A design method for dual-card redundant diagnosis and switching based on FPGA+ARM

Abstract

The present invention belongs to the field of electronic circuit technology, and specifically relates to a design method for diagnosing and switching dual-card redundancy based on FPGA+ARM. The method diagnoses important components, functions and redundant interactive signals inside the module to realize redundant switching of the module, so as to be applied to the dual-card redundancy design scheme of the industrial control system to realize the redundant card function with high system reliability.

Description

Technical Field

[0001] The invention belongs to the technical field of electronic circuits, and in particular relates to a design method for dual-card redundant diagnosis and switching based on FPGA+ARM. Background Art

[0002] Dual card redundancy is a very common design for high system reliability in industrial control systems such as distributed control systems (DCS) and programmable control systems (PLC). When dual card redundancy is working, the diagnosis-switching mechanism of dual card redundancy is the key to achieving high system reliability.

[0003] The traditional method is to judge and switch the working / standby mode of the redundant card through the heartbeat signal between the redundant dual cards. This method has a single diagnosis for the dual cards and introduces a greater risk of diagnostic errors causing the dual card redundancy to fail to achieve its function.

[0004] In summary, the dual-card redundancy mechanism that only uses the heartbeat line has the risk of reliability of the dual-card redundancy function due to lack of diagnosis. Summary of the invention

[0005] The technical problem to be solved by the present invention is to provide a design method for dual-card redundant diagnosis and switching based on FPGA+ARM, which diagnoses the important components, functions and redundant interactive signals inside the module and then realizes the redundant switching of the module, so as to be applied to the dual-card redundant design scheme of the industrial control system to realize the redundant card function with high system reliability.

[0006] In order to achieve this purpose, the technical solution adopted by the present invention is:

[0007] A design method for dual-card redundant diagnosis and switching based on FPGA+ARM, comprising the following steps:

[0008] Step 1: After the module is powered on, it will directly enter the "Redundant Standby Card - Initial State" state;

[0009] Step 2: In the "Redundant Standby Card - Initial State" state, switch the state according to the diagnosis results:

[0010] (1) When the diagnosis results meet the following conditions at the same time, the system enters the "Redundant Master Card - Initial State" state:

[0011] a) The power-on time reaches the initial state diagnosis time T1;

[0012] b) The last digit of the board address is 1;

[0013] c) Terminal redundancy diagnosis without master card;

[0014] d) Backplane redundancy diagnosis card is missing or there is a spare card;

[0015] (2) Otherwise, the state remains in the "redundant standby card - initial state" until the power-on time reaches the initial state diagnosis time T2 and then enters the "redundant standby card" state;

[0016] Step 3:

[0017] In the "Redundant Master Card - Initial State" state, wait for the power-on time to reach the initial state diagnosis time T2 before entering the "Redundant Master Card" state;

[0018] In the "redundant standby card" state, the state is switched according to the diagnosis result:

[0019] (1) When the diagnosis results meet the following conditions at the same time, the card remains in the "redundant standby" state:

[0020] a)ARM runs normally;

[0021] b) The channel works normally;

[0022] c) One of the following two conditions is met: the terminal redundancy diagnosis shows that there is a master card, the terminal redundancy diagnosis shows that there is no master card and the backplane redundancy diagnosis shows that there is a quasi-master card;

[0023] d) Bus communication is normal;

[0024] (2) When the diagnosis results meet the following conditions at the same time, the system enters the "redundant master card" state:

[0025] a)ARM runs normally;

[0026] b) The channel works normally;

[0027] c) The terminal redundancy diagnosis shows that there is no master card and the backplane redundancy diagnosis shows that there is a spare card;

[0028] d) Bus communication is normal;

[0029] (3) When the diagnosis results meet the following conditions at the same time, the system enters the "single card master card" state:

[0030] a)ARM runs normally;

[0031] b) The channel works normally;

[0032] c) The terminal redundancy diagnosis shows that there is no master card and the backplane redundancy diagnosis shows that there is no card;

[0033] d) Bus communication is normal;

[0034] (4) When the diagnosis result meets any of the following conditions, the card enters the "fault standby" state:

[0035] a) ARM operation failure;

[0036] b) Channel working failure;

[0037] c) Bus communication failure;

[0038] Step 4: In the "Redundant Master Card" state, switch the state according to the diagnosis results:

[0039] (1) The card remains in the "redundant master" state when the diagnostic results meet the following conditions at the same time:

[0040] a)ARM runs normally;

[0041] b) The channel works normally;

