Non-contact safety switch control circuit and safety door lock

Abstract

The utility model discloses a non-contact safety switch control circuit and a safety door lock. The control circuit comprises a radio frequency identification circuit, a first MCU control circuit, a second MCU control circuit, a first OSSD output unit and a second OSSD output unit. And the radio frequency identification circuit is used for identifying the legality of the matcher and respectively sending identification results to the two MCU control circuits to respectively generate a first OSSD control signal and a second OSSD control signal so as to drive respective OSSD output units to output the control signals. According to the embodiment of the utility model, through a cross monitoring and mutual control mechanism of the two MCU control circuits, when any one control access fails, the other control access can still independently send out a shutdown signal, so that the timely response of the upper computer is ensured, and the operation safety and fault-tolerant capability of the system are greatly improved.

Description

Technical Field

[0001] This utility model relates to the field of safety switch technology, and in particular to a non-contact safety switch control circuit and a safety door lock. Background Technology

[0002] Non-contact safety switches are primarily used in industrial applications, installed on the protective doors of work equipment. They prevent the door from opening and output a signal to a relay or host computer to stop the equipment. Existing non-contact safety switches mainly consist of a matching unit and an RFID circuit. The matching unit has a built-in electronic tag, and the RFID circuit wirelessly reads the tag information and transmits the identification result to the main control unit for comparison and judgment. If identification is successful, the matching unit is determined to be in a safe position, controlling the work equipment to run or unlock; if identification fails, the work equipment is stopped or kept locked. However, existing non-contact safety switches generally use a single main control unit for management and control. If the main control unit fails, the safety switch cannot continue to identify the matching unit's status, leading to a situation where the equipment is still running even when the protective door is open. If an object or person enters, a safety accident may occur.

[0003] In view of this, it is necessary to propose a new non-contact safety switch control circuit to improve the above-mentioned problems. Utility Model Content

[0004] The purpose of this utility model is to provide a non-contact safety switch control circuit and a safety door lock. By applying proximity detection and radio frequency identification electronic tags, it solves the problem that existing non-contact safety switches may fail to output a stop signal in time due to the failure of identification and safety output caused by the failure of a single main control unit, thereby improving operational safety and fault tolerance.

[0005] This utility model provides the following solution:

[0006] On the one hand, a non-contact safety switch control circuit is provided, including:

[0007] The system includes: a radio frequency identification (RFID) circuit for identifying whether the matching unit of the safety switch has a valid electronic tag and emitting an RFID signal; a first MCU control circuit electrically connected to the RFID circuit, configured to process the identification result of the RFID circuit and obtain the operating status of the second MCU control circuit to generate a first OSSD control signal; a second MCU control circuit electrically connected to the first MCU control circuit and the RFID circuit, configured to process the identification result of the RFID circuit and obtain the operating status of the first MCU control circuit to generate a second OSSD control signal; a first OSSD output unit electrically connected to the first MCU control circuit and the second MCU control circuit, used to respond to the first OSSD control signal, output a first OSSD signal to the host computer, and feed back a voltage status signal to the second MCU control circuit; and a second OSSD output unit electrically connected to the first MCU control circuit and the second MCU control circuit, used to respond to the second OSSD control signal, output a second OSSD signal to the host computer, and feed back a voltage status signal to the first MCU control circuit.

[0008] On the other hand, a security door lock is provided, including an identifier and a matcher, wherein the identifier includes a contactless security switch control circuit as described above, and the matcher includes an electronic tag.

[0009] This invention utilizes a cross-monitoring and mutual control mechanism between the first MCU control circuit and the second MCU control circuit. In the event of a fault in either the OSSD output unit or the MCU control circuit, a shutdown signal can still be independently issued through another normal path. This ensures that the system can quickly cut off the running command after identifying the abnormality, thereby achieving highly reliable safety shutdown linkage control. Attached Figure Description

[0010] To more clearly illustrate the technical solutions in the embodiments of this utility model or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0011] Figure 1 This is a circuit block diagram of the first embodiment of the present invention;

[0012] Figure 2 This is a schematic diagram of the signal wiring of the first MCU control circuit and the second MCU control circuit in the first embodiment of this utility model;

[0013] Figure 3 This is a circuit diagram of the radio frequency identification circuit of this utility model;

[0014] Figure 4 This is a circuit diagram of the first or second OSSD output unit of this utility model;

[0015] Figure 5 This is a circuit diagram of the first signal input circuit and the second signal input circuit of this utility model;

[0016] Figure 6 This is a circuit diagram of the first sampling unit or the second sampling unit of this utility model;

[0017] Figure 7 This is the circuit diagram of the voltage regulator circuit of this utility model;

[0018] Figure 8 This is the circuit diagram of the auxiliary output circuit of this utility model;

[0019] Figure 9 This is the circuit diagram of the teaching circuit of this utility model;

[0020] Figure 10 This is a circuit diagram of the first MCU control circuit of this utility model;

[0021] Figure 11 This is the circuit diagram of the second MCU control circuit of this utility model.

[0022] Reference numerals: 100, Radio Frequency Identification Circuit; 110, Signal Filtering Module; 120, Crystal Oscillator Module; 130, Reset Module; 200, First MCU Control Circuit; 300, Second MCU Control Circuit; 400, First OSSD Output Unit; 500, Second OSSD Output Unit; 600, Power Supply Circuit; 700, First Sampling Unit; 800, Second Sampling Unit; 900, Security Input Circuit; 910, First Signal Input Circuit; 920, Second Signal Input Circuit. Detailed Implementation

[0023] The present invention will be further described in detail below with reference to the accompanying drawings.

[0024] This specific embodiment is merely an explanation of the present utility model and is not intended to limit the present utility model. After reading this specification, those skilled in the art can make modifications to this embodiment without contributing any inventive element, but as long as they are within the scope of the claims of the present utility model, they are protected by patent law.

