A triple-redundant analog input self-diagnosis method and device

Abstract

A kind of triple redundancy analog input self-diagnosis method and device, self-diagnosis method includes: (1) three analog input modules based on sampling circuit respectively obtain input value as UA, UB, UC, and the interaction of input value is carried out through bus;(2) each analog input module according to the three input values received respectively carries out self-diagnosis, positioning fault;(3) three analog input modules vote through bus and obtain voting result;(4) based on voting result, the type and position of fault are judged;Three analog input modules of analog input device are inserted in base, and are connected with base by connector, and each analog input module can be flexibly plugged in and plugged out.The present application can realize accurate positioning of fault and decoupling between modules, while having the characteristics of hot plug, flexible configuration, ensuring high reliability, high safety of signal acquisition while also having certain economy.

Description

Technical Field

[0001] This invention relates to the application of triple redundancy control in the field of industrial automation control, and particularly to a self-diagnostic method and device for analog input. Background Technology

[0002] In the field of industrial automation, especially in high-reliability and high-safety applications such as chemical and nuclear power industries, triple redundancy control methods are often used to improve the high reliability of analog signal acquisition.

[0003] There are several main ways to implement triple redundancy technology. One is a centralized approach, where all three redundant hardware components are implemented on the same board. However, this requires replacing the entire board in case of a fault, resulting in poor cost-effectiveness. Another approach is a modular design, configuring three pluggable analog signal acquisition modules, allowing for flexible replacement in case of a fault. However, this requires accurate self-diagnosis and fault localization, as well as decoupling between the three modules. This is the current design bottleneck; existing technologies are not yet perfect in terms of self-diagnosis, especially in terms of accurate fault localization. This is a problem that urgently needs to be solved. Summary of the Invention

[0004] To address the problems of imperfections, inaccurate fault location, and incomplete decoupling between modules in modular triple-redundant analog input self-diagnosis schemes, this invention provides a triple-redundant analog input self-diagnosis method and device.

[0005] The present invention solves the above problems through the following technical solution: The first aspect of the present invention provides a triple-redundant analog input self-diagnosis method, comprising the following steps:

[0006] S1. The first analog input module obtains the first input voltage UB based on the sampling circuit, the second analog input module obtains the second input voltage UC based on the sampling circuit, and the third analog input module obtains the third input voltage UA based on the sampling circuit; and the input values ​​are exchanged through the bus so that each analog input module obtains three input values.

[0007] S2. Each analog input module performs self-diagnosis and fault location based on the first input voltage UB, the second input voltage UC, the third input voltage UA, the first voltage threshold US, and the second voltage threshold UM.

[0008] S3. The three analog input modules vote on the self-diagnostic results via a bus to obtain the voting result;

[0009] S4. Based on the voting results, determine the type and location of the fault.

[0010] Preferably, the sampling circuit includes: a first resistor and a second resistor connected in series, wherein the resistance values ​​of the first resistor and the second resistor are equal;

[0011] The first analog input module obtains the input voltage UB based on the first resistor, and obtains the second input voltage UC and the third input voltage UA through the bus; the second analog input module obtains the input voltage UC based on the second resistor, and obtains the first input voltage UB and the third input voltage UA through the bus; the third analog input module obtains the input voltage UA based on the first and second resistors, and obtains the first input voltage UB and the second input voltage UC through the bus.

[0012] Preferably, during normal operation, the input values ​​acquired by the three analog input modules satisfy the following relationship:

[0013]

[0014] In the formula:

[0015] Δ1, Δ2, Δ3 and Δ4 are specified values, which represent the maximum allowable error.

[0016] Preferably, S2 includes:

[0017] The sum of the first input voltage UB and the second input voltage UC is compared with the third input voltage UA. If an anomaly is found, the analog input module is determined to be faulty, and the process continues to identify and locate the faulty analog input module. If no anomaly is found, the following comparison is performed:

[0018] The first input voltage UB is compared with the second input voltage UC. If an anomaly occurs, the sampling circuit is determined to be faulty; if no anomaly occurs, the following comparison is performed:

[0019] The first input voltage UB, the second input voltage UC, and the third input voltage UA are compared with the first voltage threshold US and the second voltage threshold UM, respectively. If an abnormality occurs, it is determined that a sampling circuit fault or an external input current fault has occurred.

