitter to the receiver.

[0012] Preferably, the photoelectric switch has at least two, respectively connected to two receivers to form two high-low level signal outputs to the input port of the PLC.

[0013] Preferably, among the at least two receivers, one receiver is a photosensitive resistor RG2, and one receiver is a photosensitive triode VT3.

[0014] Preferably, among the at least two receivers, the emitter of the photosensitive triode VT3 is connected to the base of the triode VT4, and the emitter of the triode VT4 is connected to the input pin of the PLC.

[0015] Preferably, the photosensitive resistor RG2 is connected to the base of the triode VT2, and a relay is connected to the collector of the triode VT2, and the relay contact is connected to the input pin of the PLC.

[0016] Preferably, the transmitter includes at least one infrared LED and one LED.

[0017] Preferably, the infrared LED and the LED are arranged on the same side of the shielding door intersection, and the infrared LED is arranged on the upper part of one side of the shielding door intersection, and the LED is arranged on the lower part of one side of the shielding door intersection.

[0018] Preferably, the infrared LED and the LED are powered by a power source, and the infrared LED and the LED are further connected with a photoresistor RG1, the turning on and off of the infrared LED and the LED are controlled by the resistance change of the photoresistor RG1, the photoresistor RG1 is arranged on the shielding door on the same side of the LED, and a laser lamp is arranged on the other side of the shielding door, the height of the laser lamp is adapted to the photoresistor RG1, so that the photoresistor RG1 can receive the light from the laser lamp.

[0019] Preferably, the photoresistor RG1 is connected with a triode VT1, the emitter of the triode is connected with the infrared LED and the LED through resistors respectively, and the collector of the triode is connected with the power source.

[0020] Preferably, the length of the reflector is at least the distance between the infrared LED and the LED, and the lower end of the reflector reaches at least the horizontal height of the LED, and the upper end of the reflector reaches at least the horizontal height of the infrared LED.

[0021] Compared with the prior art, the utility model has the advantages of the following beneficial effects:

[0022] 1. The utility model discloses a mirror reflection type photoelectric sensor and photoresistor are used in cooperation, small volume, and the interference resistance is stronger, can detect small object and also can be transparent and translucent object. The emitter and the reflector in the utility model are cooperated, and the light source of the emitter forms multiple light rays for the receiver to identify after passing through the reflector, the receiver changes the resistance value based on the intensity of the light, and then the on-off of the photoelectric switch is controlled, the input signal of the PLC is further changed, and then the opening and closing state of the shielding door is changed.

[0023] 2. In the utility model, the receiver is provided with at least two, one is photoresistor RG2, and one is photosensitive triode VT3, two signals are inputted to the PLC through the cooperation of two kinds of photosensitive sensors, the two receivers complement each other, and the identification accuracy is improved.

[0024] 3. In the utility model, the laser lamp and the photoresistor RG1 corresponding to the laser lamp are further arranged below the shielding door, the photoresistor RG1 changes the turning on and off of the two emitters through the value received by the laser lamp, and then the resistance value of the receiver is changed, the PLC signal is also given, and then the output is controlled. In the embodiment, the laser lamp is arranged only below the shielding door, first, the shielding door below is most prone to product shielding, such as the feet when standing, the bottom when placing the product, etc. Second, the laser lamp is arranged below the shielding door, even if the children are short, the light beam of the laser lamp will not irradiate the children, and the human eyes are further protected. BRIEF DESCRIPTION OF DRAWINGS

[0025] In order to more clearly illustrate the technical scheme of the embodiments of the present application, the following will briefly introduce the drawings needed to be used in the embodiment description. In all the drawings, similar elements or parts are generally identified by similar reference signs. In the drawings, the elements or parts are not necessarily drawn according to the actual proportion.

[0026] Figure 1 is a schematic diagram of a reflective photoelectric sensor.

[0027] Figure 2 is a structural schematic diagram of the circuit in embodiment 1 applied to a shielding door;

[0028] Figure 3 is a position schematic diagram of the circuit in embodiment 1 applied to a shielding door;

[0029] Figure 4 is a specific implementation circuit diagram in embodiment 1;

[0030] Figure 5 is a program operation flow schematic diagram in embodiment 1;

[0031] Figure 6 is a program operation logic schematic diagram in embodiment 1.

