System and method for disconnection detection circuit of analog quantity acquisition circuit

Abstract

The invention discloses a system and method for a broken line detection circuit of an analog quantity acquisition circuit, and relates to the technical field of sensors, and the system comprises a signal switching module, an excitation source generation and amplification module, an excitation source feedback acquisition module, a broken line analysis module and a display terminal. Whether the sensor is abnormal or not can be judged, the specific abnormal type of the sensor can be analyzed, the type and the channel position of the abnormal sensor can be quickly positioned through characteristic analysis of the pulse signal, different indicating lights are displayed according to the type of the abnormal sensor, meanwhile predictive maintenance is conducted on the system, and the stability of the system is improved.

Description

Technical Field

[0001] The present invention relates to the field of sensor technology, and in particular to a system and method for a disconnection detection circuit of an analog quantity acquisition circuit. Background Art

[0002] Sensors are devices used to detect and sense various physical quantities in the production process. They can convert the sensed signals into digital or analog electrical signals and output them to the controller for processing, and can be integrated with other automation equipment. They are widely used in industrial automation control systems to monitor the changes of key parameters in the production process in real time, including temperature, pressure, liquid level, flow, vibration, etc. Most sensors sample analog signal transmission acquisition values, such as current signals, voltage signals, and impedance signals. These signals are continuously changing and can more accurately feedback the changes in the state quantity on site. However, during the installation, wiring construction, and wiring of the sensors, there may be poor contact and disconnection in the middle of the cable. Generally, to deal with this problem on site, staff are required to detect and patrol each line, which is a waste of time and poses a safety hazard. Therefore, it is particularly important to invent a system and method for disconnection detection circuits for analog quantity acquisition circuits.

[0003] The prior art, such as the invention application patent with announcement number: CN109425803A, discloses an analog disconnection fault detection method, system and acquisition device. The application generates a fault simulation signal, performs analog-to-digital conversion on the input signal and the fault simulation signal of each analog channel, and collects the analog-to-digital converted data of each analog channel at a set sampling frequency; reads the converted data, takes the sampling data of the disconnection fault simulation signal as the reference value, and determines whether the sampling data of each analog channel meets the set conditions. The set condition value compares the sampling data of each analog channel with the reference value, and compares the data collected by the same analog-to-digital conversion channel of two adjacent samples. If the difference obtained by the two subtractions is less than the corresponding set value, it is determined that the analog channel has an analog disconnection fault. The application has strong real-time performance, high detection result accuracy and detection efficiency, reduces the risk of false operation caused by analog disconnection, and improves the stability and reliability of the operation of the relay protection device.

[0004] The existing technology also has the following defects, which are specifically reflected in: 1. The existing circuit break detection does not pay much attention to the classification of sensor abnormalities. When a sensor abnormality occurs, maintenance personnel are unable to accurately determine the specific type of fault when facing a sensor failure, resulting in a lack of specificity in troubleshooting by maintenance personnel, which prolongs the maintenance time and increases the maintenance cost. It may not be possible to completely solve the root cause of the problem, increasing the probability of system failure.

[0005] 2. The existing circuit disconnection detection does not pay much attention to the type and channel position of the abnormal sensor. When the sensor is abnormal, the type and channel position of the abnormal sensor cannot be quickly located. The abnormal sensor will continue to send wrong signals to the system. These signals will interfere with the operation of other normal sensors and equipment, reducing the stability of the system. Due to the uncertainty of the sensor type, it is difficult for maintenance personnel to prepare appropriate maintenance tools and spare parts in advance, which reduces maintenance efficiency and increases maintenance costs. Summary of the invention

[0006] The purpose of the present invention is to provide a system and method for a disconnection detection circuit for an analog quantity acquisition circuit, which solves the problems existing in the background technology.

[0007] To solve the above technical problems, the present invention adopts the following technical solutions: The present invention provides a system and method for a disconnection detection circuit for an analog quantity acquisition circuit, including: a signal switching module, which is used to realize the switching between the sensor disconnection analysis function and the normal sampling function through an analog switching switch.

[0008] The excitation source generation and amplification module is used to generate various pulse signals and amplify various pulse-shaped signals through operational amplifiers.

[0009] The excitation source feedback acquisition module is used to collect various feedback pulse signals.