[0042] c) Terminal redundancy diagnosis without master card;

[0043] d) The backplane redundancy diagnosis shows that there is a spare card;

[0044] e) Bus communication is normal;

[0045] (2) When the diagnosis results meet the following conditions at the same time, the system enters the "redundant standby card" state:

[0046] a)ARM runs normally;

[0047] b) The channel works normally;

[0048] c) One of the following two conditions is met: the terminal redundancy diagnosis shows that there is a master card, the terminal redundancy diagnosis shows that there is no master card, and the backplane redundancy diagnosis shows that there is a master card or a quasi-master card;

[0049] d) Bus communication is normal;

[0050] (3) When the diagnosis results meet the following conditions at the same time, the system enters the "single card master card" state:

[0051] a)ARM runs normally;

[0052] b) The channel works normally;

[0053] c) Terminal redundancy diagnosis without master card;

[0054] d) The backplane redundancy diagnosis is no card;

[0055] e) Bus communication is normal;

[0056] (4) When the diagnosis results meet the following conditions at the same time, the card enters the "fault standby" state:

[0057] a) ARM operation failure, or channel operation failure, or bus communication failure;

[0058] b) Terminal redundancy diagnosis without master card;

[0059] c) The backplane redundancy diagnosis shows that there is a spare card or a semi-master card;

[0060] d) The online time of the backup card reaches the available time of the backup card T3;

[0061] Step 5: In the "Single Card Primary Card" state, switch the state according to the diagnosis result: (1) When the diagnosis result meets the following conditions at the same time, remain in the "Single Card Primary Card" state:

[0062] a)ARM runs normally;

[0063] b) The channel works normally;

[0064] c) Terminal redundancy diagnosis without master card;

[0065] d) The backplane redundancy diagnosis is no card;

[0066] e) Bus communication is normal;

[0067] (2) When the diagnosis results meet the following conditions at the same time, the system enters the "redundant master card" state:

[0068] a)ARM runs normally;

[0069] b) The channel works normally;

[0070] c) Terminal redundancy diagnosis without master card;

[0071] d) The backplane redundancy diagnosis shows that there is a spare card;

[0072] e) Bus communication is normal;

[0073] (3) When the diagnosis results meet the following conditions at the same time, the system enters the "redundant standby card" state:

[0074] a)ARM runs normally;

[0075] b) The channel works normally;

[0076] c) The terminal redundancy diagnosis shows that there is a master card, or the terminal redundancy diagnosis shows that there is no master card and the backplane redundancy diagnosis shows that there is a master card or a quasi-master card;

[0077] d) Bus communication is normal;

[0078] (4) When the diagnosis results meet the following conditions at the same time, the card enters the "fault standby" state:

[0079] a) ARM operation failure, or channel operation failure, or bus communication failure;

[0080] b) Terminal redundancy diagnosis without master card;

[0081] c) The backplane redundancy diagnosis shows that there is a spare card or a semi-master card;

[0082] d) The online time of the backup card reaches the available time of the backup card T3;

[0083] Step 6: In the "faulty spare card" state, maintain the current state and do not switch.

[0084] Furthermore, in the design method of dual-card redundant diagnosis and switching based on FPGA+ARM as described above, during the steps of the above method, when the redundant dual cards are powered on and initialized at the same time, the main card and the backup card are determined according to the module address, backplane heartbeat, and terminal board channel connection status.

[0085] Furthermore, in the design method of dual-card redundant diagnosis and switching based on FPGA+ARM as described above, during the execution of each step of the above method, the master-slave state switching of the control module is controlled according to the last bit of the physical address, ARM heartbeat diagnostic information, channel diagnostic information read back by ADC, serial port diagnostic information, backplane heartbeat signal diagnostic information, and terminal board redundant card status information.

[0086] Furthermore, as described above, in the design method of dual-card redundant diagnosis and switching based on FPGA+ARM, during the execution of each step of the method, the LED redundant indicator light, the backplane heartbeat signal output, and the redundant output enable signal output are controlled according to the master, backup, and fault status of the module.

[0087] Furthermore, in the above-mentioned design method for dual-card redundant diagnosis and switching based on FPGA+ARM, during the execution of each step of the above-mentioned method, a state machine is used to implement the redundant switching control function of the board.

[0088] Furthermore, in the design method of dual-card redundant diagnosis and switching based on FPGA+ARM as described above, during the steps of the above method, after the module initialization is completed, the master and backup cards respectively perform real-time diagnosis of the module address, ARM heartbeat, bus communication, backplane heartbeat, and terminal board status.

