Grounding detection and protection circuit and method based on safety switch

Abstract

The embodiment of the application relates to the field of circuit safety detection control, and discloses a ground conduction detection and protection circuit based on a safety switch, which comprises a safety switch module, a verification detection switch K0, a sampling module, a threshold value logic conversion module and a detection module. The safety switch module comprises a first safety switch S0, a second safety switch S1 and an optocoupler U1, the S0 is connected in series with a first end of a power supply, the S1 is connected in series with a second end of the power supply, the S0 and the S1 are connected to the U1, and the U1 is connected to the detection module. The K0 is connected in series to a circuit and outputs a periodic pulse signal. The sampling module comprises a first sampling resistor RS1 and a second sampling resistor RS2, and the RS1 and the RS2 are connected in series. The threshold value logic conversion module is connected to the detection module and is used for converting a voltage between the sampling resistors into a digital signal after comparison with a threshold value. The detection module is used for detecting ground conduction conditions of the S0 and the S1, and improves safety detection and protection mode reliability.

Description

Technical Field

[0001] This application relates to the field of circuit safety detection, and in particular to a circuit and method for detecting and protecting ground continuity based on a safety switch. Background Technology

[0002] Currently, there are basically two methods for detecting short circuits to ground in elevator safety switches. One method is to detect leakage current to check for ground continuity. This method uses a high-voltage AC safety circuit, but the high voltage peak of the AC safety circuit poses a risk of electric shock. The other method uses a low-voltage DC safety circuit. One end of the safety circuit is grounded and a fuse is connected in series. When any node in the safety circuit is short-circuited to ground, the fuse blows, cutting off the safety circuit and the traction machine power supply. The problem with this method is that the low-voltage DC power supply has a hiccup protection function. When a short circuit is detected, the power output will be automatically cut off, and the power output will be restored after the short circuit disappears. This does not meet the elevator standard requirement that the elevator must be manually reset after a short circuit to ground. Furthermore, when the safety switch becomes conductive to ground, it can cause both the safety circuit and the system power supply to fail simultaneously.

[0003] Therefore, there is an urgent need for a new type of ground continuity detection and protection circuit and method based on safety switches, which can achieve the technical effect that ground continuity detection is not limited by the safety circuit voltage, the protection method is safe and reliable, and the safety circuit and system power supply will not fail when the safety switch is connected to ground. Summary of the Invention

[0004] The purpose of this application is to provide a ground continuity detection and protection circuit and method based on a safety switch. The ground continuity detection and protection circuit and method of this application can achieve the technical effect that ground continuity detection is not limited by the voltage of the safety circuit, the safety detection and protection method is safe and reliable, and the safety circuit and system power supply will not fail when the safety switch is connected to ground.

[0005] To address the aforementioned technical problems, embodiments of this application provide a ground continuity detection and protection circuit based on a safety switch, comprising a safety switch module, a verification and detection switch K0, a sampling module, a TLC (Threshold Logic Converter, TLC) module, and a detection module. The safety switch module includes a first safety switch S0, a second safety switch S1, and an optocoupler U1. The first safety switch S0 is connected in series with a first terminal of the power supply, and the second safety switch S1 is connected in series with a second terminal of the power supply. Both the first safety switch S0 and the second safety switch S1 are connected to the optocoupler U1, which is connected to the detection module. The verification and detection switch K0 is connected in series in the circuit and outputs a periodic pulse signal to detect whether the circuit is functioning correctly. The sampling module includes a first sampling resistor RS1 and a second sampling resistor RS2, which are connected in series to analyze the power supply voltage. The voltage is provided to the threshold logic conversion module. The threshold logic conversion module includes a first threshold logic converter TLC1 and a second threshold logic converter TLC2. The threshold logic conversion module is connected to the detection module. The first threshold logic converter TLC1 is used to compare the voltage across the first sampling resistor RS1 with a threshold and perform logic conversion to obtain a digital signal. The second threshold logic converter TLC2 is used to compare the voltage across the second sampling resistor RS2 with a threshold and perform logic conversion to obtain a digital signal. The detection module includes a safety input interface X0, a first input interface XS1, and a second input interface XS2, used to detect the grounding status of the first safety switch S0 and the second safety switch S1.

[0006] As described above, in the ground continuity detection and protection circuit based on a safety switch, the detection module is further used to detect the input signal of the safety input interface X0 and the signal of the verification detection switch K0. When the first safety switch S0 is closed and the second safety switch S1 is closed, if the input signal of the safety input interface X0 is the same as the signal of the verification detection switch K0, the circuit is determined to be normal. When the first safety switch S0 and / or the second safety switch S1 is open, if the safety input interface X0 has no input, the circuit is determined to be normal.

