Self-locking circuit and protection system for emergency communication equipment

Abstract

This invention discloses a self-locking circuit and protection system for emergency communication equipment, relating to the field of emergency communication. The self-locking circuit includes: a Schmitt trigger, an RS latch, a magnetic latching relay, a first driver transistor, a second driver transistor, an inverter, and a reset switch. The Schmitt trigger's input receives an abnormal signal and a reference voltage, and its output is connected to the RS latch's set terminal. The RS latch's output is connected to the base of the first driver transistor. The collector of the first driver transistor is connected to the magnetic latching relay's set terminal, and its emitter is grounded. The reset switch's first terminal is grounded, and its second terminal is connected to the RS latch's reset terminal via the inverter. The RS latch's reset terminal is connected to the base of the second driver transistor. The second driver transistor's collector is connected to the magnetic latching relay's reset terminal, and its emitter is grounded. The magnetic latching relay's output is connected to the emergency communication equipment. By implementing this invention, the problem of repeated device restarts in existing software-based communication management is solved, improving the equipment's operational stability.

Description

Technical Field

[0001] This invention relates to the field of emergency communication, and in particular to a self-locking circuit and protection system for an emergency communication device. Background Technology

[0002] In the field of emergency communications, the stable operation of emergency communication equipment is directly related to the efficiency of critical tasks such as disaster relief and public safety, as well as personnel safety. To cope with complex and ever-changing emergency scenarios, existing emergency communication equipment generally adopts software-controlled switching to achieve dynamic communication management. This approach uses an MCU (microcontroller unit) or general-purpose processor to run a preset program to monitor and make decisions on the link status in real time. For example, when the main link signal attenuation, excessive bit error rate, or physical layer interruption is detected, the system evaluates the quality of alternative links based on an algorithm model and ultimately drives the hardware to complete the link switching.

[0003] However, when an overheating anomaly occurs, software-based devices may restart to temporarily reduce the load and alleviate the temperature rise. But before the root cause of the overheating is eliminated, the temperature will quickly rise back to the threshold after restarting, and the software will trigger a reset again, thus continuously restarting and repeatedly cutting off and restoring power ("hiccuping and draining power"), which cannot maintain the stable operation of the device. Summary of the Invention

[0004] This invention provides a self-locking circuit and protection system for emergency communication equipment, which can solve the problem of repeated device restarts in existing software-based communication management and improve the stability of device operation.

[0005] One embodiment of the present invention provides a self-locking circuit for an emergency communication device, comprising: a Schmitt trigger, an RS latch, a magnetic latching relay, a first driving transistor, a second driving transistor, an inverter, and a reset switch; The signal input terminal of the Schmitt trigger is used to receive abnormal signals; the reference voltage terminal of the Schmitt trigger is connected to the reference voltage; the output terminal of the Schmitt trigger is connected to the set terminal of the RS latch. The output of the RS latch is connected to the base of the first driving transistor; the collector of the first driving transistor is connected to the set terminal of the magnetic latching relay; the emitter of the first driving transistor is grounded. The first terminal of the reset switch is grounded; the second terminal of the reset switch is connected to the reset terminal of the RS latch via an inverter; the reset terminal of the RS latch is connected to the base of the second driving transistor; the collector of the second driving transistor is connected to the reset terminal of the magnetic latching relay; the emitter of the second driving transistor is grounded. The output terminal of the magnetic latching relay is connected to the emergency communication equipment.

[0006] Furthermore, the self-locking circuit also includes: a freewheeling diode; The anode of the freewheeling diode is connected to the reset terminal of the magnetic latching relay; the cathode of the freewheeling diode is connected to the set terminal of the magnetic latching relay.

[0007] Furthermore, the self-locking circuit also includes: a filter capacitor; The first terminal of the filter capacitor is connected to the second terminal of the reset switch; the second terminal of the filter capacitor is grounded.

[0008] Furthermore, the self-locking circuit also includes: a first resistor, a second resistor, and a third resistor; The first terminal of the first resistor is connected to VCC; the second terminal of the first resistor is connected to the set terminal of the RS latch. The first end of the second resistor is connected to VCC; the second end of the second resistor is connected to the second end of the reset switch. The reset terminal of the RS latch is connected to the base of the second driver transistor, including: The reset terminal of the RS latch is connected to the base of the second driver transistor via a third resistor.

[0009] An embodiment of the present invention provides a protection system for an emergency communication device, comprising: a multi-input module, a core control module, a self-locking circuit, and an emergency communication device; wherein the self-locking circuit is as described in the self-locking circuit of the emergency communication device provided in an embodiment of the present invention. The multi-input module includes: a power input interface, a communication signal input interface, a power output interface, and a communication signal output interface; wherein, the power input interface is connected to the power supply of the emergency communication equipment; and the communication signal input interface is used to receive the communication signals of the emergency communication equipment. The core control module includes: a first microcontroller; a power output interface and a communication signal output interface are respectively connected to the input terminals of the first microcontroller; the output terminal of the first microcontroller is connected to the signal input terminal of the Schmitt trigger in the self-locking circuit; The first microcontroller is used to monitor power and communication signals in real time; when an abnormal power supply or communication signal is detected, it sends an abnormal signal to the signal input terminal of the Schmitt trigger in the self-locking circuit. The self-locking circuit is used to receive abnormal signals sent by the core control module and control the emergency communication equipment through the output of the magnetic latching relay.

[0010] Furthermore, the protection system for the emergency communication equipment also includes: an output switching module; the output switching module includes: a second microcontroller; the input terminal of the second microcontroller is connected to the output terminal of the magnetic latching relay in the self-locking circuit; the output terminal of the second microcontroller is connected to several communication interfaces in the emergency communication equipment respectively; The second microcontroller is used to switch the communication interface according to the preset interface priority when it receives a low level output from the output terminal of the magnetic latching relay.

[0011] Furthermore, the multi-input module also includes: a multiplexer; a power input interface including: a main power input interface and several backup power input interfaces; a power output interface including: a main power output interface and several backup power output interfaces; the main power output interface and all backup power output interfaces are respectively connected to each input terminal of the multiplexer; the output terminal of the multiplexer is connected to the first microcontroller; the main power input interface is connected to the main power supply of the emergency communication equipment; the backup power input interface is connected to the backup power supply of the emergency communication equipment. The communication signal input interface includes a local data input interface and a superior command input interface; the communication signal output interface includes a local data output interface and a superior command output interface; the local data output interface and the superior command output interface are connected in parallel to the first microcontroller; the local data input interface is used to receive sensor data from emergency communication equipment; the superior command input interface is used to receive Ethernet command signals from the command center.

