An encoder break detection apparatus and method

Abstract

The application discloses an encoder disconnection detection device and method, comprising a sampling unit, a detection module, an MCU and an encoder; the detection module is used for pulling up the voltage at the input end of the sampling unit to the voltage at the power supply end, and also controls the connection and disconnection of the pull-up loop and the ground loop; the pull-up resistor and the pull-up switch are connected in series between the input end and the power supply end of the sampling unit; the ground end of the sampling unit is connected with the ground signal end of the encoder to form a ground loop, and the ground loop is also connected in series with a ground loop switch; and the output end of the sampling unit is connected with the MCU. The application does not need motor rotation and pulse detection, realizes the disconnection detection of the collector open circuit output encoder, solves the problem of detecting the disconnection of the encoder in the scene of the motor being static and no pulse output, and avoids the safety risk caused by starting the motor for detection.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of encoder signal detection, in particular to an encoder broken line detection device and method. BACKGROUND

[0002] At present, the encoder detects the rotating speed and direction of the forklift lifting motor or walking motor in real time, helps the controller to accurately control the lifting, tilting or moving action, and the broken line of the encoder has many causes, among which the contact failure caused by loose interface is more common. The broken line of the encoder will cause inaccurate reading and large error.

[0003] The existing scheme with the patent application number CN201210592058.0 and the patent name "Incremental encoder broken line detection circuit" includes a rectifier unit and an optical coupling detection module. When any phase difference signal transmission line of the encoder output is not broken, the secondary side of the three optical couplings is turned on, and the level of the output side of the three optical couplings is pulled low. When any phase or multiple phase difference signal transmission line is broken, the optical coupling in the loop where the broken line is located is not turned on, the secondary side of the optical coupling is cut off, and the level of the output end of the optical coupling is high. When one phase or multiple phase detection loop detects that the output level of the optical coupling is high, the system reports an encoder broken line error.

[0004] The above technical scheme relies on the differential signal (i.e. the motor needs to rotate to generate pulses) output by the encoder, and must have the differential signal input of the encoder, otherwise the rectifier bridge has no signal, the state of the optical coupling cannot be judged, and the detection fails.

[0005] For the encoder broken line detection, the pulse change can be judged when the controller is in dynamic state, but in some special occasions such as hill holding, the self-checking of the encoder wiring condition of the electric control needs to be detected without pulse. For the encoder with open collector (OC gate) output, the open state of the OC gate and the broken line are both high impedance for the input circuit of the electric control, and cannot be distinguished and recognized. SUMMARY

[0006] The purpose of the present application is to provide an encoder broken line detection device and method, which can actively change the circuit state through double switch control, does not rely on the pulse signal of the encoder, and realizes the broken line detection in the pulse-free scene through active control of the circuit state.

[0007] The present application adopts the following technical scheme:

[0008] An encoder broken line detection device, comprising a sampling unit, a detection module, an MCU and an encoder.

[0009] The sampling unit is used for receiving the voltage signal output by the encoder and dividing the received voltage signal, and then transmitting to the MCU; the sampling unit is correspondingly connected to the A, B and Z signal output terminals of the encoder by using the input terminal composed of the first terminal, the second terminal and the third terminal; the sampling unit is connected to the MCU by using the output terminal; the sampling unit is also grounded and connected to the power supply terminal by using the ground terminal and the power supply terminal respectively;

[0010] The ground signal terminal and the power signal terminal of the encoder are connected to the ground terminal and the power terminal of the sampling unit respectively;

[0011] The detection module comprises a pull-up circuit, a pull-up circuit on-off controller and a ground circuit on-off controller; the two ends of the pull-up circuit are connected to the input terminal and the power terminal of the sampling unit respectively; the pull-up circuit is used for pulling up the voltage at the input terminal of the sampling unit to the voltage at the power terminal; the pull-up circuit on-off controller is connected in series between the input terminal and the power terminal of the sampling unit, and the ground circuit on-off controller is connected in series between the ground terminal of the sampling unit and the ground signal terminal of the encoder;

[0012] The MCU controls the pull-up circuit on-off controller and the ground circuit on-off controller to control the connection and disconnection of the pull-up circuit and the ground circuit; the MCU is used for receiving the voltage signal output by the sampling unit and outputting a truth table, and judging the disconnection of the encoder based on the opening and closing conditions of the pull-up circuit on-off controller and the ground circuit on-off controller in combination with the truth table.