[0007] As described above, in the ground continuity detection and protection circuit based on a safety switch, the detection module is further configured to determine whether the first safety switch S0 at the first end of the power supply is connected to ground based on the signal from the first input interface XS1; and to determine whether the second safety switch S1 at the second end of the power supply is connected to ground based on the signal from the second input interface XS2.

[0008] As described above, in the ground continuity detection and protection circuit based on a safety switch, the signal of XS1 is a digital signal obtained by converting the voltage across the first sampling resistor RS1 through the first threshold logic converter TLC1, and the signal of XS2 is a digital signal obtained by converting the voltage across the second sampling resistor RS2 through the second threshold logic converter TLC2.

[0009] The ground continuity detection and protection circuit based on the safety switch described above includes multiple safety modules in the multiple ground continuity detection and protection circuits based on the safety switch; the multiple safety modules in the multiple ground continuity detection and protection circuits based on the safety switch are connected in series.

[0010] An embodiment of the present invention also provides a method for detecting and protecting ground continuity based on a safety switch, applied to the circuit described in the previous embodiment, including acquiring the input signal of the safety input interface X0 of the detection module; detecting whether the circuit is normal based on the input signal of X0; acquiring the signal of the first input interface XS1 of the detection module, and determining whether the first safety switch S0 at the first end of the power supply is connected to ground based on the signal of XS1; acquiring the signal of the second input interface XS2 of the detection module, and determining whether the second safety switch S1 at the second end of the power supply is connected to ground based on the signal of XS2.

[0011] As described above, the method for detecting and protecting ground continuity based on a safety switch includes the following steps: when the first safety switch S0 is closed and the second safety switch S1 is closed, if the input signal of X0 is detected to be the same as the output signal of the verification switch K0, then the circuit is determined to be normal; when the first safety switch S0 and / or the second safety switch S1 is open, if no input signal is detected for X0, then the circuit is determined to be normal.

[0012] As described above, the method for detecting and protecting ground continuity based on a safety switch includes the following steps: First, acquiring the signal from the first input interface XS1 of the detection module and determining whether the first safety switch S0 at the first power supply terminal is connected to ground based on the signal from XS1. Specifically, when the first safety switch S0 is closed and the second safety switch S1 is closed, the detection module detects that the waveform of the safety input interface X0 is the same as the waveform output by the verification detection switch K0. If there is input at the XS1 interface, the first safety switch S0 at the first power supply terminal is not connected to ground; if there is no input at the XS1 interface, it is determined that the first safety switch S0 at the first power supply terminal is connected to ground. Second, when the first safety switch S0 and / or the second safety switch S1 are open, the detection module detects that there is no input at the safety input interface X0. If there is input at the XS1 interface, the first safety switch S0 at the first power supply terminal is not connected to ground; if there is no input at the XS1 interface, it is determined that the second safety switch S0 at the first power supply terminal is connected to ground.

[0013] The ground continuity detection and protection method based on a safety switch as described above involves acquiring the signal from the second input interface XS2 of the detection module and determining whether the second safety switch S1 at the second end of the power supply is connected to ground based on the signal from XS2. This includes: when the first safety switch S0 is closed and the second safety switch S1 is closed, the detection module detects that the waveform of the input signal from the safety input interface X0 of the detection module is the same as the waveform output by the verification detection switch K0. If there is input from the XS2 interface, then the second safety switch S1 at the second end of the power supply is not connected to ground. If there is no input from the XS2 interface, then the second safety switch S1 at the second end of the power supply is connected to ground. When the first safety switch S0 and / or the second safety switch S1 is open, the detection module detects that there is no input from the safety input interface X0 of the detection module. If there is input from the XS2 interface, then the first safety switch S1 at the second end of the power supply is not connected. If there is no input from the XS2 interface, then the second safety switch S1 at the second end of the power supply is connected to ground.

[0014] As described above, in the ground continuity detection and protection method based on a safety switch, the signal of the detection module interface XS1 is a digital signal obtained by converting the voltage across the first sampling resistor RS1 through the first threshold logic converter TLC1, and the signal of the detection module interface XS2 is a digital signal obtained by converting the voltage across the second sampling resistor RS2 through the second threshold logic converter TLC2.

[0015] In this embodiment, voltage is divided by the first sampling resistor RS1 and the second sampling resistor RS2. The threshold logic conversion module converts the divided voltage into a digital signal. The digital signal output by the threshold logic conversion module is used for ground continuity detection, realizing detection using extra-low voltage, which is not limited by the voltage of the safety circuit. The second terminal of the power supply does not need to be grounded, the entire circuit has high safety, and the protection method is safe and reliable. The ground continuity of the first safety switch S0 at the first terminal of the power supply and the second safety switch S1 at the second terminal of the power supply can be detected independently. When the safety switch is connected to ground, the safety circuit and the system power supply will not fail. Attached Figure Description

[0016] One or more embodiments are illustrated by way of example with reference to the accompanying drawings. These illustrations do not constitute a limitation on the embodiments, and unless otherwise stated, the figures in the drawings are not to be limited by scale.

