Double-backup circuit of displacement sensor

Abstract

The invention provides a double-backup circuit of a displacement sensor, and relates to the technical field of sensors. Comprising three sensing circuits of a sensor, physical isolation of three sensing signal channels of a main circuit and a backup circuit is achieved through relays, two sets of switches are connected in parallel for each sensing signal, and switches of different relays are connected in parallel for the same sensing signal. By means of staggered parallel processing, even if contacts of two sets of switches in any relay are in poor contact, three paths of induction signals can still enter an induction signal processing circuit normally. In the excitation circuit, two diodes are used for redundancy blocking and backward flow prevention, and two triodes are used for redundancy to prevent a load from being disconnected due to an abnormal access between the main circuit and the backup circuit, so that the reliability is improved.

Description

Technical Field

[0001] This application belongs to the field of sensor technology, and specifically relates to a dual backup circuit for a displacement sensor. Background Technology

[0002] Displacement sensors measure the displacement of an object when it undergoes physical movement, including length and angular displacement. For example, a sensor that measures angles is called an angular displacement sensor, and a sensor that measures the length of a straight line is called a linear displacement sensor. They are widely used in machine tools and are core components of machine tools. The machining accuracy of a machine tool is greatly related to the accuracy of the sensor. A displacement sensor consists of two parts: the stationary part is called the stator, and the part that moves with the rotating axis is called the rotor (in a linear displacement sensor, the part that moves with the linear axis is called the probe).

[0003] Displacement sensors typically require signal driving and detection signal processing in applications. The signal processing flow of existing displacement sensors is as follows: the circuit generates four high-voltage square wave excitation signals to the sensor stator; the sensor rotor modulates the excitation and displacement signals, generating three induction signal outputs. These three induction signals are then demodulated and converted into displacement signals. Conventional sensor circuits use two sensors and two processing circuits; a failure in one circuit will not affect the normal operation of the other circuit and the sensors.

[0004] However, existing technologies have high hardware costs, the main circuit and backup circuit cannot be integrated to drive the sensor, and if dual backup circuits are used to drive the sensor, there will be problems such as the excitation signal S generated by one circuit affecting the other circuit, and the main circuit and backup circuit that process the sensor sensing signals A, B, and C will interfere with each other, resulting in poor circuit reliability. Summary of the Invention

[0005] In view of the aforementioned problems of excitation signal backflow and sensing signal failure between the main circuit and backup circuit, this application proposes a dual backup circuit for a displacement sensor. This reduces the hardware cost of the sensor circuit and, by providing mutual redundancy between the main circuit and backup circuit for processing sensor signals, prevents excitation signal backflow and sensing signal failure between the two circuits, thereby improving circuit reliability.

[0006] This application provides a dual backup circuit for a displacement sensor, including:

[0007] Main circuit and backup circuit;

[0008] The main circuit includes a first excitation signal unit and a first relay drive unit. The first excitation signal unit is used to send an excitation signal to the sensor, and the first relay drive unit is used to receive and process the sensor sensing signal.

[0009] The first excitation signal unit is connected to the signal input electrode of the sensor, the first relay drive unit is connected to the signal output electrode of the sensor, and there are at least three signal connections between the first relay drive unit and the signal output electrode of the sensor.

[0010] The backup circuit includes a second excitation signal unit and a second relay drive unit. The second excitation signal unit is used to send an excitation signal to the sensor, and the second relay drive unit is used to receive and process the sensor sensing signal.

[0011] The second excitation signal unit is connected to the signal input electrode of the sensor, the second relay drive unit is connected to the signal output electrode of the sensor, and there are at least three signal connections between the second relay drive unit and the signal output electrode of the sensor.

[0012] Preferably, the first excitation signal unit includes:

[0013] First transistor Q1, first resistor R1, first diode D1, and second diode D2;

[0014] The collector of the first transistor Q1 is connected to the power supply, the base of the first transistor Q1 is connected to the second end of the first resistor R1, and the first end of the first resistor R1 is connected to the square wave SIN-1.

[0015] The emitter of the first transistor Q1 is connected to the anode of the first diode D1, and the anodes of the first diode D1 and the second diode D2 are connected in series.