[0020] Preferably, condition one in the self-diagnostic logic is used to determine whether the analog input module is faulty and to locate the faulty analog input module.

[0021] Condition one in the self-diagnosis logic is as follows:

[0022] T1: The three input values ​​satisfy: (UB+UC)*(1-Δ1)>UA or UA>(UB+UC)*(1+Δ1), and 2*UB*(1-Δ3)>UA or UA>2*UB*(1+Δ3), and 2*UC*(1-Δ4)≤UA≤2*UC*(1+Δ4), which can accurately locate the fault of the first analog input module corresponding to UB;

[0023] T2: The three input values ​​satisfy: (UB+UC)*(1-Δ1)>UA or UA>(UB+UC)*(1+Δ1), and 2*UB*(1-Δ3)≤UA≤2*UB*(1+Δ3), and 2*UC*(1-Δ4)>UA or UA>2*UC*(1+Δ4), which can accurately locate the fault of the second analog input module corresponding to UC;

[0024] T3: The three input values ​​satisfy: (UB+UC)*(1-Δ1)>UA or UA>(UB+UC)*(1+Δ1), and UC*(1-Δ2)≤UB≤UC*(1+Δ2), which can accurately locate the fault of the third analog input module corresponding to UA.

[0025] Preferably, condition two in the self-diagnostic logic is as follows, used to accurately locate external input current faults:

[0026] M1: The three input values ​​satisfy: (UB+UC)*(1-Δ1)≤UA≤(UB+UC)*(1+Δ1), UC*(1-Δ2)≤UB≤UC*(1+Δ2), and the first input voltage UB, the second input voltage UC, and the third input voltage UA are all less than the first voltage threshold US, where the first voltage threshold US is a set value, which can accurately locate the external input current to find the input cable open circuit or short circuit fault;

[0027] M2: The three input values ​​satisfy: (UB+UC)*(1-Δ1)≤UA≤(UB+UC)*(1+Δ1), and *(1-Δ2)≤UB≤UC*(1+Δ2). Furthermore, the first input voltage UB, the second input voltage UC, and the third input voltage UA are all greater than the second voltage threshold UM, where the second voltage threshold UM is a set value. This can accurately locate the overcurrent fault in the external input current.

[0028] Preferably, condition three in the self-diagnostic logic is as follows, used to accurately locate faults in the sampling circuit:

[0029] N1: The three input values ​​satisfy: (UB+UC)*(1-Δ1)≤UA≤(UB+UC)*(1+Δ1), and UC*(1-Δ2)>UB or UB>UC*(1+Δ2), which can accurately locate the sampling circuit fault.

[0030] N2: If the three input values ​​satisfy the following conditions: the first input voltage UB is less than the first voltage threshold US, and the second input voltage UC and the third input voltage UA are both greater than the second voltage threshold UM, or the second input voltage UC is less than the first voltage threshold US, and the third input voltage UA and the first input voltage UB are both greater than the second voltage threshold UM, the sampling circuit fault can be accurately located.

[0031] Preferably, the self-diagnostic voting in step S3 is as follows: the analog input module adopts a two-out-of-three voting principle;

[0032] If the self-diagnostic results of the three analog input modules are valid, then the vote is taken according to the principle of selecting two out of three.

[0033] If only two of the three analog input modules have valid self-diagnostic results, and if the two analog input modules have the same self-diagnostic results, then the same result will be used as the voting result. If the two analog input modules have different self-diagnostic results: if one module's self-diagnostic result is a fault and the other module's self-diagnostic result is normal, then the staff can set the output value of the voting result according to the application scenario of the module. If both modules' self-diagnostic results are faults, but the fault locations are different, then both fault information will be output.