[0010] The disconnection analysis module is used to determine whether the sensor is abnormal. If the sensor is abnormal, the type of sensor abnormality is determined, the type of abnormal sensor is located, and the channel position of the abnormal sensor is located.

[0011] The display terminal is used to display the type of sensor abnormality, the channel location of the abnormal sensor, classify and display the abnormal sensors, and perform predictive maintenance on the system.

[0012] Preferably, the specific analysis method for judging whether the sensor is abnormal is: extracting the frequency and amplitude of each pulse signal, and comparing them with the frequency range of the pulse signal of the sensor in normal working state and the amplitude range of the pulse signal of the sensor in normal working state respectively; if the frequency of a pulse signal is within the frequency range of the pulse signal of the sensor in normal working state and the amplitude of the pulse signal is within the amplitude range of the pulse signal of the sensor in normal working state, then the sensor is judged to be normal; if the frequency of a pulse signal is not within the frequency range of the pulse signal of the sensor in normal working state or the amplitude of the pulse signal is not within the amplitude range of the pulse signal of the sensor in normal working state, then the sensor is judged to be abnormal.

[0013] Preferably, the type of sensor abnormality is determined by a specific analysis method as follows: if each pulse signal cannot be received, the sensor is determined to be disconnected; if each pulse signal can be received, the interval time of each pulse signal is calculated, and compared with the interval time difference range of each transmitted pulse signal; if the interval time of a pulse signal is higher than the interval time difference range of the transmitted pulse signal, the sensor wire is determined to have poor contact; the frequency fluctuation coefficient and amplitude fluctuation coefficient of each pulse signal are evaluated, and compared with the preset safe frequency fluctuation coefficient range and safe amplitude fluctuation coefficient range of each pulse signal, respectively; if the frequency fluctuation coefficient of a pulse signal is not within the preset safe frequency fluctuation coefficient range of the pulse signal or the amplitude fluctuation coefficient of the pulse signal is not within the preset safe amplitude fluctuation coefficient range of the pulse signal, the performance of the internal components of the sensor is determined to be unstable.

[0014] Based on this judgment, the types of sensor abnormalities are sensor disconnection, poor sensor wire contact, and unstable performance of sensor internal components.

[0015] Preferably, the frequency fluctuation coefficient of each pulse signal is evaluated by a specific analysis method: extracting the frequency of each pulse signal, evaluating the frequency fluctuation coefficient of each pulse signal, and calculating the formula as follows: where α i represents the frequency fluctuation coefficient of the i-th pulse signal, b i represents the frequency of the ith pulse signal, b i+1 represents the frequency of the i+1th pulse signal, i represents the number of each pulse signal, i=1,2,...,j, j is a positive integer greater than 2, and j represents the number of pulse signals.

[0016] Preferably, the amplitude fluctuation coefficient of each pulse signal is evaluated by a specific analysis method as follows: the amplitude of each pulse signal is sampled multiple times to obtain a sample set Ai of the amplitude of each pulse signal = {ai 1 ,ai 2 ,...,aim}, where A i represents the sample set of the amplitude of the i-th pulse signal, a im represents the amplitude of the mth sampling point of the ith pulse signal, m represents the number of each sampling point, m=1,2,...,n, n represents the number of sampling points, and n is a positive integer greater than 2.

[0017] Evaluate the amplitude fluctuation coefficient of each pulse signal, and the calculation formula is: where β i Represents the amplitude fluctuation coefficient of the i-th pulse signal.

[0018] Preferably, the type of the abnormal sensor located is specifically analyzed by the following method: extract the characteristics of each pulse signal, and compare it with the characteristics of each pulse signal stored in the database; if the characteristics of a pulse signal are consistent with the characteristics of a current type sensor under normal working conditions stored in the database, then the type of the abnormal sensor is determined to be a current type sensor; if the characteristics of a pulse signal are consistent with the characteristics of a voltage type sensor under normal working conditions stored in the database, then the type of the abnormal sensor is determined to be a voltage type sensor; if the characteristics of a pulse signal are consistent with the characteristics of a resistance type sensor under normal working conditions stored in the database, then the type of the abnormal sensor is determined to be a resistance type sensor.

[0019] Based on this judgment, the types of abnormal sensors are current type, voltage type, and resistance type.