[0016] The cathode of the first diode D1 is connected in series to the anode of the second diode D2, and the cathode of the second diode D2 is connected to the sensor signal input electrode.

[0017] Preferably, the first excitation signal unit further includes:

[0018] The second transistor Q2, the third transistor Q3, the second resistor R2, the third resistor R3, and the fourth resistor R4;

[0019] The collector of the second transistor Q2 is connected to the second end of the fourth resistor R4, the first end of the fourth resistor R4 is connected to the sensor signal input electrode, and the first end of the fourth resistor R4 is connected to the cathode of the second diode D2.

[0020] The base of the second transistor Q2 is connected to the second end of the second resistor R2, the first end of the second resistor R2 is connected to the power supply, and the emitter of the second transistor Q2 is connected to the collector of the third transistor Q3.

[0021] The base of the third transistor Q3 is connected to the second terminal of the third resistor R3, the first terminal of the third resistor R3 is connected to the power supply, and the emitter of the third transistor Q3 is grounded.

[0022] Preferably, the second excitation signal unit includes:

[0023] The fourth transistor Q4, the fifth resistor R5, the third diode D3, and the fourth diode D4;

[0024] The collector of the fourth transistor Q4 is connected to the power supply, the base of the fourth transistor Q4 is connected to the first end of the fifth resistor R5, and the second end of the fifth resistor R5 is connected to the square wave SIN-2.

[0025] The emitter of the fourth transistor Q4 is connected to the anode of the third diode D3, and the anodes of the third diode D3 and the fourth diode D4 are connected in series.

[0026] The cathode of the third diode D3 is connected in series to the anode of the fourth diode D4, and the cathode of the fourth diode D4 is connected to the sensor signal input electrode.

[0027] Preferably, the second excitation signal unit further includes:

[0028] The fifth transistor Q5, the sixth transistor Q6, the sixth resistor R6, the seventh resistor R7, and the eighth resistor R8;

[0029] The collector of the fifth transistor Q5 is connected to the second end of the eighth resistor R8, the first end of the eighth resistor R8 is connected to the sensor signal input electrode, and the first end of the eighth resistor R8 is connected to the cathode of the fourth diode D4.

[0030] The base of the fifth transistor Q5 is connected to the first end of the sixth resistor R6, the second end of the sixth resistor R6 is connected to the power supply, and the emitter of the fifth transistor Q5 is connected to the collector of the sixth transistor Q6.

[0031] The base of transistor Q6 is connected to the first terminal of resistor R7, the second terminal of resistor R7 is connected to the power supply, and the emitter of transistor Q6 is grounded.

[0032] Preferably, the first relay driving unit includes:

[0033] The seventh transistor Q7, the tenth resistor R10, and the eleventh resistor R11;

[0034] The collector of the seventh transistor Q7 is connected to the second terminal of the ninth resistor R9;

[0035] The base of the seventh transistor Q7 is connected to the second terminal of the tenth resistor R10, and the first terminal of the tenth resistor R10 is connected to the control terminal IO-1.

[0036] The emitter of the seventh transistor Q7 is connected to the second end of the eleventh resistor R11, the first end of the eleventh resistor R11 is connected to the control terminal IO-1, and the emitter of the seventh transistor Q7 is grounded.

[0037] Preferably, the first relay drive unit further includes:

[0038] The fifth diode D5 and the ninth resistor R9;

[0039] The cathode of the fifth diode D5 is connected to the power supply, the anode of the fifth diode D5 is connected to the first terminal of the ninth resistor R9, and a first driving terminal RL-1 is led out between the anode of the fifth diode D5 and the first terminal of the ninth resistor R9.

[0040] Preferably, the second relay drive unit includes:

[0041] The eighth transistor Q8, the thirteenth resistor R13, and the fourteenth resistor R14;

[0042] The collector of the eighth transistor Q8 is connected to the second terminal of the twelfth resistor R12;

[0043] The base of the eighth transistor Q8 is connected to the first terminal of the thirteenth resistor R13, and the second terminal of the thirteenth resistor R13 is connected to the control terminal IO-2.

