Detection circuit of safety limit switch, frequency converter and electronic equipment
By designing a detection circuit for safety limit switches, using series connection and logic circuits, the problem that traditional detection circuits cannot meet the safety torque stop and independent detection at the same time is solved, and the circuit structure is simplified and safety is improved.
Patent Information
- Application Number
- CN202420127011.5
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-01-18
- Publication Date
- 2025-03-25
- Estimated Expiration
- 2034-01-18
AI Technical Summary
The detection circuit of traditional safety limit switches cannot meet the functional requirements of safe torque stopping, but can independently detect each safety limit switch.
A detection circuit for a safety limit switch is designed. By connecting multiple safety limit switches in series between the first power supply and the STO circuit, the logic circuit and the control circuit output digital signals according to the voltages of both ends of the safety limit switch, realizing the functions of independent detection and safety torque stop.
It realizes that while meeting the functional requirements of safe torque stop, each safety limit switch can be independently detected, simplifying the circuit structure, reducing the hardware safety failure point, and improving the authentication and analysis ability of safe torque stop.
Smart Images
Figure CN222671913U_ABST
Abstract
Description
Technical Field
[0001] The present application belongs to the field of detection technology, and in particular relates to a detection circuit, a frequency converter and an electronic device of a safety limit switch. Background Art
[0002] In the detection circuit of the traditional safety limit switch, when the detection circuits of multiple safety limit switches realize the status detection of a single limit switch separately, since each safety limit switch has a power input terminal or a ground terminal, they cannot be connected in series as a redundant input for the safe torque stop; when the detection circuits of multiple safety limit switches are connected in series and the safe torque stop is realized when any safety limit switch is turned off, all the signals are connected in series by using a photocoupler or a relay. Although the status detection of a single limit switch can be performed, the circuit of this scheme is complex, the hardware safety failure points increase, and it is not conducive to the safety torque stop certification analysis. In addition, the external safety limit switch will be considered as an unsafe input after being connected to this circuit.
[0003] Therefore, there is an urgent need for a detection circuit that can meet the functional requirements of safe torque stop and can independently detect each safety limit switch. Summary of the invention
[0004] The purpose of the present application is to provide a detection circuit, a frequency converter and an electronic device for a safety limit switch, aiming to solve the problem that the detection circuit of the relevant safety limit switch cannot independently detect each safety limit switch while meeting the functional requirements of safe torque stop.
[0005] The embodiment of the present application provides a detection circuit of a safety limit switch, wherein the detection circuit of the safety limit switch includes a plurality of safety limit switches, a control circuit, a plurality of logic circuits and a display circuit;
[0006] A plurality of the safety limit switches are connected in series between the first power supply and the STO circuit, and the plurality of the safety limit switches are configured to trigger a safety torque off signal according to a normally open state of at least one of the safety limit switches;
[0007] Each of the logic circuits is connected to each of the safety limit switches in a one-to-one correspondence, and is configured to output a first digital signal according to the voltage across the two ends of the safety limit switch;
[0008] The control circuit is also connected to the plurality of logic circuits and is configured to perform corresponding actions according to the plurality of the first digital signals.
[0009] In one embodiment, the control circuit is further configured to output a display signal according to the plurality of the first digital signals, and the detection circuit of the safety limit switch further comprises:
[0010] The display circuit is connected to the control circuit and is configured to display according to the display signal.
[0011] In one embodiment, the control circuit is further configured to output fail-safe limit switch information according to the plurality of the first digital signals, and the detection circuit of the safety limit switch further comprises:
[0012] The communication circuit is connected to the control circuit and is configured to transmit the fail-safe limit switch information to a host computer.
