Power-off system applied to APL cable connection case

Abstract

The invention provides a power-off system applied to an APL cable connection case, a Hall sensor is arranged in a case body and is close to one side wall surface of the case body, and a magnetic body is arranged on the outer side of the case body and is configured to drive the Hall sensor to output an electric signal through a magnetic field of the magnetic body on the outer side of the case body. The signal processing circuit is electrically connected with the Hall sensor and the relay, the relay is further electrically connected with an APL cable of the case body, when the magnetic body moves into a target induction area, the Hall sensor is in an activated state, the signal processing circuit enables the relay to be disconnected, and the relay further controls the APL cable to form an open circuit. And when the magnetic body is separated from the target sensing area and the Hall sensor is in an inactive state, the signal processing circuit enables the relay to be closed, and the relay further controls the APL cable to form an access. On the basis of the invention, the power-on and power-off control of the electronic equipment in the case body can be realized through a non-contact operation method.

Description

Technical Field

[0001] The present invention belongs to the technical field of power-off control for electronic devices, and particularly relates to a power-off system applied to a chassis connected by APL cables. Background Art

[0002] APL (Advanced Physical Layer for Automation Networking) is a standard of IEEE 802.3cg-2019 based on Single-Pair Ethernet (SPE), which is a technology that uses a single-pair twisted-pair cable for both data transmission and power supply simultaneously.

[0003] During the production operation process, due to the possible dust pollution situation at the production site, before opening the electronic device for maintenance, it is first necessary to cut off the power supply of the electronic devices inside the chassis to prevent the risk of explosion and damage caused by the contact between external dust and internal electronic components after the chassis is opened. The conventional way to achieve power-off is to set a power-off device outside the chassis, such as a mechanical power-off switch, and cut off the power supply to the electronic devices by operating the power-off device outside the chassis. However, in the prior art, the conventional power-off device needs to perform operations such as grooving and fixing on the surface of the chassis, which will affect the sealing performance of the chassis and result in the risk of dust explosion inside the chassis. Summary of the Invention

[0004] The present invention aims to provide a power-off system applied to a chassis connected by APL cables to solve the technical problem that in the prior art, the conventional chassis power-off device cannot fully guarantee the sealing performance of the chassis.

[0005] To solve the above problems, the technical solution of the present invention is as follows: A power-off system applied to a chassis connected by APL cables, comprising: A chassis body, it is set that when the chassis body is in a closed state, the internal accommodation chamber thereof is in a relatively sealed state; A magnetic switch assembly, the magnetic switch assembly includes a Hall sensor and a magnetic body. The Hall sensor is arranged in the internal accommodation chamber of the chassis body and is close to one side wall surface of the chassis body. The magnetic body is arranged outside the chassis body and is configured to drive the Hall sensor to output an electrical signal through its own magnetic field outside the chassis body. It is set that the area where the Hall sensor can sense an external magnetic field outside the chassis body is the target sensing area; A signal processing module, the signal processing module is arranged in the internal accommodation chamber of the chassis body. The signal processing module includes a signal processing circuit and a relay. The signal processing circuit is electrically connected to the Hall sensor and the relay respectively, and the relay is also electrically connected to the APL cable of the chassis body; When the magnetic body moves into the target induction area, the Hall sensor is in an active state, the signal processing circuit enables the relay to disconnect, and the relay then controls the APL cable to form an open circuit; when the magnetic body leaves the target induction area and the Hall sensor is in an inactive state, the signal processing circuit enables the relay to close, and the relay then controls the APL cable to form a closed circuit.

[0006] Preferably, the chassis body is provided with an embedded accommodation notch on the outer side wall surface, and the target induction area is located at the bottom of the accommodation notch. When the magnetic body is completely inserted into the accommodation notch, the Hall sensor can sense the magnetic field of the magnetic body.

[0007] Preferably, the signal processing circuit includes a primary signal processing circuit and a secondary signal processing circuit. The primary signal processing circuit is provided with a first inductor and a second inductor. The first end of the first inductor is connected to the positive signal line of the APL cable, and the first end of the second inductor is connected to the negative signal line of the APL cable. The first inductor and the second inductor are used to achieve APL signal decoupling.

