Triple-redundancy analog input self-diagnosis method and device

Abstract

The invention discloses a triple-redundancy analog input self-diagnosis method and device, and the method comprises the steps: (1) three analog input modules respectively obtain input values UA, UB and UC based on a sampling circuit, and carry out the interaction of the input values through a bus; (2) each analog quantity input module carries out self-diagnosis according to the three received input values and locates faults; (3) the three analog input modules vote the self-diagnosis result through a bus to obtain a voting result; (4) judging the type and the position of the fault based on the voting result; the three analog quantity input modules of the analog quantity input device are inserted into the base and connected with the base through the connectors, and each analog quantity input module can be flexibly inserted and pulled out. According to the invention, accurate positioning of faults and decoupling between modules can be realized, and the system has the characteristics of hot plug and flexible configuration, and has certain economical efficiency while ensuring high reliability and high safety of signal acquisition.

Description

Technical Field

[0001] The invention relates to the application of triple redundant control in the field of industrial automation control, and in particular to a self-diagnosis method and device for analog input. Background Art

[0002] In the field of industrial automation, especially in high reliability and high safety occasions, such as chemical industry, nuclear power and other related fields, in order to improve the high reliability of analog signal acquisition, most of them adopt triple redundant control method.

[0003] There are several main ways to implement triple redundancy technology. One is a centralized way, that is, the triple redundant hardware is implemented on the same board. When a fault occurs, the entire board needs to be replaced, which is not economical. Another is a modular design, which configures three pluggable analog acquisition modules, which can be flexibly replaced when a fault occurs. However, the premise is to achieve accurate self-diagnosis and positioning of the fault, and to achieve decoupling design between the three modules. This is the current design bottleneck. The existing technical solutions are not perfect enough for self-diagnosis, especially for accurate positioning of faults. This is an urgent problem to be solved. Summary of the invention

[0004] In order to solve the problems of imperfect modular triple redundant analog input self-diagnosis scheme, inaccurate fault location, incomplete decoupling between modules, etc., the present invention provides a triple redundant analog input self-diagnosis method and device.

[0005] The present invention solves the above-mentioned problem through the following technical scheme: A 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 a first input voltage UB based on a sampling circuit, the second analog input module obtains a second input voltage UC based on a sampling circuit, and the third analog input module obtains a third input voltage UA based on a sampling circuit; and the input values ​​are interacted 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 according to the first input voltage UB, the second input voltage UC and the third input voltage UA, the first voltage threshold US and the second voltage threshold UM respectively;

[0008] S3. The three analog input modules vote on the self-diagnosis results through the bus to obtain the voting results;

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

[0010] Preferably, the sampling circuit comprises: a first resistor and a second resistor connected in series, wherein the first resistor and the second resistor have equal resistance values;

[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 ​​obtained by the three analog input modules satisfy the following relationship:

[0013]

[0014] Where:

[0015] Δ1, Δ2, Δ3 and Δ4 are specified values ​​and are the maximum allowable errors.

[0016] Preferably, S2 includes:

[0017] Compare the sum of the first input voltage UB and the second input voltage UC with the third input voltage UA. If an abnormality occurs, it is determined that the analog input module is faulty, and the analog input module where the fault occurs is further determined and located. If no abnormality occurs, the following comparison is continued:

[0018] The first input voltage UB is compared with the second input voltage UC. If an abnormality occurs, it is determined that the sampling circuit is faulty; if no abnormality occurs, the following comparison is continued:

[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 occurs.

[0020] Preferably, condition 1 in the self-diagnosis logic is used to determine whether the analog input module is faulty, and locate the analog input module where the fault is located;

[0021] Condition 1 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), the fault of the first analog input module corresponding to UB can be accurately located;

[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), the fault of the second analog input module corresponding to UC can be accurately located;

[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). The fault of the third analog input module corresponding to UA can be accurately located.

[0025] Preferably, condition 2 in the self-diagnosis logic is as follows, which is used to accurately locate the external input current fault:

[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 with an input cable disconnection 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), and 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, which can accurately locate the overcurrent fault of the external input current.