[0013] Further, the encoder disconnection detection device further comprises a conditioning circuit; the output terminal of the sampling unit is connected to the input port of the conditioning circuit, and the output terminal of the conditioning circuit is connected to the MCU; the conditioning circuit is used for optimizing the signal quality of the A, B and Z signals input by the encoder.

[0014] Further, the pull-up circuit on-off controller and the ground circuit on-off controller are MOS tubes, triodes and / or relays as switching devices.

[0015] An encoder disconnection detection method suitable for the above-mentioned encoder disconnection detection device, the pull-up circuit on-off controller is realized by using a pull-up switch, and the ground circuit on-off controller is realized by using a ground circuit switch; the detection method comprises the following steps:

[0016] S1: the MCU controls the pull-up switch and the ground circuit switch to be closed;

[0017] S2: the input terminal of the sampling unit is divided and then transmitted to the MCU, and the MCU receives the level of the output of the sampling unit and outputs a truth table,

[0018] When the input terminal of the sampling unit is low, the truth table shows that the input terminal of the sampling unit is 0;

[0019] When the input end of the sampling unit is high level, the truth table shows that the input end of the sampling unit is 1;

[0020] S3: the MCU controls the pull-up switch to be off; meanwhile, the ground loop switch is controlled to be off, and the fault detection stage is entered;

[0021] S4: in the fault detection stage,

[0022] When the MCU output truth table shows that the input end of the sampling unit is 1, that is, the input end of the sampling unit is high level, it indicates that the connection between the controller and the encoder is good;

[0023] When the MCU output truth table shows that the input end of the sampling unit is 0, that is, the input end of the sampling unit is low level, it indicates that the connection between the controller and the encoder is disconnected.

[0024] Further, the detection method further comprises:

[0025] S5: when the disconnection between the controller and the encoder is detected, the MCU controls the ground loop switch to be closed,

[0026] If the MCU output truth table shows that the input end of the sampling unit is 0, that is, the first terminal, the second terminal and the third terminal are low level, it indicates that the ground connection is normal, and the encoder power signal end is disconnected;

[0027] If the MCU output truth table shows that the input end of the sampling unit is 1, that is, the first terminal, the second terminal and the third terminal are high level, it indicates that the ground signal end of the encoder is disconnected.

[0028] Further, the step S2 is,

[0029] S2: after the input end of the sampling unit is divided, the input end transmits to the MCU through the conditioning circuit, the MCU receives the level of the output of the sampling unit and outputs the truth table;

[0030] If the input end of the sampling unit is low level, the conditioning circuit outputs low level, and the truth table shows that the input end of the sampling unit is 0;

[0031] If the input end of the sampling unit is high level, the conditioning circuit outputs high level, and the truth table shows that the input end of the sampling unit is 1.

[0032] The application can realize the broken line detection of the open-collector output encoder without rotating the motor and without pulse detection in the scene of motor static, no pulse output (such as forklift parking on slope, equipment power-on self-checking), disconnect the ground loop to make the encoder an equipotential body, construct the judgment standard of high level normal and low level broken line in no pulse, change the electrical characteristics of the OC gate when it is disconnected from high impedance to VCC isopotential high level, and form a clear distinction with the low level of the broken line state, eliminate the false judgment, solve the problem of inaccurate or large error reading caused by the broken line of the encoder, and avoid the safety risk caused by starting the motor for detection. BRIEF DESCRIPTION OF DRAWINGS

[0033] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the related art, the following will briefly introduce the drawings needed to be used in the embodiment or related art description. Obviously, the drawings in the following description are only part of the embodiments of the present application, and for those skilled in the art, other drawings can be obtained without creative labor on the basis of the provided drawings.

[0034] Fig. 1 It is a schematic diagram of a specific embodiment of the encoder broken line detection device of the present application;

[0035] Fig. 2 It is a schematic diagram of another specific embodiment of the encoder broken line detection device of the present application;

[0036] Fig. 3 It is a flowchart of a specific embodiment of the encoder broken line detection method of the present application;

[0037] Fig. 4 It is a flowchart of another specific embodiment of the encoder broken line detection method of the present application. DETAILED DESCRIPTION

[0038] In order to make the purpose, technical solutions and advantages of the embodiments herein clearer, the technical solutions in the embodiments herein will be described clearly and completely below in combination with the drawings in the embodiments herein. Obviously, the described embodiments are part of the embodiments herein, not all the embodiments. Based on the embodiments herein, all other embodiments obtained by those skilled in the art without creative labor are within the scope of protection. It should be noted that the embodiments herein and the features in the embodiments can be combined with each other arbitrarily without conflict.