[0013] In one embodiment, the logic circuit comprises:
[0014] a first voltage dividing circuit connected to the safety limit switch and configured to divide the voltage at the first end of the safety limit switch to output a first detection signal;
[0015] a second voltage dividing circuit connected to the safety limit switch and configured to divide the voltage at the second end of the safety limit switch to output a second detection signal;
[0016] an XOR gate connected to the first voltage divider circuit and the second voltage divider circuit, and configured to perform an XOR operation on the first detection signal and the second detection signal to output a second digital signal;
[0017] or
[0018] The logic circuit comprises:
[0019] a third voltage dividing circuit, connected to the safety limit switch, and configured to divide the voltage of the first end of the safety limit switch to output a third detection signal;
[0020] a fourth voltage dividing circuit, connected to the safety limit switch, and configured to divide the voltage at the second end of the safety limit switch to output a fourth detection signal;
[0021] An XNOR gate is connected to the third voltage divider circuit and the fourth voltage divider circuit, and is configured to perform an XNOR operation on the third detection signal and the fourth detection signal to output a third digital signal.
[0022] In one embodiment, the logic circuit further includes:
[0023] a first isolation circuit connected to the XOR gate and the control circuit, and configured to isolate the second digital signal to output the first digital signal;
[0024] or
[0025] The logic circuit further comprises:
[0026] The second isolation circuit is connected to the XNOR gate and the control circuit, and is configured to isolate the third digital signal to output the first digital signal.
[0027] In one embodiment, the first input end of the XOR gate is used as a first detection signal input end, connected to the first voltage divider circuit, to input the first detection signal; the second input end of the XOR gate is used as a second detection signal input end, connected to the second voltage divider circuit, to input the second detection signal; the output end of the XOR gate is used as a second digital signal output end, to output the second digital signal;
[0028] The first input terminal of the XNOR gate serves as a third detection signal input terminal, connected to the third voltage divider circuit, to input the third detection signal; the second input terminal of the XNOR gate serves as a fourth detection signal input terminal, connected to the fourth voltage divider circuit, to input the fourth detection signal; the output terminal of the XNOR gate serves as a third digital signal output terminal, to output the third digital signal.
[0029] In one embodiment, the control circuit includes a microprocessor;
[0030] The power supply end of the microprocessor is connected to the first power supply; the multiple general input and output ends of the microprocessor are respectively used as the first digital signal input ends of the control circuit, and are connected to the multiple logic circuits to respectively input the multiple first digital signals.
[0031] In one embodiment, there are n safety limit switches in total, the first end of the first safety limit switch is connected to the first power supply and the first logic circuit, the second end of the i-1th safety limit switch, the i-1th logic circuit, the i-th logic circuit and the first end of the i-th safety limit switch are connected, and the second end of the n-th safety limit switch is connected to the n-th logic circuit and the STO circuit, n is a positive integer greater than 1, and i is a positive integer greater than 1 and less than or equal to n.
[0032] An embodiment of the present application further provides a frequency converter, which includes the detection circuit of the above-mentioned safety limit switch.
[0033] An embodiment of the present application further provides an electronic device, which includes the detection circuit of the above-mentioned safety limit switch.
[0034] Compared with the prior art, the embodiments of the present application have the following beneficial effects: by connecting a plurality of safety limit switches in series between the first power supply and the STO circuit, the technical problem that each of the existing safety limit switches has a power input terminal or a ground terminal is overcome, and the detection of the safety limit switch is realized by a simple circuit; a safety torque shut-off signal is triggered by a plurality of safety limit switches according to the normally open state of at least one safety limit switch, so that a safe torque stop is realized when any safety limit switch is turned off, thereby meeting the functional requirement of a safe torque stop; each logic circuit outputs a first digital signal according to the voltage at both ends of the safety limit switch, and each first digital signal represents the state of each safety limit switch; the control circuit performs corresponding actions according to the plurality of first digital signals, thereby realizing independent detection of each safety limit switch; thereby, the functional requirement of a safe torque stop is met, and each safety limit switch can be independently detected, thereby enriching the functionality of the product. BRIEF DESCRIPTION OF THE DRAWINGS
[0035] In order to more clearly illustrate the technical application in the embodiments of the present application, the drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.