[0020] Preferably, the channel position of the abnormal sensor is located, and the specific analysis method is as follows: the display terminal sends a specific scanning signal to all analog channels to scan, identify the response signal of each analog channel, if a certain analog channel does not identify the response signal, then the channel is determined to be disconnected, if a certain analog channel identifies the response signal, then the analog channel is determined to be not disconnected, extract the address code of the response signal, and compare it with the unique address code set for the analog channel, if the address code of the response signal is inconsistent with the unique address code set for the analog channel, then the analog channel is determined to be disconnected, otherwise, the analog channel is determined to be not disconnected, and the disconnected analog channels are statistically obtained, and the unique address code of each disconnected analog channel is compared with the system wiring diagram and channel configuration document to obtain the channel position of each abnormal sensor.

[0021] Preferably, the classification displays abnormal sensors, and the specific analysis method is: extract the type of abnormal sensor, compare it with the indicator light corresponding to the type of abnormal sensor, if the type of the abnormal sensor is a current type sensor, the indicator light is red, if the type of the abnormal sensor is a voltage type sensor, the indicator light is yellow, if the type of the abnormal sensor is a resistance type sensor, the indicator light is blue, and the abnormal type of the abnormal sensor and the channel position of the abnormal sensor are displayed at the same time.

[0022] Preferably, the system is subjected to predictive maintenance, and the specific analysis method is as follows: the frequency fluctuation coefficient of each pulse signal and the amplitude fluctuation coefficient of each pulse signal are extracted, and compared with each historical fault data; if the frequency fluctuation coefficient of a pulse signal or the amplitude fluctuation coefficient of the pulse signal is the same as a certain historical fault data, it is determined that the sensor is about to fail, and the fault type in the historical fault data is extracted and displayed on the display terminal.

[0023] A second aspect of the present invention provides a method for a system of disconnection detection circuits for analog quantity acquisition circuits, comprising: step one, signal switching, for implementing switching between a sensor disconnection analysis function and a normal sampling function through an analog switching switch.

[0024] Step 2: Generate and amplify the excitation source to generate various pulse signals, and amplify various pulse signals through operational amplifiers.

[0025] Step 3: Excitation source feedback collection, used to collect various feedback pulse signals.

[0026] Step 4: Line break analysis is used to determine whether the sensor is abnormal. If the sensor is abnormal, determine the type of sensor abnormality, locate the type of abnormal sensor, and locate the channel position of the abnormal sensor.

[0027] The beneficial effects of the present invention are: 1. In the present invention, the attention to the classification of sensor abnormalities is increased. When an abnormality occurs in the sensor, maintenance personnel can quickly know the specific type of fault, improve the targeting of the fault type, reduce the maintenance time, and thus reduce the maintenance cost, reduce the probability of system failure, and improve the overall operation quality of the system.

[0028] 2. In the present invention, attention is paid to the type and channel position of abnormal sensors. When an abnormality occurs in a sensor, the type and channel position of the abnormal sensor can be quickly located, which reduces the maintenance time and improves the success rate of maintenance. The system can be optimized in a targeted manner, the stability of the system is improved, the timeliness of sensor abnormality detection is increased, and the safety and reliability of the system are improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0030] Figure 1 It is a schematic diagram of the system structure connection of the present invention.

[0031] Figure 2 The present invention is a schematic flow chart of the steps for implementing the method. DETAILED DESCRIPTION

[0032] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0033] Reference Figure 1 As shown, the present invention provides a system and method for a disconnection detection circuit for an analog quantity acquisition circuit, including: a signal switching module, which is used to realize the switching between a sensor disconnection analysis function and a normal sampling function through an analog switching switch.

[0034] It should be noted that when used to analyze the sensor disconnection analysis function, the connection between the sensor and the PLC acquisition circuit is disconnected by switching the switch, and the sensor is connected to the disconnection analysis module through the switch.

[0035] The excitation source generation and amplification module is used to generate various pulse signals and amplify various pulse-shaped signals through operational amplifiers.

[0036] It should be noted that the various pulse signals include triangular waves, square waves, sine waves and pulse waves, but are not limited to the above waveforms.

[0037] The excitation source feedback acquisition module is used to collect various feedback pulse signals.