[0008] Preferably, the primary signal processing circuit is further provided with a rectifier bridge circuit. The rectifier bridge circuit includes a first diode, a second diode, a third diode, and a fourth diode. The common node of the anodes of the first diode and the third diode is connected to the ground terminal. The negative signal line of the APL cable is connected to the common node of the cathode of the first diode and the anode of the second diode. The positive signal line of the APL cable is connected to the common node of the cathode of the third diode and the anode of the fourth diode. The common node of the cathodes of the second diode and the fourth diode is connected to the APL DC power supply terminal. The rectifier bridge circuit is used to convert APL alternating current into APL direct current.

[0009] Preferably, the secondary signal processing circuit is provided with a comparator. The power supply pin of the Hall sensor is connected to the APL DC power supply terminal, the ground pin of the Hall sensor is connected to the ground terminal, the output pin of the Hall sensor is connected to the non-inverting input terminal of the comparator, and a reference voltage is input to the inverting input terminal of the comparator; When the Hall sensor is in an active state, the Hall sensor changes the voltage value of the output analog electrical signal according to the distance from the magnetic body. When the input voltage at the non-inverting input terminal of the comparator is higher than the reference voltage at its inverting input terminal, the output terminal of the comparator outputs a high level. When the Hall sensor is in an inactive state, the output voltage of the Hall sensor is 0V, the input voltage at the non-inverting input terminal of the comparator is lower than the reference voltage at its inverting input terminal, and the output terminal of the comparator outputs a low level.

[0010] Preferably, the secondary signal processing circuit is provided with a sixth resistor and a seventh resistor. The first end of the sixth resistor is connected to the APL DC power supply terminal. The common node of the second end of the sixth resistor and the first end of the seventh resistor is connected to the inverting input terminal of the comparator. The second end of the seventh resistor is connected to the ground terminal; The sixth resistor and the seventh resistor form a voltage dividing network for providing a reference voltage to the inverting input terminal of the comparator.

[0011] Preferably, the secondary signal processing circuit is provided with an energy storage capacitor and an NMOS transistor. The output terminal of the comparator is connected to the common node of the first end of the energy storage capacitor, the gate of the NMOS transistor, and the relay power supply input terminal. The common node of the second end of the energy storage capacitor and the source of the NMOS transistor is connected to the ground terminal. The drain of the NMOS transistor is connected to the power ground terminal of the relay; When the Hall sensor is in the active state, the comparator outputs a high level, and the energy storage capacitor is charged. When the voltage of the gate of the NMOS transistor relative to the source is greater than the turn-on voltage, the NMOS transistor conducts, and the relay is disconnected. When the Hall sensor is in the non-active state, the comparator outputs a low level, and the voltage of the gate of the NMOS transistor relative to the source is less than the turn-on voltage, and the relay is closed.

[0012] Preferably, the secondary signal processing circuit is provided with a fourth resistor and a fifth resistor. The first end of the fifth resistor is connected to the output terminal of the comparator. The second end of the fifth resistor is connected to the common node of the first end of the fourth resistor and the relay power supply input terminal. The second end of the fourth resistor is connected to the first end of the energy storage capacitor; The fourth resistor and the fifth resistor are used to limit the current amplitude in the secondary signal processing circuit.

[0013] Preferably, the secondary signal processing circuit is provided with a PNP transistor and a third resistor. The emitter of the PNP transistor is connected to the first end of the energy storage capacitor. The collector of the PNP transistor is connected to the first end of the third resistor. The base of the PNP transistor is connected to the second end of the fifth resistor. The second end of the third resistor is connected to the ground terminal; When the Hall sensor is in the active state, the comparator outputs a high level. During the charging process of the energy storage capacitor, the base voltage of the PNP transistor is greater than its emitter voltage, and the PNP transistor is cut off. When the Hall sensor is in the non-active state, the comparator outputs a low level, and the residual voltage of the energy storage capacitor enables the emitter voltage of the PNP transistor to be greater than its base voltage, the PNP transistor conducts, and the energy storage capacitor discharges through the third resistor.