[0017] Figure 1 This is a schematic diagram of a ground continuity detection and protection circuit based on a safety switch provided in one embodiment of this application;

[0018] Figure 2 This is a circuit diagram showing the safety switch at the first terminal of the power supply being connected to ground, according to an embodiment of this application.

[0019] Figure 3 This is a signal timing diagram of the safety switch at the first terminal of the power supply being connected to ground, provided in one embodiment of this application.

[0020] Figure 4 This is a circuit diagram showing the safety switch at the second terminal of the power supply being connected to ground, according to an embodiment of this application.

[0021] Figure 5 This is a signal timing diagram of the safety switch at the second terminal of the power supply being connected to ground, provided in one embodiment of this application;

[0022] Figure 6 This is a circuit diagram showing multiple safety switch-based ground continuity detection and protection circuits connected in series, provided in one embodiment of this application.

[0023] Figure 7 This is a flowchart illustrating a ground continuity detection and protection method based on a safety switch, provided in one embodiment of this application. Detailed Implementation

[0024] In related technologies, there are two methods for detecting short circuits to ground in the safety switches of elevator safety circuits. The first method is to detect leakage current using a high-voltage AC safety circuit. However, the high voltage peak of the high-voltage AC safety circuit poses a risk of electric shock. The second method involves grounding one end of the safety circuit and connecting a fuse in series. When any node in the safety circuit short-circuits to ground, the fuse blows, cutting off the safety circuit and the traction machine power supply. This method uses a low-voltage DC safety circuit for detection. The low-voltage DC power supply has a hiccup protection function; when a short circuit is detected, it automatically cuts off the power output and restores the power output after the short circuit disappears. This does not meet the elevator standard requirement that the elevator must be manually reset after a short circuit to ground. Furthermore, both detection methods in these technologies will cause the safety circuit and system power supply to fail simultaneously if the safety switch becomes conductive to ground, leading to safety hazards.

[0025] To address the aforementioned issues, this application proposes a ground continuity detection and protection circuit based on a safety switch, comprising a safety switch module, a verification and detection switch K0, a sampling module, a threshold logic conversion module, and a detection module. The safety switch module includes a first safety switch S0, a second safety switch S1, and an optocoupler U1. The first safety switch S0 is connected in series with a first power supply terminal, and the second safety switch S1 is connected in series with a second power supply terminal. Both the first and second safety switches S0 and S1 are connected to the optocoupler U1, which is connected to the detection module. The verification and detection switch K0 is connected in series in the circuit and outputs a periodic pulse signal to detect whether the circuit is functioning correctly. The sampling module includes a first sampling resistor RS1 and a second sampling resistor RS2. The sampling resistor RS2 is connected in series to divide the power supply voltage, providing voltage to the threshold logic conversion module. The threshold logic conversion module includes a first threshold logic converter TLC1 and a second threshold logic converter TLC2, which are connected to the detection module. The first threshold logic converter TLC1 compares the voltage across the first sampling resistor RS1 with a threshold value to perform logic conversion and obtain a digital signal. The second threshold logic converter TLC2 compares the voltage across the second sampling resistor RS2 with a threshold value to perform logic conversion and obtain a digital signal. The detection module includes a safety input interface X0, a first input interface XS1, and a second input interface XS2, used to detect the grounding status of the first safety switch S0 and the second safety switch S1.

[0026] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the various embodiments of this application will be described in detail below with reference to the accompanying drawings. However, those skilled in the art will understand that many technical details have been provided in the various embodiments of this application to help readers better understand this application. However, the technical solutions claimed in this application can be implemented even without these technical details and various changes and modifications based on the following embodiments. The division of the various embodiments below is for the convenience of description and should not constitute any limitation on the specific implementation of this application. The various embodiments can be combined with and referenced by each other without contradiction.

[0027] Figure 1 This is a schematic diagram of a ground continuity detection and protection circuit based on a safety switch according to an embodiment of this application. The implementation details of the ground continuity detection and protection circuit based on a safety switch in this embodiment are described in detail below. The following implementation details are provided for ease of understanding only and are not necessary for implementing this solution.

[0028] This embodiment features a ground continuity detection and protection circuit based on a safety switch, such as... Figure 1 As shown, it includes a safety switch module, a verification and detection switch K0, a sampling module, a threshold logic conversion module, and a detection module.

[0029] The safety switch module in this embodiment includes a first safety switch S0, a second safety switch S1, and an optocoupler U1.