[0044] The emitter of the eighth transistor Q8 is connected to the second terminal of the fourteenth resistor R14, the first terminal of the fourteenth resistor R14 is connected to the control terminal IO-2, and the emitter of the eighth transistor Q8 is grounded.

[0045] Preferably, the second relay drive unit further includes:

[0046] The sixth diode D6 and the twelfth resistor R12;

[0047] The cathode of the sixth diode D6 is connected to the power supply, the anode of the sixth diode D6 is connected to the first end of the twelfth resistor R12, and a second driving terminal RL-2 is led out between the anode of the sixth diode D6 and the first end of the twelfth resistor R12.

[0048] Preferably, the backup circuit also includes:

[0049] First magnetic latching relay K1, second magnetic latching relay K2 and third magnetic latching relay K3;

[0050] Each magnetic latching relay includes a front excitation coil and a rear excitation coil.

[0051] The input terminal of the front excitation coil is connected to the first power supply 15V-1, and the output terminal of the front excitation coil is connected to the first drive terminal RL-1.

[0052] The input terminal of the post-excitation coil is connected to the second power supply 15V-2, and the output terminal of the post-excitation coil is connected to the second drive terminal RL-2.

[0053] The output terminal of the first magnetic latching relay K1 includes A-1 (first signal contact A-1), A-2 (second signal contact A-2), C-1 (first signal contact C-1), and C-2 (second signal contact C-2);

[0054] The input terminal of the first magnetic latching relay K1 is connected to the sensor output signals A and C;

[0055] The output terminals of the second magnetic latching relay K2 include A-1 (first signal contact A-1), A-2 (second signal contact A-2), B-1 (first signal contact B-1), and B-2 (second signal contact B-2);

[0056] The input terminal of the second magnetic latching relay K2 is connected to the sensor output signals A and B;

[0057] The output terminals of the third magnetic latching relay K3 include C-1 (first signal contact), C-2 (second signal contact), B-1 (first signal contact), and B-2 (second signal contact);

[0058] The input terminal of the third magnetic latching relay K3 is connected to the sensor output signals C and B.

[0059] The beneficial effects of this application are as follows: Based on the above technical solution, this disclosure designs a three-channel sensing circuit for the sensor. Physical isolation of the three sensing signal paths in the main and backup circuits is achieved through relays. Two sets of switches are connected in parallel for redundancy in each sensing signal path, and different relays are used for the same sensing signal path. This staggered parallel connection ensures that even if the contacts of the two sets of switches inside any relay malfunction, the three sensing signals can still enter the sensing signal processing circuit normally. The excitation circuit uses two redundant diodes to prevent backflow and two redundant transistors to prevent abnormal paths between the main and backup circuits from causing the load to remain connected, thus improving reliability.

[0060] Other features and advantages of this application will be set forth in the following description and will be apparent in part from the description or may be learned by practicing the application. The objectives and other advantages of this application may be realized and obtained by means of the structures pointed out in the description and the accompanying drawings. Attached Figure Description

[0061] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0062] Figure 1 This paper shows a dual backup circuit structure diagram of a displacement sensor according to an embodiment of the present application;

[0063] Figure 2 The topology diagrams of the first excitation signal unit and the second excitation signal unit according to embodiments of this application are shown;

[0064] Figure 3 The topology diagram of the first relay driving unit and the second relay driving unit according to the embodiments of this application is shown. Detailed Implementation

[0065] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0066] It should be noted that the terms "first," "second," etc., used in this application are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate for the embodiments of this application described herein. In this application, the terms "upper," "lower," "left," "right," "front," "rear," "top," "bottom," "inner," "outer," "middle," "vertical," "horizontal," "lateral," "longitudinal," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings.

[0067] This application provides a dual backup circuit for a displacement sensor, see [link to relevant documentation]. Figure 1 ,include:

[0068] Main circuit and backup circuit;

[0069] The main circuit includes a first excitation signal unit and a first relay drive unit. The first excitation signal unit is used to send an excitation signal to the sensor, and the first relay drive unit is used to receive and process the sensor sensing signal.