[0034] The second invention provides a triple-redundant analog input device, which, when running the triple-redundant analog input self-diagnostic method, includes:

[0035] The system consists of a base, a first analog input module, a second analog input module, and a third analog input module. The three analog input modules are installed on the base and connected to it via connectors. Each analog input module can be flexibly plugged in and out. The input current generates three voltage values ​​on the base. The three analog input modules respectively acquire, convert analog to digital, and perform logical judgments on these three voltage values.

[0036] Preferably, the base includes: a sampling circuit and a port protection circuit; the sampling circuit includes a first resistor and a second resistor connected in series, the first end of the first resistor is connected to the positive terminal of the current signal input, the second end of the first resistor is connected to the first end of the second resistor, and the second end of the second resistor is connected to the negative terminal of the current signal input.

[0037] The first resistor and the second resistor have the same resistance value, temperature drift, accuracy and other parameters. The current generates the first input voltage UB in the first resistor, the second input voltage UC in the second resistor, and the third input voltage UA after the first resistor and the second resistor are connected in series. The protection circuit includes a TVS for overvoltage protection of the analog input port.

[0038] Preferably, the three analog input modules have identical hardware, and each analog input module includes: a signal conditioning circuit, an ADC sampling circuit, and a logic processing circuit;

[0039] The voltage signal enters the conditioning circuit for amplitude adjustment and filtering, and then enters the ADC sampling circuit to achieve analog-to-digital conversion. The conversion result is sent to the logic processing unit to perform logical operations with the sampling results of the other two analog input modules for self-diagnosis.

[0040] Preferably, the positive terminal of the voltage input of the first analog input module is connected to the first end of the first resistor, and the negative terminal is connected to the second end of the first resistor; the positive terminal of the voltage input of the second analog input module is connected to the first end of the second resistor, and the negative terminal is connected to the second end of the second resistor; the positive terminal of the voltage input of the third analog input module is connected to the first end of the first resistor, and the negative terminal is connected to the second end of the second resistor.

[0041] Preferably, the signal conditioning circuit has a resistor with a set resistance value connected in series at the front end, including: a first decoupling resistor connected in series at the positive input terminal of the signal conditioning circuit, and a second decoupling resistor connected in series at the negative input terminal of the signal conditioning circuit, for decoupling voltage input signals between analog input modules.

[0042] Preferably, the three analog input modules communicate with each other at a rate of 10MHz via a base, and the communication method is point-to-point, including: communication between the first analog input module and the second analog input module, communication between the first analog input module and the third analog input module, and communication between the first analog input module and the third analog input module.

[0043] Preferably, when any analog input module fails, the faulty module is replaced by hot-swapping.

[0044] At the same time, the number of analog input modules is configured according to the usage environment of the analog input device.

[0045] Preferably, the base also includes an address circuit, comprising: a slot address circuit and a slave address circuit, wherein the slot address circuit is used to set the slot address of each analog input module to distinguish the first, second, and third analog input modules; the slave address circuit is used to set the slave address of the three analog input modules, the slave addresses of the three analog input modules being the same, which is the communication address to the upper-level control device.

[0046] The advantages and beneficial effects of this invention are as follows:

[0047] The triple-redundant analog input self-diagnostic method and device of this invention enables accurate self-diagnosis and fault location for analog input devices in high-safety environments such as nuclear power and chemical industries, ensuring high safety and reliability of analog signal acquisition. This invention establishes a complete self-diagnostic method and device, employing three analog input modules to sample different components in the same circuit. Accurate fault location is achieved based on self-diagnostic logic and a voting mechanism. A large-value resistor is connected in series with the signal conditioning circuit of the analog input modules, thereby decoupling the three modules and preventing a faulty module from affecting the other two. It also features hot-swappable functionality, allowing for convenient replacement of faulty modules. The number of analog input modules can be flexibly configured according to the application scenario, demonstrating high economic efficiency and applicability. Attached Figure Description

[0048] Figure 1 This is a block diagram of the triple-redundant analog input self-diagnosis of the present invention.