[0039] The present application will be described in detail below in combination with the drawings and embodiments: Figs. 1 to 4

[0040] ​The application is suitable for an encoder with open collector output, such as an incremental photoelectric encoder, and the output signal of the incremental photoelectric encoder is output by open collector (OC gate), and the angle is determined by pulse counting.

[0041] The application discloses an encoder wire breakage detection device, and specifically discloses a specific embodiment.

[0042] The sampling unit, the detection module and the MCU can be integrated in the forklift controller.

[0043] The sampling unit is used for receiving a voltage signal output by the encoder and performing voltage division on the received voltage signal, and then transmitting the voltage signal to the MCU; the sampling unit is connected to the A, B and Z phase signal output ends of the encoder through the input end composed of the first terminal ENC_A, the second terminal ENC_B and the third terminal ENC_Z; the sampling unit is connected to the MCU through the output end; and the sampling unit is grounded through the ground end GND2 and connected to the power supply end through the power supply end VCC2.

[0044] The ground signal end GND1 and the power supply signal end VCC1 of the encoder are connected to the ground end GND2 and the power supply end VCC2 of the sampling unit, respectively.

[0045] The detection module comprises a pull-up circuit, a pull-up circuit on-off controller and a ground circuit on-off controller; the two ends of the pull-up circuit are connected to the input end of the sampling unit and the power supply end VCC2, respectively; the pull-up circuit is used for pulling up the voltage of the input end of the sampling unit to be consistent with the voltage of the power supply end VCC2; the pull-up circuit on-off controller is connected in series between the input end of the sampling unit and the power supply end VCC2, and the ground circuit on-off controller is connected in series between the ground end GND2 of the sampling unit and the ground signal end GND1 of the encoder.

[0046] The MCU controls the pull-up circuit on-off controller and the ground circuit on-off controller, so as to control the connection and disconnection of the pull-up circuit and the ground circuit; the MCU is used for receiving the voltage signal output by the sampling unit and outputting a truth table, and judging the wire breakage of the encoder based on the opening and closing of the ground circuit switch and the pull-up switch and the truth table.

[0047] In the embodiment,

[0048] The pull-up circuit on-off controller is realized by using the pull-up switch S1, and the ground circuit on-off controller is realized by using the ground circuit switch S2.

[0049] The first terminal ENC_A, the second terminal ENC_B and the third terminal ENC_Z of the sampling unit are respectively connected with the signal output ends A phase, B phase and Z phase of the encoder;

[0050] The power supply end VCC2 of the sampling unit is electrically connected with the power supply signal end VCC1 of the encoder;

[0051] The pull-up resistor R and the pull-up switch S1 are connected in series between the input end and the power supply end VCC2 of the sampling unit;

[0052] The ground end GND2 of the sampling unit and the ground loop switch S2 form a ground loop after being connected in series with the ground signal end GND1 of the encoder, and the ground loop switch S2 is connected in series in the ground loop;

[0053] The output port of the sampling unit is connected with the MCU.

[0054] In the embodiment, the pull-up switch S1 and the ground loop switch S2 can be switching devices such as MOS tubes, triodes and / or relays.

[0055] In the application, in the scene of motor static, no pulse output (such as forklift parking on slope, equipment power-on self-checking), the motor does not need to rotate and pulse detection is not needed, the broken line detection of the open collector output encoder can be realized, the problem of inaccurate or large error reading caused by broken line of the encoder is solved, and the safety risk caused by starting the motor for detection is avoided.

[0056] The application provides a broken line detection device of an encoder, and a specific embodiment two of the application is as follows:

[0057] In the application, the sampling unit, the conditioning circuit, the detection module and the MCU are integrated on a forklift controller.

[0058] The sampling unit is used for receiving a voltage signal output by the encoder and performing voltage division on the received voltage signal, and then transmitting the voltage signal to the MCU through the conditioning circuit; the sampling unit is connected with the A, B and Z phase signal output ends of the encoder through the input end composed of the first terminal ENC_A, the second terminal ENC_B and the third terminal ENC_Z; the output end of the sampling unit is connected with the input end of the conditioning circuit, and the output end of the conditioning circuit is connected with the MCU; the ground end GND2 and the power supply end VCC2 of the sampling unit are respectively connected with the ground and the power supply end.