[0014] Due to the adoption of the above technical solutions, the present invention has the following advantages and positive effects compared with the prior art: The present invention provides a power-off system applied to an APL cable connection chassis. A Hall sensor, a signal processing circuit and a relay are provided inside the chassis body, and a magnetic body is provided outside the chassis body. When the magnetic body approaches the target induction area of the chassis body, the Hall sensor changes to an active state, and the operation state of the relay is controlled through the signal processing circuit. The relay further controls the APL cable to be open-circuited, achieving the effect of power-off of the electronic components inside the chassis body. On the contrary, when the magnetic body disengages from the target induction area of the chassis body, the Hall sensor changes to a non-active state, and the operation state of the relay is controlled through the signal processing circuit. The relay further controls the APL cable to be conductive, achieving the effect of power-on of the electronic components inside the chassis body. That is, through the present invention, based on the Hall sensor and the magnetic body, the function of remotely controlling the power-on and power-off of the electronic components inside the chassis body is realized, and there is no need to additionally set a power-off device on the chassis body, effectively improving the sealing performance of the chassis body. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 Structural schematic diagram of a power-off system applied to an APL cable connection chassis provided by the present invention; Figure 2 Structural schematic diagram of the signal processing circuit provided by the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0016] The following further describes in detail a power-off system applied to an APL cable connection chassis proposed by the present invention in conjunction with the accompanying drawings and specific embodiments. The advantages and features of the present invention will be clearer according to the following description and the claims.

[0017] Refer to Figure 1 - Figure 2 , this embodiment provides a power-off system applied to an APL cable connection chassis, which is used to realize the function of non-contact control of the power-on and power-off of the electronic components inside the APL cable connection chassis on the outside of the APL cable connection chassis.

[0018] Specifically, the power-off system applied to the APL cable connection chassis provided in this embodiment mainly includes a chassis body, a magnetic switch assembly, and a signal processing module. An accommodation chamber is provided inside the chassis body, and the accommodation chamber is used to place various electronic devices. An APL cable is passed through the chassis body to realize the power supply and data communication functions of various electronic devices. It is set that when the chassis body is in a closed state, the accommodation chamber inside the chassis body is in a relatively sealed state.

[0019] The magnetic switch assembly includes a Hall sensor and a magnetic body. The Hall sensor is fixedly arranged in a chamber inside the chassis body and close to a side wall of the chassis body. The magnetic body is arranged outside the chassis body and is movable and can be freely carried by the operator. The Hall sensor is preferably a linear Hall sensor. When a magnetic field approaches, the linear Hall sensor will output a voltage value related to the magnetic field strength. That is, in this embodiment, the magnetic body located outside the chassis body can drive the linear Hall sensor to output an electrical signal through its own magnetic field, separated by the side wall of the chassis body, and set the area where the Hall sensor can sense the external magnetic field outside the chassis body as the target sensing area.

[0020] The signal processing module is arranged in the internal accommodating chamber of the chassis body, and includes a signal processing circuit and a relay. The signal processing circuit is electrically connected to the Hall sensor and the relay respectively, and is used to control the on-off working state of the relay according to the output electrical signal of the Hall sensor. The relay is further electrically connected to the APL cable of the chassis body, and is used to further realize the on-off control of the APL cable according to its own on-off working state.

[0021] In summary, this embodiment provides a power-off system for connecting an APL cable to a chassis. When the magnetic body moves into the target sensing area, the Hall sensor is in an activated state and outputs an analog electrical signal. The signal processing circuit enables the relay to switch to a disconnected state according to the electrical signal output by the Hall sensor. The disconnection of the relay controls the APL cable to form a circuit break, that is, the APL cable stops providing power to the electronic equipment inside the chassis body. The electronic equipment is in a power-off state before opening the box, and the chassis body can be opened safely at this time. Conversely, when the chassis body is closed and sealed again, if the magnetic body leaves the target sensing area, the Hall sensor is in an inactive state, the Hall sensor outputs a 0V voltage, and the signal processing circuit enables the relay to switch to a closed state according to the electrical signal output by the Hall sensor. The relay controls the APL cable to form a path, that is, the APL cable supplies power to the electronic equipment inside the chassis body again.