[0049] Figure 2 This is a flowchart of the triple-redundant analog input self-diagnosis method of the present invention.

[0050] Figure 3 This is a schematic diagram of the triple-redundant analog input device architecture of the present invention. Detailed Implementation

[0051] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0052] The terms "first," "second," "third," etc., used in the specification, claims, and drawings of this invention are used to distinguish different objects, rather than to describe a specific order.

[0053] Example 1

[0054] As attached Figure 1 As shown, Embodiment 1 of the present invention provides a triple-redundant analog input self-diagnosis method, comprising the following steps:

[0055] S1. The first analog input module obtains the first input voltage UB based on the sampling circuit, the second analog input module obtains the second input voltage UC based on the sampling circuit, and the third analog input module obtains the third input voltage UA based on the sampling circuit.

[0056] The first analog input module, the second analog input module, and the third analog input module exchange input values ​​through a bus, so that each analog input module receives three input values.

[0057] In a preferred but non-limiting embodiment of the present invention, the sampling circuit includes a first resistor and a second resistor connected in series, wherein the resistance values ​​of the first resistor and the second resistor are equal.

[0058] The first analog input module obtains the first input voltage UB based on the first resistor, the second analog input module obtains the second input voltage UC based on the second resistor, and the third analog input module obtains the third input voltage UA based on the first and second resistors.

[0059] Specifically, the first analog input module obtains the input voltage UB based on the first resistor, and obtains the second input voltage UC and the third input voltage UA through the bus; the second analog input module obtains the input voltage UC based on the second resistor, and obtains the first input voltage UB and the third input voltage UA through the bus; the third analog input module obtains the input voltage UA based on the first and second resistors, and obtains the first input voltage UB and the second input voltage UC through the bus.

[0060] During normal operation, the input values ​​acquired by the three analog input modules satisfy the following relationship:

[0061]

[0062] In the formula:

[0063] Δ1, Δ2, Δ3 and Δ4 are specified values, which represent the maximum allowable error.

[0064] S2. Each analog input module performs self-diagnosis and fault location based on the three received input values.

[0065] In a preferred but non-limiting embodiment of the invention, as shown in the appendix Figure 2 As shown below, the flowchart of the triple-redundant analog input self-diagnosis method of the present invention will be described in detail.

[0066] Taking the first analog input module as an example, the first analog input module obtains the input voltage UB based on the first resistor, and interacts with the second and third analog input modules through the bus to obtain the second input voltage UC and the third input voltage UA.

[0067] S2 includes:

[0068] S2.1, self-diagnose whether the analog input module is faulty, and locate the analog input module where the fault is located.

[0069] Specifically, the sum of the first input voltage UB and the second input voltage UC is compared with the third input voltage UA. If an abnormality occurs, it is determined that the analog input module is faulty, and the process continues to determine and locate the analog input module where the fault is located.

[0070] Use condition one in the self-diagnostic logic to determine whether the analog input module is faulty, and locate the analog input module where the fault is located;

[0071] More specifically, condition one in the self-diagnostic logic, as described below, can accurately pinpoint a fault in the analog input module:

[0072] T1: The three input values ​​satisfy: (UB+UC)*(1-Δ1)>UA or UA>(UB+UC)*(1+Δ1), and 2*UB*(1-Δ3)>UA or UA>2*UB*(1+Δ3), and 2*UC*(1-Δ4)≤UA≤2*UC*(1+Δ4), which can accurately locate the fault of the first analog input module corresponding to UB;

[0073] T2: The three input values ​​satisfy: (UB+UC)*(1-Δ1)>UA or UA>(UB+UC)*(1+Δ1), and 2*UB*(1-Δ3)≤UA≤2*UB*(1+Δ3), and 2*UC*(1-Δ4)>UA or UA>2*UC*(1+Δ4), which can accurately locate the fault of the second analog input module corresponding to UC;

[0074] T3: The three input values ​​satisfy: (UB+UC)*(1-Δ1)>UA or UA>(UB+UC)*(1+Δ1), and UC*(1-Δ2)≤UB≤UC*(1+Δ2), which can accurately locate the fault of the third analog input module corresponding to UA.