[0089] Furthermore, in the above-mentioned design method for dual-card redundant diagnosis and switching based on FPGA+ARM, during the execution of each step of the above-mentioned method, the fault diagnosis status of each module is exchanged through the heartbeat line and the switching strategy is adjusted.

[0090] Furthermore, in the design method of dual-card redundant diagnosis and switching based on FPGA+ARM as described above, during the steps of the above method, when the main card diagnoses a module failure and the self-diagnosis of the standby card is fault-free, the original main card is switched to the standby card, and the original standby card is upgraded to the main card.

[0091] Furthermore, in the design method of dual-card redundant diagnosis and switching based on FPGA+ARM as described above, during the execution of each step of the method, when redundant switching occurs or the fault diagnosis status of the primary and standby cards changes, the redundant and fault information will be sent up through the bus.

[0092] The beneficial effect of the technical solution of the present invention is that a design method of a dual-card redundant diagnosis-switching mechanism based on FPGA+ARM of the present invention can diagnose important components, functions and redundant interaction signals inside the module and thus realize redundant switching of the module, and is applied to the dual-card redundant design scheme of the industrial control system to realize redundant card functions with high system reliability. BRIEF DESCRIPTION OF THE DRAWINGS

[0093] Figure 1 The figure is a schematic diagram of the diagnosis-switching mechanism of dual-card redundancy based on FPGA+ARM. DETAILED DESCRIPTION

[0094] The technical solution of the present invention is described in detail below with reference to the accompanying drawings and specific embodiments.

[0095] like Figure 1 As shown, the present invention provides a design method for dual-card redundancy diagnosis and switching based on FPGA+ARM, comprising the following steps:

[0096] Step 1: After the module is powered on, it will directly enter the "Redundant Standby Card - Initial State" state;

[0097] Step 2: In the "Redundant Standby Card - Initial State" state, switch the state according to the diagnosis results:

[0098] (1) When the diagnosis results meet the following conditions at the same time, the system enters the "Redundant Master Card - Initial State" state:

[0099] e) The power-on time reaches the initial state diagnosis time T1;

[0100] f) The last digit of the board address is 1;

[0101] g) Terminal redundancy diagnosis without master card;

[0102] h) Backplane redundancy diagnosis: no card or spare card;

[0103] (2) Otherwise, the state remains in the "redundant standby card - initial state" until the power-on time reaches the initial state diagnosis time T2 and then enters the "redundant standby card" state;

[0104] Step 3:

[0105] In the "Redundant Master Card - Initial State" state, wait for the power-on time to reach the initial state diagnosis time T2 before entering the "Redundant Master Card" state;

[0106] In the "redundant standby card" state, the state is switched according to the diagnosis result:

[0107] (1) When the diagnosis results meet the following conditions at the same time, the card remains in the "redundant standby" state:

[0108] e)ARM runs normally;

[0109] f) The channel works normally;

[0110] g) One of the following two conditions is met: the terminal redundancy diagnosis shows that there is a master card, the terminal redundancy diagnosis shows that there is no master card and the backplane redundancy diagnosis shows that there is a quasi-master card;

[0111] h) Bus communication is normal;

[0112] (2) When the diagnosis results meet the following conditions at the same time, the system enters the "redundant master card" state:

[0113] e)ARM runs normally;

[0114] f) The channel works normally;

[0115] g) The terminal redundancy diagnosis shows that there is no master card and the backplane redundancy diagnosis shows that there is a spare card;

[0116] h) Bus communication is normal;

[0117] (3) When the diagnosis results meet the following conditions at the same time, the system enters the "single card master card" state:

[0118] e)ARM runs normally;

[0119] f) The channel works normally;

[0120] g) The terminal redundancy diagnosis shows that there is no master card and the backplane redundancy diagnosis shows that there is no card;

[0121] h) Bus communication is normal;

[0122] (4) When the diagnosis result meets any of the following conditions, the card enters the "fault standby" state:

[0123] d) ARM operation failure;

[0124] e) Channel working failure;

[0125] f) Bus communication failure;

[0126] Step 4: In the "Redundant Master Card" state, switch the state according to the diagnosis results:

[0127] (1) The card remains in the "redundant master" state when the diagnostic results meet the following conditions at the same time:

[0128] f)ARM runs normally;

[0129] g) The channel works normally;

[0130] h) Terminal redundancy diagnosis without master card;

[0131] i) The backplane redundancy diagnosis shows that there is a spare card;

[0132] j) Bus communication is normal;