[0012] Furthermore, the multi-input module also includes: a first TVS diode, several second TVS diodes, a first resettable fuse, several second resettable fuses, a first Zener diode, and several second Zener diodes; wherein, the main power input interface is connected to the main power output interface in sequence via the first TVS diode, the first resettable fuse, and the first Zener diode; the backup power input interface is connected to the backup power output interface in sequence via the second TVS diode, the second resettable fuse, and the second Zener diode. The multi-input module further includes: a first ESD protection diode, a second ESD protection diode, a first common-mode choke, and a second common-mode choke; wherein, the local data input interface is connected to the local data output interface in sequence through the first ESD protection diode and the first common-mode choke; the upper-level instruction input interface is connected to the upper-level instruction output interface in sequence through the second ESD protection diode and the second common-mode choke.

[0013] Furthermore, the core control module also includes: a digital temperature sensor interface; the digital temperature sensor interface is used to receive internal temperature data from emergency communication equipment; The first microcontroller is also used to monitor the internal temperature data of emergency communication equipment in real time; when an abnormal internal temperature data is detected, it sends an abnormal signal to the signal input terminal of the Schmitt trigger in the self-locking circuit.

[0014] Furthermore, the first microcontroller is also equipped with a diagnostic interface; the diagnostic interface is connected to the emergency communication equipment; the diagnostic interface is used to report the lock status and logs of the emergency communication equipment; it receives remote reset commands, and drives the reset switch to close when a remote reset command is received.

[0015] Compared with the prior art, the beneficial effects of this embodiment are as follows: When an anomaly is detected, this invention transmits the anomaly signal to a Schmitt trigger. By comparing the trigger threshold, the signal is transmitted to the RS latch after triggering. The RS latch remains in the set state, thereby driving the first transistor to conduct and controlling the magnetic latching relay to cut off the main power supply or load. After the magnetic latching relay is activated, it remains in the open state, requiring no continuous power supply and unable to be automatically reset. Power supply can only be restored after the RS latch is reset by triggering the RS latch via a reset switch and an inverter. This eliminates the possibility of automatic restart before the fault is eliminated at the hardware level.

[0016] In summary, this invention achieves hardware self-locking through RS latches and magnetic latching relays, enabling the system to forcibly cut off power and stably maintain the disconnected state after an anomaly occurs. Manual reset is required after troubleshooting, thus solving the problem of repeated device restarts in existing software-based communication management systems and improving device operational stability. Attached Figure Description

[0017] Figure 1 This is a schematic diagram of the structure of the self-locking circuit of an emergency communication device provided in an embodiment of the present invention; Figure 2 This is another structural schematic diagram of the self-locking circuit of the emergency communication device provided in one embodiment of the present invention; Figure 3 This is a schematic diagram of the structure of a protection system for an emergency communication device provided in an embodiment of the present invention; The reference numerals for the accompanying drawings in the specification are as follows: Schmitt trigger; RS latch; Magnetic latching relay; First driving transistor; Second driver transistor; Reset switch; Inverter; Freewheeling diode; Filter capacitors; First resistor; Second resistor; The third resistor; 1. Multi-input module; 101. Power input interface; 102. Communication signal input interface; 103. Power output interface; 104. Communication signal output interface; 2. Core control module; 201. First microcontroller; 3. Self-locking circuit; 4. Emergency communication equipment. Detailed Implementation

[0018] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0019] In the description of this invention, it should be understood that the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated.

[0020] like Figure 1 As shown, to address the problem of repeated device restarts in existing software-based communication management systems, an embodiment of the present invention provides a self-locking circuit for an emergency communication device, comprising: a Schmitt trigger. RS latch Magnetic latching relay First driving transistor Second drive transistor Inverter and reset switch ; Schmitt trigger The signal input terminal is used to receive abnormal signals; Schmitt trigger. The reference voltage terminal is connected to the reference voltage; Schmitt trigger The output terminal is connected to the RS latch The set terminal is connected; RS latch The output terminal is connected to the first driving transistor. The base connection; the first driving transistor collector and magnetic latching relay The set terminal is connected; the first driver transistor. The emitter is grounded; Reset switch The first terminal is grounded; reset switch The second end is connected to an inverter With RS latch Reset terminal connection; RS latch The reset terminal and the second driver transistor The base connection; the second driving transistor collector and magnetic latching relay The reset terminal is connected; the second driver transistor is connected. The emitter is grounded; Magnetic latching relay The output end is connected to the emergency communication equipment.

[0021] Specifically, the working principle of the above self-locking circuit is as follows: In the self-locking circuit of this invention, a Schmitt trigger... The negative input terminal (-) is the signal input terminal, used to receive abnormal signals from external input. (Schmitt trigger) The positive input terminal (+) is the reference voltage terminal; connect the reference voltage. Reference voltage It provides a clear threshold benchmark for the determination of abnormal signals.

[0022] When Schmitt trigger When the signal input terminal receives an abnormal signal, the Schmitt trigger... Compare the voltage of the abnormal signal with the reference voltage. By comparison, if the voltage of the abnormal signal is lower than the reference voltage... Schmitt trigger The output will be high, and this high level will be fed into the RS latch. The set terminal S is used to reset the switch. When in the off state, VCC supplies power to the inverter. Provide a high-level input, which passes through an inverter. The logic inversion outputs a low level, therefore, the RS latch... The reset terminal R is at a low level.

[0023] Under the set condition of S=1 and R=0, the RS latch When set, the output terminal Q goes high and the inverting output terminal Q' goes low. The high level at the Q terminal is then fed into the first driver transistor. The base of the first driving transistor After the base voltage reaches the conduction threshold, the first driving transistor... When the magnetic latching relay is saturated and conducting, current flows from VCC through the magnetic latching relay. The set coil, the first driving transistor The current flows from the collector to the emitter and finally to ground, energizing the set coil and generating a magnetic field, which drives the magnetic latching relay. The internal mechanical contacts switch, causing the normally open contact NO to close, thereby forcibly cutting off the power supply circuit of the emergency communication equipment and achieving hardware-level power-off protection for the equipment.

[0024] Due to magnetic latching relay The contact switching requires only a momentary pulse current and can maintain the contact state after power failure thanks to its internal permanent magnet. The RS latch also has a self-locking characteristic; when both the set terminal S and the reset terminal R are low, the latch will maintain its current state, even if subsequent abnormal signals disappear. The output returns to a low level, RS latch It will remain in the set state of Q=1, causing the first driver transistor to... Maintain conduction to ensure the magnetic latching relay is in operation. The contacts remain in a state of power cut-off, thereby achieving a "self-locking" effect, preventing the equipment from repeatedly restarting due to faults, and avoiding repeated triggering and expansion of faults.

[0025] After maintenance personnel confirm that the malfunction of the emergency communication equipment has been eliminated, they operate the reset switch. This makes the reset switch When the circuit is closed to establish grounding, a low-level signal is sent to the inverter. The input terminal, via an inverter After logic level inversion, a high-level signal is output, which is then fed into the RS latch. The reset terminal R is at this time the Schmitt trigger The signal input has returned to normal, and the output is low, i.e., the RS latch. With the set terminal S=0 and the reset terminal R=1, the RS latch... Reset.