[0030] A safety switch is a switch that prevents personnel from entering a hazardous area until all safety conditions are met. There are various types, including latch switches, safety magnetic switches, safety door lock switches, safety pull-cord switches, emergency stop buttons, hinged interlock switches, safety enable switches, safety limit switches, and explosion-proof switches. In the embodiments of this application, the first safety switch S0 is connected in series with the first terminal of the power supply, and the second safety switch S1 is connected in series with the second terminal of the power supply. Both the first safety switch S0 and the second safety switch S1 are connected to the optocoupler U1, and the optocoupler U1 is connected to the detection module to form a detection circuit.

[0031] The power supply in this embodiment can be a DC power supply or an AC power supply; there is no limitation here. When the power supply is a DC power supply, the first terminal of the power supply can be the positive terminal, and the second terminal of the power supply can be the negative terminal.

[0032] In this embodiment, the verification and detection switch K0 is connected in series in the circuit and outputs a periodic pulse signal to detect whether the circuit is functioning correctly. The verification and detection switch K0 can be connected to any position in the detection loop.

[0033] In the embodiments of this application, the verification detection switch K0 is connected to the detection circuit in series and outputs a periodic pulse signal. The periodic pulse signal can be a rectangular wave signal, a square wave signal, or other periodic pulse signals, and there are no restrictions on it.

[0034] The sampling module includes a first sampling resistor RS1 and a second sampling resistor RS2. In the embodiments of this application, the first sampling resistor RS1 and the second sampling resistor RS2 are connected in series and can be connected between the first and second terminals of the power supply to divide the power supply voltage and provide input voltage for the threshold logic conversion module.

[0035] In the embodiments of this application, the resistance values ​​of the first sampling resistor RS1 and the second sampling resistor RS2 may be equal or unequal, and no limitation is made here.

[0036] A threshold logic converter is a circuit or device based on threshold logic. It determines the output state by comparing the weighted sum of the input signals with a pre-set threshold. Its basic function is to perform logical processing on the input signals, generating a specific output when a certain combination of the input signals reaches or exceeds a specific threshold.

[0037] Threshold logic converters typically have multiple input ports, each receiving one signal. These input signals are first assigned different weights, the magnitude of which determines the degree of influence each input signal has on the final result. For example, in a threshold logic converter with three input signals A, B, and C, suppose the weight of A is 2, the weight of B is 3, and the weight of C is 1. Each input signal is multiplied by its corresponding weight and then summed to obtain a weighted sum. For example, if input signals A=1, B=0, and C=1, the weighted sum is 2*1 + 3*0 + 1*1 = 3. The resulting weighted sum is compared with a pre-set threshold. If the weighted sum is greater than or equal to the threshold, the output is high or logic 1; if the weighted sum is less than the threshold, the output is low or logic 0. For example, if the threshold is set to 2, then in the above example, the weighted sum 3 is greater than the threshold 2, and the output is 1.

[0038] In an embodiment of this application, the threshold logic conversion module includes a first threshold logic converter TLC1 and a second threshold logic converter TLC2. The threshold logic conversion module is connected to the detection module. The first threshold logic converter TLC1 is used to compare the voltage across the sampling resistor RS1 with a threshold and perform logic conversion to obtain a digital signal. The digital signal is a 0 / 1 signal. Specifically, when the input voltage of the first threshold logic converter TLC1 is not lower than the first threshold, the first threshold logic converter TLC1 outputs a signal 1; when the input voltage of the first threshold logic converter TLC1 is lower than the first threshold, the first threshold logic converter TLC1 outputs a signal 0.

[0039] The second threshold logic converter TLC2 is used to compare the voltage across the second sampling resistor RS2 with a threshold and perform logic conversion to obtain a digital signal. The digital signal is a 0 / 1 signal. Specifically, when the input voltage of the second threshold logic converter TLC2 is not lower than the second threshold, the second threshold logic converter TLC2 outputs a signal 1; when the input voltage of the second threshold logic converter TLC2 is lower than the second threshold, the second threshold logic converter TLC2 outputs a signal 0.

[0040] The first threshold and the second threshold can be equal or unequal, and their values ​​can be set according to the actual situation. No restrictions are imposed here.

[0041] The detection module in this embodiment includes a safety input interface X0, a first input interface XS1, and a second input interface XS2, used to detect the ground continuity of the first safety switch S0 and the second safety switch S1.

[0042] Specifically, the detection module can be an MCU.

[0043] In the embodiments of this application, the first safety switch S0 is connected to the first input interface of the optocoupler U1. The signal passes through the first safety switch S0 and is input to the optocoupler U1 from the first input interface of the optocoupler U1. The output signal of the optocoupler U1 is input to the detection module via X0.

[0044] In embodiments of this application, the detection module is further configured to detect the input signal of X0 and determine whether the circuit is functioning correctly.

[0045] When the first safety switch S0 is closed and the second safety switch S1 is closed, if the input signal of X0 is the same as the signal of the verification and detection switch K0, then the circuit is determined to be normal.