[0025] To make the objectives, technical solutions, and advantages of the embodiments of this utility model clearer, the technical solutions of the embodiments of this utility model will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this utility model, and not all embodiments. The components of the embodiments of this utility model described and shown in the accompanying drawings can generally be arranged and designed in various different configurations.

[0026] Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without inventive effort are within the scope of protection of the present invention.

[0027] In existing technologies, non-contact safety switches are widely used in the safety control of protective doors for industrial equipment. Non-contact safety switches use radio frequency identification (RFID) technology to detect the position status of the matching unit and send a stop signal to the equipment when the protective door is accidentally opened. Traditional non-contact safety switches rely on a single main control unit to process the identification signal and control the output module, which poses a single point of failure risk. If the main control unit malfunctions, the system cannot accurately determine the status of the protective door, potentially causing the equipment to continue operating in a dangerous state, posing a safety hazard of personnel accidentally entering a dangerous area.

[0028] To address the aforementioned issues, the applicant identified the reliability bottleneck of the existing architecture as stemming from its centralized control structure. Analysis of industrial safety standards revealed that redundant design can effectively improve system fault tolerance. Based on this, the applicant proposes constructing dual independent control channels, enabling safe switching under fault conditions through mutual monitoring.

[0029] First embodiment:

[0030] Reference Figure 1 This utility model embodiment provides a non-contact safety switch control circuit, including a radio frequency identification circuit 100, used to identify whether the matching device of the safety switch has a valid electronic tag and to send a radio frequency identification signal;

[0031] The first MCU control circuit 200 is electrically connected to the radio frequency identification circuit 100 and is configured to process the identification result of the radio frequency identification circuit 100 and obtain the working state of the second MCU control circuit 300 to generate a first OSSD control signal.

[0032] The second MCU control circuit 300 is electrically connected to the first MCU control circuit 200 and the radio frequency identification circuit 100, and is configured to process the identification result of the radio frequency identification circuit 100, obtain the working state of the first MCU control circuit 200, and generate a second OSSD control signal.

[0033] The first OSSD output unit 400 is electrically connected to the first MCU control circuit 200 and the second MCU control circuit 300. It is used to respond to the first OSSD control signal, output the first OSSD signal to the host computer, and feed back the voltage status signal to the second MCU control circuit 300.

[0034] The second OSSD output unit 500 is electrically connected to the first MCU control circuit 200 and the second MCU control circuit 300. It is used to respond to the second OSSD control signal, output the second OSSD signal to the host computer, and feed back the voltage status signal to the first MCU control circuit 200.

[0035] It should be noted that OSSD is an abbreviation for Optical Sensor Switching Device, an electrical device used to protect the safety of people and equipment. The OSSD signal is a safety output signal that informs the user or other devices whether the door lock is currently in a normal working state.

[0036] It should be noted that the first and second OSSD control signals have two states: a high level indicates that the system is in a safe or permissible operating state, while a low level indicates that there is a fault or abnormality, and a shutdown or disconnection operation needs to be performed.

[0037] In specific implementation, the radio frequency identification circuit 100 continuously scans the electronic tag information of the matching device. When a valid tag is detected, it sends a radio frequency identification signal to the first MCU control circuit 200 and the second MCU control circuit 300. The first MCU control circuit 200 and the second MCU control circuit 300 independently process the radio frequency identification signal. Under normal conditions, the first OSSD output unit 400 and the second OSSD output unit 500 synchronously output a high level to allow the device to operate.

[0038] When the first MCU control circuit 200 detects an abnormal voltage output (such as short circuit, open circuit, or illegal level) in the second OSSD output unit 500, or detects abnormal operating status such as abnormal power supply or communication interruption in the second MCU control circuit 300, the first MCU control circuit 200 controls the first OSSD output unit 400 connected to it to generate a shutdown control signal and transmits the signal to the host computer through the first OSSD output channel, so that the host computer can still receive the shutdown signal in time and perform protection actions in the event of failure of the peer device.

[0039] Similarly, when the second MCU control circuit 300 detects an output abnormality in the first OSSD output unit 400 or a fault in the first MCU control circuit 200 itself, the second MCU control circuit 300 will control the second OSSD output unit 500 to actively output a shutdown control signal, which will then output a valid disconnect command to the host computer, ensuring that the system still has complete safety linkage capability when the first control path fails.

[0040] Through the cross-monitoring and mutual control mechanism between the first MCU control circuit and the second MCU control circuit, if any OSSD output unit or MCU control circuit fails, a shutdown signal can still be issued independently by another normal path, ensuring that the system can quickly cut off the running command after identifying the abnormality and achieve highly reliable safe shutdown linkage control.

[0041] In one embodiment, see Figure 2 The first MCU control circuit 200 includes MCU1, and the second MCU control circuit 300 includes MCU2. Multiple signal electrical connection lines are provided between MCU1 and MCU2 to realize control signal transmission, status monitoring and dual-machine communication.

[0042] Specifically, MCU1 and MCU2 communicate via an SPI interface for master-slave data exchange, including SPI_CLK, MISO, MOSI, and SPI_NSS. SPI_CLK is the clock signal line for SPI communication, output by MCU1; MISO is the master input / slave output line used for MCU2 to transmit data to MCU1; and MOSI is the master output / slave input line used for MCU1 to transmit data to MCU2.

[0043] Through the aforementioned SPI bus, MCU1 and MCU2 can synchronize key control information in real time to achieve master-slave linkage logic processing.

[0044] Furthermore, to enhance system stability and security, MCU1 and MCU2 also construct a handshake or interrupt channel through GPIO_PB1 and GPIO_PB6. GPIO_PB1 and GPIO_PB6 can be configured as input or output ports, respectively, for transmitting synchronization instructions, interrupt requests, or error status indications.