[0026] RS latch After the reset is complete, the output Q level switches from high to low, and the low-level signal is transmitted to the first driver transistor. The base of the first driving transistor... When the base voltage is lower than the turn-on threshold, the first driving transistor... Rapid cut-off, magnetic latching relay When the set coil is de-energized, it stops generating a magnetic field.

[0027] Meanwhile, inverter The high-level output signal is sent to the second driver transistor. The base of the second driving transistor, when the high-level signal reaches the base of the second driving transistor. When the conduction threshold is reached, the second driving transistor When saturated and conducting, current flows from VCC through the reset coil of the magnetic latching relay and the second drive transistor. The collector and emitter are ultimately connected to ground. The reset coil generates a magnetic field under current drive, and the magnetic field interacts with the magnetic latching relay. The interaction of the magnetic fields of the internal permanent magnets drives the internal mechanical contact components to operate, causing the contacts to switch to the return position. The normally open contact NO opens, thus releasing the self-locking state of the self-locking circuit, and the emergency communication equipment is powered on again and enters normal operation mode.

[0028] When an anomaly is detected, this invention immediately disconnects the power supply and maintains a locked state through a hardware self-locking mechanism until maintenance personnel manually press the reset button after on-site inspection, thus restoring normal operation. This prevents repeated restarts after overheating or overcurrent, significantly improving system reliability.

[0029] Furthermore, this invention utilizes hardware triggering for faster response; for example, when millisecond-level or even microsecond-level power surges or overcurrent spikes occur, the Schmitt trigger... Anomalies can be detected within microseconds and an electrical level signal can be output, which is then latched by an RS latch. The magnetic latching relay is triggered immediately, and the entire response process takes only tens of microseconds, which is much faster than solutions that rely on CPU interrupts and software judgment (which usually take tens of milliseconds or even longer). It can cut off the power supply before the fault spreads, avoid secondary damage to the equipment caused by repeated restarts or continuous failures, and effectively prevent the accident from escalating.

[0030] In a preferred embodiment, the self-locking circuit further includes: a freewheeling diode. ; freewheeling diode anode and magnetic latching relay The reset terminal is connected; the freewheeling diode is connected. Cathode and magnetic latching relay The set terminal is connected.

[0031] Specifically, magnetic latching relays Both the set coil and the reset coil are inductive components. When the first driving transistor... Or the second driving transistor When the circuit is suddenly cut off, the current in the coil cannot disappear instantly. According to Lenz's law, the coil will generate an extremely high reverse induced electromotive force. If this electromotive force is not suppressed, it may break down the driver transistor or cause the circuit to malfunction.

[0032] Therefore, a freewheeling diode is added to the above self-locking circuit. By connecting the anode to the reset coil terminal and the cathode to the set coil terminal, a freewheeling circuit is provided for both coils.

[0033] When magnetic latching relay When the set coil is de-energized, the current driven by its reverse electromotive force flows out from the set coil and through the freewheeling diode. The current then flows through the reset coil and finally returns to the set coil to form a complete closed loop, clamping the reverse electromotive force within the forward voltage drop range of the diode. This effectively suppresses the generation of high-voltage spikes and avoids damage to the first driving transistor. Caused breakdown; When magnetic latching relay When the reset coil is de-energized, the current driven by its reverse electromotive force flows out from the reset coil and through the freewheeling diode. The current then flows through the set coil and finally returns to the reset coil to complete the freewheeling, thus protecting the second driver transistor. Protected from high-pressure impacts.

[0034] In this embodiment, a freewheeling diode is added. This not only effectively suppresses the damage of the back electromotive force to the driving transistor, but also reduces electromagnetic interference when the coil is de-energized, and avoids arcing at the magnetic latching relay contacts due to sudden current changes, thereby extending the lifespan of the magnetic latching relay. This extends the service life of the circuit and further enhances the reliability and stability of the entire self-locking circuit.

[0035] In a preferred embodiment, the self-locking circuit further includes: a filter capacitor. ; Filter capacitor The first end and the reset switch The second terminal is connected to the filter capacitor. The second end is grounded.

[0036] Specifically, reset switch Since these are mechanical contacts, mechanical vibration occurs at the moment of closing or opening, causing the contacts to repeatedly open and close and generating high-frequency noise signals. If these signals are directly fed into an inverter... The input terminal is prone to frequent changes in input level, causing the RS latch to... The reset terminal R receives an erroneous pulse, causing the circuit to malfunction.

[0037] Therefore, a filter capacitor is added to the above self-locking circuit. Filter capacitor By connecting one end to a reset switch and the other end to ground, in the reset switch When closed, it discharges rapidly, stabilizing the node voltage and then resetting the switch. After releasing, VCC is the filter capacitor. Slow charging allows the node voltage to rise smoothly. This charging and discharging process can effectively absorb noise generated by mechanical jitter, keep the input level of the inverter stable, and avoid repeated resets of the RS latch. Meanwhile, filter capacitor It can also filter out external electromagnetic interference and power supply noise, further stabilize the input signal of the inverter, and ensure that the reset command is reliably triggered only when the switch is manually operated, thereby improving the stability and anti-interference capability of the entire self-locking circuit reset process.

[0038] In a preferred embodiment, the self-locking circuit further includes: a first resistor. Second resistor and the third resistor ; First resistor The first terminal is connected to VCC; the first resistor The second end is connected to the RS latch The set terminal is connected; Second resistor The first terminal is connected to VCC; the second resistor The second end is connected to the reset switch The second end is connected; RS latch The reset terminal and the second driver transistor The base connection includes: RS latch The reset terminal is connected to the third resistor With the second driving transistor The base connection.

[0039] Specifically, in order to further improve the logic stability, anti-interference capability, and component safety of the self-locking circuit, a first resistor is added to the above-mentioned self-locking circuit. Second resistor and the third resistor .

[0040] First resistor One end is connected to the power supply VCC, and the other end is connected to the RS latch. The set input S of the Schmitt trigger When the output is low, the first resistor It can stabilize the level of the set terminal S at a high level, avoid noise interference introduced by floating, and enhance the driving capability of the RS latch, ensuring reliable input of the set signal and preventing the latch from making logical misjudgments after the abnormal signal disappears.

[0041] Similarly, the second resistor One end is connected to VCC, and the other end is connected to a reset switch. The second end, at the reset switch When disconnected, the second resistor Inverter The input level is pulled high, inverted, and then output low to ensure the RS latch... The reset terminal R remains low when there is no reset operation to prevent the latch from being accidentally reset; in addition, when the reset switch... When closed, the second resistor With filter capacitor An RC charging and discharging circuit is formed, which provides a delay through slow charging to ensure that the reset coil receives a sufficient pulse width to complete a reliable reset. At the same time, it absorbs noise generated by mechanical switch jitter and improves the stability of the reset process.