[0046] Specifically, when both the first safety switch S0 and the second safety switch S1 of the safety switch module are closed, the input signal of the safety input interface X0 is detected. If the waveform of the input signal of X0 is the same as the waveform output by the verification detection switch K0, then the circuit is normal. (See also...) Figure 3 and Figure 5 The waveform diagram shows that when the signals S0 and S1 are at high level, the waveform of X0 is consistent with the waveform of K0, indicating that the detection circuit is normal.

[0047] If the safety input interface X0 has no input signal when the first safety switch S0 and / or the second safety switch S1 is open, the circuit is determined to be normal.

[0048] Specifically, when either the first safety switch S0 or the second safety switch S1 of the safety switch module is open, the input signal of the safety input interface X0 of the detection module is detected. If there is no input signal at X0, the circuit is normal. (See also...) Figure 3 and Figure 5 The waveform diagram shows that when the S0 or S1 signal is low, X0 is also low, indicating that the detection circuit is normal.

[0049] In embodiments of this application, the detection module is further configured to detect the signals of the first input interface XS1 and the second input interface XS2, and determine whether the first safety switch S0 and the second safety switch S1 are connected to ground. Figure 1 As shown, specifically, the output terminal of the first threshold logic converter TLC1 is connected to the first input interface XS1 of the detection module. The detection module determines whether the first safety switch S0 at the first end of the power supply is connected to ground by detecting the signal of XS1. The output terminal of the second threshold logic converter TLC2 is connected to the second input interface XS2 of the detection module. The detection module determines whether the second safety switch S1 at the second end of the power supply is connected to ground by detecting the signal of XS2.

[0050] In the embodiments of this application, when the first safety switch S0 is closed and the second safety switch S1 is closed, the detection module detects the input signal of the safety input interface X0 of the detection module. If the waveform of the input signal of X0 is the same as the waveform output by the verification detection switch K0, then the circuit is normal. At this time, if there is input at the XS1 interface, that is, the first threshold logic converter TLC1 outputs a digital signal 1, therefore the voltage across the TLC1 is not lower than the first threshold, and the voltage across the first sampling resistor RS1 is not 0. Figure 1 It can be seen that if one side of the first sampling resistor RS1 is grounded, then the first terminal of the power supply is not grounded. Therefore, the first safety switch S0 at the first terminal of the power supply does not have a grounding phenomenon. (See [reference]). Figure 3 In the waveform diagram, S0 is at a high level, and XS1 is also at a high level. If there is no input to the XS1 interface, that is, the first threshold logic converter TLC1 outputs a digital signal of 0, therefore the voltage across TLC1 is lower than the first threshold, and the voltage across the first sampling resistor RS1 is 0. Figure 1 It can be seen that one side of the first sampling resistor RS1 is grounded, therefore the first terminal of the power supply is also grounded. Therefore, it is determined that the first safety switch S0 at the first terminal of the power supply is connected to ground. (See [reference]). Figure 3 In the waveform diagram, S0 is the high level and XS1 is the low level segment.

[0051] In the embodiments of this application, when the first safety switch S0 and / or the second safety switch S1 are open, the detection module detects that there is no input at the X0 interface of the detection module, then the circuit is normal. At this time, if there is input at the XS1 interface, that is, the first threshold logic converter TLC1 outputs a digital signal 1, therefore the voltage across the TLC1 is not lower than the first threshold, and the voltage across the first sampling resistor RS1 is not 0. Figure 1 It can be seen that if one side of the first sampling resistor RS1 is grounded, then the first terminal of the power supply is not grounded. Therefore, the first safety switch S0 at the first terminal of the power supply has no grounding phenomenon. At this time, if the XS1 interface has no input, that is, the first threshold logic converter TLC1 outputs a digital signal 0, the voltage across the TLC1 is lower than the first threshold, and the voltage across the first sampling resistor RS1 is 0. Figure 1 It can be seen that one side of the first sampling resistor RS1 is grounded, therefore the first terminal of the power supply is also grounded, indicating that the first safety switch S0 at the first terminal of the power supply is connected to ground. The circuit diagram showing the first safety switch S0 being connected to ground is shown below. Figure 2 As shown, the grounding point of the first safety switch S0 can be any point between the first power supply terminal and the optocoupler U1, and there is no restriction here.