[0075] S2.2, self-diagnose whether the external input current is faulty and determine the fault type.

[0076] Specifically, the sum of the first input voltage UB and the second input voltage UC is compared with the third input voltage UA. If there is no abnormality, and the first input voltage UB is also compared with the second input voltage UC, the first input voltage UB, the second input voltage UC, and the third input voltage UA are compared with the set voltage thresholds to determine the fault type.

[0077] More specifically, condition two in the self-diagnostic logic, as described below, can accurately pinpoint an external input current fault:

[0078] M1: The three input values ​​satisfy: (UB+UC)*(1-Δ1)≤UA≤(UB+UC)*(1+Δ1), and UC*(1-Δ2)≤UB≤UC*(1+Δ2). Furthermore, the first input voltage UB, the second input voltage UC, and the third input voltage UA are all less than the first voltage threshold US, where the first voltage threshold US is a set value. This can accurately locate the external input current and identify whether there is an open circuit or short circuit fault in the input cable.

[0079] M2: The three input values ​​satisfy: (UB+UC)*(1-Δ1)≤UA≤(UB+UC)*(1+Δ1), and UC*(1-Δ2)≤UB≤UC*(1+Δ2). Furthermore, the first input voltage UB, the second input voltage UC, and the third input voltage UA are all greater than the second voltage threshold UM, where the second voltage threshold UM is a set value. This can accurately locate the overcurrent fault in the external input current.

[0080] S2.3, self-diagnose whether the sampling circuit is faulty and determine the fault type.

[0081] Specifically, if the sum of the first input voltage UB and the second input voltage UC is compared with the third input voltage UA, and there is no abnormality, but there is an abnormality when comparing the first input voltage UB with the second input voltage UC, then the sampling circuit is faulty.

[0082] More specifically, condition three in the self-diagnostic logic, as described below, can accurately pinpoint the fault in the sampling circuit:

[0083] N1: The three input values ​​satisfy: (UB+UC)*(1-Δ1)≤UA≤(UB+UC)*(1+Δ1), and UC*(1-Δ2)>UB or UB>UC*(1+Δ2), which can accurately locate the sampling circuit fault.

[0084] N2: If the three input values ​​satisfy the following conditions: the first input voltage UB is less than the first voltage threshold US, and the second input voltage UC and the third input voltage UA are both greater than the second voltage threshold UM, or the second input voltage UC is less than the first voltage threshold US, and the third input voltage UA and the first input voltage UB are both greater than the second voltage threshold UM, the sampling circuit fault can be accurately located.

[0085] S3. The three analog input modules vote on the self-diagnostic results via a bus to obtain the voting result, thereby achieving accurate fault location.

[0086] In a preferred but non-limiting embodiment of the present invention, the voting method is as follows: the analog input module adopts a two-out-of-three voting principle.

[0087] Specifically, if the self-diagnostic results of the three analog input modules are valid, the voting will proceed according to the principle of selecting two out of three. If only two of the three analog input modules have valid self-diagnostic results, and the two analog input modules have the same self-diagnostic results, the same result will be used as the voting result. If the self-diagnostic results of the two analog input modules are different: if one module's self-diagnostic result is a fault and the other module's self-diagnostic result is normal, the staff can set the output value of the voting result according to the application scenario of the module. If both modules' self-diagnostic results are faults, but the fault locations are different, both fault information will be output.

[0088] S4. Based on the voting results, determine the type and location of the fault.

[0089] Example 2

[0090] As attached Figure 3 As shown, Embodiment 2 of the present invention provides a triple-redundant analog input device, which is implemented based on the above-described triple-redundant analog input self-diagnosis method.

[0091] The triple-redundant analog input device adopts a modular design architecture, including: a base, a first analog input module, a second analog input module, and a third analog input module. The three analog input modules are plugged into the base via connectors, and each module can be flexibly plugged in and out. The hardware and software of the three modules are identical.