[0042] Third resistor As a current-limiting isolation resistor, it is connected in series in the RS latch. The reset terminal R and the second driver transistor Between the bases, used to limit the flow into the second drive transistor. The base current is controlled to prevent excessive current from causing the transistor to break down and to ensure the second driver transistor is functioning correctly. It operates in a safe on / off state.

[0043] Meanwhile, the third resistor RS latch can be isolated The output of the transistor is connected to the base of the transistor, which prevents the reverse current of the transistor from affecting the logic level of the latch. It can also reduce the coupling of external electromagnetic interference to the base signal, further improving the anti-interference capability and reliability of the circuit.

[0044] Based on the optimized design of the above optional embodiments, such as Figure 2 The diagram shows another structural schematic of the aforementioned self-locking circuit. This circuit uses a Schmitt trigger. With RS latches and magnetic latching relays at its core, the system achieves rapid detection of abnormal signals, self-locking of fault states, and reliable execution of manual reset through hardware logic. Furthermore, the coordinated design of freewheeling diodes, filter capacitors, and various resistors effectively protects the driving components and relays, reducing electromagnetic interference and mechanical wear. Its self-locking mechanism prevents repeated restarts due to faults, and its rapid response capability can cut off power within microseconds to prevent the accident from escalating. The RC delay and anti-interference design ensure the reliability of the reset process, ultimately significantly improving the stability and safety of emergency communication equipment under extreme conditions.

[0045] like Figure 3As shown, an embodiment of the present invention provides a protection system for an emergency communication device, including: a multi-input module 1, a core control module 2, a self-locking circuit 3, and an emergency communication device 4; wherein, the self-locking circuit 3 is as described in the self-locking circuit of the emergency communication device provided in an embodiment of the present invention; The multi-input module 1 includes: a power input interface 101, a communication signal input interface 102, a power output interface 103, and a communication signal output interface 104; wherein, the power input interface 101 is connected to the power supply of the emergency communication device 4; the communication signal input interface 102 is used to receive the communication signals of the emergency communication device 4. The core control module 2 includes: a first microcontroller 201; a power output interface 103 and a communication signal output interface 104, which are respectively connected to the input terminals of the first microcontroller 201; and the output terminal of the first microcontroller 201 connected to a Schmitt trigger in a self-locking circuit. Connect the signal input terminal; The first microcontroller 201 is used to monitor power supply and communication signals in real time; when an abnormal power supply or communication signal is detected, it sends a signal to the Schmitt trigger in the self-locking circuit 3. The signal input terminal sends an abnormal signal; The self-locking circuit 3 is used to receive abnormal signals sent by the core control module 2, and then, via the magnetic latching relay... 4. The output terminal controls the emergency communication equipment.

[0046] Specifically, based on the aforementioned self-locking circuit, this invention provides a protection system that realizes a closed-loop protection process from abnormal monitoring to rapid power-off, self-locking retention, and reliable reset.

[0047] The multi-input module 1 serves as the hub for signal transfer and status acquisition. It provides power and communication signal transmission to the emergency communication equipment through the power input interface 101 and the communication signal input interface 102, and transmits the power and communication signals to the core control module 2 through the power output interface 103 and the communication signal output interface 104.

[0048] The core control module 2 is based on the first microcontroller 201. In this embodiment, the STM32F103 series microcontroller is used as the main control chip. The first microcontroller 201 continuously performs dynamic analysis on the power supply and communication signals. For the power supply, the power supply voltage is monitored in real time through the ADC analog-to-digital converter. When the power supply voltage is detected to be 0 or exceeds the preset normal range, in this embodiment, a rated value is set, and the preset normal range is within ±15% of the rated value. At this time, it is determined that the power supply path has failed. For the communication signal, the link status register of the communication physical layer chip is read to obtain the physical connection valid signal, such as the Ethernet Link signal, or the level signal of the serial port receive pin is directly detected. If the physical connection valid signal is not detected within the preset timeout period (such as 3 seconds), or no valid data frame conforming to the format is received, it is determined that the communication path has failed.

[0049] It should be noted that the entire fault diagnosis only focuses on whether the basic functions of the link exist, specifically whether the power path is powered or not, and whether the communication path is connected or disconnected. It does not evaluate the quality of communication. Once an anomaly is detected in any path, the first microcontroller 201 will immediately output a high-level pulse as an anomaly signal, which is directly sent to the Schmitt trigger in the self-locking circuit 3. The signal input terminal triggers the subsequent hardware-level protection action of the self-locking circuit 3.

[0050] In the self-locking circuit 3, the Schmitt trigger... The negative input terminal (-) is the signal input terminal, used to receive abnormal signals from external input. (Schmitt trigger) The positive input terminal (+) is the reference voltage terminal; connect the reference voltage. Reference voltage It provides a clear threshold benchmark for the determination of abnormal signals.

[0051] When Schmitt trigger When the signal input terminal receives an abnormal signal, the Schmitt trigger... Compare the voltage of the abnormal signal with the reference voltage. By comparison, if the voltage of the abnormal signal is lower than the reference voltage... Schmitt trigger The output will be high, and this high level will be fed into the RS latch. The set terminal S is used to reset the switch. When in the off state, VCC supplies power to the inverter. Provide a high-level input, which passes through an inverter. The logic inversion outputs a low level, therefore, the RS latch... The reset terminal R is at a low level.

[0052] Under the set condition of S=1 and R=0, the RS latch When set, the output terminal Q goes high and the inverting output terminal Q' goes low. The high level at the Q terminal is then fed into the first driver transistor. The base of the first driving transistor After the base voltage reaches the conduction threshold, the first driving transistor... When the magnetic latching relay is saturated and conducting, current flows from VCC through the magnetic latching relay. The set coil, the first driving transistor The current flows from the collector to the emitter and finally to ground, energizing the set coil and generating a magnetic field, which drives the magnetic latching relay. The internal mechanical contacts switch, causing the normally open contact NO to close, thereby forcibly cutting off the power supply circuit of the emergency communication equipment and achieving hardware-level power-off protection for the equipment.

[0053] Due to magnetic latching relay The contact switching requires only a momentary pulse current and can maintain the contact state after power failure thanks to its internal permanent magnet. The RS latch also has a self-locking characteristic; when both the set terminal S and the reset terminal R are low, the latch will maintain its current state, even if subsequent abnormal signals disappear. The output returns to a low level, RS latch It will remain in the set state of Q=1, causing the first driver transistor to... Maintain conduction to ensure the magnetic latching relay is in operation. The contacts remain in a state of power cut-off, thereby achieving a "self-locking" effect, preventing the equipment from repeatedly restarting due to faults, and avoiding repeated triggering and expansion of faults.