[0045] In addition, the MCU_TX is used by MCU1 to send serial data commands to MCU2. It can be used as an auxiliary communication path to deal with SPI anomalies or to synchronize redundant information during the initialization and configuration phase.

[0046] SC1 and SC2 are control signal acquisition lines. SC1 is electrically connected to the OSSD control signal input terminal of MCU1, and SC2 is electrically connected to the OSSD control signal input terminal of MCU2. SC1 and SC2 are used to sample the OSSD output status controlled by the other MCU to realize OSSD mutual monitoring and protection logic: when any MCU detects an abnormal control output of the other MCU, it can actively put itself into a shutdown state to ensure the safety and reliability of the output signal channel.

[0047] In practice, MCU1 and / or MCU2 can use a microcontroller unit of model APM32F103TBU6, or other microcontroller units with similar functions can be used instead.

[0048] Second embodiment:

[0049] This utility model provides another non-contact safety switch control circuit, wherein: the ADC output terminal of the first OSSD output unit 400 is electrically connected to the OSSD feedback terminal of the second MCU control circuit 300, so that the second MCU control circuit 300 can detect the output status of the first OSSD output unit 400.

[0050] The ADC output terminal of the second OSSD output unit 500 is electrically connected to the OSSD feedback terminal of the first MCU control circuit 200 so that the first MCU control circuit 200 can detect the output status of the second OSSD output unit 500.

[0051] The ADC output terminal refers to the interface that converts the analog voltage signal of the OSSD output unit into a digital signal and transmits it to the corresponding MCU control circuit. Specifically, it can be implemented by combining an analog-to-digital converter with a resistor voltage divider circuit, which is used to convert the output voltage of the switching power supply chip into a level range that the MCU can recognize proportionally.

[0052] The OSSD feedback terminal refers to the input port in the MCU control circuit used to receive the status signal of the OSSD output unit. Specifically, it can be implemented using a GPIO pin with ADC function, which is used to monitor in real time whether the OSSD output unit is in a normal on or off state.

[0053] Among them, the switching power supply chip refers to the power switching device that controls the power supply of the OSSD output unit. Specifically, it can be implemented by an intelligent power chip with integrated overcurrent protection and short circuit detection functions, which is used to quickly cut off the 24V power supply output according to the MCU control signal.

[0054] In practical implementation, when the first OSSD output unit 400 experiences a short circuit or open circuit fault, its output voltage will deviate from the preset threshold range. At this time, the second MCU detects the abnormality through its ADC sampling terminal and immediately sends a shutdown command to the second OSSD output unit 500 through its own control channel. Similarly, the first MCU achieves reverse state monitoring by electrically connecting to the ADC sampling terminal of the second OSSD output unit 500, forming a bidirectional cross-detection mechanism. This effectively prevents monitoring blind spots caused by the failure of a single MCU control circuit, ensuring that the equipment power can still be cut off promptly through the other control unit even if one control unit fails.

[0055] Reference Figure 4 This application further proposes that the first OSSD output unit 400 and the second OSSD output unit 500 have the same structure. The first OSSD output unit 400 includes a first resistor R1, a second resistor R2, a third resistor R3, a fourth resistor R4, a fifth resistor R5, a first switching transistor Q1, a first diode D1, a second diode D2, a third diode D3, a switching power supply chip U1, and the first switching transistor is an N-channel MOSFET.

[0056] The OSSD control signal terminal SC2 of the first MCU control circuit 200 is electrically connected to the gate of the first switching transistor Q1 through the first resistor R1, and electrically connected to the source and ground terminal of the first switching transistor Q1 through the second resistor R2. The drain of the first switching transistor Q1 is electrically connected to the input terminal IN of the switching power supply chip U1. The power input terminal VBB of the switching power supply chip U1 is electrically connected to the second DC power supply. The output terminal OUT of the switching power supply chip U1 is electrically connected to the ADC sampling terminal FK1-ADC / FK2-ADC of the second MCU control circuit 300 through the second diode D2 and the third resistor R3. The ADC sampling terminal FK1-ADC / FK2-ADC is connected in parallel with ground through the third diode D3 and the fifth resistor R5. The anode of the second diode D2 is electrically connected to ground through the first diode D1 and the fourth resistor R4.

[0057] The output terminal OUT of the switching power supply chip U1 of the second OSSD output unit 500 is electrically connected to the ADC sampling terminal FK1-ADC / FK2-ADC of the first MCU control circuit 200 through the second diode D2 and the third resistor R3.

[0058] It should be noted that the second diode D2 is a diode used for reverse voltage protection. Specifically, it can be a silicon-based diode with a forward voltage drop of 0.7V. Its anode is connected to the output terminal OUT of the switching power supply chip U1 to prevent reverse voltage from damaging the output terminal OUT.

[0059] Among them, the switching power supply chip U1 can be a power driving device used to control the output signal. For example, it can be a smart switching power supply chip with model BTS4140N. Its input terminal IN receives the switching signal output by the MOSFET and converts the 24V power supply into the first OSSD output signal or the second OSSD output signal through the internal circuit.

[0060] The third resistor R3 is used for voltage division. It is connected in series with the second diode D2 and electrically connected to the ADC sampling terminal to convert the output voltage of the switching power supply chip into a low voltage range that the MCU can recognize.