[0133] (2) When the diagnosis results meet the following conditions at the same time, the system enters the "redundant standby card" state:

[0134] e)ARM runs normally;

[0135] f) The channel works normally;

[0136] g) One of the following two conditions is met: the terminal redundancy diagnosis shows that there is a master card, the terminal redundancy diagnosis shows that there is no master card, and the backplane redundancy diagnosis shows that there is a master card or a quasi-master card;

[0137] h) Bus communication is normal;

[0138] (3) When the diagnosis results meet the following conditions at the same time, the system enters the "single card master card" state:

[0139] f)ARM runs normally;

[0140] g) The channel works normally;

[0141] h) Terminal redundancy diagnosis without master card;

[0142] i) The backplane redundancy diagnosis is no card;

[0143] j) Bus communication is normal;

[0144] (4) When the diagnosis results meet the following conditions at the same time, the card enters the "fault standby" state:

[0145] e) ARM operation failure, or channel operation failure, or bus communication failure;

[0146] f) Terminal redundancy diagnosis without master card;

[0147] g) The backplane redundancy diagnosis shows that there is a spare card or a semi-master card;

[0148] h) The online time of the backup card reaches the backup card available time T3;

[0149] Step 5: In the "Single Card Primary Card" state, switch the state according to the diagnosis result: (1) When the diagnosis result meets the following conditions at the same time, remain in the "Single Card Primary Card" state:

[0150] f)ARM runs normally;

[0151] g) The channel works normally;

[0152] h) Terminal redundancy diagnosis without master card;

[0153] i) The backplane redundancy diagnosis is no card;

[0154] j) Bus communication is normal;

[0155] (2) When the diagnosis results meet the following conditions at the same time, the system enters the "redundant master card" state:

[0156] f)ARM runs normally;

[0157] g) The channel works normally;

[0158] h) Terminal redundancy diagnosis without master card;

[0159] i) The backplane redundancy diagnosis shows that there is a spare card;

[0160] j) Bus communication is normal;

[0161] (3) When the diagnosis results meet the following conditions at the same time, the system enters the "redundant standby card" state:

[0162] e)ARM runs normally;

[0163] f) The channel works normally;

[0164] g) Terminal redundancy diagnosis shows that there is a master card, or terminal redundancy diagnosis shows that there is no master card and backplane redundancy diagnosis shows that there is a master card or a quasi-master card;

[0165] h) Bus communication is normal;

[0166] (4) When the diagnosis results meet the following conditions at the same time, the card enters the "fault standby" state:

[0167] e) ARM operation failure, or channel operation failure, or bus communication failure;

[0168] f) Terminal redundancy diagnosis without master card;

[0169] g) The backplane redundancy diagnosis shows that there is a spare card or a semi-master card;

[0170] h) The online time of the backup card reaches the backup card available time T3;

[0171] Step 6: In the "faulty spare card" state, maintain the current state and do not switch.

[0172] During the execution of each step of the above method, when the redundant dual cards are powered on and initialized at the same time, the master card and the standby card are determined according to the module address, the backplane heartbeat, and the terminal board channel connection status; the master-slave state switching of the module is controlled according to the last bit of the physical address, the ARM heartbeat diagnostic information, the channel diagnostic information read back by the ADC, the serial port diagnostic information, the backplane heartbeat signal diagnostic information, and the terminal board redundant card status information; according to the master, standby, and fault status of the module, the LED redundant indicator light is controlled to turn on and off, the backplane heartbeat signal output, and the redundant output enable signal output; the state machine is used to implement the redundant switching control function of the board; after the module initialization is completed, the master and standby cards respectively perform real-time diagnosis on the module address, ARM heartbeat, bus communication, backplane heartbeat, and terminal board status; the fault diagnosis status of each module is exchanged through the heartbeat line and the switching strategy is adjusted; when the master card diagnoses a module fault and the self-diagnosis of the standby card is fault-free, the original master card is switched to the standby card, and the original standby card is upgraded to the master card; when redundant switching occurs or the fault diagnosis status of the master and standby cards changes, the redundant and fault information will be sent up through the bus.