[0070] The first excitation signal unit is connected to the signal input electrode of the sensor, the first relay drive unit is connected to the signal output electrode of the sensor, and there are at least three signal connections between the first relay drive unit and the signal output electrode of the sensor.

[0071] The backup circuit includes a second excitation signal unit and a second relay drive unit. The second excitation signal unit is used to send an excitation signal to the sensor, and the second relay drive unit is used to receive and process the sensor sensing signal.

[0072] The second excitation signal unit is connected to the signal input electrode of the sensor, the second relay drive unit is connected to the signal output electrode of the sensor, and there are at least three signal connections between the second relay drive unit and the signal output electrode of the sensor.

[0073] Specifically, the sensor backup circuit of this application can be illustrated using a displacement sensor as an example. The signal processing flow of the displacement sensor is as follows: the circuit generates four high-voltage square wave excitation signals to the stator end of the sensor; the rotor end of the sensor modulates the excitation signal and the displacement signal to generate three induction signal outputs. These three induction signals are then demodulated by the circuit and converted into displacement signals. Since the structure of the four square wave excitation signals is the same, this application uses a single excitation signal as an example to explain this design method. Similarly, for different sensors, the induction may not be three-way; this application uses a three-way induction signal as an example to explain this design method.

[0074] It should be noted that the sensor body itself does not contain electronic components. In this application, two circuits share one sensor, which can reduce costs and simplify installation. The excitation signals S of the two circuits are connected together and input to the sensor. The three sensing signals A, B, and C of the sensor are also connected to the two circuits respectively. However, the following problems exist: firstly, the excitation signal S generated by one circuit affects the other circuit; secondly, the main circuit and backup circuit that process the sensor sensing signals A, B, and C interfere with each other. Therefore, this application provides the following specific circuit structure to solve the above problems.

[0075] In some specific embodiments, see Figure 2 The first excitation signal unit in this embodiment includes:

[0076] First transistor Q1, first resistor R1, first diode D1, and second diode D2;

[0077] The collector of the first transistor Q1 is connected to the power supply, the base of the first transistor Q1 is connected to the second end of the first resistor R1, and the first end of the first resistor R1 is connected to the square wave SIN-1.

[0078] The emitter of the first transistor Q1 is connected to the anode of the first diode D1, and the anodes of the first diode D1 and the second diode D2 are connected in series.

[0079] The cathode of the first diode D1 is connected in series to the anode of the second diode D2, and the cathode of the second diode D2 is connected to the sensor signal input electrode.

[0080] The first excitation signal unit also includes:

[0081] The second transistor Q2, the third transistor Q3, the second resistor R2, the third resistor R3, and the fourth resistor R4;

[0082] The collector of the second transistor Q2 is connected to the second end of the fourth resistor R4, the first end of the fourth resistor R4 is connected to the sensor signal input electrode, and the first end of the fourth resistor R4 is connected to the cathode of the second diode D2.

[0083] The base of the second transistor Q2 is connected to the second end of the second resistor R2, the first end of the second resistor R2 is connected to the power supply, and the emitter of the second transistor Q2 is connected to the collector of the third transistor Q3.

[0084] The base of the third transistor Q3 is connected to the second terminal of the third resistor R3, the first terminal of the third resistor R3 is connected to the power supply, and the emitter of the third transistor Q3 is grounded.

[0085] Specifically, the second excitation signal unit includes:

[0086] The fourth transistor Q4, the fifth resistor R5, the third diode D3, and the fourth diode D4;

[0087] The collector of the fourth transistor Q4 is connected to the power supply, the base of the fourth transistor Q4 is connected to the first end of the fifth resistor R5, and the second end of the fifth resistor R5 is connected to the square wave SIN-2.

[0088] The emitter of the fourth transistor Q4 is connected to the anode of the third diode D3, and the anodes of the third diode D3 and the fourth diode D4 are connected in series.

[0089] The cathode of the third diode D3 is connected in series to the anode of the fourth diode D4, and the cathode of the fourth diode D4 is connected to the sensor signal input electrode.