[0038] The disconnection analysis module is used to determine whether the sensor is abnormal. If the sensor is abnormal, the type of sensor abnormality is determined, the type of abnormal sensor is located, and the channel position of the abnormal sensor is located.

[0039] In a specific embodiment, the specific analysis method for determining whether the sensor is abnormal is as follows: extract the frequency and amplitude of each pulse signal, and compare them with the frequency range of the pulse signal of the sensor in a normal working state and the amplitude range of the pulse signal of the sensor in a normal working state, respectively; if the frequency of a pulse signal is within the frequency range of the pulse signal of the sensor in a normal working state and the amplitude of the pulse signal is within the amplitude range of the pulse signal of the sensor in a normal working state, then the sensor is determined to be normal; if the frequency of a pulse signal is not within the frequency range of the pulse signal of the sensor in a normal working state or the amplitude of the pulse signal is not within the amplitude range of the pulse signal of the sensor in a normal working state, then the sensor is determined to be abnormal.

[0040] It should be noted that the frequency and amplitude of each pulse signal are extracted by an oscilloscope, and the frequency range of the pulse signal of the sensor under normal working conditions and the amplitude range of the pulse signal of the sensor under normal working conditions are set by professionals.

[0041] In a specific embodiment, the type of sensor abnormality is determined by a specific analysis method: if each pulse signal cannot be received, the sensor is determined to be disconnected; if each pulse signal can be received, the interval time of each pulse signal is calculated and compared with the interval time difference range of each transmitted pulse signal; if the interval time of a pulse signal is higher than the interval time difference range of the transmitted pulse signal, the sensor wire is determined to have poor contact; the frequency fluctuation coefficient and amplitude fluctuation coefficient of each pulse signal are evaluated and compared with the preset safe frequency fluctuation coefficient range and safe amplitude fluctuation coefficient range of each pulse signal; if the frequency fluctuation coefficient of a pulse signal is not within the preset safe frequency fluctuation coefficient range of the pulse signal or the amplitude fluctuation coefficient of the pulse signal is not within the preset safe amplitude fluctuation coefficient range of the pulse signal, the performance of the internal components of the sensor is determined to be unstable.

[0042] Based on this judgment, the types of sensor abnormalities are sensor disconnection, poor sensor wire contact, and unstable performance of sensor internal components.

[0043] It should be noted that the preset safe frequency fluctuation coefficient range and safe amplitude fluctuation coefficient range of each pulse signal are set by professionals.

[0044] In a specific embodiment, the frequency fluctuation coefficient of each pulse signal is evaluated by a specific analysis method: extracting the frequency of each pulse signal, evaluating the frequency fluctuation coefficient of each pulse signal, and calculating the formula: where α i represents the frequency fluctuation coefficient of the i-th pulse signal, b i represents the frequency of the ith pulse signal, b i+1 represents the frequency of the i+1th pulse signal, i represents the number of each pulse signal, i=1,2,...,j, j is a positive integer greater than 2, and j represents the number of pulse signals.

[0045] In a specific embodiment, the amplitude fluctuation coefficient of each pulse signal is evaluated by a specific analysis method: the amplitude of each pulse signal is sampled multiple times to obtain a sample set Ai of the amplitude of each pulse signal = {ai 1 ,ai 2 ,...,aim}, where A i represents the sample set of the amplitude of the i-th pulse signal, a im represents the amplitude of the mth sampling point of the ith pulse signal, m represents the number of each sampling point, m=1,2,...,n, n represents the number of sampling points, and n is a positive integer greater than 2.

[0046] Evaluate the amplitude fluctuation coefficient of each pulse signal, and the calculation formula is: where βi Represents the amplitude fluctuation coefficient of the i-th pulse signal.

[0047] In a specific embodiment, the type of abnormal sensor located is specifically analyzed by the following method: extract the characteristics of each pulse signal, and compare it with the characteristics of each pulse signal stored in the database; if the characteristics of a pulse signal are consistent with the characteristics of a current type sensor under normal working conditions stored in the database, then the type of the abnormal sensor is determined to be a current type sensor; if the characteristics of a pulse signal are consistent with the characteristics of a voltage type sensor under normal working conditions stored in the database, then the type of the abnormal sensor is determined to be a voltage type sensor; if the characteristics of a pulse signal are consistent with the characteristics of a resistance type sensor under normal working conditions stored in the database, then the type of the abnormal sensor is determined to be a resistance type sensor.