[0061] In practical implementation, the first OSSD output unit 400 and the second OSSD output unit 500 adopt the same circuit topology. They are driven by two independent MCU control circuits, but their output signals are mutually monitored through a cross-feedback path. Taking the first MCU control circuit 200 as an example, when the first MCU control circuit 200 outputs the first OSSD control signal through the SC2 pin, the first OSSD control signal, after being current-limited by the first resistor R1, drives the gate of the first switching transistor, causing the MOSFET to turn on or off, thereby controlling the input state of the switching power supply chip U1. The output terminal OUT of the switching power supply chip converts the 24V OSSD signal into a 3.3V level signal through a voltage divider network and transmits it to the ADC sampling terminal of the second MCU control circuit 300. Simultaneously, the output terminal of the switching power supply chip of the second OSSD output unit 500 is electrically connected to the ADC sampling terminal of the first MCU in the same manner, forming a bidirectional cross-detection mechanism. The operating state of any OSSD output unit can be monitored in real time by another MCU control circuit, thereby immediately triggering redundant control logic when an output abnormality is detected, avoiding the safety function loss problem caused by a single point of failure in traditional solutions.

[0062] In one embodiment, the first MCU control circuit 200 includes a first sampling unit 700 for sampling the operating voltage state of the second MCU control circuit 300;

[0063] The second MCU control circuit 300 includes a second sampling unit 800, which is used to sample the operating voltage state of the first MCU control circuit 200.

[0064] The first sampling unit 700 acquires the power supply voltage signal of the second MCU through the ADC port. The second sampling unit 800 is a detection circuit with the same structure as the first sampling unit 700, specifically using the same voltage division ratio and filtering parameters, and is used to monitor the power supply status of the first MCU. The first sampling unit 700 and the second sampling unit 800 achieve mutual status monitoring between the two control units through a cross-circuit voltage detection mechanism.

[0065] Furthermore, refer to Figure 6 The first sampling unit 700 and the second sampling unit 800 have the same structure. The first sampling unit 700 includes a sixth resistor R6, a seventh resistor R7, an eighth resistor R8, a ninth resistor R9, a tenth resistor R10, an eleventh resistor R11, a first capacitor C1, and a second capacitor C2. The output terminal of the first MCU control circuit 200 is electrically connected to the ADC input terminal MCU2-ADC_3.3V of the second MCU control circuit 300 through the sixth resistor R6 and the seventh resistor R7. The sixth resistor R6 is grounded through the eighth resistor R8. The first capacitor C1 is connected in parallel across the eighth resistor R8. The second DC power supply is electrically connected to another ADC input terminal MCU2-ADC_24V of the second MCU control circuit 300 through the ninth resistor R9 and the tenth resistor R10. The ninth resistor R9 is grounded through the eleventh resistor R11. The second capacitor C2 is connected in parallel across the eleventh resistor R11.

[0066] In practical implementation, when the first MCU needs to detect the operating voltage of the second MCU, its output terminal reduces the 3.3V operating voltage proportionally through a voltage divider network before transmitting it to the ADC port of the second MCU. The voltage signal after voltage division is processed by an RC filter circuit to eliminate the impact of switching noise on sampling accuracy. Simultaneously, the 24V power supply voltage is converted into a low-voltage detection signal through another voltage divider network and input to the second MCU, also undergoing filtering. Through two independent detection channels, the two MCUs can cross-monitor the operating power status of each other in real time. For example, when the second MCU detects that the 3.3V power supply of the first MCU drops below 2.5V, or the 24V power supply drops below 2.4V, it can determine a power supply abnormality and trigger a protection mechanism, effectively preventing erroneous control signal output due to power failure and significantly improving the operational reliability of the safety switch in industrial scenarios.

[0067] In one embodiment, reference is made to... Figure 3The radio frequency identification circuit 100 includes a radio frequency identification chip U3, a radio frequency antenna L6, and a signal filtering module 110. The radio frequency identification chip U3 is electrically connected to the radio frequency antenna L6 through the signal filtering module 110. The radio frequency identification chip U3 is electrically connected to the first MCU control circuit 200 and the second MCU control circuit 300.

[0068] In a specific implementation, the radio frequency identification circuit 100 can identify the electronic tag on the matching device that is close to it through the radio frequency antenna L6, and determine whether the electronic tag is valid. The determination result will be sent to the first MCU control circuit 200 and / or the second MCU control circuit 300.

[0069] In one embodiment, reference is made to... Figure 3 The signal filtering module 110 includes a first inductor L1, a second inductor L2, a third capacitor C3, a fourth capacitor C4, a fifth capacitor C5, a sixth capacitor C6, a seventh capacitor C7, an eighth capacitor C8, a ninth capacitor C9, a tenth capacitor C10, an eleventh capacitor C11, a twelfth capacitor C12, a twelfth resistor R12, a thirteenth resistor R13, a fourteenth resistor R14, and a fifteenth resistor R15. One end of the first inductor L1 is electrically connected to the TX2 pin of the RFID chip U3, and the other end is connected to one end of the fourth capacitor C4, one end of the seventh capacitor C7, and one end of the sixth capacitor C6. The other end of the sixth capacitor C6 is electrically connected to one end of the twelfth resistor R12 and the RX pin of the RFID chip U3 through the thirteenth resistor R13. The other end of the twelfth resistor R12 is electrically connected to the VMID pin of the RFID chip U3 and grounded through the third capacitor C3.

[0070] One end of the second inductor L2 is electrically connected to the TX1 pin of the RFID chip U3, and the other end is electrically connected to one end of the fifth capacitor C5 and one end of the eighth capacitor C8. The other end of the fifth capacitor C5 is electrically connected to the other end of the fourth capacitor C4, one end of the ninth capacitor C9, one end of the tenth capacitor C10, one end of the eleventh capacitor C11, one end of the twelfth capacitor C12, and the ground terminal. The other end of the seventh capacitor C7 is electrically connected to the other end of the ninth capacitor C9, the other end of the eleventh capacitor C11, and one end of the fourteenth resistor R14. The other end of the eighth capacitor C8 is electrically connected to the other end of the tenth capacitor C10, the other end of the twelfth capacitor C12, and one end of the fifteenth resistor R15. The other ends of the fourteenth resistor R14 and the fifteenth resistor R15 are electrically connected to the antenna L6.