[0090] The second excitation signal unit further includes:

[0091] The fifth transistor Q5, the sixth transistor Q6, the sixth resistor R6, the seventh resistor R7, and the eighth resistor R8;

[0092] The collector of the fifth transistor Q5 is connected to the second end of the eighth resistor R8, the first end of the eighth resistor R8 is connected to the sensor signal input electrode, and the first end of the eighth resistor R8 is connected to the cathode of the fourth diode D4.

[0093] The base of the fifth transistor Q5 is connected to the first end of the sixth resistor R6, the second end of the sixth resistor R6 is connected to the power supply, and the emitter of the fifth transistor Q5 is connected to the collector of the sixth transistor Q6.

[0094] The base of transistor Q6 is connected to the first terminal of resistor R7, the second terminal of resistor R7 is connected to the power supply, and the emitter of transistor Q6 is grounded.

[0095] The first excitation signal unit and its implementation principle in the embodiments of this application will be described in detail below with reference to the accompanying drawings.

[0096] See Figure 2 The circuit structure of the first excitation signal unit of the main circuit and the second excitation signal unit of the backup circuit is similar. The first excitation signal unit of the main circuit on the left is also the excitation signal generation circuit, and the second excitation signal unit of the backup circuit on the right is also the excitation signal generation circuit.

[0097] When the main circuit is working, a square wave is input to terminal SIN-1. When the square wave input is high, the first transistor Q1 turns on, and the excitation signal S outputs a high level, which is connected in parallel with the fourth resistor R4. At this time, the second transistor Q2 and the third transistor Q3 are both turned on and in saturation, with a small voltage drop, and a higher voltage can be obtained on the sensor.

[0098] When the input at terminal SIN-1 is low, the first transistor Q1 is turned off, while the second transistor Q2 and the third transistor Q3 remain on. The charge on the excitation signal S is released through a loop formed by the fourth resistor R4, the second transistor Q2, and the third transistor Q3. Thus, when a square wave signal with alternating high and low values ​​is input at terminal SIN-1, the excitation signal S will also generate a square wave signal.

[0099] When the main circuit is working, the backup circuit is not powered on. Therefore, the fifth transistor Q5 and the sixth transistor Q6 in the second excitation signal unit of the backup circuit are not turned on, and the eighth resistor R8 is not connected in parallel to the sensor. Its resistance value does not affect the sensor load. At the same time, due to the obstruction of the fourth diode D4, the excitation signal S will not flow back to the fourth transistor Q4 of the backup circuit.

[0100] The sensor excitation circuit designed in this application can automatically open the transistor's ground channel upon power-up, forming a path for the excitation signal. Furthermore, it can release the charge on the sensor when the input signal is low, and disconnect the ground channel upon power-off, without affecting the load on the sensor during backup circuit operation. This prevents the excitation signal from one circuit from affecting the other, improving circuit reliability.

[0101] The third diode D3 and the fourth diode D4 are connected in series to provide two-stage reverse current protection. Even if one of them conducts in reverse due to reverse breakdown or failure, reverse current will not occur. The excitation circuit uses two redundant diodes to block reverse current and two redundant transistors to prevent abnormal paths from causing the load to remain connected, thus improving reliability.

[0102] The fifth transistor Q5 and the sixth transistor Q6 also have two levels of protection. Even if one of them fails and opens abnormally, the eighth resistor R8 will not form a parallel load on the sensor, further improving the reliability of the circuit.

[0103] In some specific embodiments, see Figure 3 The first relay driving unit in this embodiment includes:

[0104] The seventh transistor Q7, the tenth resistor R10, and the eleventh resistor R11;

[0105] The collector of the seventh transistor Q7 is connected to the second terminal of the ninth resistor R9;

[0106] The base of the seventh transistor Q7 is connected to the second terminal of the tenth resistor R10, and the first terminal of the tenth resistor R10 is connected to the control terminal IO-1.

[0107] The emitter of the seventh transistor Q7 is connected to the second end of the eleventh resistor R11, the first end of the eleventh resistor R11 is connected to the control terminal IO-1, and the emitter of the seventh transistor Q7 is grounded.