[0052] In the embodiments of this application, when the first safety switch S0 is closed and the second safety switch S1 is closed, the detection module detects that the waveform of the safety input interface X0 of the detection module is the same as the waveform output by the verification detection switch K0, then the circuit is normal. At this time, if there is input at the XS2 interface, that is, the second threshold logic converter TLC2 outputs a digital signal 1, therefore the voltage across the TLC2 is not lower than the second threshold, and the voltage across the second sampling resistor RS2 is not 0. Figure 1 It can be seen that if one side of the second sampling resistor RS2 is grounded, then the second terminal of the power supply is not grounded. Therefore, the second safety switch S1 at the second terminal of the power supply does not have a ground connection. (See [reference]). Figure 5In the waveform diagram, S1 is at a high level, and XS2 is also at a high level. If there is no input to the XS2 interface, meaning the second threshold logic converter TLC2 outputs a digital signal of 0, the voltage across TLC2 is lower than the second threshold, and the voltage across the second sampling resistor RS2 is 0. Figure 1 It can be seen that one side of the second sampling resistor RS2 is grounded, therefore the second terminal of the power supply is also grounded. This indicates that the second safety switch S1 at the second terminal of the power supply is connected to ground. (See [reference]). Figure 5 In the waveform diagram, S1 is the high level segment and XS2 is the low level segment.

[0053] In the embodiments of this application, when the first safety switch S0 and / or the second safety switch S1 is open, the detection module detects that there is no input at the safety input interface X0 of the detection module, then the circuit is normal. At this time, if there is input at the XS2 interface, that is, the second threshold logic converter TLC2 outputs a digital signal 1, therefore the voltage across the TLC2 is not lower than the second threshold, and the voltage across the second sampling resistor RS2 is not 0. Figure 1 It can be seen that if one side of the second sampling resistor RS2 is grounded, then the second terminal of the power supply is not grounded. Therefore, the second safety switch S1 at the second terminal of the power supply is not connected to ground. At this time, if there is no input to the XS2 interface, that is, the second threshold logic converter TLC2 outputs a digital signal of 0, the voltage across TLC2 is lower than the second threshold, and the voltage across the second sampling resistor RS2 is 0. Figure 1 It can be seen that if one side of the second sampling resistor RS2 is grounded, then the second terminal of the power supply is also grounded, and it is determined that the second safety switch S1 of the second terminal of the power supply is connected to ground.

[0054] The circuit diagram showing that the second safety switch S1 at the second terminal of the power supply is connected to ground is as follows: Figure 4 As shown, the grounding point of the second safety switch S1 can be any point between the second power supply terminal and the optocoupler U1, and there is no restriction here.

[0055] In another embodiment of this application, multiple safety modules in a ground continuity detection and protection circuit based on a safety switch can be connected in parallel to form a circuit, such as... Figure 6 As shown, the first safety switch of the first safety module is represented by S00, the second safety switch of the first safety module is represented by S10, the first safety switch of the second safety module is represented by S01, the second safety switch of the second safety module is represented by S11, and so on. The first safety switch of the Nth safety module is represented by S0N, and the second safety switch of the Nth safety module is represented by S1N.

[0056] In this embodiment, voltage is divided by the first sampling resistor RS1 and the second sampling resistor RS2. The threshold logic conversion module converts the divided voltage into a digital signal. The digital signal output by the threshold logic conversion module is used for ground continuity detection, realizing detection using extra-low voltage, which is not limited by the voltage of the safety circuit. The second terminal of the power supply does not need to be grounded, the entire circuit has high safety, and the protection method is safe and reliable. The ground continuity of the first safety switch S0 at the first terminal of the power supply and the second safety switch S1 at the second terminal of the power supply can be detected independently. When the safety switch is connected to ground, the safety circuit and the system power supply will not fail.

[0057] It is worth mentioning that all units involved in this embodiment are logical units. In practical applications, a logical unit can be a physical unit, a part of a physical unit, or a combination of multiple physical units. Furthermore, to highlight the innovative aspects of this invention, this embodiment does not introduce units that are not closely related to solving the technical problem proposed by this invention; however, this does not mean that other units are absent from this embodiment.

[0058] Furthermore, the examples mentioned in the above embodiments can be freely combined, and any combination can be understood as an embodiment. The terms "embodiment" or "example" appearing in various locations in the specification do not necessarily refer to the same embodiment, nor are they independent or alternative embodiments mutually exclusive with other embodiments. Those skilled in the art will understand that the embodiments described herein can be combined with other embodiments.

[0059] Another embodiment of the present invention relates to a method for detecting and protecting ground continuity based on a safety switch, applied to the aforementioned circuit for detecting and protecting ground continuity based on a safety switch, with reference to... Figure 7 The process of the ground continuity detection and protection method based on safety switches includes:

[0060] Step S71: Obtain the input signal of the safety input interface X0 of the detection module.

[0061] Step S72: Detect whether the circuit is normal based on the input signal of X0.

[0062] The step of detecting whether the circuit is normal based on the input signal of X0 includes: if the safety switch module is closed and the input signal of X0 is detected to be the same as the output signal of the verification detection switch K0, then the circuit is judged to be normal; if the safety switch module is open and the input signal of X0 is detected to be no input signal, then the circuit is judged to be normal.