[0022] It can be seen that based on this embodiment, there is no need to set up an additional power-off device on the chassis body. Through the Hall sensor and the magnetic body, non-contact power-on and power-off control of the electronic equipment inside the chassis body can be achieved. When the chassis body is in a closed state, the internal accommodating chamber of the chassis body can be in a relatively sealed state, which effectively improves the safety of the electronic equipment inside the chassis body and prevents the accident of dust explosion. At the same time, in this embodiment, the electronic equipment inside the chassis body is connected to the external power supply equipment and control equipment using APL cables. The twisted pair APL cable can realize the transmission of data and power at the same time, which greatly saves the cable cost and facilitates the construction and installation of on-site operations.

[0023] Next, the specific structure and function of the power-off system applied to the APL cable connection chassis provided in this embodiment will be further described in detail: Preferably, in this embodiment, the chassis body is provided with an embedded receiving notch on the outer wall surface, defining that the target induction area is located in the bottom space of the receiving notch, and the magnetic body is a cylindrical structure. When the magnetic body is completely inserted into the receiving notch, the Hall sensor can sense the magnetic field of the magnetic body, preventing the power-on and power-off operation of the power-off system from being accidentally triggered when the magnetic body approaches the chassis body by mistake.

[0024] Preferably, in this embodiment, the signal processing circuit includes a primary signal processing circuit and a secondary signal processing circuit. The primary signal processing circuit is provided with a first inductor L1 and a second inductor L2. The first end of the first inductor L1 is connected to the APL cable positive signal line APL_+, and the first end of the second inductor L2 is connected to the APL cable negative signal line APL_-. In this embodiment, the first inductor L1 and the second inductor L2 play the role of impedance. For AC signals, the inductor can present a relatively high impedance, thus effectively preventing the passage of AC signals. For DC signals, the impedance of the inductor is relatively low. Therefore, it is ensured that the DC signal can pass smoothly. That is, in this embodiment, the first inductor L1 and the second inductor L2 cooperate to separate the AC signal and the DC signal of the APL cable, so as to achieve the purpose of signal decoupling, suppress the AC signal, and retain the DC signal required for passing through the subsequent signal processing circuit.

[0025] Preferably, in this embodiment, the primary signal processing circuit is further provided with a rectifier bridge circuit. The rectifier bridge circuit includes a first diode D1, a second diode D2, a third diode D3, and a fourth diode D4. The common node of the anodes of the first diode D1 and the third diode D3 is connected to the ground terminal. The APL cable negative signal line APL_- is connected to the common node of the cathode of the first diode D1 and the anode of the second diode D2. The APL cable positive signal line APL_+ is connected to the common node of the cathode of the third diode D3 and the anode of the fourth diode D4. The common node of the cathodes of the second diode D2 and the fourth diode D4 is connected to the APL DC power supply terminal VCC_APL. Among them, the APL DC power supply terminal VCC_APL is used to supply power to the secondary signal processing circuit.

[0026] In this embodiment, the primary suppression of the AC signal is achieved through the first inductor L1 and the second inductor L2, but the AC signal cannot be completely filtered out. Therefore, a rectifier bridge circuit is further provided to convert the APL alternating current into APL direct current, realizing the DC power taking function of the APL cable for use by the secondary signal processing circuit. And setting the rectifier bridge circuit can prevent the reverse connection of the power supply and ensure the power consumption safety of the signal processing circuit and electronic equipment.