[0108] The first relay driving unit further includes:

[0109] The fifth diode D5 and the ninth resistor R9;

[0110] The cathode of the fifth diode D5 is connected to the power supply, the anode of the fifth diode D5 is connected to the first terminal of the ninth resistor R9, and a first driving terminal RL-1 is led out between the anode of the fifth diode D5 and the first terminal of the ninth resistor R9.

[0111] In some specific embodiments, see Figure 3 In this embodiment of the application, the second relay driving unit includes:

[0112] The eighth transistor Q8, the thirteenth resistor R13, and the fourteenth resistor R14;

[0113] The collector of the eighth transistor Q8 is connected to the second terminal of the twelfth resistor R12;

[0114] The base of the eighth transistor Q8 is connected to the first terminal of the thirteenth resistor R13, and the second terminal of the thirteenth resistor R13 is connected to the control terminal IO-2.

[0115] The emitter of the eighth transistor Q8 is connected to the second terminal of the fourteenth resistor R14, the first terminal of the fourteenth resistor R14 is connected to the control terminal IO-2, and the emitter of the eighth transistor Q8 is grounded.

[0116] The second relay driving unit further includes:

[0117] The sixth diode D6 and the twelfth resistor R12;

[0118] The cathode of the sixth diode D6 is connected to the power supply, the anode of the sixth diode D6 is connected to the first end of the twelfth resistor R12, and a second driving terminal RL-2 is led out between the anode of the sixth diode D6 and the first end of the twelfth resistor R12.

[0119] In some specific embodiments, see Figure 3 The backup circuit in this embodiment further includes:

[0120] First magnetic latching relay K1, second magnetic latching relay K2 and third magnetic latching relay K3;

[0121] Each magnetic latching relay includes a front excitation coil and a rear excitation coil.

[0122] The input terminal of the front excitation coil is connected to the first power supply 15V-1, and the output terminal of the front excitation coil is connected to the first drive terminal RL-1.

[0123] The input terminal of the post-excitation coil is connected to the second power supply 15V-2, and the output terminal of the post-excitation coil is connected to the second drive terminal RL-2.

[0124] The output terminal of the first magnetic latching relay K1 includes A-1 (first signal contact A-1), A-2 (second signal contact A-2), C-1 (first signal contact C-1), and C-2 (second signal contact C-2);

[0125] The input terminal of the first magnetic latching relay K1 is connected to the sensor output signals A and C;

[0126] The output terminals of the second magnetic latching relay K2 include A-1 (first signal contact A-1), A-2 (second signal contact A-2), B-1 (first signal contact B-1), and B-2 (second signal contact B-2);

[0127] The input terminal of the second magnetic latching relay K2 is connected to the sensor output signals A and B;

[0128] The output terminals of the third magnetic latching relay K3 include C-1 (first signal contact), C-2 (second signal contact), B-1 (first signal contact), and B-2 (second signal contact);

[0129] The input terminal of the third magnetic latching relay K3 is connected to the sensor output signals C and B.

[0130] The implementation principles of the first relay driving unit and the second relay driving unit in the embodiments of this application will be described in detail below with reference to the accompanying drawings.

[0131] See Figure 3 The first magnetic latching relay K1, the second magnetic latching relay K2, and the third magnetic latching relay K3 are three double-pole double-throw magnetic latching relays. A, B, and C are the three-channel sensing signal outputs of the sensor. The left side of the three magnetic latching relays is the first relay driving unit in the main circuit, which is used to drive the front excitation coil of the relay. The right side is the second relay driving unit in the backup circuit, which is used to drive the rear excitation coil of the relay.

[0132] When the main circuit is operating, the control terminal IO-1 outputs a high level, turning on the seventh transistor Q7. Simultaneously, this drives the pre-excitation coils of the three relays. All three relays' double-pole double-throw switches will be pulled to their left contacts. The A, B, and C signals output by the sensor enter the relays and are output from contacts A-1, B-1, and C-1 respectively, connecting to the main circuit's sensing signal processing circuit. Since these are magnetically latched relays, a short-term high-level output from the control terminal IO-1 is sufficient; continuous driving of the relay coils is unnecessary, thus reducing power consumption.