[0054] After maintenance personnel confirm that the malfunction of the emergency communication equipment has been eliminated, they operate the reset switch. This makes the reset switch When the circuit is closed to establish grounding, a low-level signal is sent to the inverter. The input terminal, via an inverter After logic level inversion, a high-level signal is output, which is then fed into the RS latch. The reset terminal R is at this time the Schmitt trigger The signal input has returned to normal, and the output is low, i.e., the RS latch. With the set terminal S=0 and the reset terminal R=1, the RS latch... Reset.

[0055] RS latch After the reset is complete, the output Q level switches from high to low, and the low-level signal is transmitted to the first driver transistor. The base of the first driving transistor... When the base voltage is lower than the turn-on threshold, the first driving transistor... Rapid cut-off, magnetic latching relay When the set coil is de-energized, it stops generating a magnetic field.

[0056] Meanwhile, inverter The high-level output signal is sent to the second driver transistor. The base of the second driving transistor, when the high-level signal reaches the base of the second driving transistor. When the conduction threshold is reached, the second driving transistor When saturated and conducting, current flows from VCC through the reset coil of the magnetic latching relay and the second drive transistor. The collector and emitter are ultimately connected to ground. The reset coil generates a magnetic field under current drive, and the magnetic field interacts with the magnetic latching relay. The interaction of the magnetic fields of the internal permanent magnets drives the internal mechanical contact components to operate, causing the contacts to switch to the return position. The normally open contact NO opens, and at this point, the self-locking state of the self-locking circuit 3 is released, the emergency communication equipment is powered on again, and enters the normal working mode.

[0057] When an abnormality is detected, the self-locking circuit 3 immediately disconnects the power supply and remains locked through the hardware self-locking mechanism until maintenance personnel manually press the reset button after on-site inspection, thus restoring normal operation. This prevents repeated restarts after overheating or overcurrent, significantly improving system reliability.

[0058] Furthermore, the self-locking circuit 3 is hardware-triggered, resulting in a faster response. For example, when a power surge or overcurrent spike occurs at the millisecond or even microsecond level, the Schmitt trigger can detect the anomaly and output a level signal within a few microseconds, which is then latched by the RS latch. The magnetic latching relay is triggered immediately, and the entire response process takes only tens of microseconds, which is much faster than solutions that rely on CPU interrupts and software judgment (which usually take tens of milliseconds or even longer). It can cut off the power supply before the fault spreads, avoid secondary damage to the equipment caused by repeated restarts or continuous failures, and effectively prevent the accident from escalating.

[0059] Preferably, the self-locking circuit 3 further includes: a freewheeling diode. ; freewheeling diode anode and magnetic latching relay The reset terminal is connected; the freewheeling diode is connected. Cathode and magnetic latching relay The set terminal is connected.

[0060] Specifically, both the set coil and reset coil of the magnetic latching relay are inductive components. When the first driving transistor... Or the second driving transistor When the circuit is suddenly cut off, the current in the coil cannot disappear instantaneously. According to Lenz's law, the coil will generate an extremely high reverse induced electromotive force. If this electromotive force is not suppressed, it may damage the driver transistor or cause the circuit to malfunction. Therefore, a freewheeling diode is added to the self-locking circuit 3. By connecting the anode to the reset coil terminal and the cathode to the set coil terminal, a freewheeling circuit is provided for both coils.

[0061] When the set coil is de-energized, the current driven by its reverse electromotive force flows out of the set coil and through the freewheeling diode. The current then flows through the reset coil and finally returns to the set coil to form a complete closed loop, clamping the reverse electromotive force within the forward voltage drop range of the diode and preventing damage to the first driving transistor. This can cause a breakdown; when the reset coil is de-energized, the current driven by its reverse electromotive force will flow out of the reset coil and through the freewheeling diode. The current then flows through the set coil and finally returns to the reset coil to complete the freewheeling, thus protecting the second driver transistor. Protected from high-pressure impacts.

[0062] By adding a freewheeling diode This not only effectively suppresses the damage of the reverse electromotive force to the driving transistor, but also reduces electromagnetic interference when the coil is de-energized, and avoids arcing at the contacts of the magnetic latching relay due to sudden current changes, thereby extending the service life of the magnetic latching relay and further improving the reliability and stability of the entire self-locking circuit 3.

[0063] Preferably, the self-locking circuit 3 further includes: a filter capacitor. ; Filter capacitor The first end and the reset switch The second terminal is connected to the filter capacitor. The second end is grounded.

[0064] Specifically, reset switch Since these are mechanical contacts, mechanical vibration occurs at the moment of closing or opening, causing the contacts to repeatedly open and close and generating high-frequency noise signals. If these signals are directly fed into an inverter... The input terminal is prone to frequent changes in input level, causing the RS latch to... The reset terminal R receives an erroneous pulse, causing the circuit to malfunction. Therefore, a filter capacitor is added to the self-locking circuit 3. Filter capacitor By connecting one end to a reset switch and the other end to ground, in the reset switch When closed, it discharges rapidly, stabilizing the node voltage and then resetting the switch. After releasing, VCC is the filter capacitor. Slow charging allows the node voltage to rise smoothly. This charging and discharging process can effectively absorb noise generated by mechanical jitter, keep the input level of the inverter stable, and avoid repeated resets of the RS latch. Meanwhile, filter capacitor It can also filter out external electromagnetic interference and power supply noise, further stabilize the input signal of the inverter, and ensure that the reset command is reliably triggered only when the switch is manually operated, thereby improving the stability and anti-interference capability of the entire self-locking circuit 3 reset process.

[0065] Preferably, the self-locking circuit 3 further includes: a first resistor. Second resistor and the third resistor ; First resistor The first terminal is connected to VCC; the first resistor The second end is connected to the RS latch The set terminal is connected; Second resistor The first terminal is connected to VCC; the second resistor The second end is connected to the reset switch The second end is connected; RS latch The reset terminal and the second driver transistor The base connection includes: RS latch The reset terminal is connected to the third resistor With the second driving transistor The base connection.

[0066] Specifically, in order to further improve the logic stability, anti-interference capability, and component safety of the self-locking circuit, a first resistor is added to the self-locking circuit 3. Second resistor and the third resistor .

[0067] First resistor One end is connected to the power supply VCC, and the other end is connected to the RS latch. The set input S of the Schmitt trigger When the output is low, the first resistor It can stabilize the level of the set terminal S at a high level, avoid noise interference introduced by floating, and enhance the driving capability of the RS latch, ensuring reliable input of the set signal and preventing the latch from making logical misjudgments after the abnormal signal disappears.