[0048] Based on this judgment, the types of abnormal sensors are current type, voltage type, and resistance type.

[0049] It should be noted that the characteristics of the pulse signal include pulse frequency, amplitude, pulse width and duty cycle.

[0050] In the present invention, more attention is paid to the classification of sensor abnormalities. When a sensor abnormality occurs, maintenance personnel can quickly know the specific type of fault, which improves the targeting of the fault type, reduces the maintenance time, and thus reduces the maintenance cost, reduces the probability of system failure, and improves the overall operation quality of the system.

[0051] In a specific embodiment, the channel position of the abnormal sensor is located, and the specific analysis method is as follows: the display terminal sends a specific scanning signal to all analog channels to scan, identify the response signal of each analog channel, if a certain analog channel does not identify the response signal, then the channel is determined to be disconnected, if a certain analog channel identifies the response signal, then the analog channel is determined to be not disconnected, extract the address code of the response signal, and compare it with the unique address code set for the analog channel, if the address code of the response signal is inconsistent with the unique address code set for the analog channel, then the analog channel is determined to be disconnected, otherwise, the analog channel is determined to be not disconnected, and the disconnected analog channels are statistically obtained, and the unique address code of each disconnected analog channel is compared with the system wiring diagram and channel configuration document to obtain the channel position of each abnormal sensor.

[0052] In the present invention, more attention is paid to the type and channel position of abnormal sensors. When an abnormality occurs in a sensor, the type and channel position of the abnormal sensor can be quickly located, which reduces the maintenance time and improves the success rate of maintenance. The system can be optimized in a targeted manner, the stability of the system is improved, the timeliness of sensor abnormality detection is increased, and the safety and reliability of the system are improved.

[0053] It should be noted that during the circuit design and construction phase, each analog sensor channel is clearly physically marked. Channel locations can be identified by using digital numbers, letter codes, or color markings on the circuit board, near the sensor interface, or on the connecting harness. The wiring diagram and channel configuration document of the system, where the wiring diagram includes the corresponding channel to which each sensor is connected, and the document records the location of each channel in the entire system.

[0054] The display terminal is used to display the type of sensor abnormality, the channel location of the abnormal sensor, classify and display the abnormal sensors, and perform predictive maintenance on the system.

[0055] In a specific embodiment, the classification displays abnormal sensors, and the specific analysis method is: extract the type of abnormal sensor, and compare it with the indicator light corresponding to the type of abnormal sensor; if the type of the abnormal sensor is a current type sensor, the indicator light is red; if the type of the abnormal sensor is a voltage type sensor, the indicator light is yellow; if the type of the abnormal sensor is a resistance type sensor, the indicator light is blue, and the abnormal type of the abnormal sensor and the channel position of the abnormal sensor are displayed at the same time.

[0056] In a specific embodiment, the system is subjected to predictive maintenance, and the specific analysis method is as follows: the frequency fluctuation coefficient of each pulse signal and the amplitude fluctuation coefficient of each pulse signal are extracted, and compared with each historical fault data; if the frequency fluctuation coefficient of a pulse signal or the amplitude fluctuation coefficient of the pulse signal is the same as a certain historical fault data, it is determined that the sensor is about to fail, and the fault type in the historical fault data is extracted and displayed on the display terminal.

[0057] It should be noted that the signal switching module is connected to the excitation source generation and amplification module, the excitation source generation and amplification module is connected to the excitation source feedback acquisition module, the excitation source feedback acquisition module is connected to the disconnection analysis module, the disconnection analysis module is connected to the display terminal, and the disconnection analysis module and the display terminal are connected to the database at the same time.

[0058] It should be noted that the present invention also includes a database, wherein the database includes the frequency range of the pulse signal of the sensor under normal working conditions and the amplitude range of the pulse signal of the sensor under normal working conditions, the preset safe frequency stability coefficient range and safe amplitude stability coefficient range of the pulse signal, the characteristics of the current sensor, voltage sensor, and resistance sensor under normal working conditions, a unique address code set for each analog channel, the system wiring diagram and channel configuration document, and various historical fault data.