[0133] Similarly, when the backup circuit is working, the control terminal IO-2 outputs a high level to turn on the eighth transistor Q8, which in turn drives the post-excitation coils of the three relays. The double-pole double-throw switches of the three relays will all be attracted to the right contact. The A, B, and C signals output by the sensor enter the relays and are output from the A-2, B-2, and C-2 contacts respectively, and are connected to the sensing signal processing circuit of the backup circuit.

[0134] The sensor circuit with three sensing channels involved in the embodiments of this application uses relays to achieve physical isolation of the three sensing signal paths of the main and backup circuits. Two sets of switches are connected in parallel for redundancy for each sensing signal, and the same sensing signal uses switches from different relays connected in parallel. This staggered parallel connection process ensures that even if the contacts of the two sets of switches inside any relay are not making good contact, the three sensing signals can still enter the sensing signal processing circuit normally.

[0135] The above embodiments are only used to illustrate the technical solutions of this application, and are not intended to limit them. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of this application.

Claims

1. A dual backup circuit for a displacement sensor, characterized in that, include: Main circuit and backup circuit; The main circuit includes a first excitation signal unit and a first relay drive unit. The first excitation signal unit is used to send an excitation signal to the sensor, and the first relay drive unit is used to receive and process the sensor sensing signal. The first excitation signal unit is connected to the signal input electrode of the sensor, the first relay driving unit is connected to the signal output electrode of the sensor, and there are no less than three signal connections between the first relay driving unit and the signal output electrode of the sensor. The backup circuit includes a second excitation signal unit and a second relay drive unit. The second excitation signal unit is used to send an excitation signal to the sensor, and the second relay drive unit is used to receive and process the sensor sensing signal. The second excitation signal unit is connected to the signal input electrode of the sensor, the second relay drive unit is connected to the signal output electrode of the sensor, and there are at least three signal connections between the second relay drive unit and the signal output electrode of the sensor.

2. The circuit according to claim 1, characterized in that, The first excitation signal unit includes: First transistor Q1, first resistor R1, first diode D1, and second diode D2; The collector of the first transistor Q1 is connected to the power supply, the base of the first transistor Q1 is connected to the second end of the first resistor R1, and the first end of the first resistor R1 is connected to the square wave SIN-1. The emitter of the first transistor Q1 is connected to the anode of the first diode D1, and the anodes of the first diode D1 and the second diode D2 are connected in series. The cathode of the first diode D1 is connected in series to the anode of the second diode D2, and the cathode of the second diode D2 is connected to the sensor signal input electrode.

3. The circuit according to claim 2, characterized in that, The first excitation signal unit further includes: The second transistor Q2, the third transistor Q3, the second resistor R2, the third resistor R3, and the fourth resistor R4; The collector of the second transistor Q2 is connected to the second end of the fourth resistor R4, the first end of the fourth resistor R4 is connected to the sensor signal input electrode, and the first end of the fourth resistor R4 is connected to the cathode of the second diode D2. The base of the second transistor Q2 is connected to the second end of the second resistor R2, the first end of the second resistor R2 is connected to the power supply, and the emitter of the second transistor Q2 is connected to the collector of the third transistor Q3. The base of the third transistor Q3 is connected to the second terminal of the third resistor R3, the first terminal of the third resistor R3 is connected to the power supply, and the emitter of the third transistor Q3 is grounded.

4. The circuit according to claim 1, characterized in that, The second excitation signal unit includes: The fourth transistor Q4, the fifth resistor R5, the third diode D3, and the fourth diode D4; The collector of the fourth transistor Q4 is connected to the power supply, the base of the fourth transistor Q4 is connected to the first end of the fifth resistor R5, and the second end of the fifth resistor R5 is connected to the square wave SIN-2. The emitter of the fourth transistor Q4 is connected to the anode of the third diode D3, and the anodes of the third diode D3 and the fourth diode D4 are connected in series. The cathode of the third diode D3 is connected in series to the anode of the fourth diode D4, and the cathode of the fourth diode D4 is connected to the sensor signal input electrode.