[0068] Similarly, the second resistor One end is connected to VCC, and the other end is connected to a reset switch. The second end, at the reset switch When disconnected, the second resistor Inverter The input level is pulled high, inverted, and then output low to ensure the RS latch... The reset terminal R remains low when there is no reset operation to prevent the latch from being accidentally reset; in addition, when the reset switch... When closed, the second resistor With filter capacitor An RC charging and discharging circuit is formed, which provides a delay through slow charging to ensure that the reset coil receives a sufficient pulse width to complete a reliable reset. At the same time, it absorbs noise generated by mechanical switch jitter and improves the stability of the reset process.

[0069] Third resistor As a current-limiting isolation resistor, it is connected in series in the RS latch. The reset terminal R and the second driver transistor Between the bases, used to limit the flow into the second drive transistor. The base current is controlled to prevent excessive current from causing the transistor to break down and to ensure the second driver transistor is functioning correctly. It operates in a safe on / off state.

[0070] Meanwhile, the third resistor RS latch can be isolated The output of the transistor is connected to the base of the transistor, which prevents the reverse current of the transistor from affecting the logic level of the latch. It can also reduce the coupling of external electromagnetic interference to the base signal, further improving the anti-interference capability and reliability of the circuit.

[0071] In the self-locking circuit 3 of the protection system, a Schmitt trigger is used. With RS latches and magnetically latched relays at its core, the system achieves rapid detection of abnormal signals, self-locking of fault states, and reliable execution of manual reset through hardware logic. Furthermore, the coordinated design of freewheeling diodes, filter capacitors, and various resistors effectively protects the driving components and relays, reducing electromagnetic interference and mechanical wear. The self-locking mechanism of self-locking circuit 3 prevents repeated restarts due to faults, and its rapid response capability can cut off power within microseconds to prevent the accident from escalating. RC delay and anti-interference design ensure the reliability of the reset process. Through the optimized design of the above optional embodiments, the stability and safety of the protection system under extreme operating conditions are significantly improved, ensuring the continuous and reliable operation of critical services.

[0072] The protection system of this invention, through the software logic of the microcontroller, realizes the abnormal monitoring of the power supply and communication links, and provides a precise triggering basis for the high-speed hardware response of the subsequent self-locking circuit, ensuring that the protection is activated at the first time when the power supply or communication is abnormal, and avoiding the spread of the fault and causing irreversible damage to the equipment.

[0073] Compared to pure software protection solutions, the protection system of this invention avoids the inherent risks of software crashes and interruptions through a layered architecture of software monitoring and hardware locking. At the same time, the hardware locking mechanism of the self-locking circuit prevents secondary damage caused by repeated restarts and recovery attempts due to faults. This significantly improves the operational stability and reliability of emergency communication equipment under unattended and extreme conditions, ensuring the continuous availability of critical communication links.

[0074] In a preferred embodiment, the protection system for the emergency communication equipment further includes: an output switching module; the output switching module includes: a second microcontroller; the input terminal of the second microcontroller is connected to the magnetic latching relay in the self-locking circuit 3. The output terminal of the first microcontroller is connected to the output terminal of the second microcontroller, which is connected to several communication interfaces in the emergency communication device 4. A second microcontroller is used to receive a magnetic latching relay. When the output terminal outputs a low level, the communication interface is switched according to the preset interface priority.

[0075] Specifically, based on the aforementioned protection system, an output switching module is added. This module is centered around a second microcontroller, whose input terminal is connected to the magnetic latching relay in the self-locking circuit 3. The output of the first microcontroller is connected to the second microcontroller, while the output of the second microcontroller is connected to several communication interfaces of the emergency communication device 4.

[0076] When the self-locking circuit 3 triggers the protection action, the magnetic latching relay... When the output is low, the second microcontroller will respond immediately and automatically switch the communication link according to the preset communication interface priority. In this embodiment, several communication interfaces include the Tiantong satellite communication interface, the wireless self-organizing network interface based on Mesh technology, and the gigabit fiber optic interface, so as to quickly restore the communication connection when the communication path fails, further improving the link redundancy and fault self-healing capability of the emergency communication equipment, and ensuring the continuous availability of critical communication services.

[0077] In a preferred embodiment, the multiplexer module 1 further includes: a multiplexer; a power input interface 101 including: a main power input interface and a plurality of backup power input interfaces; a power output interface 103 including: a main power output interface and a plurality of backup power output interfaces; the main power output interface and all backup power output interfaces are respectively connected to each input terminal of the multiplexer; the output terminal of the multiplexer is connected to the first microcontroller 201; the main power input interface is connected to the main power supply of the emergency communication equipment; the backup power input interface is connected to the backup power supply of the emergency communication equipment. The communication signal input interface 102 includes a local data input interface and a superior command input interface; the communication signal output interface 104 includes a local data output interface and a superior command output interface; the local data output interface and the superior command output interface are connected in parallel to the first microcontroller 201; the local data input interface is used to receive sensor data from emergency communication equipment; the superior command input interface is used to receive Ethernet command signals from the command center.

[0078] Specifically, based on the aforementioned protection system, the multi-input module 1 adds a multiplexer 105, and redundancy is designed for the power and communication input interfaces, constructing a power supply architecture with primary / backup switching and multi-source complementarity. Specifically: Both the power input interface 101 and the power output interface 103 adopt a primary-backup redundancy architecture. The power input interface 101 includes one primary power input interface and several backup power input interfaces. Correspondingly, the power output interface 103 includes one primary power output interface and several backup power output interfaces. The backup power output interfaces correspond one-to-one with the aforementioned backup power input interfaces to form independent power supply channels, ensuring that each backup power supply can supply power to the system through the corresponding link, thus avoiding mutual interference and switching conflicts between multiple power supplies.

[0079] In practical scenarios, the main power input interface can connect to external main power sources such as vehicle power supplies, generators, or AC-DC converters, serving as the system's primary power source. The backup power input interface can connect to backup power sources such as solar panels, external power banks, UPS systems, or batteries, providing a reliable supplement in case of main power failure. This primary / backup redundancy architecture allows the system to flexibly adapt to different power supply methods based on environmental conditions. For example, in vehicle-mounted scenarios, the vehicle power supply is the primary source, while in remote areas without grid coverage, solar panels or power banks serve as the core power source.

[0080] In this embodiment, the power input interface 101 is configured with three backup power input interfaces, which are respectively connected to a solar panel, an external mobile power supply and a UPS uninterruptible power supply to form a three-level backup power supply team; correspondingly, the power output interface 103 is also configured with three backup power output interfaces, forming a one-to-one independent power supply link with the above three backup power input interfaces.

[0081] It should be noted that the number of backup power input interfaces can be flexibly adjusted according to the actual needs of the scenario. That is, it can be three as in this embodiment, or it can be expanded to more according to the power supply diversity needs of the deployment environment, so as to meet the multi-source power supply guarantee needs under different emergency scenarios.