[0071] In practical implementation, the TX1 and TX2 pins of the RFID chip U3 are used to control the matching network of antenna L6, so that the antenna L6 and the RFID chip U3 can transmit signals better and reduce reflection loss. By adjusting the voltage value on the TX1 pin, the parameters of the antenna matching network can be optimized to achieve good near-field communication function.

[0072] In practical implementation, when the RFID chip U3 transmits RF signals through the TX1 and TX2 pins, the first and second inductors suppress high-frequency harmonics in the signal, preventing them from causing electromagnetic interference through antenna radiation. The fourth capacitor C4, the fifth capacitor C5, and the eighth capacitor C8 form the first-stage filter network, filtering out low-frequency noise components in the signal. The seventh capacitor C7, the ninth capacitor C8, and the eleventh capacitor C11 form the second-stage filter network, further attenuating mid-to-high-frequency interference. The sixth capacitor C6 and the thirteenth resistor R13 work together to form a feedback loop at the RX pin, avoiding identification errors caused by signal reflection. The fourteenth resistor R14 and the fifteenth resistor R15 perform impedance matching at the antenna input, ensuring efficient transmission of RF energy to the antenna. Through the synergistic effect of the multi-stage LC filter network and the resistor attenuation structure, the RF signal exhibits stable amplitude-frequency characteristics during transmission, while suppressing common-mode interference introduced by the external environment, thereby improving the accuracy of electronic tag identification.

[0073] In one embodiment, reference is made to... Figure 3 The RFID circuit 100 further includes a crystal oscillator module 120 and a reset module 130. The crystal oscillator module 120 is used to generate the operating frequency required by the RFID chip U3. The reset module 130 can send a reset signal to the NPD pin of the RFID chip U3 when powered on. The crystal oscillator module 120 includes a crystal oscillator X3, a thirteenth capacitor C13, and a fourteenth capacitor C14. The two signal terminals of the crystal oscillator X3 are respectively connected to the OSCIN pin and the OSCOUT pin of the RFID chip U3, and are grounded through the thirteenth capacitor C13 and the fourteenth capacitor C14, respectively. The crystal oscillator X3 provides the required operating frequency signal to the RFID chip U3. The thirteenth capacitor C13 and the fourteenth capacitor C14 are used to filter out high-frequency noise in the oscillation signal and improve oscillation stability, thereby ensuring the communication frequency accuracy and anti-interference capability of the RFID circuit 100 in actual operation.

[0074] The reset module 130 includes a fifteenth capacitor C15 and a sixteenth resistor R16. The first end of the sixteenth resistor R16 is electrically connected to the first DC power supply, and the second end of the sixteenth resistor R16 is electrically connected to the NPD pin of the RFID chip U3 and grounded through the fifteenth capacitor C15. The sixteenth resistor R16 and the fifteenth capacitor C15 together form an RC delay circuit, which is used to output a low-level reset signal to the NPD pin of the RFID chip U3 at the initial stage of system power-on, so that the chip can start up after the power supply is stable, avoiding the problem of chip false start-up caused by power fluctuations or jitter, and effectively improving the reliability and stability of the RFID chip.

[0075] In one embodiment, reference is made to... Figure 5 It also includes a safety input circuit 900, which includes a first signal input circuit 910 and a second signal input circuit 920, wherein:

[0076] The first signal input circuit 910 includes a fourth diode D4, a first optocoupler U4, a seventeenth resistor R17, and an eighteenth resistor R18. The collector of the phototransistor in the first optocoupler U4 is the first safety input terminal, the emitter of the phototransistor in the first optocoupler U4 is grounded, the positive terminal of the light-emitting diode of the first optocoupler U4 is connected in series with the seventeenth resistor R17, the negative terminal of the light-emitting diode of the first optocoupler U4 is grounded, and the eighteenth resistor R18 is connected across the positive and negative terminals of the light-emitting diode of the first optocoupler U4. The first signal input circuit 910 also includes a fourth diode D4, one end of which is electrically connected to the seventeenth resistor R17, and the other end of which is grounded.

[0077] The second signal input circuit 920 includes a fifth diode D5, a second optocoupler U5, a nineteenth resistor R19, and a twentieth resistor R20. The collector of the phototransistor in the second optocoupler U5 is the second safety input terminal, and the emitter of the phototransistor in the second optocoupler U5 is grounded. The positive terminal of the light-emitting diode of the second optocoupler U5 is connected in series with the nineteenth resistor R19, and the negative terminal of the light-emitting diode of the second optocoupler U5 is grounded. The twentieth resistor R20 is connected across the positive and negative terminals of the light-emitting diode of the second optocoupler U5. The second signal input circuit 920 also includes a fifth diode D5, one end of which is electrically connected to the nineteenth resistor R19, and the other end of which is grounded.

[0078] It's important to note that an optocoupler is a device that achieves electrical isolation through optical signals. It blocks the direct electrical connection between external input signals and internal control circuits, preventing voltage surges or interference signal transmission. In specific implementations, when an external safety signal is input through the first safety input terminal, current flows through the seventeenth resistor R17 and the LED of the first optocoupler, causing it to emit light and triggering the phototransistor to conduct, transmitting the signal to the internal control circuit. The fourth diode D4 clamps the input voltage; for example, when the input voltage exceeds 24V, the diode conducts in reverse to protect the LED. The eighteenth resistor R18 discharges residual charge when there is no input signal, preventing false triggering. The second signal input circuit 920 operates on the same principle, forming a redundant signal acquisition channel. The two independent circuits are isolated from each other; if either circuit fails, the other circuit can still transmit the safety signal normally, ensuring that the control circuit continuously acquires external status information.