[0027] Preferably, in this embodiment, the secondary signal processing circuit is provided with a comparator U1. The power supply pin of the Hall sensor J1_1 is connected to the APL DC power supply terminal VCC_APL, the ground pin of the Hall sensor J1_3 is connected to the ground terminal, and the output pin of the Hall sensor J1_2 is connected to the non-inverting input terminal of the comparator U1. A reference voltage is input to the inverting input terminal of the comparator U1. When the magnetic body approaches the Hall sensor, the Hall sensor can change the voltage value of the output analog electrical signal according to the distance from the magnetic body. That is, the closer the magnetic body is to the Hall sensor, the higher the voltage value of the electrical signal output by the Hall sensor. Conversely, the farther the magnetic body is from the Hall sensor, the lower the voltage value of the electrical signal output by the Hall sensor. It is set that when the magnetic body completely enters the target detection area, the Hall sensor switches to the active state, that is, the voltage value transmitted by the Hall sensor to the comparator U1 makes the input voltage of the non-inverting input terminal of the comparator U1 higher than the reference voltage of its inverting input terminal. At this time, the output terminal of the comparator U1 outputs a high level. It is set that when the magnetic body completely moves out of the target detection area, the Hall sensor is in the non-active state, that is, the output voltage of the Hall sensor is 0V, making the input voltage of the non-inverting input terminal of the comparator U1 lower than the reference voltage of its inverting input terminal, and the output terminal of the comparator U1 outputs a low level.

[0028] In this embodiment, the comparator U1 is used to convert the analog signal directly output by the Hall sensor into a digital signal, that is, to realize the high and low level output, for realizing the control function of the subsequent circuit in the secondary signal processing circuit. And through the comparator U1, when the magnetic body approaches the edge position of the target detection area, since the voltage value of the electrical signal output by the Hall sensor is small, it will not change the output level of the comparator U1. Only when the magnetic body is determined to completely enter the target sensing area, the comparator U1 will output a high level, preventing the power on and off operation of the power off system from being accidentally triggered when the magnetic body approaches the chassis body by mistake.

[0029] Further, in this embodiment, the secondary signal processing circuit is provided with a sixth resistor R6 and a seventh resistor R7. The first end of the sixth resistor R6 is connected to the APL DC power supply terminal VCC_APL, the common node of the second end of the sixth resistor R6 and the first end of the seventh resistor R7 is connected to the inverting input terminal of the comparator U1, and the second end of the seventh resistor R7 is connected to the ground terminal. The sixth resistor R6 and the seventh resistor R7 form a voltage dividing network for providing a reference voltage to the inverting input terminal of the comparator U1.

[0030] Preferably, in this embodiment, the secondary signal processing circuit is provided with a storage capacitor C1 and an NMOS transistor. The output terminal of the comparator U1 is connected to the common node of the first end of the storage capacitor C1, the gate of the NMOS transistor, and the power input terminal of the relay U2. The common node of the second end of the storage capacitor C1 and the source of the NMOS transistor is connected to the ground terminal. The drain of the NMOS transistor is connected to the power ground terminal of the relay U2. In this embodiment, when the magnetic body completely moves into the target induction area and the Hall sensor is in the active state, when the comparator U1 outputs a high level, the storage capacitor C1 is charged. When the voltage of the storage capacitor C1 is higher than the turn-on voltage of the NMOS transistor, that is, the voltage of the gate of the NMOS transistor relative to the source is higher than the turn-on voltage, the NMOS transistor conducts, and the power ground terminal of the relay U2 is grounded, and the relay switches to the off state, thereby controlling the APL cable to be open. When the magnetic body leaves the target induction area and the Hall sensor is in the non-active state, when the comparator U1 outputs a low level, the storage capacitor C1 discharges. When the voltage of the storage capacitor C1 is lower than the turn-on voltage of the NMOS transistor, that is, the voltage of the gate of the NMOS transistor relative to the source is lower than the turn-on voltage, the NMOS transistor is cut off, the power ground terminal of the relay U2 is not grounded, and the relay switches to the closed state, thereby controlling the APL cable to be conductive.

[0031] Furthermore, the secondary signal processing circuit is provided with a fourth resistor R4 and a fifth resistor R5. The first end of the fifth resistor is connected to the output terminal of the comparator U1. The second end of the fifth resistor R5 is connected to the common node of the first end of the fourth resistor R4 and the power input terminal of the relay U2. The second end of the fourth resistor R4 is connected to the first end of the storage capacitor C1. The fourth resistor R4 and the fifth resistor R5 are used to limit the current amplitude in the secondary signal processing circuit to prevent excessive current from damaging the electronic components in the secondary signal processing circuit. At the same time, the fourth resistor R4 and the fifth resistor R5 control the charging time of the storage capacitor C1, and the charging time is the delay time of the power-off operation of the power-off system, preventing the mis-triggering of the power-off system.