[0063] Step S73: Obtain the signal of the first input interface XS1 of the detection module, and determine whether the first safety switch S0 at the first end of the power supply is connected to ground based on the signal of XS1.

[0064] Specifically, when the first safety switch S0 is closed and the second safety switch S1 is closed, the detection module detects that the waveform of the input signal of the safety input interface X0 of the detection module is the same as the waveform output by the verification detection switch K0. If there is input at the XS1 interface, the first safety switch S0 at the first end of the power supply is not connected to ground. If there is no input at the XS1 interface, it is determined that the first safety switch S0 at the first end of the power supply is connected to ground. When the first safety switch S0 and / or the second safety switch S1 are open, the detection module detects that there is no input at the safety input interface X0 of the detection module. If there is input at the XS1 interface, the first safety switch S0 at the first end of the power supply is not connected to ground. If there is no input at the XS1 interface, it is determined that the second safety switch S0 at the first end of the power supply is connected to ground.

[0065] Step S74: Obtain the signal from the second input interface XS2 of the detection module, and determine whether the second safety switch S1 at the second end of the power supply is connected to ground based on the signal from XS2.

[0066] Specifically, when the first safety switch S0 is closed and the second safety switch S1 is closed, the detection module detects that the waveform of the input signal of the safety input interface X0 of the detection module is the same as the waveform output by the verification detection switch K0. When there is input at the XS2 interface, the second safety switch S1 at the second end of the power supply is not connected to ground. If there is no input at the XS2 interface, it is determined that the second safety switch S1 at the second end of the power supply is connected to ground. When the first safety switch S0 and / or the second safety switch S1 is open, the detection module detects that there is no input at the safety input interface X0 of the detection module. If there is input at the XS2 interface, the first safety switch S1 at the second end of the power supply is not connected. If there is no input at the XS2 interface, it is determined that the second safety switch S1 at the second end of the power supply is connected to ground.

[0067] In the embodiments of this application, the signal of the detection module interface XS1 is a digital signal obtained by converting the voltage across the first sampling resistor RS1 through the first threshold logic converter TLC1, and the signal of the detection module interface XS2 is a digital signal obtained by converting the voltage across the second sampling resistor RS2 through the second threshold logic converter TLC2.

[0068] In this embodiment, voltage is divided by the first sampling resistor RS1 and the second sampling resistor RS2. The threshold logic conversion module converts the divided voltage into a digital signal. The digital signal output by the threshold logic conversion module is used for ground continuity detection, realizing detection using extra-low voltage, which is not limited by the voltage of the safety circuit. The second terminal of the power supply does not need to be grounded, the entire circuit has high safety, and the protection method is safe and reliable. The ground continuity of the first safety switch S0 at the first terminal of the power supply and the second safety switch S1 at the second terminal of the power supply can be detected independently. When the safety switch is connected to ground, the safety circuit and the system power supply will not fail.

[0069] The various steps described above are only for clarity. In practice, they can be combined into one step or some steps can be broken down into multiple steps. As long as they include the same logical relationship, they are all within the scope of protection of this patent. Adding insignificant modifications or introducing insignificant designs to the process, but without changing the core design of the process, are also within the scope of protection of this patent.

[0070] Those skilled in the art will understand that the above embodiments are specific embodiments for implementing this application, and in practical applications, various changes can be made to them in form and detail without departing from the spirit and scope of this application.

Claims

1. A safety switch based ground-fault detection and protection circuit, characterized by: It includes a safety switch module, a verification and detection switch K0, a sampling module, a threshold logic conversion module, and a detection module; The safety switch module includes a first safety switch S0, a second safety switch S1, and an optocoupler U1. The first safety switch S0 is connected in series with a first terminal of the power supply, and the second safety switch S1 is connected in series with a second terminal of the power supply. Both the first safety switch S0 and the second safety switch S1 are connected to the optocoupler U1, and the optocoupler U1 is connected to the detection module. The verification and detection switch K0 is connected in series in the circuit and outputs a periodic pulse signal to detect whether the circuit is normal. The sampling module includes a first sampling resistor RS1 and a second sampling resistor RS2, which are connected in series to divide the power supply voltage and provide voltage to the threshold logic conversion module. The threshold logic conversion module includes a first threshold logic converter TLC1 and a second threshold logic converter TLC2. The threshold logic conversion module is connected to the detection module. The first threshold logic converter TLC1 is used to compare the voltage across the first sampling resistor RS1 with a threshold and perform logic conversion to obtain a digital signal. The second threshold logic converter TLC2 is used to compare the voltage across the second sampling resistor RS2 with a threshold and perform logic conversion to obtain a digital signal. The detection module includes a safety input interface X0, a first input interface XS1, and a second input interface XS2, and is used to detect the grounding continuity of the first safety switch S0 and the second safety switch S1.