[0079] In some specific implementations, the optocoupler can be a TLP521-1, with a forward conduction voltage of approximately 1.2V at its input terminal and a maximum allowable current of 50mA; the fourth diode can be an SMAJ33A type TVS diode with a breakdown voltage of 33V, used to suppress electrostatic discharge or surge voltage that may occur at the input terminal.

[0080] In one embodiment, reference is made to... Figure 7 It also includes a power supply circuit 600, which provides a first DC power supply (3.3V) to the RFID circuit 100, the first MCU control circuit 200, and the second MCU control circuit 300, and a second DC power supply (24V) to the OSSD output unit. The power supply circuit 600 includes two identical voltage regulator circuits for regulating the +24V DC voltage to the 3.3V voltage required by the MCU. The voltage regulator circuit includes a first boost inductor L3, a voltage regulator chip U6, a seventeenth capacitor C17, an eighteenth capacitor C18, a nineteenth capacitor C19, a twenty-first resistor R21, a twenty-second resistor R22, and a twenty-third resistor R23.

[0081] In specific implementation, the voltage regulator chip U6 can be an LGS5148 DC-DC buck chip. Its BST pin 1 is electrically connected to SW pin 6 through the seventeenth capacitor C16 to drive the gate of the internal high-side MOSFET to improve efficiency. The GND pin 2 of the voltage regulator chip U6 is grounded. The FB pin 3 of the voltage regulator chip U6 forms a voltage divider network through the twenty-first resistor R21 and the twenty-second resistor R22 to feed back the output voltage to the error amplifier inside the chip for closed-loop control, thereby stabilizing the output voltage. The EN pin 4 of the voltage regulator chip U6 is pulled up to +2 through the twenty-third resistor R23. A 4V power supply is used to enable the chip's operating state. The VIN pin 5 of the voltage regulator chip U6 is connected to a +24V DC power supply as the chip's input power. The SW pin 6 of the voltage regulator chip U6 is electrically connected to the input of the third inductor L3. The other end of L3 is connected to the output terminals MCU1_3.3V / MCU2_3.3V for a stable 3.3V output voltage. The output terminals MCU1_3.3V / MCU2_3.3V are connected in parallel with an eighteenth capacitor C18 and a nineteenth capacitor C19 to filter out voltage ripple and improve output voltage stability. A seventeenth capacitor C17 is connected in parallel to ground to absorb high-frequency interference generated during switching. In practical implementation, the LGS5148 chip has a soft-start function and overcurrent protection capability. Combined with the voltage divider feedback design, it can achieve output voltage deviation control within ±2%, ensuring stable operation of the MCU control circuit in complex industrial environments. Simultaneously, the third inductor L3 has low DC resistance, effectively reducing losses and improving voltage regulation efficiency.

[0082] In one embodiment, reference is made to... Figure 8 The non-contact safety switch control circuit also includes an auxiliary output circuit. The function of this auxiliary output circuit is to output abnormal status signals to external devices, such as LED warning lights, buzzers, or host computers, so that when the circuit detects an abnormal state, it can promptly alert or control other devices via the auxiliary output terminal (AUX). It should be noted that when the system is working normally, the auxiliary output terminal is at a low level (0V); when a fault or abnormal event is detected, the auxiliary output terminal outputs a high level (24V).

[0083] Specifically, the auxiliary output circuit includes resistors R24 (24th), R25 (25th), R26 (26th), R27 (27th), R28 (28th), and R29 (29th), a second switch Q2, a third switch Q3, a sixth diode D6, a seventh diode D7, an eighth diode D8, and a first fuse F1. In a specific implementation, the auxiliary control signal terminal SC0 is electrically connected to the gate of the second switch Q2 through resistor R24 ​​and to ground through resistor R25 to maintain a low level. The second switch Q2 is an N-channel MOSFET with its source grounded and its drain connected to the gate of the third switch Q3 through resistor R26. The third switch Q3 is a P-channel MOSFET with its source connected to the OSSD output power supply terminal OSSD_24V and its drain connected to the auxiliary output terminal AUX through diode D6 and the first resettable fuse F1 in series. When Q2 is turned on, its drain pulls down the gate potential of Q3, causing Q3 to turn on, thereby sending OSSD_24V to the AUX terminal through D6 and F1; a voltage divider circuit between the 28th resistor R28 and ground is connected in parallel on the AUX output path. This voltage divider point is electrically connected to the OUT_FK sampling terminal through the 7th diode D7, which is used to feed back the output status to the control circuit; the 29th resistor R29 and the 8th diode D8 are connected in series to ground, which is used to discharge charge and protect the circuit.

[0084] This embodiment adopts a structure that combines two-stage MOSFET control with overvoltage protection, which has the advantages of fast response speed, strong level reversal capability, and high false trigger suppression capability. In addition, a self-resetting fuse F1 and a diode clamping circuit are set in the output branch to effectively ensure the safe operation of downstream equipment and the entire system.

[0085] In one embodiment, reference is made to... Figure 9 It also includes a teaching circuit, which provides an identity configuration signal to the MCU under specific operation instructions to reset the internal identifier of the MCU, thereby switching the recognition mode. Specifically, this teaching operation can be used to switch between a unique matching mode and a general matching mode. For example, in the unique mode, a subject can only be paired with a specific matcher, while in the general mode, the subject can recognize any valid matcher.