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

[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: The three input values ​​satisfy: 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-diagnosis voting in step S3 is as follows: the analog input module adopts the voting principle of two out of three;

[0032] If the self-diagnosis results of the three analog input modules are valid, voting is performed according to the principle of two out of three;

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

[0034] The second invention of the present invention provides a triple redundant analog input device, and the triple redundant analog input self-diagnosis method is executed, comprising:

[0035] The base, the first analog input module, the second analog input module and the third analog input module, the three analog input modules are plugged into the base and connected to the base through a connector. Each analog input module can be flexibly plugged in and out. The input current generates three voltages in the base. The three analog input modules respectively collect, convert analog-to-digital and make logical judgments on these three voltages.

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

[0037] Among them, the first resistor and the second resistor have the same parameters such as resistance value, temperature drift, and accuracy. The current generates a first input voltage UB in the first resistor and a second input voltage UC in the second resistor. After the first resistor and the second resistor are connected in series, a third input voltage UA is generated. The protection circuit includes: TVS, which is used for overvoltage protection of the analog input port.

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

[0039] The voltage enters the conditioning circuit for amplitude adjustment and filtering, and then enters the ADC sampling circuit for analog-to-digital conversion. The conversion result is sent to the logic processing unit for logical operation 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 quantity 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 quantity 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 quantity 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 of set resistance connected in series at the front end, including: a first decoupling resistor connected in series at the positive input end of the signal conditioning circuit, and a second decoupling resistor connected in series at the negative input end of the signal conditioning circuit, for decoupling voltage input signals between analog input modules.

[0042] Preferably, the three analog input modules communicate at a rate of 10 MHz through the base, and the communication mode 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 failed module is replaced by hot-swap;

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

[0045] Preferably, the base also includes an address circuit, including: 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, for distinguishing the first, second, and third analog input modules; the slave address circuit is used to set the slave addresses 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.

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

[0047] The triple redundant analog input self-diagnosis method and device of the present invention enable accurate self-diagnosis and fault location for analog input devices in high-security occasions, such as nuclear power, chemical industry, etc., ensuring high safety and high reliability of analog quantity acquisition. The present invention has established a complete self-diagnosis method and device, using three analog input modules to achieve sampling of different components of the same circuit, and accurately locate the fault according to the self-diagnosis logic and voting mechanism. The front stage of the signal conditioning circuit of the analog input module is connected in series with a large resistance resistor, thereby achieving decoupling between the three analog input modules, avoiding the influence of the faulty module on the other two modules, and having a hot-swap function, which can easily replace the faulty module, and can also flexibly configure the number of analog input modules according to the application scenario of the device, with high economy and applicability. BRIEF DESCRIPTION OF THE DRAWINGS

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

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

[0050] Figure 3 It is a diagram of the architecture of the triple redundant analog input device of the present invention. DETAILED DESCRIPTION

[0051] 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 making creative work are within the scope of protection of the present invention.

[0052] The terms “first”, “second”, “third”, etc. in the specification, claims and drawings of the present 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 a first input voltage UB based on a sampling circuit, the second analog input module obtains a second input voltage UC based on a sampling circuit, and the third analog input module obtains a third input voltage UA based on a sampling circuit.

[0056] The first analog quantity input module, the second analog quantity input module and the third analog quantity input module interact with each other in input values ​​through the bus, so that each analog quantity input module obtains three input values.

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

[0058] The first analog input module obtains a first input voltage UB based on the first resistor, the second analog input module obtains a second input voltage UC based on the second resistor, and the third analog input module obtains a 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 ​​obtained by the three analog input modules satisfy the following relationship:

[0061]

[0062] Where:

[0063] Δ1, Δ2, Δ3 and Δ4 are specified values ​​and are the maximum allowable errors.

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

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

[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, exchanges data with the second and third analog input modules through the bus, and obtains 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.

[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 analog input module where the fault occurs is further determined and located.

[0070] Use condition 1 in the self-diagnosis logic to determine whether the analog input module is faulty, and locate the analog input module where the fault is;

[0071] More specifically, condition 1 in the self-diagnosis logic is as follows, which can accurately locate the analog input module fault:

[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), the fault of the first analog input module corresponding to UB can be accurately located;

[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), the fault of the second analog input module corresponding to UC can be accurately located;

[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). The fault of the third analog input module corresponding to UA can be accurately located.

[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 compared with the second input voltage UC and there is also no abnormality, the first input voltage UB, the second input voltage UC, and the third input voltage UA are further compared with the set voltage thresholds to determine the fault type.