[0059] refer to Figure 2A method for a system of disconnection detection circuits for analog quantity acquisition circuits, comprising: step one, signal switching, for realizing the switching between a sensor disconnection analysis function and a normal sampling function through an analog switching switch.

[0060] Step 2: Generate and amplify the excitation source to generate various pulse signals, and amplify various pulse signals through operational amplifiers.

[0061] Step 3: Excitation source feedback collection, used to collect various feedback pulse signals.

[0062] Step 4: Line break analysis is used to determine whether the sensor is abnormal. If the sensor is abnormal, determine the type of sensor abnormality, locate the type of abnormal sensor, and locate the channel position of the abnormal sensor.

[0063] The above contents are merely examples and explanations of the concept of the present invention. Those skilled in the art may make various modifications or additions to the specific embodiments described or replace them in a similar manner. As long as they do not deviate from the concept of the invention or exceed the scope defined by the present invention, they shall all fall within the protection scope of the present invention.

Claims

1. A system for disconnection detection circuit of analog quantity acquisition circuit, characterized in that: include: The signal switching module is used to switch between the sensor disconnection analysis function and the normal sampling function through a simulated switching switch; The excitation source generation and amplification module is used to generate various pulse signals and amplify various pulse-shaped signals through operational amplifiers; Excitation source feedback acquisition module, used to collect various pulse signals of feedback; The disconnection analysis module is used to determine whether the sensor is abnormal. If the sensor is abnormal, the type of sensor abnormality is determined, the type of abnormal sensor is located, and the channel position of the abnormal sensor is located; The display terminal is used to display the type of sensor abnormality, the channel location of the abnormal sensor, classify and display the abnormal sensors, and perform predictive maintenance on the system.

2. A system for disconnection detection circuit of analog quantity acquisition circuit according to claim 1, characterized in that: The specific analysis method for determining whether the sensor is abnormal is as follows: The frequency and amplitude of each pulse signal are extracted, and compared with the frequency range of the pulse signal of the sensor in normal working state and the amplitude range of the pulse signal of the sensor in normal working state respectively. If the frequency of a pulse signal is within the frequency range of the pulse signal of the sensor in normal working state and the amplitude of the pulse signal is within the amplitude range of the pulse signal of the sensor in normal working state, the sensor is judged to be normal. If the frequency of a pulse signal is not within the frequency range of the pulse signal of the sensor in normal working state or the amplitude of the pulse signal is not within the amplitude range of the pulse signal of the sensor in normal working state, the sensor is judged to be abnormal.

3. A system for disconnection detection circuit of analog quantity acquisition circuit according to claim 2, characterized in that: The specific analysis method for determining the type of sensor abnormality is as follows: If each pulse signal cannot be received, the sensor is determined to be disconnected. If each pulse signal can be received, the interval time of each pulse signal is calculated and compared with the interval time difference range of each pulse signal transmitted. If the interval time of a certain pulse signal is higher than the interval time difference range of the transmitted pulse signal, the sensor wire is determined to have poor contact. The frequency fluctuation coefficient and amplitude fluctuation coefficient of each pulse signal are evaluated and compared with the preset safe frequency fluctuation coefficient range and safe amplitude fluctuation coefficient range of each pulse signal. If the frequency fluctuation coefficient of a pulse signal is not within the preset safe frequency fluctuation coefficient range of the pulse signal or the amplitude fluctuation coefficient of the pulse signal is not within the preset safe amplitude fluctuation coefficient range of the pulse signal, the performance of the internal components of the sensor is determined to be unstable. Based on this judgment, the types of sensor abnormalities are sensor disconnection, poor sensor wire contact, and unstable performance of sensor internal components.

4. A system for disconnection detection circuit of analog quantity acquisition circuit according to claim 3, characterized in that: The specific analysis method for evaluating the frequency fluctuation coefficient of each pulse signal is as follows: Extract the frequency of each pulse signal and evaluate the frequency fluctuation coefficient of each pulse signal. The calculation formula is: where α i represents the frequency fluctuation coefficient of the i-th pulse signal, b i represents the frequency of the ith pulse signal, b i+1 represents the frequency of the i+1th pulse signal, i represents the number of each pulse signal, i=1,2,...,j, j is a positive integer greater than 2, and j represents the number of pulse signals.