[0086] The teaching circuit includes a ninth diode D9, a thirtieth resistor R30, a thirty-first resistor R31, and a seventh optocoupler U7. The teaching input port IN2 serves as the trigger input for the teaching signal. Its input signal is first clamped between the ninth diode D9 and ground to prevent the input voltage from exceeding the range and damaging the circuit. The thirtieth resistor R30 is connected in series between IN2 and the seventh optocoupler U7 for current limiting protection. The thirty-first resistor R31 acts as a bias pull-down resistor connected in parallel with the input side of the optocoupler U7 to ensure a stable level when there is no input, preventing false triggering. The seventh optocoupler U7 provides electrical isolation; its LED side conducts in response to the IN2 input signal, driving the phototransistor side to conduct, thereby outputting a valid teaching signal to the control port TEACHING. This signal is then received and processed by the MCU, which determines whether to clear or rewrite the current ID based on the trigger timing, completing the switching of the matching mode.

[0087] Reference Figures 10-11 Since the first MCU control circuit 200 and the second MCU control circuit 300 have the same circuit structure, this article only uses one as an example for explanation, and the other will not be described in detail. Those skilled in the art can directly implement the corresponding circuit based on the accompanying drawings without any creative effort.

[0088] The above is only used to illustrate the technical solution of this utility model and not to limit it. Any other modifications or equivalent substitutions made by those skilled in the art to the technical solution of this utility model, as long as they do not depart from the spirit and scope of the technical solution of this utility model, should be covered within the scope of the claims of this utility model.

Claims

1. A non-contact safety switch control circuit, characterized in that, include: Radio frequency identification circuit (100) is used to identify whether the matching device of the safety switch has a valid electronic tag and to emit a radio frequency identification signal; The first MCU control circuit (200) is electrically connected to the radio frequency identification circuit (100) and configured to process the identification result of the radio frequency identification circuit (100) and obtain the working state of the second MCU control circuit (300) to generate a first OSSD control signal; The second MCU control circuit (300) is electrically connected to the first MCU control circuit (200) and the radio frequency identification circuit (100), and is configured to process the identification result of the radio frequency identification circuit (100), obtain the working state of the first MCU control circuit (200), and generate a second OSSD control signal. The first OSSD output unit (400) is electrically connected to the first MCU control circuit (200) and the second MCU control circuit (300). It is used to respond to the first OSSD control signal, output the first OSSD signal to the host computer, and feed back the voltage status signal to the second MCU control circuit (300). The second OSSD output unit (500) is electrically connected to the first MCU control circuit (200) and the second MCU control circuit (300). It is used to respond to the second OSSD control signal, output the second OSSD signal to the host computer, and feed back the voltage status signal to the first MCU control circuit (200).

2. The non-contact safety switch control circuit according to claim 1, characterized in that, The ADC output terminal of the first OSSD output unit (400) is electrically connected to the OSSD feedback terminal of the second MCU control circuit (300) so that the second MCU control circuit (300) can detect the output status of the first OSSD output unit (400). The ADC output terminal of the second OSSD output unit (500) is electrically connected to the OSSD feedback terminal of the first MCU control circuit (200) so that the first MCU control circuit (200) can detect the output status of the second OSSD output unit (500).

3. The non-contact safety switch control circuit according to claim 2, characterized in that, It also includes a power supply circuit (600) for providing a first DC power supply (3.3V) to the radio frequency identification circuit (100), the first MCU control circuit (200) and the second MCU control circuit (300), and for providing a second DC power supply (24V) to the OSSD output unit; the first OSSD output unit (400) and the second OSSD output unit (500) have the same structure; The first OSSD output unit (400) includes a first resistor (R1), a second resistor (R2), a third resistor (R3), a fourth resistor (R4), a fifth resistor (R5), a first switching transistor (Q1), a first diode (D1), a second diode (D2), a third diode (D3), and a switching power supply chip (U1). The first switching transistor is an N-channel MOSFET. The OSSD control signal terminal (SC2) of the first MCU control circuit (200) is electrically connected to the gate of the first switching transistor (Q1) through the first resistor (R1), and electrically connected to the source and ground terminal of the first switching transistor (Q1) through the second resistor (R2). The drain of the first switching transistor (Q1) is electrically connected to the input terminal (IN) of the switching power supply chip (U1). The power input terminal (VBB) of the switching power supply chip (U1) is electrically connected to the second DC power supply. The output terminal (OUT) of the switching power supply chip (U1) is electrically connected to the ADC sampling terminal of the second MCU control circuit (300) through the second diode (D2) and the third resistor (R3). The third diode (D3) and the fifth resistor (R5) are connected in parallel between the ADC sampling terminal and ground. The anode of the second diode (D2) is electrically connected to ground through the first diode (D1) and the fourth resistor (R4). The output terminal (OUT) of the switching power supply chip (U1) of the second OSSD output unit (500) is electrically connected to the ADC sampling terminal of the first MCU control circuit (200) through the second diode (D2) and the third resistor (R3).

4. The non-contact safety switch control circuit according to claim 3, characterized in that, The first MCU control circuit (200) includes a first sampling unit (700) for sampling the operating voltage state of the second MCU control circuit (300); The second MCU control circuit (300) includes a second sampling unit (800) for sampling the operating voltage state of the first MCU control circuit (200).

5. The non-contact safety switch control circuit according to claim 4, characterized in that, The first sampling unit (700) and the second sampling unit (800) have the same structure. The first sampling unit (700) includes a sixth resistor (R6), a seventh resistor (R7), an eighth resistor (R8), a ninth resistor (R9), a tenth resistor (R10), an eleventh resistor (R11), a first capacitor (C1), and a second capacitor (C2). The output terminal of the first MCU control circuit (200) is electrically connected to the ADC input terminal (MCU2-ADC_3.3V) of the second MCU control circuit (300) through the sixth resistor (R6) and the seventh resistor (R7). The sixth resistor (R6) is grounded through the eighth resistor (R8), and the first capacitor (C1) is connected in parallel across the eighth resistor (R8). The second DC power supply is electrically connected to another ADC input terminal (MCU2-ADC_24V) of the second MCU control circuit (300) through the ninth resistor (R9) and the tenth resistor (R10). The ninth resistor (R9) is grounded through the eleventh resistor (R11), and the second capacitor (C2) is connected in parallel across the eleventh resistor (R11).