[0092] The base mainly includes sampling circuits, port protection circuits, and address circuits.

[0093] (1) The sampling circuit includes: a first resistor and a second resistor connected in series. The first end of the first resistor is connected to the positive terminal of the current signal input, the second end of the first resistor is connected to the first end of the second resistor, and the second end of the second resistor is connected to the negative terminal of the current signal input. The first resistor and the second resistor have the same resistance, temperature drift, accuracy and other parameters.

[0094] (2) The port protection circuit includes: TVS (Transient Voltage Suppressor) to realize the overvoltage protection function.

[0095] (3) The address circuit is divided into a slot address circuit and a slave address circuit. The slot address circuit is used to set the slot address of each analog input module, such as 0, 1, 2, to distinguish the first, second and third analog input modules. The slave address circuit is used to set the slave address of the three analog input modules. The slave address of the three analog input modules is the same, which is the communication address to the upper control device.

[0096] The analog input module includes signal conditioning circuits, ADC sampling circuits (Analog to Digital Converter), logic processing circuits, etc. The voltage signal enters the conditioning circuit for amplitude adjustment and filtering, and then enters the ADC sampling circuit to achieve analog-to-digital conversion. The conversion result is sent to the logic processing unit to perform logical operations with the sampling results of the other two analog input modules to achieve self-diagnosis.

[0097] The three analog input modules should have decoupling functionality, especially when one module fails, such as a short circuit between the positive and negative input terminals of the signal conditioning circuit, which will affect the sampling results of the other two modules. Therefore, [further details are needed]. Figure 2 In this circuit, the analog input modules have resistors with a value of several hundred kiloohms connected in series before the positive and negative inputs of the signal conditioning circuit, thereby decoupling the voltage input signals between the analog input modules.

[0098] The three analog input modules communicate with each other via a bus in a point-to-point manner, namely: communication between the first and second analog input modules, communication between the first and third analog input modules, and communication between the first and third analog input modules.

[0099] In practical applications, when a certain analog input module fails, the faulty module can be replaced by hot-swapping. At the same time, if the usage scenario of this device does not have high requirements for redundancy configuration, the staff can flexibly configure the number of analog input modules according to the needs.

[0100] The specific embodiments described above further illustrate the purpose, technical solution, and beneficial effects of the present invention. However, those skilled in the art should understand that the above descriptions are merely specific embodiments of the present invention, and the scope of protection of the present invention is defined by the appended claims. Those skilled in the art can make various changes or modifications to these embodiments without departing from the principles and essence of the present invention, but all such changes and modifications fall within the scope of protection of the present invention.

Claims

1. A triple-redundant analog input self-diagnosis method, characterized in that, Includes the following steps: S1. The first analog input module obtains the first input voltage UB based on the sampling circuit, the second analog input module obtains the second input voltage UC based on the sampling circuit, and the third analog input module obtains the third input voltage UA based on the sampling circuit. The input values ​​are exchanged via a bus, so that each analog input module receives three input values. The sampling circuit includes: a first resistor and a second resistor connected in series, wherein the resistance values ​​of the first resistor and the second resistor are equal; a first analog input module obtains the input voltage UB based on the first resistor, and obtains the second input voltage UC and the third input voltage UA through a bus; a second analog input module obtains the input voltage UC based on the second resistor, and obtains the first input voltage UB and the third input voltage UA through a bus; a third analog input module obtains the input voltage UA based on the first and second resistors, and obtains the first input voltage UB and the second input voltage UC through a bus. S2. Each analog input module performs self-diagnosis and fault location based on the first input voltage UB, the second input voltage UC, the third input voltage UA, the first voltage threshold US, and the second voltage threshold UM. S3. The three analog input modules vote on the self-diagnostic results via a bus to obtain the voting result; S4. Based on the voting results, determine the type and location of the fault.

2. The triple-redundant analog input self-diagnosis method as described in claim 1, characterized in that: During normal operation, the input values ​​acquired by the three analog input modules satisfy the following relationship: In the formula: Δ1, Δ2, Δ3 and Δ4 are specified values, which represent the maximum allowable error.