5. The system for disconnection detection circuit of analog quantity acquisition circuit according to claim 3, characterized in that: The specific analysis method for evaluating the amplitude fluctuation coefficient of each pulse signal is as follows: The amplitude of each pulse signal is sampled multiple times to obtain a sample set Ai={ai1,ai2,...,aim} of the amplitude of each pulse signal, where A i represents the sample set of the amplitude of the i-th pulse signal, a im represents the amplitude of the mth sampling point of the ith pulse signal, where m represents the number of each sampling point, m=1, 2, ..., n, where n represents the number of sampling points, and n is a positive integer greater than 2; Evaluate the amplitude fluctuation coefficient of each pulse signal, and the calculation formula is: where β i Represents the amplitude fluctuation coefficient of the i-th pulse signal.

6. The system for disconnection detection circuit of analog quantity acquisition circuit according to claim 1, characterized in that: The type of the positioning abnormality sensor, and the specific analysis method are as follows: Extract the characteristics of each pulse signal, and compare it with the characteristics of each pulse signal stored in the database. If the characteristics of a pulse signal are consistent with the characteristics of a current-type sensor in a normal working state stored in the database, then the type of the abnormal sensor is determined to be a current-type sensor. If the characteristics of a pulse signal are consistent with the characteristics of a voltage-type sensor in a normal working state stored in the database, then the type of the abnormal sensor is determined to be a voltage-type sensor. If the characteristics of a pulse signal are consistent with the characteristics of a resistance-type sensor in a normal working state stored in the database, then the type of the abnormal sensor is determined to be a resistance-type sensor. Based on this judgment, the types of abnormal sensors are current type, voltage type, and resistance type.

7. The system for disconnection detection circuit of analog quantity acquisition circuit according to claim 1, characterized in that: The channel position of the positioning abnormal sensor is specifically analyzed by: The display terminal sends a specific scanning signal to all analog channels to scan and identify the response signal of each analog channel. If an analog channel does not identify the response signal, it is determined that the channel is disconnected. If an analog channel identifies the response signal, it is determined that the analog channel is not disconnected. The address code of the response signal is extracted and compared with the unique address code set for the analog channel. If the address code of the response signal is inconsistent with the unique address code set for the analog channel, it is determined that the analog channel is disconnected. Otherwise, it is determined that the analog channel is not disconnected. Statistics of each disconnected analog channel are obtained, and the unique address code of each disconnected analog channel is compared with the system wiring diagram and channel configuration document to obtain the channel position of each abnormal sensor.

8. The system for disconnection detection circuit of analog quantity acquisition circuit according to claim 7, characterized in that: The classification shows abnormal sensors, and the specific analysis method is as follows: Extract the type of abnormal sensor and compare it with the indicator light corresponding to the type of abnormal sensor. If the type of abnormal sensor is a current type sensor, the indicator light is red; if the type of abnormal sensor is a voltage type sensor, the indicator light is yellow; if the type of abnormal sensor is a resistance type sensor, the indicator light is blue. At the same time, the abnormal type of the abnormal sensor and the channel position of the abnormal sensor are displayed.

9. The system for disconnection detection circuit of analog quantity acquisition circuit according to claim 5, characterized in that: The specific analysis method for predictive maintenance of the system is as follows: The frequency fluctuation coefficient and the amplitude fluctuation coefficient of each pulse signal are extracted and compared with the historical fault data. If the frequency fluctuation coefficient or the amplitude fluctuation coefficient of a pulse signal is the same as a historical fault data, it is determined that the sensor is about to fail, and the fault type in the historical fault data is extracted and displayed on the display terminal.

10. A method for executing the system of a disconnection detection circuit for an analog quantity acquisition circuit according to claims 1 to 9, characterized in that: include: Step 1: Signal switching, which is used to switch between the sensor disconnection analysis function and the normal sampling function through a simulated switching switch; Step 2: generating and amplifying the excitation source, which is used to generate various pulse signals, and amplifying various pulse-shaped signals through operational amplifiers; Step 3: Excitation source feedback collection, used to collect various pulse signals of feedback; Step 4: Line break analysis is used to determine whether the sensor is abnormal. If the sensor is abnormal, determine the type of sensor abnormality, locate the type of abnormal sensor, and locate the channel position of the abnormal sensor.

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