[0059] The conditioning circuit is used for optimizing the A, B and Z signal quality input by the encoder, so that the signal is more suitable for MCU acquisition and processing.

[0060] The ground signal end GND1 and the power supply signal end VCC1 of the encoder are respectively connected with the ground end GND2 and the power supply end VCC2 of the sampling unit.

[0061] The detection module comprises a pull-up circuit, a pull-up circuit on-off controller and a ground circuit on-off controller; two ends of the pull-up circuit are connected with the input end of the sampling unit and the power supply end VCC2 respectively; the pull-up circuit is used for pulling up the voltage of the input end of the sampling unit to be consistent with the voltage of the power supply end VCC2; the pull-up circuit on-off controller is connected in series between the input end of the sampling unit and the power supply end VCC2, and the ground circuit on-off controller is connected in series between the ground end GND2 of the sampling unit and the ground signal end GND1 of the encoder.

[0062] The MCU controls the pull-up circuit on-off controller and the ground circuit on-off controller respectively, so as to control the connection and disconnection of the pull-up circuit and the ground circuit; the MCU is used for receiving the voltage signal output by the conditioning circuit and outputting a truth table, and judging the disconnection of the encoder based on the on-off state of the ground circuit switch and the pull-up switch in combination with the truth table.

[0063] In the embodiment,

[0064] The pull-up circuit on-off controller is realized by using a pull-up switch S1, and the ground circuit on-off controller is realized by using a ground circuit switch S2.

[0065] The first terminal ENC_A, the second terminal ENC_B and the third terminal ENC_Z of the sampling unit are connected with the output ports A-phase, B-phase and Z-phase of the encoder respectively;

[0066] The pull-up resistor R and the pull-up switch S1 are connected in series between the input end of the sampling unit and the power supply end VCC2;

[0067] The power supply end VCC2 of the sampling unit is electrically connected with the power supply signal end VCC1 of the encoder;

[0068] The ground end GND2 of the sampling unit, the ground circuit switch S2 and the ground signal end GND1 of the encoder are connected in series to form a ground circuit, and the ground circuit switch S2 is connected in series in the ground circuit;

[0069] The output port of the sampling unit is connected with the input port of the conditioning circuit, and the output port of the conditioning circuit is connected with the MCU.

[0070] In the embodiment, the pull-up switch and the ground circuit switch can be a switching device such as a MOS tube, a triode and / or a relay.

[0071] In the application, in the scene of motor static and no pulse output (such as forklift parking on slope, equipment power-on self-checking), the motor does not need to rotate and the pulse does not need to be detected, the disconnection detection of the encoder with open collector output can be realized, the problem of inaccurate or large error reading caused by the disconnection of the encoder is solved, and the safety risk caused by starting the motor for detection is avoided.

[0072] An encoder wire break detection method, the present application gives specific embodiment three, applicable to the encoder wire break detection device of the above specific embodiment one, sequentially includes the following steps:

[0073] S1: the MCU controls the closing of the pull-up switch and the ground loop switch;

[0074] S2: the input end of the sampling unit is transmitted to the MCU after voltage division, and the MCU receives the level of the sampling unit output and outputs a truth table; voltage division on the input end belongs to the conventional technology in the art, which will not be described here,

[0075] When the input end of the sampling unit is low, the truth table shows that the input end of the sampling unit is 0;

[0076] When the input end of the sampling unit is high, the truth table shows that the input end of the sampling unit is 1;

[0077] S3: the MCU controls the opening of the pull-up switch; at the same time, the ground loop switch is controlled to be opened, and the fault detection stage is entered;

[0078] S4: in the fault detection stage,

[0079] When the MCU output truth table shows that the input end of the sampling unit is 1, that is, the input end of the sampling unit is high, it indicates that the connection between the controller and the encoder is good;

[0080] When the MCU output truth table shows that the input end of the sampling unit is 0, that is, the input end of the sampling unit is low, it indicates that the wire break occurs between the controller and the encoder;

[0081] S5: when the wire break between the controller and the encoder is detected, the MCU controls the closing of the ground loop switch,

[0082] If the MCU output truth table shows that the input port of the sampling unit is 0, that is, the first terminal ENC_A, the second terminal ENC_B and the third terminal ENC_Z are low, it indicates that the ground connection is normal, and the encoder power signal end is broken;

[0083] If the MCU output truth table shows that the input port of the sampling unit is 1, that is, the first terminal ENC_A, the second terminal ENC_B and the third terminal ENC_Z are high, it indicates that the ground signal end GND1 of the encoder is broken.