[0032] Preferably, in this embodiment, the secondary signal processing circuit is provided with a PNP transistor Q1 and a third resistor R3. The emitter of the PNP transistor Q1 is connected to the first end of the energy storage capacitor C1. The collector of the PNP transistor Q1 is connected to the first end of the third resistor R3. The base of the PNP transistor Q1 is connected to the second end of the fifth resistor R5. The second end of the third resistor R3 is connected to the ground terminal. In this embodiment, when the magnetic body completely moves into the target detection area, the Hall sensor is in an active state, and the comparator U1 outputs a high level. During the charging process of the energy storage capacitor C1, the base voltage of the PNP transistor Q1 is greater than its emitter voltage, and the PNP transistor Q1 is cut off, which does not affect the charging process of the energy storage capacitor C1. When the magnetic body leaves the target detection area, the Hall sensor is in an inactive state, and the comparator U1 outputs a low level. If the energy storage capacitor C1 still has a residual voltage at this time, the energy storage capacitor C1 enables the emitter voltage of the PNP transistor Q1 to be greater than its base voltage, and the PNP transistor Q1 conducts. The energy storage capacitor C1 discharges rapidly through the third resistor R3. Through the settings of the energy storage capacitor C1, the PNP transistor Q1, and the third resistor R3, it is possible to effectively prevent signal fluctuations in the secondary signal processing circuit when the magnetic body approaches or moves away from the target induction area, and effectively improve the stability of the signal processing circuit.

[0033] The embodiments of the present invention have been described in detail above with reference to the accompanying drawings. However, the present invention is not limited to the above embodiments. Even if various changes are made to the present invention, provided that these changes fall within the scope of the claims of the present invention and their equivalent technologies, they still fall within the protection scope of the present invention.

Claims

1. A power-off system for an APL cable connection chassis, characterized in that: include: The chassis body is set to be in a closed state, and the internal accommodating chamber thereof is in a relatively sealed state; A magnetic switch assembly, the magnetic switch assembly comprising a Hall sensor and a magnetic body, the Hall sensor being arranged in an accommodating chamber inside the chassis body and close to a side wall of the chassis body, the magnetic body being arranged outside the chassis body and configured to drive the Hall sensor to output an electrical signal through its own magnetic field outside the chassis body, and setting an area outside the chassis body where the Hall sensor can sense an external magnetic field as a target sensing area; A signal processing module, the signal processing module is arranged in the internal accommodating chamber of the chassis body, the signal processing module includes a signal processing circuit and a relay, the signal processing circuit is electrically connected to the Hall sensor and the relay respectively, and the relay is also electrically connected to the APL cable of the chassis body; When the magnetic body moves into the target sensing area, the Hall sensor is activated, the signal processing circuit enables the relay to be disconnected, and the relay further controls the APL cable to form a circuit breaker; When the magnetic body leaves the target sensing area and the Hall sensor is in an inactive state, the signal processing circuit enables the relay to close, and the relay further controls the APL cable to form a path.

2. The power-off system for APL cable connection chassis as claimed in claim 1, characterized in that: The chassis body is provided with an embedded receiving slot on the outer wall surface, and the target sensing area is located at the bottom of the receiving slot. When the magnetic body is fully inserted into the receiving slot, the Hall sensor can sense the magnetic field of the magnetic body.

3. The power-off system for APL cable connection chassis according to claim 1, characterized in that: The signal processing circuit includes a primary signal processing circuit and a secondary signal processing circuit. The primary signal processing circuit is provided with a first inductor and a second inductor. The first end of the first inductor is connected to the positive signal line of the APL cable, and the first end of the second inductor is connected to the negative signal line of the APL cable. The first inductor and the second inductor are used to realize APL signal decoupling.