[0036] Figure 1 A structural schematic diagram of a detection circuit of a safety limit switch provided in one embodiment of the present application;
[0037] Figure 2 Another structural schematic diagram of a detection circuit of a safety limit switch provided in an embodiment of the present application;
[0038] Figure 3 Another structural schematic diagram of a detection circuit of a safety limit switch provided in an embodiment of the present application;
[0039] Figure 4 Another structural schematic diagram of a detection circuit of a safety limit switch provided in an embodiment of the present application;
[0040] Figure 5 Another structural schematic diagram of a detection circuit of a safety limit switch provided in an embodiment of the present application;
[0041] Figure 6 Another structural schematic diagram of a detection circuit of a safety limit switch provided in an embodiment of the present application;
[0042] Figure 7 Another structural schematic diagram of a detection circuit of a safety limit switch provided in an embodiment of the present application;
[0043] Figure 8 A partial exemplary circuit schematic diagram of a detection circuit for a safety limit switch provided in one embodiment of the present application. DETAILED DESCRIPTION
[0044] In order to make the technical problems, technical solutions and beneficial effects to be solved by the present application more clearly understood, the present application is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and are not used to limit the present application.
[0045] It should be noted that when an element is referred to as being "fixed to" or "disposed on" another element, it can be directly on the other element or indirectly on the other element. When an element is referred to as being "connected to" another element, it can be directly connected to the other element or indirectly connected to the other element.
[0046] It should be understood that the orientation or position relationship indicated by terms such as "length", "width", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside" and "outside" are based on the orientation or position relationship shown in the drawings, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present application.
[0047] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of the features. In the description of this application, the meaning of "plurality" is two or more, unless otherwise clearly and specifically defined.
[0048] Figure 1 The following is a schematic diagram of the structure of a detection circuit of a safety limit switch provided in an embodiment of the present application. For ease of explanation, only the part related to the present embodiment is shown, which is described in detail as follows:
[0049] The detection circuit of the safety limit switch includes a plurality of safety limit switches S1 , a control circuit 100 , a plurality of logic circuits 300 and a display circuit 200 .
[0050] A plurality of safety limit switches S1 are connected in series between a first power source and a safe torque off (STO) circuit 400 , and the plurality of safety limit switches S1 are configured to trigger a safe torque off signal according to a normally open state of at least one safety limit switch S1 .
[0051] Each logic circuit 300 is connected to each safety limit switch S1 in a one-to-one correspondence, and is configured to output a first digital signal according to the voltage across the two ends of the safety limit switch S1.
[0052] The control circuit 100 is also connected to a plurality of logic circuits 300 and is configured to perform corresponding actions according to a plurality of first digital signals.
[0053] The STO circuit 400 is configured to perform corresponding actions according to the safe torque off signal.
[0054] Directly connecting multiple safety limit switches S1 in series has a simple circuit and can achieve safe torque stop when any safety limit switch S1 is turned off. The safety limit switch S1 that triggers the safe torque stop function can also be directly detected through the voltage at both ends of the safety limit switch S1.
[0055] By way of example and not limitation, Figure 2 As shown, the control circuit 100 is further configured to output a display signal according to the plurality of first digital signals, and the detection circuit of the safety limit switch further includes a display circuit 200 .
[0056] The display circuit 200 is connected to the control circuit 100 and is configured to perform display according to a display signal.
[0057] The display signal is displayed by the display circuit 200, which facilitates the user to intuitively and quickly understand the working status of the safety limit switch S1, and enriches the functions of the product.
[0058] By way of example and not limitation, Figure 3 As shown, the control circuit 100 is further configured to output fail-safe limit switch information according to the plurality of first digital signals, and the detection circuit of the safety limit switch further includes a communication circuit 500 .
[0059] The communication circuit 500 is connected to the control circuit 100 and is configured to transmit the fail-safe limit switch information to the host computer.
[0060] The host computer may be a mobile terminal or a computer, and this application does not impose any restrictions on this.
[0061] By transmitting the communication signal to the host computer via the communication circuit 500, real-time status monitoring of the safety limit switch S1 can be provided, thereby improving the reliability of the equipment.
[0062] By way of example and not limitation, Figure 4 As shown, the logic circuit 300 includes a first voltage dividing circuit 310, a second voltage dividing circuit 320 and an XOR gate M1.