[0032] Main drawing mark explanation:

[0033] 1-PLC, 2-infrared LED, 3-RG2, 4-VT3, 5-LED, 6-RG1, 7-mirror, 8-laser lamp, 9-shielding door, 10-wire. DETAILED DESCRIPTION

[0034] The technical scheme in the embodiments of the present application will be described clearly and completely in combination with the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all the embodiments. Based on the embodiments in the present application, all the other embodiments obtained by those skilled in the art without creative labor belong to the protection scope of the present application.

[0035] In the description of the present application, it should be noted that the terms "center", "longitudinal", "transverse", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "top", "bottom", "top surface", "bottom surface", "inner", "outer", "inner side", "outer side" and the like indicate the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the devices or elements referred to must have a particular orientation, be constructed and operated in a particular orientation, therefore it cannot be understood as a limitation of the present application.

[0036] In the description of this utility model, "several" means one or more, "multiple" means two or more, "greater than," "less than," and "exceeding" are understood to exclude the stated number, while "above," "below," and "within" are understood to include the stated number. If the terms "first," "second," and "third" are used in the description, they are for descriptive purposes and to distinguish technical features, and should not be construed as indicating or implying relative importance, or implicitly indicating the number of indicated technical features, or implicitly indicating the sequential relationship of the indicated technical features.

[0037] In the description of this utility model, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," and "setting" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this utility model based on the specific circumstances. The embodiments of this utility model will now be described based on its overall structure.

[0038] Example 1

[0039] like Figure 1 As shown, the transmitter (light source) in the photoelectric switch emits light, which is directed towards the reflector. After being reflected by the reflector, the light returns along its original path and is normally received by the receiver in the photoelectric switch. When an object enters the detection area (the area between the reflector and the receiver) in the light propagation path, it blocks some or all of the reflected light, causing a change in the amount of light received by the receiver. The receiver converts this change in light signal into an electrical signal, which is transmitted to the PLC. The PLC then performs corresponding control based on the received signal state.

[0040] The installation location of the reflective photoelectric detection device and the platform screen doors of urban rail transit is shown in [reference needed]. Figure 2 and Figure 3 The PLC is installed above the shielding door. Photoelectric sensors (RG2, VT3), a photosensitive sensor (RG1), and infrared LEDs are installed on the left side of the shielding door. A reflector is installed on the right side of the shielding door. The components are connected by wires and optical fibers. The infrared LEDs emit infrared light, while the photoelectric and photosensitive sensors are light-sensitive sensors used to detect light intensity. The PLC controls the opening and closing of the shielding door. A laser light is also installed on the right side of the shielding door, primarily for precise measurement and positioning.

[0041] Circuit example of a reflective photoelectric detection device is as follows Figure 4 As shown, the function of each component in the circuit diagram will be explained below:

[0042] Photoconductive resistance RG1: as a light signal detection element in the photoelectric sensor, it has the characteristic of changing its resistance value according to the light intensity. When the light signal is enhanced, the resistance decreases; when the light signal is weakened, the resistance increases, thereby changing the current in the circuit and providing a varying base signal for the transistor VT1. The core advantage of this device is that it can accurately detect small objects less than 5mm through this principle, which is crucial for safety protection.

[0043] Transistor VT1: mainly functions as a current amplifier, its base is connected to the photoconductive resistance RG1, and the base current will change with the change of RG1 resistance. After amplification, the transistor VT1 can control the collector current, thereby affecting the working state of the laser spotlight 1, infrared LED, and LED connected thereto. The laser spotlight 1, infrared LED, and LED are all light-emitting indicating elements, among which the LED light covers a wider area and has a larger detection range. Even if small objects such as hair and clothing corners less than 0.5mm appear in the blind area of the infrared spotlight detection, they can also take advantage of the wide coverage of the LED light to feed back information to the PLC terminal. After receiving the signal, the PLC can quickly control the shielding door to ensure the safety of the passengers. When the transistor VT1 collector current meets certain conditions and the circuit voltage reaches the corresponding requirements, these light-emitting indicating elements will be in a light-emitting state, indicating the state of the shielding door and detecting whether there are objects blocking the light.

[0044] Resistance (300Ω, 10K, etc.): its function is to divide voltage and limit current, ensuring that each element in the circuit works under appropriate voltage and current, protecting components and stabilizing the circuit.