3. The triple-redundant analog input self-diagnosis method as described in claim 2, characterized in that: S2 includes: The sum of the first input voltage UB and the second input voltage UC is compared with the third input voltage UA. If an anomaly is found, the analog input module is determined to be faulty, and the process continues to identify and locate the faulty analog input module. If no anomaly is found, the following comparison is performed: The first input voltage UB is compared with the second input voltage UC. If an anomaly occurs, the sampling circuit is determined to be faulty; if no anomaly occurs, the following comparison is performed: The first input voltage UB, the second input voltage UC, and the third input voltage UA are compared with the first voltage threshold US and the second voltage threshold UM, respectively. If an abnormality occurs, it is determined that there is a sampling circuit fault or an external input current fault.

4. The triple-redundant analog input self-diagnosis method as described in claim 3, characterized in that: Use condition one in the self-diagnostic logic to determine whether the analog input module is faulty, and locate the analog input module where the fault is located; Condition one in the self-diagnosis logic is as follows: T1: The three input values ​​satisfy: (UB+UC)*(1-Δ1)>UA or UA>(UB+UC)*(1+Δ1), and 2*UB*(1-Δ3)>UA or UA>2*UB*(1+Δ3), and 2*UC*(1-Δ4)≤UA≤2*UC*(1+Δ4), which can accurately locate the fault of the first analog input module corresponding to UB; T2: The three input values ​​satisfy: (UB+UC)*(1-Δ1)>UA or UA>(UB+UC)*(1+Δ1), and 2*UB*(1-Δ3)≤UA≤2*UB*(1+Δ3), and 2*UC*(1-Δ4)>UA or UA>2*UC*(1+Δ4), which can accurately locate the fault of the second analog input module corresponding to UC; T3: The three input values ​​satisfy: (UB+UC)*(1-Δ1)>UA or UA>(UB+UC)*(1+Δ1), and UC*(1-Δ2)≤UB≤UC*(1+Δ2), which can accurately locate the fault of the third analog input module corresponding to UA.

5. The triple-redundant analog input self-diagnosis method as described in claim 3, characterized in that: Condition two in the self-diagnostic logic is as follows, used to accurately locate faults in the external input current: M1: The three input values ​​satisfy: (UB+UC)*(1-Δ1)≤UA≤(UB+UC)*(1+Δ1), UC*(1-Δ2)≤UB≤UC*(1+Δ2), and the first input voltage UB, the second input voltage UC, and the third input voltage UA are all less than the first voltage threshold US, where the first voltage threshold US is a set value, which can accurately locate the external input current to find the input cable open circuit or short circuit fault; M2: The three input values ​​satisfy: (UB+UC)*(1-Δ1)≤UA≤(UB+UC)*(1+Δ1), and UC*(1-Δ2)≤UB≤UC*(1+Δ2). Furthermore, the first input voltage UB, the second input voltage UC, and the third input voltage UA are all greater than the second voltage threshold UM, where the second voltage threshold UM is a set value. This can accurately locate the overcurrent fault in the external input current.

6. The triple-redundant analog input self-diagnosis method as described in claim 3, characterized in that: Condition three in the self-diagnostic logic is as follows, used to accurately locate faults in the sampling circuit: N1: The three input values ​​satisfy: (UB+UC)*(1-Δ1)≤UA≤(UB+UC)*(1+Δ1), and UC*(1-Δ2)>UB or UB>UC*(1+Δ2), which can accurately locate the sampling circuit fault. N2: If the three input values ​​satisfy the following conditions: the first input voltage UB is less than the first voltage threshold US, and the second input voltage UC and the third input voltage UA are both greater than the second voltage threshold UM, or the second input voltage UC is less than the first voltage threshold US, and the third input voltage UA and the first input voltage UB are both greater than the second voltage threshold UM, the sampling circuit fault can be accurately located.