[0063] The first voltage dividing circuit 310 is connected to the safety limit switch S1 and is configured to divide the voltage at the first end of the safety limit switch S1 to output a first detection signal.
[0064] The second voltage dividing circuit 320 is connected to the safety limit switch S1 and is configured to divide the voltage at the second end of the safety limit switch S1 to output a second detection signal.
[0065] The XOR gate M1 is connected to the first voltage divider circuit 310 and the second voltage divider circuit 320 , and is configured to perform an XOR operation on the first detection signal and the second detection signal to output a second digital signal.
[0066] It can be understood that when any safety limit switch S1 is disconnected, the voltages at its two ends are different. Then, in the logic circuit 300 corresponding to the safety limit switch S1, the voltages of the first detection signal and the second detection signal are different, so the level states of the two input ends of the XOR gate M1 will be changed, thereby being able to output a high-level second digital signal.
[0067] The voltage across the safety limit switch S1 is detected through the XOR gate M1. The circuit is simple and the XOR gate M1 has a fast response speed, which improves the reliability of the circuit.
[0068] By way of example and not limitation, Figure 5 As shown, the logic circuit 300 further includes a first isolation circuit 330 .
[0069] The first isolation circuit 330 is connected to the XOR gate M1 and the control circuit 100 , and is configured to isolate the second digital signal to output a first digital signal.
[0070] The high-level second digital signal is isolated by the first isolation circuit 330, thereby reducing interference and further improving the reliability of the circuit.
[0071] By way of example and not limitation, Figure 6 As shown, the logic circuit 300 includes a third voltage dividing circuit 340, a fourth voltage dividing circuit 350 and an XNOR gate M2.
[0072] The third voltage dividing circuit 340 is connected to the safety limit switch S1 and is configured to divide the voltage at the first end of the safety limit switch S1 to output a third detection signal.
[0073] The fourth voltage dividing circuit 350 is connected to the safety limit switch S1 and is configured to divide the voltage at the second end of the safety limit switch S1 to output a fourth detection signal.
[0074] The XNOR gate M2 is connected to the third voltage divider circuit 340 and the fourth voltage divider circuit 350 , and is configured to perform an XNOR operation on the third detection signal and the fourth detection signal to output a third digital signal.
[0075] It can be understood that when any safety limit switch S1 is disconnected, the voltages at its two ends are different. Then, in the logic circuit 300 corresponding to the safety limit switch S1, the voltages of the first detection signal and the second detection signal are different, so the level states of the two input ends of the XOR gate M2 will be changed, thereby being able to output a low-level third digital signal.
[0076] The XNOR gate M2 has a fast reaction speed and can quickly output a low-level third digital signal according to the voltages of the received first detection signal and the second detection signal, thereby improving the reliability of the circuit.
[0077] By way of example and not limitation, Figure 7 As shown, the logic circuit 300 further includes a second isolation circuit 360 .
[0078] The second isolation circuit 360 is connected to the XNOR gate M2 and the control circuit 100 , and is configured to isolate the third digital signal to output the first digital signal.
[0079] The low-level third digital signal is isolated by the second isolation circuit 360, thereby reducing interference and further improving the reliability of the circuit.
[0080] Figure 8 A partial exemplary circuit structure of a detection circuit of a safety limit switch provided in an embodiment of the present application is shown. For ease of description, only the part related to the embodiment of the present application is shown, which is described in detail as follows:
[0081] The first isolation circuit 330 includes a photocoupler Q1 , a fifth resistor R5 , and a sixth resistor R6 .
[0082] The first end of the fifth resistor R5 serves as the second digital signal input end of the first isolation circuit 330, and is connected to the XOR gate M1 to input the second digital signal; the second end of the fifth resistor R5 is connected to the positive electrode of the photocoupler Q1, and the negative electrode of the photocoupler Q1 is connected to the power ground; the collector of the photocoupler Q1 and the first end of the sixth resistor R6 serve together as the first digital signal output end of the first isolation circuit 330, and are connected to the control circuit 100 to output the first digital signal; the second end of the sixth resistor R6 is connected to the second power supply, and the emitter of the photocoupler Q1 is connected to the power ground.