6. The non-contact safety switch control circuit according to claim 3, characterized in that, The radio frequency identification circuit (100) includes a radio frequency identification chip (U3), a radio frequency antenna (L6), and a signal filtering module (110). The radio frequency identification chip (U3) is electrically connected to the radio frequency antenna (L6) through the signal filtering module (110). The radio frequency identification chip (U3) is electrically connected to the first MCU control circuit (200) and the second MCU control circuit (300).

7. The non-contact safety switch control circuit according to claim 6, characterized in that, The signal filtering module (110) includes a first inductor (L1), a second inductor (L2), a third capacitor (C3), a fourth capacitor (C4), a fifth capacitor (C5), a sixth capacitor (C6), a seventh capacitor (C7), an eighth capacitor (C8), a ninth capacitor (C9), a tenth capacitor (C10), an eleventh capacitor (C11), a twelfth capacitor (C12), a twelfth resistor (R12), a thirteenth resistor (R13), a fourteenth resistor (R14), and a fifteenth resistor (R15). One end of the first inductor (L1) is electrically connected to the TX2 pin of the RFID chip (U3), and the other end is connected to one end of the fourth capacitor (C4), one end of the seventh capacitor (C7), and one end of the sixth capacitor (C6). The other end of the sixth capacitor (C6) is electrically connected to one end of the twelfth resistor (R12) and the RX pin of the RFID chip (U3) through the thirteenth resistor (R13). The other end of the twelfth resistor (R12) is electrically connected to the VMID pin of the RFID chip (U3) and grounded through the third capacitor (C3). One end of the second inductor (L2) is electrically connected to the TX1 pin of the RFID chip (U3), and the other end is electrically connected to one end of the fifth capacitor (C5) and one end of the eighth capacitor (C8). The other end of the fifth capacitor (C5) is electrically connected to the other end of the fourth capacitor (C4), one end of the ninth capacitor (C9), one end of the tenth capacitor (C10), one end of the eleventh capacitor (C11), one end of the twelfth capacitor (C12), and the ground terminal. The other end of the seventh capacitor (C7) is electrically connected to the other end of the ninth capacitor (C9), the other end of the eleventh capacitor (C11), and one end of the fourteenth resistor (R14). The other end of the eighth capacitor (C8) is electrically connected to the other end of the tenth capacitor (C10), the other end of the twelfth capacitor (C12), and one end of the fifteenth resistor (R15). The other ends of the fourteenth resistor (R14) and the fifteenth resistor (R15) are electrically connected to the antenna (L6).

8. The non-contact safety switch control circuit according to claim 6, characterized in that, The RFID circuit (100) further includes a crystal oscillator module (120) and a reset module (130). The crystal oscillator module (120) is used to generate the operating frequency required by the RFID chip (U3). The reset module (130) can send a reset signal to the NPD pin of the RFID chip (U3) upon power-up. The crystal oscillator module (120) includes a crystal oscillator (X3), a thirteenth capacitor (C13) and a fourteenth capacitor (C14). The two signal terminals of the crystal oscillator (X3) are respectively connected to the OSCIN pin and OSCOUT pin of the radio frequency identification chip (U3), and are grounded through the thirteenth capacitor (C13) and the fourteenth capacitor (C14). The reset module (130) includes a fifteenth capacitor (C15) and a sixteenth resistor (R16). The first end of the sixteenth resistor (R16) is electrically connected to the first DC power supply, and the second end of the sixteenth resistor (R16) is electrically connected to the NPD pin of the radio frequency identification chip (U3) and grounded through the fifteenth capacitor (C15).

9. The non-contact safety switch control circuit according to claim 1, characterized in that, It also includes a safety input circuit (900), which comprises a first signal input circuit (910) and a second signal input circuit (920), wherein: The first signal input circuit (910) includes a fourth diode (D4), a first optocoupler (U4), a seventeenth resistor (R17), and an eighteenth resistor (R18). The collector of the phototransistor in the first optocoupler (U4) is the first safety input terminal. The emitter of the phototransistor in the first optocoupler (U4) is grounded. The positive terminal of the light-emitting diode of the first optocoupler (U4) is connected in series with the seventeenth resistor (R17). The negative terminal of the light-emitting diode of the first optocoupler (U4) is grounded. The eighteenth resistor (R18) is connected across the positive and negative terminals of the light-emitting diode of the first optocoupler (U4). The first signal input circuit (910) also includes a fourth diode (D4). One end of the fourth diode (D4) is electrically connected to the seventeenth resistor (R17), and the other end of the fourth diode (D4) is grounded. The second signal input circuit (920) includes a fifth diode (D5), a second optocoupler (U5), a nineteenth resistor (R19), and a twentieth resistor (R20). The collector of the phototransistor in the second optocoupler (U5) is the second safety input terminal. The emitter of the phototransistor in the second optocoupler (U5) is grounded. The positive terminal of the light-emitting diode of the second optocoupler (U5) is connected in series with the nineteenth resistor (R19). The negative terminal of the light-emitting diode of the second optocoupler (U5) is grounded. The twentieth resistor (R20) is connected across the positive and negative terminals of the light-emitting diode of the second optocoupler (U5). The second signal input circuit (920) also includes a fifth diode (D5). One end of the fifth diode (D5) is electrically connected to the nineteenth resistor (R19), and the other end of the fifth diode (D5) is grounded.

10. A security door lock, characterized in that, It includes an identifier and a matcher, the identifier including a contactless safety switch control circuit as described in any one of claims 1 to 9, and the matcher including an electronic tag.

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