[0084] The pull-up resistor is used to pull up the input end voltage to the power supply voltage; the pull-up switch is used to connect or disconnect the pull-up resistor to pull up the input port voltage to the power supply voltage, and the closing and opening of the pull-up switch is controlled by the MCU; the ground loop switch is used to control the connection or disconnection of the ground loop, and the opening and closing of the ground loop switch is controlled by the MCU.

[0085] The method realizes the pulse-free line break detection by disconnecting the ground loop to make the encoder equipotential, constructs the judgment standard of high level normal and low level line break in the pulse-free state, realizes the effective detection of the static pulse-free output scene (such as forklift parking on slope, equipment power-on self-checking and the like), changes the electrical characteristics of the OC gate disconnection from high impedance to VCC potential high level by actively controlling the ground loop and pull-up voltage, forms clear distinction with the low level of the line break state, and eliminates the misjudgment.

[0086] A kind of encoder line break detection method, the present application gives specific embodiment four, it is applicable to the encoder line break detection device of above-mentioned specific embodiment two, sequentially includes the following steps:

[0087] S1: MCU controls the closing of pull-up switch and ground loop switch;

[0088] S2: the input end of sampling unit is transmitted to MCU after voltage division, and MCU receives the level of sampling unit output and outputs truth table;Voltage division to input end belongs to the conventional technology in the art, and will not be repeated here,

[0089] When the input end of sampling unit is low level, the output of conditioning circuit is low level, and the truth table shows that the input end of sampling unit is 0;

[0090] When the input end of sampling unit is high level, the output of conditioning circuit is high level, and the truth table shows that the input end of sampling unit is 1;

[0091] S3: MCU controls the disconnection of pull-up switch;At the same time, control the disconnection of ground loop switch, enter the fault detection stage;

[0092] S4: in the fault detection stage,

[0093] When the input end of sampling unit is 1 in the truth table output by MCU, i.e. the input port of sampling unit is high level, it indicates that the line between controller and encoder is good;

[0094] When the input port of sampling unit is 0 in the truth table output by MCU, i.e. the input port of sampling unit is low level, it indicates that line break occurs between controller and encoder;

[0095] S5: when line break occurs between controller and encoder, MCU controls the closing of ground loop switch,

[0096] If the input port of sampling unit is 0 in the truth table output by MCU, i.e. the first terminal ENC_A, the second terminal ENC_B and the third terminal ENC_Z are low level, it indicates that ground connection is normal, and the power signal end of encoder is line break;

[0097] If the MCU output truth table shows that the sampling unit input port is 1, i.e. the first terminal ENC_A, the second terminal ENC_B and the third terminal ENC_Z are high, it indicates that the ground signal end GND1 of the encoder is disconnected.

[0098] In the application, in the ground wire detection, the pull-up switch is controlled to be disconnected by the controller, the pull-up circuit is disconnected, the ground circuit is controlled to be closed, the ground circuit is connected, the pull-up voltage is disconnected, the sampling unit input port should be low, the MCU output truth table shows that the sampling unit input port is 0, but if the ground signal end GND1 of the encoder is disconnected, even if the S2 ground circuit is closed, it is in a disconnected state, and the monitoring result is as in step 4, the first terminal ENC_A, the second terminal ENC_B and the third terminal ENC_Z are high, the MCU output truth table shows that the sampling unit input port is 1.

[0099] The method designs a detection method according to the detection circuit to distinguish the disconnection condition in the off state of the OC gate, realizes the no-pulse disconnection detection, makes the encoder become an equipotential body by disconnecting the ground circuit, constructs the judgment standard of high level normal and low level disconnection in the no-pulse state, realizes the effective detection of the static no-pulse output scene (such as the forklift parked on the slope, the equipment power-on self-test and the like), actively controls the ground circuit and the pull-up voltage, changes the electrical characteristics of the OC gate in the off state from high impedance to VCC equipotential high level, and forms clear distinction with the low level of the disconnection state, and eliminates the misjudgment.

[0100] The above is only a preferred specific embodiment of the application, but the protection scope of the application is not limited thereto, any person skilled in the art can make equivalent replacement or change according to the technical solution and the inventive concept of the application within the technical range disclosed by the application, which should be covered in the protection scope of the application.