[0082] All main and backup power input interfaces are connected to the input terminals of the multiplexer. The output terminals of the multiplexer are connected to the first microcontroller 201. The first microcontroller 201 can monitor the voltage and current status of each power supply in real time. When the main power supply experiences an abnormality such as power failure, overvoltage, or undervoltage, it will control the multiplexer to automatically switch to the available backup power input interface. Both power inputs enter independent power protection channels to continuously provide stable power to the emergency communication equipment and the core modules of the system.

[0083] The protection system in this embodiment improves the continuity and reliability of the system power supply by combining primary and backup redundancy with multiple selection.

[0084] Both the communication signal input interface 102 and the communication signal output interface 104 adopt a dual-path parallel redundant design. The communication signal input interface 102 includes a local data input interface and a superior command input interface; the communication signal output interface 104 includes a local data output interface and a superior command output interface. The local data input interface is used to receive sensor data from the emergency communication equipment itself, covering local sensing information such as equipment operating status and environmental monitoring parameters. The superior command input interface is used to receive Ethernet command signals from the command center, supporting the transmission of remote command and dispatch commands.

[0085] The local data output interface and the upper-level command output interface are connected in parallel to the first microcontroller 201 to ensure the synchronization of local status perception and remote command transmission. At the same time, multiple communication signals will enter the communication protection channel composed of multiple independent protection areas. These protection channels are physically isolated on the local PCB, which can protect communication data from different sources such as fiber optic communication signals, Ethernet link signals, and satellite communication module signals, avoiding interference and fault propagation between different signals, thereby improving the reliability and anti-interference capability of the communication link and ensuring the stability and security of data transmission in emergency scenarios.

[0086] In a preferred embodiment, the multi-input module 1 further includes: a first TVS diode, a plurality of second TVS diodes, a first resettable fuse, a plurality of second resettable fuses, a first Zener diode, and a plurality of second Zener diodes; wherein, the main power input interface is connected to the main power output interface in sequence via the first TVS diode, the first resettable fuse, and the first Zener diode; the backup power input interface is connected to the backup power output interface in sequence via the second TVS diode, the second resettable fuse, and the second Zener diode; The multi-input module 1 further includes: a first ESD protection diode, a second ESD protection diode, a first common-mode choke, and a second common-mode choke; wherein, the local data input interface is connected to the local data output interface via the first ESD protection diode and the first common-mode choke in sequence; and the upper-level instruction input interface is connected to the upper-level instruction output interface via the second ESD protection diode and the second common-mode choke in sequence.

[0087] Specifically, based on the aforementioned protection system, the multi-input module 1 adds independent component-level protection circuits for the power and communication input paths, constructing an input safety protection system to ensure the stable operation of the subsequent self-locking circuit. Specifically: On the power input side, the main power input interface and each backup power input interface are equipped with a dedicated protection link. The main power input interface is connected to the main power output interface in sequence through a first TVS diode, a first resettable fuse, and a first Zener diode. The backup power input interface is connected to the backup power output interface in sequence through a second TVS diode, a second resettable fuse, and a second Zener diode. In the protection chain of each power input, TVS diodes serve as the first line of defense, responding rapidly at nanosecond to microsecond speeds to clamp peak voltages within a safe range and prevent high voltage from impacting downstream components in the event of power surges or transient overvoltages. Resetting fuses serve as the second line of defense, quickly transitioning to a high-resistance state during overcurrent, effectively creating a "breakpoint" in the fault path, physically preventing the fault from spreading to the core control module. They also automatically resume conduction after the fault is cleared, requiring no manual intervention and improving system maintainability and continuous operation. Zener diodes serve as the third line of defense, further stabilizing the input voltage within the rated range, filtering out residual ripple, and providing stable power to subsequent self-locking circuits. These multiple layers of protection ensure the safety and stability of each power input.

[0088] On the communication input side, the local data input interface and the upper-level command input interface are also configured with independent protection links. The local data input interface is connected to the local data output interface after passing through the first ESD electrostatic protection diode and the first common-mode choke in sequence. The upper-level command input interface is connected to the local data output interface after passing through the second ESD electrostatic protection diode and the second common-mode choke in sequence. In the protection link of each communication input, the ESD protection diode can quickly release electrostatic discharge energy to prevent environmental electrostatic damage to the communication interface chip; the common mode choke can effectively filter out common mode interference in the communication signal, suppress electromagnetic radiation and conducted interference, improve the anti-interference capability and signal quality of data transmission, and ensure reliable transmission of local data in complex electromagnetic environments.

[0089] By configuring independent component-level protection circuits for the power and communication input paths, the multi-input module achieves dual protection for both power input and communication signal input. This ensures the stability and safety of the power input, preventing damage to the core module from faults such as surges and overcurrents, while also improving the reliability of communication signal transmission. This lays a solid foundation for the stable operation of the subsequent core control module and self-locking circuit, significantly enhancing the stability and safety of the entire emergency communication protection system under complex operating conditions.

[0090] In a preferred embodiment, the core control module 2 further includes: a digital temperature sensor interface; the digital temperature sensor interface is used to receive internal temperature data of the emergency communication device; The first microcontroller is also used to monitor the internal temperature data of emergency communication equipment in real time; when an abnormal internal temperature data is detected, it sends an abnormal signal to the signal input terminal of the Schmitt trigger in the self-locking circuit.

[0091] Specifically, based on the aforementioned protection system, the core control module 2 also integrates a digital temperature sensor interface, which can stably receive internal temperature data from the emergency communication equipment. Preferably, the internal temperature data is filtered to eliminate instantaneous errors caused by electromagnetic interference. The first microcontroller 201 monitors the internal temperature data in real time. When the value reported by the temperature sensor exceeds the safety threshold (e.g., 85°C) and remains above it for more than 3 seconds, it is determined to be an abnormal temperature state. At this time, the first microcontroller 201 immediately sends a signal to the Schmitt trigger in the self-locking circuit 3. Sending an abnormal signal triggers hardware-level protection actions, quickly cutting off the relevant power supply circuits of the equipment, thereby preventing irreversible damage such as core chip burnout and accelerated aging of circuit components caused by prolonged overheating, and further improving the reliability and safety of the system in extreme environments such as high temperature.

[0092] In a preferred embodiment, the first microcontroller 201 is further provided with a diagnostic interface; the diagnostic interface is connected to the emergency communication device 4; the diagnostic interface is used to report the lock status and logs of the emergency communication device 4; receive a remote reset command, and drive a reset switch upon receiving the remote reset command. closure.

[0093] Specifically, based on the aforementioned protection system, the first microcontroller 201 is also equipped with a diagnostic interface capable of data interaction and command parsing. This diagnostic interface supports wired or wireless communication and can connect to maintenance personnel's laptops or remote monitoring platforms such as remote monitoring systems. It can report the device's lock status and logs during device operation in real time, such as abnormal temperature records, communication fault logs, and power fluctuation data. Simultaneously, at the remote control level, the diagnostic interface supports receiving remote reset commands issued by the remote monitoring platform.