7. The triple-redundant analog input self-diagnosis method according to any one of claims 4-6, characterized in that: In step S3, the self-diagnostic voting is as follows: the analog input module adopts a two-out-of-three voting principle; If the self-diagnostic results of the three analog input modules are valid, then the vote is taken according to the principle of selecting two out of three. If only two of the three analog input modules have valid self-diagnostic results, and if the two analog input modules have the same self-diagnostic results, then the same result shall be used as the voting result; if the two analog input modules have different self-diagnostic results: if one module's self-diagnostic result is a fault and the other module's self-diagnostic result is normal, then the staff can set the output value of the voting result according to the application of the module. If both modules' self-diagnostic results indicate a fault, but the fault locations are different, then both fault information will be output.

8. A triple-redundant analog input device, operating the triple-redundant analog input self-diagnostic method as described in any one of claims 1-7, characterized in that, include: The system consists of a base, a first analog input module, a second analog input module, and a third analog input module. The three analog input modules are installed on the base and connected to it via connectors. Each analog input module can be flexibly plugged in and out. The input current generates three voltage values ​​on the base. The three analog input modules respectively acquire, convert analog to digital, and perform logical judgments on these three voltage values.

9. The triple-redundant analog input device as described in claim 8, characterized in that: The base includes: a sampling circuit and a port protection circuit; the sampling circuit includes a first resistor and a second resistor connected in series, the first end of the first resistor is connected to the positive terminal of the current signal input, the second end of the first resistor is connected to the first end of the second resistor, and the second end of the second resistor is connected to the negative terminal of the current signal input. The first resistor and the second resistor have the same resistance value, temperature drift, accuracy and other parameters. The current generates the first input voltage UB in the first resistor, the second input voltage UC in the second resistor, and the third input voltage UA after the first resistor and the second resistor are connected in series. The protection circuit includes a TVS for overvoltage protection of the analog input port.

10. The triple-redundant analog input device as described in claim 9, characterized in that: The three analog input modules have identical hardware. Each analog input module includes: signal conditioning circuit, ADC sampling circuit, and logic processing circuit. The voltage signal enters the conditioning circuit for amplitude adjustment and filtering, and then enters the ADC sampling circuit to achieve analog-to-digital conversion. The conversion result is sent to the logic processing unit to perform logical operations with the sampling results of the other two analog input modules for self-diagnosis.

11. The triple-redundant analog input device as described in claim 10, characterized in that: The positive terminal of the voltage input of the first analog input module is connected to the first end of the first resistor, and the negative terminal is connected to the second end of the first resistor; the positive terminal of the voltage input of the second analog input module is connected to the first end of the second resistor, and the negative terminal is connected to the second end of the second resistor; the positive terminal of the voltage input of the third analog input module is connected to the first end of the first resistor, and the negative terminal is connected to the second end of the second resistor.

12. The triple-redundant analog input device as described in claim 11, characterized in that: The signal conditioning circuit has a resistor with a set resistance value connected in series at the front end, including: a first decoupling resistor connected in series at the positive input terminal of the signal conditioning circuit, and a second decoupling resistor connected in series at the negative input terminal of the signal conditioning circuit, which is used to decouple the voltage input signals between analog input modules.

13. The triple-redundant analog input device as described in claim 12, characterized in that: The three analog input modules communicate with each other at a rate of 10MHz via a base station. The communication method is point-to-point, including: communication between the first analog input module and the second analog input module, communication between the first analog input module and the third analog input module, and communication between the first analog input module and the third analog input module.

14. The triple-redundant analog input device as described in claim 13, characterized in that: When any analog input module fails, the faulty module is replaced by hot-swapping. At the same time, the number of analog input modules is configured according to the usage environment of the analog input device.

15. The triple-redundant analog input device as described in claim 14, characterized in that: The base also includes address circuitry, including a slot address circuit and a slave address circuit. The slot address circuit is used to set the slot address of each analog input module to distinguish between the first, second, and third analog input modules. The slave address circuit is used to set the slave address of the three analog input modules. The slave addresses of the three analog input modules are the same and are used to realize the communication address with the upper-level control device.

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