5. The circuit according to claim 4, characterized in that, The second excitation signal unit further includes: The fifth transistor Q5, the sixth transistor Q6, the sixth resistor R6, the seventh resistor R7, and the eighth resistor R8; The collector of the fifth transistor Q5 is connected to the second end of the eighth resistor R8, the first end of the eighth resistor R8 is connected to the sensor signal input electrode, and the first end of the eighth resistor R8 is connected to the cathode of the fourth diode D4. The base of the fifth transistor Q5 is connected to the first end of the sixth resistor R6, the second end of the sixth resistor R6 is connected to the power supply, and the emitter of the fifth transistor Q5 is connected to the collector of the sixth transistor Q6. The base of transistor Q6 is connected to the first terminal of resistor R7, the second terminal of resistor R7 is connected to the power supply, and the emitter of transistor Q6 is grounded.

6. The circuit according to claim 1, characterized in that, The first relay driving unit includes: The seventh transistor Q7, the tenth resistor R10, and the eleventh resistor R11; The collector of the seventh transistor Q7 is connected to the second terminal of the ninth resistor R9; The base of the seventh transistor Q7 is connected to the second terminal of the tenth resistor R10, and the first terminal of the tenth resistor R10 is connected to the control terminal IO-1. The emitter of the seventh transistor Q7 is connected to the second end of the eleventh resistor R11, the first end of the eleventh resistor R11 is connected to the control terminal IO-1, and the emitter of the seventh transistor Q7 is grounded.

7. The circuit according to claim 6, characterized in that, The first relay driving unit further includes: The fifth diode D5 and the ninth resistor R9; The cathode of the fifth diode D5 is connected to the power supply, the anode of the fifth diode D5 is connected to the first terminal of the ninth resistor R9, and a first driving terminal RL-1 is led out between the anode of the fifth diode D5 and the first terminal of the ninth resistor R9.

8. The circuit according to claim 1, characterized in that, The second relay drive unit includes: The eighth transistor Q8, the thirteenth resistor R13, and the fourteenth resistor R14; The collector of the eighth transistor Q8 is connected to the second terminal of the twelfth resistor R12; The base of the eighth transistor Q8 is connected to the first terminal of the thirteenth resistor R13, and the second terminal of the thirteenth resistor R13 is connected to the control terminal IO-2. The emitter of the eighth transistor Q8 is connected to the second terminal of the fourteenth resistor R14, the first terminal of the fourteenth resistor R14 is connected to the control terminal IO-2, and the emitter of the eighth transistor Q8 is grounded.

9. The circuit according to claim 8, characterized in that, The second relay drive unit further includes: The sixth diode D6 and the twelfth resistor R12; The cathode of the sixth diode D6 is connected to the power supply, the anode of the sixth diode D6 is connected to the first end of the twelfth resistor R12, and a second driving terminal RL-2 is led out between the anode of the sixth diode D6 and the first end of the twelfth resistor R12.

10. The circuit according to any one of claims 6 to 9, characterized in that, The backup circuit also includes: First magnetic latching relay K1, second magnetic latching relay K2 and third magnetic latching relay K3; Each magnetic latching relay includes a front excitation coil and a rear excitation coil. The input terminal of the front excitation coil is connected to the first power supply 15V-1, and the output terminal of the front excitation coil is connected to the first drive terminal RL-1. The input terminal of the post-excitation coil is connected to the second power supply 15V-2, and the output terminal of the post-excitation coil is connected to the second drive terminal RL-2. The output terminal of the first magnetic latching relay K1 includes A-1 (first signal contact A-1), A-2 (second signal contact A-2), C-1 (first signal contact C-1), and C-2 (second signal contact C-2); The input terminal of the first magnetic latching relay K1 is connected to the sensor output signals A and C; The output terminals of the second magnetic latching relay K2 include A-1 (first signal contact A-1), A-2 (second signal contact A-2), B-1 (first signal contact B-1), and B-2 (second signal contact B-2); The input terminal of the second magnetic latching relay K2 is connected to the sensor output signals A and B; The output terminals of the third magnetic latching relay K3 include C-1 (first signal contact), C-2 (second signal contact), B-1 (first signal contact), and B-2 (second signal contact); The input terminal of the third magnetic latching relay K3 is connected to the sensor output signals C and B.

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