[0094] After receiving a remote reset command, the first microcontroller 201 first verifies the validity of the remote reset command and the current status of the device. In the event of a non-hardware level fault, it remotely sends a reset command to control a level-triggered small relay to drive the reset switch. The closed loop enables remote restart of the equipment, eliminating the need for on-site maintenance personnel and significantly improving the maintenance efficiency of emergency communication equipment.

[0095] The above description represents the preferred embodiments of the present invention. It should be noted that those skilled in the art can make various improvements and modifications without departing from the principles of the present invention, and these improvements and modifications are also considered to be within the scope of protection of the present invention.

Claims

1. A self-locking circuit for an emergency communication device, characterized in that, include: Schmitt trigger, RS latch, magnetic latching relay, first driver transistor, second driver transistor, inverter, and reset switch; The signal input terminal of the Schmitt trigger is used to receive abnormal signals; the reference voltage terminal of the Schmitt trigger is connected to a reference voltage; the output terminal of the Schmitt trigger is connected to the set terminal of the RS latch. The output terminal of the RS latch is connected to the base of the first driving transistor; the collector of the first driving transistor is connected to the set terminal of the magnetic latching relay; the emitter of the first driving transistor is grounded. The first terminal of the reset switch is grounded; the second terminal of the reset switch is connected to the reset terminal of the RS latch via an inverter; the reset terminal of the RS latch is connected to the base of the second driving transistor; the collector of the second driving transistor is connected to the reset terminal of the magnetic latching relay; the emitter of the second driving transistor is grounded. The output terminal of the magnetic latching relay is connected to the emergency communication equipment.

2. The self-locking circuit of the emergency communication device according to claim 1, characterized in that, Also includes: Freewheeling diode; The anode of the freewheeling diode is connected to the reset terminal of the magnetic latching relay; the cathode of the freewheeling diode is connected to the set terminal of the magnetic latching relay.

3. The self-locking circuit of the emergency communication device according to claim 2, characterized in that, It also includes: filter capacitors; The first terminal of the filter capacitor is connected to the second terminal of the reset switch; the second terminal of the filter capacitor is grounded.

4. The self-locking circuit of the emergency communication device according to claim 3, characterized in that, Also includes: First resistor, second resistor, and third resistor; The first end of the first resistor is connected to VCC; the second end of the first resistor is connected to the set terminal of the RS latch. The first end of the second resistor is connected to VCC; the second end of the second resistor is connected to the second end of the reset switch. The reset terminal of the RS latch is connected to the base of the second driving transistor, including: The reset terminal of the RS latch is connected to the base of the second driving transistor via a third resistor.

5. A protection system for emergency communication equipment, characterized in that, include: The system comprises a multi-input module, a core control module, a self-locking circuit, and an emergency communication device; wherein the self-locking circuit is the self-locking circuit of the emergency communication device as described in any one of claims 1-4. The multi-input module includes: a power input interface, a communication signal input interface, a power output interface, and a communication signal output interface; wherein, the power input interface is connected to the power supply of the emergency communication equipment; and the communication signal input interface is used to receive communication signals from the emergency communication equipment. The core control module includes: a first microcontroller; the power output interface and the communication signal output interface are respectively connected to the input terminal of the first microcontroller; the output terminal of the first microcontroller is connected to the signal input terminal of the Schmitt trigger in the self-locking circuit; The first microcontroller is used to monitor power supply and communication signals in real time; when an abnormal power supply or communication signal is detected, it sends an abnormal signal to the signal input terminal of the Schmitt trigger in the self-locking circuit. The self-locking circuit is used to receive abnormal signals sent by the core control module and control the emergency communication equipment through the output of the magnetic latching relay.

6. The protection system for emergency communication equipment according to claim 5, characterized in that, Also includes: Output switching module; The output switching module includes: a second microcontroller; the input terminal of the second microcontroller is connected to the output terminal of the magnetic latching relay in the self-locking circuit; the output terminal of the second microcontroller is respectively connected to several communication interfaces in the emergency communication device; The second microcontroller is used to switch the communication interface according to a preset interface priority when it receives a low level output from the output terminal of the magnetic latching relay.

7. The protection system for emergency communication equipment according to claim 5, characterized in that, The multi-input module further includes: a multiplexer; the power input interface includes: a main power input interface and several backup power input interfaces; the power output interface includes: a main power output interface and several backup power output interfaces; the main power output interface and all backup power output interfaces are respectively connected to each input terminal of the multiplexer; the output terminal of the multiplexer is connected to the first microcontroller; the main power input interface is connected to the main power supply of the emergency communication equipment; the backup power input interface is connected to the backup power supply of the emergency communication equipment. The communication signal input interface includes a local data input interface and a superior command input interface; the communication signal output interface includes a local data output interface and a superior command output interface; the local data output interface and the superior command output interface are connected in parallel to the first microcontroller; the local data input interface is used to receive sensor data from emergency communication equipment; the superior command input interface is used to receive Ethernet command signals from the command center.

8. The protection system for emergency communication equipment according to claim 7, characterized in that, The multi-input module further includes: a first TVS diode, a plurality of second TVS diodes, a first resettable fuse, a plurality of second resettable fuses, a first Zener diode, and a plurality of second Zener diodes; wherein, the main power input interface is connected to the main power output interface via the first TVS diode, the first resettable fuse, and the first Zener diode in sequence; the backup power input interface is connected to the backup power output interface via the second TVS diode, the second resettable fuse, and the second Zener diode in sequence; The multi-input module further includes: a first ESD protection diode, a second ESD protection diode, a first common-mode choke, and a second common-mode choke; wherein, the local data input interface is connected to the local data output interface via the first ESD protection diode and the first common-mode choke in sequence; and the upper-level instruction input interface is connected to the upper-level instruction output interface via the second ESD protection diode and the second common-mode choke in sequence.

9. The protection system for emergency communication equipment according to claim 5, characterized in that, The core control module also includes: a digital temperature sensor interface; the digital temperature sensor interface is used to receive internal temperature data from emergency communication equipment; The first microcontroller is also used to monitor the internal temperature data of the emergency communication equipment in real time; when an abnormality is detected in the internal temperature data, it sends an abnormal signal to the signal input terminal of the Schmitt trigger in the self-locking circuit.

10. The protection system for emergency communication equipment according to claim 5, characterized in that, The first microcontroller is also provided with a diagnostic interface; the diagnostic interface is connected to the emergency communication device; the diagnostic interface is used to report the lock status and logs of the emergency communication device; receive remote reset commands, and drive the reset switch to close upon receiving a remote reset command.

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