4. The power-off system for APL cable connection chassis as claimed in claim 3, characterized in that: The primary signal processing circuit is also provided with a rectifier bridge circuit, which includes a first diode, a second diode, a third diode and a fourth diode, the common node of the anode of the first diode and the anode of the third diode is connected to the ground terminal, the negative signal line of the APL cable is connected to the common node of the cathode of the first diode and the anode of the second diode, the positive signal line of the APL cable is connected to the common node of the cathode of the third diode and the anode of the fourth diode, the common node of the cathode of the second diode and the cathode of the fourth diode is connected to the APL DC power supply terminal, and the rectifier bridge circuit is used to convert the APL alternating current into the APL direct current.

5. The power-off system for APL cable connection chassis as claimed in claim 4, characterized in that: The secondary signal processing circuit is provided with a comparator, the power pin of the Hall sensor is connected to the APL DC power supply terminal, the ground pin of the Hall sensor is connected to the ground terminal, the output pin of the Hall sensor is connected to the non-inverting input terminal of the comparator, and the inverting input terminal of the comparator inputs a reference voltage; When the Hall sensor is in an activated state, the Hall sensor changes the voltage value of the analog electrical signal output according to the distance from the magnetic body. When the input voltage of the comparator's non-inverting input terminal is higher than the reference voltage of its inverting input terminal, the output terminal of the comparator outputs a high level. When the Hall sensor is in an inactive state, the Hall sensor outputs a voltage of 0V, the input voltage of the comparator's non-inverting input terminal is lower than the reference voltage of its inverting input terminal, and the output terminal of the comparator outputs a low level.

6. The power-off system for APL cable connection chassis as claimed in claim 5, characterized in that: The secondary signal processing circuit is provided with a sixth resistor and a seventh resistor, the first end of the sixth resistor is connected to the APL DC power supply end, the common node of the second end of the sixth resistor and the first end of the seventh resistor is connected to the inverting input end of the comparator, and the second end of the seventh resistor is connected to the ground end; The sixth resistor and the seventh resistor form a voltage divider network for providing a reference voltage to the inverting input terminal of the comparator.

7. The power-off system for APL cable connection chassis as claimed in claim 5, characterized in that: The secondary signal processing circuit is provided with an energy storage capacitor and an NMOS tube, the output end of the comparator is connected to the common node of the first end of the energy storage capacitor, the gate of the NMOS tube and the power input end of the relay, the common node of the second end of the energy storage capacitor and the source of the NMOS tube is connected to the ground end, and the drain of the NMOS tube is connected to the power ground end of the relay; When the Hall sensor is in an activated state, the comparator outputs a high level, the energy storage capacitor is charged, and when the voltage of the NMOS tube gate relative to the source is greater than the turn-on voltage, the NMOS tube is turned on and the relay is disconnected; when the Hall sensor is in an inactive state, the comparator outputs a low level, the voltage of the NMOS tube gate relative to the source is less than the turn-on voltage, and the relay is closed.

8. The power-off system for APL cable connection chassis as claimed in claim 7, characterized in that: The secondary signal processing circuit is provided with a fourth resistor and a fifth resistor, the first end of the fifth resistor is connected to the output end of the comparator, the second end of the fifth resistor is connected to the common node of the first end of the fourth resistor and the input end of the relay power supply, and the second end of the fourth resistor is connected to the first end of the energy storage capacitor; The fourth resistor and the fifth resistor are used to limit the current amplitude in the secondary signal processing circuit.

9. The power-off system for APL cable connection chassis as claimed in claim 8, characterized in that: The secondary signal processing circuit is provided with a PNP tube and a third resistor, the emitter of the PNP tube is connected to the first end of the energy storage capacitor, the collector of the PNP tube is connected to the first end of the third resistor, the base of the PNP tube is connected to the second end of the fifth resistor, and the second end of the third resistor is connected to the ground end; When the Hall sensor is in an activated state, the comparator outputs a high level. During the charging process of the energy storage capacitor, the base voltage of the PNP tube is greater than its emitter voltage, and the PNP tube is cut off. When the Hall sensor is in an inactive state, the comparator outputs a low level. The residual voltage of the energy storage capacitor enables the emitter voltage of the PNP tube to be greater than its base voltage, the PNP tube is turned on, and the energy storage capacitor is discharged through the third resistor.

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