[0083] The sixth resistor R6 is a pull-up resistor.
[0084] The input and output ends are completely electrically isolated through the optocoupler Q1, which improves the anti-interference ability of the circuit.
[0085] The first input terminal of the XOR gate M1 is used as a first detection signal input terminal, connected to the first voltage divider circuit 310, to input the first detection signal; the second input terminal of the XOR gate M1 is used as a second detection signal input terminal, connected to the second voltage divider circuit 320, to input the second detection signal; the output terminal of the XOR gate M1 is used as a second digital signal output terminal, to output the second digital signal.
[0086] The first input terminal of the XNOR gate M2 is used as the third detection signal input terminal, connected to the third voltage divider circuit 340, to input the third detection signal; the second input terminal of the XNOR gate M2 is used as the fourth detection signal input terminal, connected to the fourth voltage divider circuit 350, to input the fourth detection signal; the output terminal of the XNOR gate M2 is used as the third digital signal output terminal, to output the third digital signal.
[0087] The XOR gate M1 has a fast operation speed, which can reduce the action time when the circuit fails and improve the safety of the circuit.
[0088] The first voltage divider circuit 310 includes a first resistor R1 and a second resistor R2.
[0089] The first end of the first resistor R1 is connected to the first power supply and the first end of the safety limit switch S1, the second end of the first resistor R1 and the first end of the second resistor R2 together serve as the first detection signal output end of the first voltage divider circuit 310, and are connected to the first end of the XOR gate M1 to output the first detection signal; the second end of the second resistor R2 is connected to the power ground.
[0090] The first resistor R1 and the second resistor R2 are easily available and inexpensive, so the circuit cost is low.
[0091] The second voltage divider circuit 320 includes a third resistor R3 and a fourth resistor R4.
[0092] The first end of the third resistor R3 is connected to the second end of the safety limit switch S1, and the second end of the third resistor R3 and the first end of the fourth resistor R4 together serve as the second detection signal output end of the second voltage divider circuit 320, and are connected to the second end of the XOR gate M1 to output the second detection signal; the second end of the fourth resistor R4 is connected to the power ground.
[0093] The third resistor R3 and the fourth resistor R4 are easily available and inexpensive, so the circuit cost is low.
[0094] The control circuit 100 includes a microprocessor U1.
[0095] The power supply terminal VCC of the microprocessor U1 is connected to the first power supply; multiple general input and output terminals of the microprocessor U1 are respectively used as first digital signal input terminals of the control circuit 100, and are connected to multiple logic circuits 300 to input first digital signals respectively.
[0096] It should be noted that the first universal input and output terminal P2.0 of the microprocessor U1 serves as the first first digital signal input terminal of the control circuit 100, and is connected to the first logic circuit 300 to input the first first digital signal; the second universal input and output terminal P2.1 of the microprocessor U1 serves as the second first digital signal input terminal of the control circuit 100, and is connected to the second logic circuit 300 to input the second first digital signal; the third universal input and output terminal P2.2 of the microprocessor U1 serves as the third first digital signal input terminal of the control circuit 100, and is connected to the third logic circuit 300 to input the third first digital signal.
[0097] The control circuit 100 is composed of a microprocessor U1, and the circuit is simple and reliable.
[0098] There are n safety limit switches S1 in total, the first end of the first safety limit switch S1 is connected to the first power supply and the first logic circuit 300, the second end of the i-1th safety limit switch S1, the i-1th logic circuit 300, the i-th logic circuit 300 and the first end of the i-th safety limit switch S1 are connected, the second end of the n-th safety limit switch S1 is connected to the n-th logic circuit 300 and the STO circuit 100, n is a positive integer greater than 1, and i is a positive integer greater than 1 and less than or equal to n.
[0099] A pull-down resistor can be set between each safety limit switch S1.
[0100] The closer the safety limit switch S1 is to the first power source, the higher the detection level can be set.