[0045] Transistor VT2: forms a switching circuit with the surrounding resistance, which can be turned on or off under certain conditions, thereby controlling the on-off of the relay KA1.

[0046] Relay KA1: as an electrical isolation and signal amplification element, the closing and opening of its contacts can control the on-off of the subsequent circuit, realizing the switching of the input signal of the PLC control system.

[0047] Photoconductive resistance RG2: used to detect changes in ambient light or specific light signals, the change in its resistance value will affect the base current of the transistor VT2, thereby affecting the state of the relay KA1.

[0048] Transistors VT3 and VT4: form a signal detection and transmission circuit. When the infrared light emitted by the infrared LED irradiates the photoconductive transistor VT3, the internal resistance of VT3 decreases, driving the transistor VT4 to turn on and transmitting the electrical signal to the PLC control system. With the high sensitivity of this circuit, it can accurately determine whether an object less than 5mm is trapped.

[0049] PLC control system (S7-200 CPU 224): as the core control element, through the input port (I0.0-I0.7) receives the signal from the sensor, through internal logic processing and judgment, from the output port (Q0.0-Q0.6) output control signal, control motor and other actuators, realize the control of the shielding door.

[0050] Button (SB1-SB8): for manual input control signal, can realize the manual opening, closing and other operations of the shielding door, connected to the input port of the PLC control system.

[0051] Contactor (KM1-KM7): under the control of the PLC control system, for connecting or disconnecting the main circuit, to realize the control of the motor and other high-power equipment, connected between the output port of the PLC control system and the power supply.

[0052] When the photosensitive resistance RG1 on the photoelectric sensor receives the light signal gradually enhanced, the photosensitive resistance RG1 resistance gradually decreases, the photosensitive resistance RG1 as the base of the transistor VT1, resistance decreases, current output increases. The change of the base current of the transistor will cause the large change of the collector current, to realize the amplification of the signal. Again by Ohm's law U=R*I, the voltage is now in the amplification state, and the amplification state is controlled by the light intensity, the higher the light intensity, the greater the voltage. The conduction condition of the transistor is that the emitter junction adds a positive voltage, and the collector junction adds a reverse voltage. The emitter junction adds a positive voltage, that is, the voltage U be between the base and the emitter is added to the PN junction voltage of the silicon tube, which is 0.7V, and the voltage of the germanium tube is 0.2V. The collector junction adds a reverse voltage, that is, a reverse voltage U be is added to the PN junction of the collector junction to attract the charge in the base region. To make the transistor in a saturated conduction state, the conditions to be met are described from the voltage: the emitter junction of the transistor is positively biased, and the collector junction is zero biased or positively biased; U be ≈0.7V, U bc ≥0V.

[0053] When the triode is in the conductor state, the voltage change is observed, when the voltage is in the amplification multiple that can satisfy 5V, the laser lamp, the infrared LED, the LED1 are in the light-emitting state, when the voltage amplification multiple is less than 5V (the shielding door is in the state of not being closed), the laser lamp, the LED1 are in the light-emitting state. The voltage amplification multiple Au=Uo / Ui, the current amplification multiple beta=ICE / IBE=(IC-ICBO) / (IBE-ICBO)≈IC / IB. The photoresistor should be affected by the light intensity of the spotlight, so that the resistance becomes smaller, but at this time the spotlight is blocked, the light intensity becomes smaller, the resistance becomes larger, there is not enough voltage in the circuit to drive the light-emitting diode and the infrared LED, so that the reflective infrared sensor has no signal input and output; at this time the circuit voltage can only drive the light-emitting diode and the laser signal lamp, and output a signal to the photoelectric sensor. After the corresponding signals are integrated, the sensor sends a signal to the PLC control system, and when the system judges that only one signal is received, the PLC control system controls the motor to execute the door opening action, so that the person or object is separated.

[0054] When the infrared light emitted by the infrared LED irradiates the photosensitive triode TV3, the internal resistance of the photosensitive triode TV3 is reduced, the triode VT4 is turned on, and the circuit is connected to send an electrical signal to the PLC. Since the on-off of the circuit depends on the intensity of the infrared light irradiating the photosensitive triode VT1, and the device is designed with high sensitivity, it can accurately judge whether an object smaller than 5mm is clamped.