2. The ground continuity detection and protection circuit based on a safety switch according to claim 1, characterized in that: The detection module is also used to detect the input signal of the security input interface X0 and the signal of the verification detection switch K0. When the first security switch S0 is closed and the second security switch S1 is closed, if the input signal of the security input interface X0 is the same as the signal of the verification detection switch K0, the circuit is determined to be normal. If the safety input interface X0 has no input when the first safety switch S0 and / or the second safety switch S1 is open, the circuit is determined to be normal.

3. The ground continuity detection and protection circuit based on a safety switch according to claim 1, characterized in that: The detection module is also used to determine whether the first safety switch S0 at the first end of the power supply is connected to ground based on the signal from the first input interface XS1; and to determine whether the second safety switch S1 at the second end of the power supply is connected to ground based on the signal from the second input interface XS2.

4. The ground continuity detection and protection circuit based on a safety switch according to claim 3, characterized in that: The signal of XS1 is a digital signal obtained by converting the voltage across the first sampling resistor RS1 through the first threshold logic converter TLC1, and the signal of XS2 is a digital signal obtained by converting the voltage across the second sampling resistor RS2 through the second threshold logic converter TLC2.

5. The ground continuity detection and protection circuit based on a safety switch according to claim 1, characterized in that: The circuit includes multiple safety modules in a ground continuity detection and protection circuit based on safety switches; The safety modules in the multiple safety switch-based ground continuity detection and protection circuits are connected in parallel.

6. A method for detecting and protecting ground continuity based on a safety switch, applied to the circuit as described in any one of claims 1-5, characterized in that: Obtain the input signal from the safety input interface X0 of the detection module; The circuit is checked for proper functioning based on the input signal of X0. Obtain the signal from the first input interface XS1 of the detection module, and determine whether the first safety switch S0 at the first end of the power supply is connected to ground based on the signal from XS1. The signal from the second input interface XS2 of the detection module is obtained, and the second safety switch S1 at the second end of the power supply is determined to be connected to ground based on the signal from XS2.

7. The ground-fault detection and protection method based on a safety switch according to claim 6, characterized in that, The step of detecting whether the circuit is functioning properly based on the input signal of X0 includes: When the first safety switch S0 is closed and the second safety switch S1 is closed, if the input signal of X0 is detected to be the same as the output signal of the verification detection switch K0, then the circuit is determined to be normal. When the first safety switch S0 and / or the second safety switch S1 are open, and no input signal is detected in X0, the circuit is determined to be normal.

8. The ground-fault detection and protection method based on a safety switch according to claim 6, characterized in that, The step of acquiring the signal from the first input interface XS1 of the detection module and determining whether the first safety switch S0 at the first power supply terminal is connected to ground based on the signal from XS1 includes: When the first safety switch S0 is closed and the second safety switch S1 is closed, the detection module detects that the waveform of the input signal of the safety input interface X0 of the detection module is the same as the waveform output by the verification detection switch K0. If there is input at the XS1 interface, the first safety switch S0 at the first end of the power supply is not connected to ground. If there is no input at the XS1 interface, it is determined that the first safety switch S0 at the first end of the power supply is connected to ground. When the first safety switch S0 and / or the second safety switch S1 are open, the detection module detects that there is no input at the safety input interface X0 of the detection module. If there is input at the XS1 interface, the first safety switch S0 at the first end of the power supply is not connected to ground. If there is no input at the XS1 interface, it is determined that the second safety switch S0 at the first end of the power supply is connected to ground.

9. The ground-fault detection and protection method based on a safety switch according to claim 6, characterized in that, Obtaining the signal from the second input interface XS2 of the detection module, and determining whether the second safety switch S1 at the second terminal of the power supply is connected to ground based on the signal from XS2, includes: When the first safety switch S0 is closed and the second safety switch S1 is closed, the detection module detects that the waveform of the input signal of the safety input interface X0 of the detection module is the same as the waveform output by the verification detection switch K0. When there is input to the XS2 interface, the second safety switch S1 at the second end of the power supply is not connected to ground. If there is no input to the XS2 interface, it is determined that the second safety switch S1 at the second end of the power supply is connected to ground. When the first safety switch S0 and / or the second safety switch S1 is open, the detection module detects that there is no input at the safety input interface X0 of the detection module. If there is input at the XS2 interface, the first safety switch S1 at the second end of the power supply is not conducting. If there is no input at the XS2 interface, it is determined that the second safety switch S1 at the second end of the power supply is conducting to ground.

10. The ground fault detection and protection method based on a safety switch according to any one of claims 6-9, characterized in that, The signal of the XS1 interface of the detection module is a digital signal obtained by converting the voltage across the first sampling resistor RS1 through the first threshold logic converter TLC1, and the signal of the XS2 interface of the detection module is a digital signal obtained by converting the voltage across the second sampling resistor RS2 through the second threshold logic converter TLC2.

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