[0077] More specifically, condition 2 in the self-diagnosis logic is as follows, which can accurately locate the 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), 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 with an input cable disconnection or short circuit fault;

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

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

[0081] 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, but the first input voltage UB is compared with the second input voltage UC and there is an abnormality, then the sampling circuit fails.

[0082] More specifically, condition three in the self-diagnosis logic is as follows, which can accurately locate the sampling circuit fault:

[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: The three input values ​​satisfy: 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-diagnosis results through the bus to obtain the voting results, thereby achieving accurate positioning of the fault.

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

[0087] Specifically, if the self-diagnosis results of the three analog input modules are valid, voting is carried out according to the principle of two out of three; if the self-diagnosis results of only two analog input modules among the three analog input modules are valid, if the self-diagnosis results of the two analog input modules are the same, the same result is used as the voting result; if the self-diagnosis results of the two analog input modules are different: if the self-diagnosis result of one module is a fault and the self-diagnosis result of the other module is normal, the staff can set the output value of the voting result according to the application scenario of the module; if the self-diagnosis results of the two modules are both 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 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 through connectors, and each module can be flexibly plugged in and out. The hardware and software of the three modules are the same.

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

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

[0094] (2) The port protection circuit includes a TVS (Transient Voltage Suppressor) to achieve overvoltage protection.

[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, which is used to distinguish the first, second, and third analog input modules; the slave address circuit is used to set the slave addresses 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.

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

[0097] The three analog input modules should have a decoupling function, especially when a module fails, such as: the positive input terminal and the negative input terminal of the signal conditioning circuit are short-circuited, which will affect the sampling results of the other two modules. Figure 2 The analog input modules in the circuit are connected in series with resistors with a resistance of several hundred kilo-ohms before the positive and negative input stages of the signal conditioning circuit, so as to achieve decoupling of the voltage input signals between the analog input modules.

[0098] The three analog input modules exchange data through a bus, and the communication mode is point-to-point, namely: 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.

[0099] In actual applications, when an analog input module fails, the faulty module can be replaced by hot-swapped. At the same time, if the usage scenario of this device does not require high redundant configuration, the staff can flexibly configure the number of analog input modules according to demand.

[0100] The specific implementations described above further describe the purpose, technical solutions and beneficial effects of the present invention in detail, but those skilled in the art should understand that the above are only specific implementations of the present invention, and the protection scope of the present invention is defined by the attached claims. Those skilled in the art can make various changes or modifications to these implementations without departing from the principle and essence of the present invention, but these changes and modifications fall within the protection scope of the present invention.

Claims

1. A triple redundant analog input self-diagnosis method, It is characterized in that The following steps are involved: S1. The first analog input module obtains a first input voltage UB based on a sampling circuit, the second analog input module obtains a second input voltage UC based on a sampling circuit, and the third analog input module obtains a third input voltage UA based on a sampling circuit; and the input values ​​are interacted through the bus so that each analog input module obtains three input values; S2. Each analog input module performs self-diagnosis and fault location according to the first input voltage UB, the second input voltage UC and the third input voltage UA, the first voltage threshold US and the second voltage threshold UM respectively; S3. The three analog input modules vote on the self-diagnosis results through the bus to obtain the voting results; S4. Based on the voting results, determine the type and location of the fault.

2. The triple redundant analog input self-diagnosis method according to claim 1, Features: The sampling circuit comprises: a first resistor and a second resistor connected in series, wherein the first resistor and the second resistor have equal resistance values; 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.

3. The triple redundant analog input self-diagnosis method as claimed in claim 2, Features: During normal operation, the input values ​​obtained by the three analog input modules satisfy the following relationship: Where: Δ1, Δ2, Δ3 and Δ4 are specified values ​​and are the maximum allowable errors.

4. The triple redundant analog input self-diagnosis method as claimed in claim 3, Features: S2 includes: Compare the sum of the first input voltage UB and the second input voltage UC with the third input voltage UA. If an abnormality occurs, it is determined that the analog input module is faulty, and the analog input module where the fault occurs is further determined and located. If no abnormality occurs, the following comparison is continued: The first input voltage UB is compared with the second input voltage UC. If an abnormality occurs, it is determined that the sampling circuit is faulty; if no abnormality occurs, the following comparison is continued: 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 occurs.