[0055] The PLC program control flow chart is shown in Figure 5 Figure 6 It should be known that the program control of the utility model is based on simple logic judgment of input high and low levels and threshold comparison based on time, which are common switch control programs in the field. The following gives an example of judgment logic and control process:

[0056] 1. Start

[0057] The PLC control system is initialized and enters a running state, and the signal scanning and logic processing cycle is started.

[0058] The initialization state is that the signals of the photosensitive resistors RG1 and RG2 are connected to input points I0.0 and I0.1 respectively, the signal of the photoelectric sensor is connected to I0.2, and the signals of the manual buttons are connected to I0.3-I0.5; the door opening and closing control signals are connected to output points Q0.0 and Q0.1 respectively. The timer T37 has a timing length of 0.2 seconds, which functions to start timing when the shielding signal is detected. The initialization is used to record the flag bit of the system state, and whether the shielding is detected and the current state of the door.

[0059] 2. Read the input signal

[0060] Read photoresistor RG1 / RG2 signal (I0.0 / I0.1): Photoresistor is generally used to detect light changes. When there is an object blocking, the light intensity changes, and the resistance of the photoresistor will also change, causing the level of the PLC input point to change. If a low level (I0.0 or I0.1 is 0) is detected, it indicates that there is an object blocking.

[0061] Read photoelectric sensor signal (I0.2): Photoelectric sensor can detect light intensity, and when an object enters the detection range, the sensor output signal will change. A low level (I0.2 is 0) indicates that an object has been detected.

[0062] Read manual button signal (I0.3-I0.5): Manual buttons include manual opening door button (I0.3), manual closing door button (I0.4), and emergency stop button (I0.5). When the button is pressed, the corresponding input point level will change.

[0063] 3. Judgment logic

[0064] (1) Press the manual button

[0065] Manual opening door button press: If the manual opening door button (I0.3) is pressed, the shielding door will be forced to open, and the output point Q0.0 will be set to high (Q0.0 = 1) to drive the opening control circuit.

[0066] Manual closing door button press: If the manual closing door button (I0.4) is pressed, the shielding door will be forced to close, and the output point Q0.1 will be set to high (Q0.1 = 1) to drive the closing control circuit.

[0067] Emergency stop button press: If the emergency stop button (I0.5) is pressed, all actions will be stopped, and the output points Q0.0 and Q0.1 will be set to low (Q0.0 / Q0.1 = 0), so that the shielding door stops moving.

[0068] (2) Read the blocking signal

[0069] Detect the blocking signal: If there is a blocking (such as a passenger or an obstacle) during the closing process, i.e. the photoresistor RG1 / RG2 or the photoelectric sensor has a blocking signal (I0.0 = 0 or I0.1 = 0 or I0.2 = 0), the timer T37 will start timing. If the timer T37 times out (timing reaches 0.2 seconds), the forced opening operation will be triggered, and the output point Q0.0 will be set to high (Q0.0 = 1).

[0070] No blocking signal: If no blocking signal is detected, the shielding door will be allowed to close normally, and the output point Q0.1 will be set to high (Q0.1 = 1).

[0071] 4. End loop

[0072] After one cycle of detection and judgment is completed, the program will return to the cycle detection reading part again, continuously detecting signals and controlling the opening and closing of the shielding door.

[0073] It should be known that the above is only an example of common logic control in the art based on the level signal of the input port of the PLC. In actual application, those skilled in the art can change the logic judgment method based on the actual situation and practical conventional technical means, and then output different switch control signals than the above examples.

[0074] Next, the working principle of this embodiment will be described in detail to make those skilled in the art better understand the utility model:

[0075] Personnel-oriented:

[0076] (1) When no personnel passes: the shielding door is in an open or closed state, the ambient light is stable, the resistance of the photoresistor RG1 is relatively stable, the base current of the triode VT1 is stable, the collector current is also stable, the laser spotlight 1, the infrared LED, and the LED maintain the corresponding initial light-emitting state (for example, when the shielding door is open, some light-emitting indicators may be emitted; when closed, all light-emitting indicators meet the conditions). The resistance of the photoresistor RG2 is stable, the triode VT2 is in a stable state of cutoff or conduction, the relay KA1 does not act, and the PLC control system does not receive an abnormal signal. The infrared light emitted by the infrared LED normally irradiates the photo triode VT3, the internal resistance of VT3 is small, the triode VT4 is turned on, and the PLC control system receives a normal signal.