[0101] The circuit has strong scalability, and the number of safety limit switches S1 can be selected according to actual needs. For example, there are seven safety limit switches S1 involved in the GD350-39 construction hoist integrated machine. The first safety limit switch S1 is the micro-motion of the anti-fall device, the second safety limit switch S1 is the limit of the roof, the third safety limit switch S1 is the emergency stop in the cage, the fourth safety limit switch S1 is the emergency stop on the cage top, the fifth safety limit switch S1 is the limit of the feed door, the sixth safety limit switch S1 is the limit of the discharge door, and the seventh safety limit switch S1 is the limit of the skylight door. The seven safety limit switches S1 are all normally closed safety switches. If any safety limit switch S1 is disconnected, the safety torque can be stopped, thereby cutting off the inverter torque.
[0102] The following is a combination of working principles Figure 8 As shown for further explanation:
[0103] The following description is made by taking three safety limit switches S1 and three logic circuits 300 as an example. Assuming that the first safety limit switch S1 is disconnected, the three safety limit switches S1 connected in series trigger a safety torque off signal from the second end of the last safety limit switch S1 to the STO circuit 400, and the STO circuit 400 performs corresponding actions according to the safety torque off signal; the first resistor R1 and the second resistor R2 corresponding to the first safety limit switch S1 divide the voltage of the first power supply, and output the divided voltage as the first detection signal from the second end of the first resistor R1 and the first end of the second resistor R2 to the first input end of the corresponding XOR gate M1, the third resistor R3 and the fourth resistor R4 corresponding to the safety limit switch S1 output a 0V second detection signal from the second end of the third resistor R3 and the first end of the fourth resistor R4 to the second input end of the corresponding XOR gate M1, the XOR gate M1 performs an XOR operation on the first detection signal and the second detection signal, and outputs a high-level second digital signal from the output end of the XOR gate M1 to the first end of the corresponding fifth resistor R5, the corresponding photoelectric coupler Q1 isolates the high-level second digital signal, and outputs the high-level second digital signal from the photoelectric coupler Q1 The collector of the coupler Q1 and the first end of the sixth resistor R6 output a low-level first digital signal to the first general input-output terminal P2.0 of the microprocessor U1; the second safety limit switch S1 remains closed, and its corresponding XOR gate M1 outputs a low-level second digital signal to the first end of the corresponding fifth resistor R5, and the corresponding photoelectric coupler Q1 isolates the low-level second digital signal, and outputs a high-level second first digital signal from the collector of the photoelectric coupler Q1 and the first end of the sixth resistor R6 to the second general input-output terminal P2.1 of the microprocessor U1; the third safety limit switch S1 remains closed, and its corresponding XOR gate M1 outputs a low-level second digital signal to the first end of the corresponding fifth resistor R5, and the corresponding photoelectric coupler Q1 isolates the low-level second digital signal, and outputs a high-level third first digital signal from the collector of the photoelectric coupler Q1 and the first end of the sixth resistor R6 to the third general input-output terminal P2.2 of the microprocessor U1, and the microprocessor U1 performs corresponding actions according to the three first digital signals.
[0104] An embodiment of the present application further provides a frequency converter, which includes the detection circuit of the above-mentioned safety limit switch.
[0105] An embodiment of the present application further provides an electronic device, which includes the detection circuit of the above-mentioned safety limit switch.
[0106] It should be understood that the size of the serial numbers of the steps in the above embodiments does not mean the order of execution. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of the present application.
[0107] The embodiments described above are only used to illustrate the technical solutions of the present application, rather than to limit them. Although the present application has been described in detail with reference to the aforementioned embodiments, a person skilled in the art should understand that the technical solutions described in the aforementioned embodiments may still be modified, or some of the technical features may be replaced by equivalents. Such modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present application, and should all be included in the protection scope of the present application.
Claims
1. A detection circuit for a safety limit switch, characterized in that: The detection circuit of the safety limit switch includes a plurality of safety limit switches, a control circuit and a plurality of logic circuits; A plurality of the safety limit switches are connected in series between the first power supply and the STO circuit, and the plurality of the safety limit switches are configured to trigger a safety torque off signal according to a normally open state of at least one of the safety limit switches; Each of the logic circuits is connected to each of the safety limit switches in a one-to-one correspondence, and is configured to output a first digital signal according to the voltage across the two ends of the safety limit switch; The control circuit is also connected to the plurality of logic circuits and is configured to perform corresponding actions according to the plurality of the first digital signals.