Claims

1. An encoder break detection apparatus, characterized by: Includes a sampling unit, a detection module, an MCU, and an encoder; The sampling unit is used to receive the voltage signal output by the encoder, divide the received voltage signal, and then transmit it to the MCU. The sampling unit uses the input terminal consisting of the first terminal, the second terminal, and the third terminal to connect to the A, B, and Z phase signal output terminals of the encoder. The sampling unit uses the output terminal to connect to the MCU. The sampling unit also uses the ground terminal and the power supply terminal to ground and connect to the power supply terminal respectively. The encoder's ground signal terminal and power signal terminal are respectively connected to the ground terminal and power terminal of the sampling unit; The detection module includes a pull-up circuit, a pull-up circuit on / off controller, and a ground circuit on / off controller. The two ends of the pull-up circuit are connected to the input terminal of the sampling unit and the power supply terminal, respectively. The pull-up circuit is used to pull up the voltage at the input terminal of the sampling unit to the voltage at the power supply terminal. The pull-up circuit on / off controller is connected in series between the input terminal of the sampling unit and the power supply terminal, and the ground circuit on / off controller is connected in series between the ground terminal of the sampling unit and the ground signal terminal of the encoder. The MCU controls the pull-up circuit on / off controller and the ground circuit on / off controller respectively, thereby controlling the connection and disconnection of the pull-up circuit and the ground circuit; the MCU is used to receive the voltage signal output by the sampling unit and output the truth table, and also to determine the encoder's disconnection status based on the on / off status of the pull-up circuit on / off controller and the ground circuit on / off controller combined with the truth table.

2. The encoder wire breakage detection device according to claim 1, characterized in that: The encoder disconnection detection device further includes a conditioning circuit; the output terminal of the sampling unit is connected to the input port of the conditioning circuit, and the output terminal of the conditioning circuit is connected to the MCU; the conditioning circuit is used to optimize the quality of the A, B, and Z signals input by the encoder.

3. The encoder wire breakage detection device according to claim 1, characterized in that: The pull-up circuit on / off controller and the ground circuit on / off controller are used as switching devices, which employ MOSFETs, transistors and / or relays.

4. A method for detecting encoder wire breakage, applicable to the encoder wire breakage detection device according to any one of claims 1 to 3, characterized in that, The pull-up circuit on / off controller utilizes a pull-up switch, and the ground circuit on / off controller utilizes a ground circuit switch; the detection method includes the following steps: S1: The MCU controls the closing of the pull-up switch and the ground loop switch; S2: The input of the sampling unit is divided and transmitted to the MCU. The MCU receives the level output from the sampling unit and outputs a truth table. When the input of the sampling unit is low, the truth table shows that the input of the sampling unit is 0; When the input of the sampling unit is high, the truth table shows that the input of the sampling unit is 1; S3: The MCU controls the pull-up switch to open; at the same time, it controls the ground loop switch to open, entering the fault detection stage; S4: During the fault detection phase When the MCU output truth table shows that the sampling unit input is 1, that is, the sampling unit input is at a high level, it indicates that the connection between the controller and the encoder is good. When the MCU output truth table shows that the sampling unit input is 0, that is, the sampling unit input is at a low level, it indicates that there is a disconnection between the controller and the encoder.

5. The encoder wire breakage detection method according to claim 4, characterized in that, The detection methods also include: S5: When a disconnection is detected between the controller and the encoder, the MCU controls the ground loop switch to close. If the MCU output truth table shows that the sampling unit input port is 0, that is, the first terminal, the second terminal and the third terminal are low level, it indicates that the ground connection is normal and the encoder power signal terminal is disconnected. If the MCU output truth table shows that the sampling unit input port is 1, that is, the first terminal, the second terminal and the third terminal are at a high level, it indicates that the encoder's ground signal terminal is disconnected.

6. The encoder wire breakage detection method according to claim 4, characterized in that: Step S2 is as follows: S2: After the input of the sampling unit is divided, it is transmitted to the MCU through the conditioning circuit. The MCU receives the level output of the sampling unit and outputs the truth table. If the input of the sampling unit is low, the output of the conditioning circuit is low, and the truth table shows that the input of the sampling unit is 0. If the input of the sampling unit is high, the output of the conditioning circuit is high, and the truth table shows that the input of the sampling unit is 1.

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