[0077] (2) When personnel passes: the personnel enter the shielding door area, shielding part of the light, the resistance of the photoresistor RG1 instantaneously increases, the base current of the triode VT1 decreases, the collector current decreases, and the light-emitting state of the laser spotlight 1, the infrared LED, and the LED may change. The infrared light emitted by the infrared LED may not normally irradiate the photo triode VT3 due to the shielding of the personnel, the internal resistance of VT3 increases, the triode VT4 is cut off, and the signal received by the PLC control system changes. If the personnel moves fast, after a short shielding, the light returns to normal, and the state of each component will gradually recover.

[0078] (3) When personnel passes instantaneously: during instantaneous shielding, the photoresistor RG1 and the related circuit state change rapidly, but since the time is extremely short, if the triggering threshold of the PLC control system is not reached, the system will not trigger an abnormal action, and each component will quickly recover to a state close to that before shielding.

[0079] (4) Personnel through: after the personnel pass, the light returns to normal, the resistance of the photoresistor RG1 decreases, the base current of the transistor VT1 increases, the collector current returns to normal, and the laser spotlight 1, infrared LED, and LED return to normal light-emitting state. The infrared light emitted by the infrared LED normally irradiates the photosensitive transistor VT3 again, the internal resistance of VT3 decreases, the transistor VT4 is turned on, and the PLC control system receives a normal signal.

[0080] (5) Personnel stay in the doorway for a long time: the resistance of the photoresistor RG1 continuously increases, the collector current of the transistor VT1 continuously decreases, and the normal light-emitting state of the laser spotlight 1, infrared LED, and LED cannot be maintained. The infrared light emitted by the infrared LED is blocked for a long time, the internal resistance of the photosensitive transistor VT3 continuously increases, the transistor VT4 is turned off, and the PLC control system receives an abnormal signal. At the same time, the photoresistor RG2 detects changes in light, which may change the state of the transistor VT2, the relay KA1 acts, and sends an additional abnormal signal to the PLC control system. The PLC control system determines that there is an object blocking for a long time, can accurately detect objects less than 5mm, and controls the motor to forcibly execute the opening action.

[0081] Door-oriented:

[0082] (1) The door from the open state to the closed state, no obstruction throughout the journey: the light signal received by the photoresistor RG1 gradually increases, the resistance continuously decreases, the base current of the transistor VT1 increases, and the collector current increases. When the circuit voltage reaches the required value, the laser spotlight 1, infrared LED, and LED are fully lit. The resistance of the photoresistor RG2 changes within the normal range, and the transistor VT2 and the relay KA1 have no abnormal action. The infrared light emitted by the infrared LED normally irradiates the photosensitive transistor VT3, the internal resistance of VT3 is small, the transistor VT4 is turned on, the PLC control system receives a normal signal, and the motor normally executes the closing action.

[0083] (2) The door from the open state to the closed state, with transient obstruction: when there is transient obstruction, the resistance of the photoresistor RG1 instantaneously increases, the base current of the transistor VT1 decreases, and the collector current decreases. The light-emitting state of the laser spotlight 1, infrared LED, and LED may change temporarily. The infrared light emitted by the infrared LED is temporarily blocked, the internal resistance of the photosensitive transistor VT3 instantaneously increases, and the transistor VT4 may be temporarily turned off. However, since the time is short, the light returns to normal before the system completes signal determination and response, each component returns to the state before the obstruction, and the motor continues to execute the closing action, without triggering the abnormal opening action.

[0084] (3) the door from the open state to the closed state, long time blocking in the middle: the resistance of the photoresistor RG1 continues to increase, the current of the collector of the triode VT1 continues to decrease, the laser spotlight 1, the infrared LED, and the LED cannot normally emit light. The infrared light emitted by the infrared LED is blocked for a long time, the internal resistance of the photosensitive triode VT3 continues to increase, and the triode VT4 is cut off. At the same time, the photoresistor RG2 detects the change of light, which may change the state of the triode VT2, and the relay KA1 acts to send an abnormal signal to the PLC control system. The PLC control system determines that there is an object blocking for a long time, and the device has high sensitivity detection capability for objects less than 5mm, and controls the motor to forcibly execute the door opening action to prevent people or objects from being clamped.