2. The detection circuit of the safety limit switch according to claim 1, characterized in that: The control circuit is further configured to output a display signal according to the plurality of the first digital signals, and the detection circuit of the safety limit switch further comprises: The display circuit is connected to the control circuit and is configured to display according to the display signal.
3. The detection circuit of the safety limit switch according to claim 1, characterized in that: The control circuit is further configured to output fail-safe limit switch information according to the plurality of the first digital signals, and the detection circuit of the safety limit switch further comprises: The communication circuit is connected to the control circuit and is configured to transmit the fail-safe limit switch information to a host computer.
4. The detection circuit of the safety limit switch according to claim 1, characterized in that: The logic circuit comprises: a first voltage dividing circuit connected to the safety limit switch and configured to divide the voltage at the first end of the safety limit switch to output a first detection signal; a second voltage dividing circuit connected to the safety limit switch and configured to divide the voltage at the second end of the safety limit switch to output a second detection signal; an XOR gate connected to the first voltage divider circuit and the second voltage divider circuit, and configured to perform an XOR operation on the first detection signal and the second detection signal to output a second digital signal; or The logic circuit comprises: a third voltage dividing circuit, connected to the safety limit switch, and configured to divide the voltage of the first end of the safety limit switch to output a third detection signal; a fourth voltage dividing circuit, connected to the safety limit switch, and configured to divide the voltage at the second end of the safety limit switch to output a fourth detection signal; An XNOR gate is connected to the third voltage divider circuit and the fourth voltage divider circuit, and is configured to perform an XNOR operation on the third detection signal and the fourth detection signal to output a third digital signal.
5. The detection circuit of the safety limit switch according to claim 4, characterized in that: The logic circuit further comprises: a first isolation circuit connected to the XOR gate and the control circuit, and configured to isolate the second digital signal to output the first digital signal; or The logic circuit further comprises: The second isolation circuit is connected to the XNOR gate and the control circuit, and is configured to isolate the third digital signal to output the first digital signal.
6. The detection circuit of the safety limit switch according to claim 4, characterized in that: The first input end of the XOR gate is used as a first detection signal input end, connected to the first voltage divider circuit, so as to input the first detection signal; the second input end of the XOR gate is used as a second detection signal input end, connected to the second voltage divider circuit, so as to input the second detection signal; the output end of the XOR gate is used as a second digital signal output end, so as to output the second digital signal; The first input terminal of the XNOR gate serves as a third detection signal input terminal, connected to the third voltage divider circuit, to input the third detection signal; the second input terminal of the XNOR gate serves as a fourth detection signal input terminal, connected to the fourth voltage divider circuit, to input the fourth detection signal; the output terminal of the XNOR gate serves as a third digital signal output terminal, to output the third digital signal.
7. The detection circuit of the safety limit switch according to claim 1, characterized in that: The control circuit includes a microprocessor; The power supply terminal of the microprocessor is connected to the first power supply, and the multiple general input and output terminals of the microprocessor are respectively used as the first digital signal input terminals of the control circuit, and are connected to the multiple logic circuits to respectively input multiple first digital signals.
8. The detection circuit of the safety limit switch according to claim 1, characterized in that: There are n safety limit switches in total, the first end of the first safety limit switch is connected to the first power supply and the first logic circuit, the second end of the i-1th safety limit switch, the i-1th logic circuit, the i-th logic circuit and the first end of the i-th safety limit switch are connected, and the second end of the n-th safety limit switch is connected to the n-th logic circuit and the STO circuit, n is a positive integer greater than 1, and i is a positive integer greater than 1 and less than or equal to n.
9. A frequency converter, characterized in that: The frequency converter comprises a detection circuit of a safety limit switch as claimed in any one of claims 1 to 8.
10. An electronic device, characterized in that: The electronic device comprises a detection circuit of a safety limit switch as claimed in any one of claims 1 to 8.