5. The triple redundant analog input self-diagnosis method as claimed in claim 4, Features: Use condition 1 in the self-diagnosis logic to determine whether the analog input module is faulty, and locate the analog input module where the fault is; Condition 1 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), the fault of the first analog input module corresponding to UB can be accurately located; 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), the fault of the second analog input module corresponding to UC can be accurately located; 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). The fault of the third analog input module corresponding to UA can be accurately located.

6. The triple redundant analog input self-diagnosis method as claimed in claim 4, Features: The second condition in the self-diagnosis logic is as follows, which is used to accurately locate the external input current fault: 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 with an input cable disconnection 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), and 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, which can accurately locate the overcurrent fault of the external input current.

7. The triple redundant analog input self-diagnosis method as claimed in claim 4, Features: Condition three in the self-diagnosis logic is as follows, which is used to accurately locate the sampling circuit fault: N1: The three input values ​​satisfy: (UB+UC)*(1-Δ1)≤UA≤(UB+UC)*(1+Δ1), and *(1-Δ2)>UB or UB>UC*(1+Δ2), which can accurately locate the sampling circuit fault; N2: The three input values ​​satisfy: 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.

8. The triple redundant analog input self-diagnosis method according to any one of claims 5 to 7, Features: The self-diagnosis voting in step S3 is as follows: the analog input module adopts the voting principle of two out of three; If the self-diagnosis results of the three analog input modules are valid, voting is performed according to the principle of two out of three; If the self-diagnosis results of only two analog quantity input modules among the three analog quantity input modules are valid, if the self-diagnosis results of the two analog quantity input modules are the same, the same result shall be used as the voting result; if the self-diagnosis results of the two analog quantity input modules are different: if the self-diagnosis result of one module is faulty and the self-diagnosis result of the other module is normal, the staff can set the output value of the voting result according to the application of the module; If the self-diagnosis results of both modules are faulty, but the fault locations are different, both fault information will be output.

9. A triple redundant analog input device, running the triple redundant analog input self-diagnosis method as described in any one of claims 1 to 8, It is characterized in that include: The base, the first analog input module, the second analog input module and the third analog input module, the three analog input modules are plugged into the base and connected to the base through a connector. Each analog input module can be flexibly plugged in and out. The input current generates three voltages in the base. The three analog input modules respectively collect, convert analog-to-digital and make logical judgments on these three voltages.

10. The triple redundant analog input device according to claim 9, Features: 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 end 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 end of the current signal input; Among them, the first resistor and the second resistor have the same parameters such as resistance value, temperature drift, and accuracy. The current generates a first input voltage UB in the first resistor and a second input voltage UC in the second resistor. After the first resistor and the second resistor are connected in series, a third input voltage UA is generated. The protection circuit includes: TVS, which is used for overvoltage protection of the analog input port.

11. The triple redundant analog input device according to claim 10, Features: The three analog input modules have the same hardware. The analog input modules include: signal conditioning circuit, ADC sampling circuit, and logic processing circuit; The voltage enters the conditioning circuit for amplitude adjustment and filtering, and then enters the ADC sampling circuit for analog-to-digital conversion. The conversion result is sent to the logic processing unit for logical operation with the sampling results of the other two analog input modules for self-diagnosis.

12. The triple redundant analog input device according to claim 11, Features: The positive terminal of the voltage input of the first analog quantity 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 quantity 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 quantity 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.

13. The triple redundant analog input device according to claim 12, Features: 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 end of the signal conditioning circuit, and a second decoupling resistor connected in series at the negative input end of the signal conditioning circuit, which is used for decoupling voltage input signals between analog input modules.

14. The triple redundant analog input device according to claim 13, Features: The three analog input modules communicate at a rate of 10MHz through the base, and the communication mode 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.

15. The triple redundant analog input device according to claim 14, Features: When any analog input module fails, the faulty module can be replaced by hot-swap; At the same time, the number of analog input modules is configured according to the use environment of the analog input device.

16. The triple redundant analog input device according to claim 15, Features: The base also includes an address circuit, including: 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, and is used to distinguish the first, second, and third analog input modules; the slave address circuit is used to set the slave addresses of the three analog input modules. The slave addresses of the three analog input modules are the same, which is used to realize the communication address with the upper control device.

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