[0085] In summary, the utility model is sensitive and reliable. The high sensitivity to light ensures that the sensing device can respond in time once the ambient light changes, thereby accurately controlling the opening and closing of the shielding door. The stability is crucial for ensuring the normal operation of the shielding door control system, and can effectively avoid misoperation or safety accidents caused by sensing device failure. Moreover, the utility model has fast response time. The sensor can respond more quickly to environmental changes, ensuring that the shielding door opening and closing operation is more timely, improving passenger traffic efficiency, and also helping to prevent unnecessary waiting or safety hazards caused by delayed response. The detection is accurate. The light transmission channel is optimized, which can accurately and quickly detect small objects less than 5mm and transparent or semi-transparent objects.

[0086] The foregoing description of specific exemplary embodiments of the utility model is for the purpose of illustration and example, and these descriptions are not intended to limit the utility model to the precise forms disclosed, and it is obvious that many changes and variations can be made according to the above-mentioned teaching, although the embodiments of the utility model have been shown and described, the specific embodiments are only an explanation of the utility model, and are not a limitation of the utility model, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable way, the purpose of selecting and describing the exemplary embodiments is to explain the specific principles of the utility model and its practical application, so that those skilled in the art can make modifications, replacements, variations and various different selections and changes to the embodiments without creative contribution after reading the specification without departing from the principles and purposes of the utility model, as long as they are within the scope of the claims of the utility model, they are protected by the patent law.

Claims

1. A reflective photoelectric detection device, characterized in that, include: A transmitter is used to emit a light source for the receiver to identify. A receiver is used to receive the light emitted by the transmitter and change its internal resistance based on the light source. A photoelectric switch is connected to a receiver. The photoelectric switch is composed of at least a transistor. The base of the transistor is controlled by the internal resistance of the receiver, thereby controlling the transistor's on / off state. The PLC is connected to the photoelectric switch and obtains the high and low levels by the on and off of the photoelectric switch. Then, it controls the high and low levels of the output based on the input high and low levels, thereby controlling the opening and closing state of the shielding door. The transmitter and receiver are installed on the same side of the junction of the shielding door, and a reflector is provided on the other side. The reflector is used to reflect the light source emitted by the transmitter onto the receiver.

2. The reflective photoelectric detection device according to claim 1, characterized in that, There are at least two photoelectric switches, each connected to a separate receiver, to generate two high and low level signals that are output to the input ports of the PLC.

3. The reflective photoelectric detection device according to claim 2, characterized in that, Of the at least two receivers, one is a photoresistor RG2 and the other is a phototransistor VT3.

4. The reflective photoelectric detection device according to claim 3, characterized in that, In at least two receivers, the transmitter of the phototransistor VT3 is connected to the base of the phototransistor VT4, and the transmitter of the phototransistor VT4 is connected to the input pin of the PLC.

5. A reflective photoelectric detection device according to claim 3, characterized in that, The photoresistor RG2 is connected to the base of the transistor VT2, and a relay is connected to the collector of the transistor VT2. The relay contacts are connected to the PLC input pins.

6. The reflective photoelectric detection device according to claim 1, characterized in that, The transmitter includes at least one infrared LED and one LED.

7. A reflective photoelectric detection device according to claim 6, characterized in that, The infrared LED and the LED are located on the same side of the junction of the shielding doors, with the infrared LED located at the upper part of one side of the junction of the shielding doors and the LED located at the lower part of the other side of the junction of the shielding doors.

8. A reflective photoelectric detection device according to claim 6, characterized in that, The infrared LED and the LED are powered by a power source and are also connected to a photoresistor RG1. The brightness of the infrared LED and the LED is controlled by the change in the internal resistance of the photoresistor RG1. The photoresistor RG1 is set on the same side of the shielding door as the LED, and a laser light is set on the other side of the shielding door. The height of the laser light is adapted to the photoresistor RG1 to ensure that the photoresistor RG1 can receive the light from the laser light.

9. A reflective photoelectric detection device according to claim 8, characterized in that, The photoresistor RG1 is connected to the transistor VT1. The emitter of the transistor is connected to the infrared LED and the LED after passing through resistors. The collector of the transistor is connected to the power supply.

10. A reflective photoelectric detection device according to claim 6, characterized in that, The length of the reflector is at least the distance between the infrared LEDs, and the lower end of the reflector reaches at least the horizontal height of the LEDs, while the upper end of the reflector reaches at least the horizontal height of the infrared LEDs.

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