Claims

1. A design method for diagnosis and switching of dual-card redundancy based on FPGA+ARM, characterized in that: The following steps are involved: Step 1: After the module is powered on, it will directly enter the "Redundant Standby Card - Initial State" state; Step 2: In the "Redundant Standby Card - Initial State" state, switch the state according to the diagnosis results: (1) When the diagnosis results meet the following conditions at the same time, the system enters the "Redundant Master Card - Initial State" state: a) The power-on time reaches the initial state diagnosis time T1; b) The last digit of the board address is 1; c) Terminal redundancy diagnosis without master card; d) Backplane redundancy diagnosis card is missing or there is a spare card; (2) Otherwise, the state remains in the "redundant standby card - initial state" until the power-on time reaches the initial state diagnosis time T2 and then enters the "redundant standby card" state; Step 3: In the "Redundant Master Card - Initial State" state, wait for the power-on time to reach the initial state diagnosis time T2 before entering the "Redundant Master Card" state; In the "redundant standby card" state, the state is switched according to the diagnosis results: (1) When the diagnosis results meet the following conditions at the same time, the card remains in the "redundant standby" state: a)ARM runs normally; b) The channel works normally; c) One of the following two conditions is met: the terminal redundancy diagnosis shows that there is a master card, the terminal redundancy diagnosis shows that there is no master card and the backplane redundancy diagnosis shows that there is a quasi-master card; d) Bus communication is normal; (2) When the diagnosis results meet the following conditions at the same time, the system enters the "redundant master card" state: a)ARM runs normally; b) The channel works normally; c) The terminal redundancy diagnosis shows that there is no master card and the backplane redundancy diagnosis shows that there is a spare card; d) Bus communication is normal; (3) When the diagnosis results meet the following conditions at the same time, the system enters the "single card master card" state: a)ARM runs normally; b) The channel works normally; c) The terminal redundancy diagnosis shows that there is no master card and the backplane redundancy diagnosis shows that there is no card; d) Bus communication is normal; (4) When the diagnosis result meets any of the following conditions, the card enters the "fault standby" state: a) ARM operation failure; b) Channel working failure; c) Bus communication failure; Step 4: In the "redundant master card" state, switch the state according to the diagnosis results: (1) The card remains in the "redundant master" state when the diagnostic results meet the following conditions at the same time: a)ARM runs normally; b) The channel works normally; c) Terminal redundancy diagnosis without master card; d) The backplane redundancy diagnosis shows that there is a spare card; e) Bus communication is normal; (2) When the diagnosis results meet the following conditions at the same time, the system enters the "redundant standby card" state: a)ARM runs normally; b) The channel works normally; c) One of the following two conditions is met: the terminal redundancy diagnosis shows that there is a master card, the terminal redundancy diagnosis shows that there is no master card, and the backplane redundancy diagnosis shows that there is a master card or a quasi-master card; d) Bus communication is normal; (3) When the diagnosis results meet the following conditions at the same time, the system enters the "single card master card" state: a)ARM runs normally; b) The channel works normally; c) Terminal redundancy diagnosis without master card; d) The backplane redundancy diagnosis is no card; e) Bus communication is normal; (4) When the diagnosis results meet the following conditions at the same time, the card enters the "fault standby" state: a) ARM operation failure, or channel operation failure, or bus communication failure; b) Terminal redundancy diagnosis without master card; c) The backplane redundancy diagnosis shows that there is a spare card or a semi-master card; d) The online time of the backup card reaches the available time of the backup card T3; Step 5: In the "single card primary card" state, switch the state according to the diagnosis results: (1) When the diagnosis results meet the following conditions at the same time, the card remains in the "single card master" state: a)ARM runs normally; b) The channel works normally; c) Terminal redundancy diagnosis without master card; d) The backplane redundancy diagnosis is no card; e) Bus communication is normal; (2) When the diagnosis results meet the following conditions at the same time, the system enters the "redundant master card" state: a)ARM runs normally; b) The channel works normally; c) Terminal redundancy diagnosis without master card; d) The backplane redundancy diagnosis shows that there is a spare card; e) Bus communication is normal; (3) When the diagnosis results meet the following conditions at the same time, the system enters the "redundant standby card" state: a)ARM runs normally; b) The channel works normally; c) The terminal redundancy diagnosis shows that there is a master card, or the terminal redundancy diagnosis shows that there is no master card and the backplane redundancy diagnosis shows that there is a master card or a quasi-master card; d) Bus communication is normal; (4) When the diagnosis results meet the following conditions at the same time, the card enters the "fault standby" state: a) ARM operation failure, or channel operation failure, or bus communication failure; b) Terminal redundancy diagnosis without master card; c) The backplane redundancy diagnosis shows that there is a spare card or a semi-master card; d) The online time of the backup card reaches the available time of the backup card T3; Step 6: In the "faulty spare card" state, maintain the current state and do not switch.

2. The design method for diagnosing and switching dual-card redundancy based on FPGA+ARM as claimed in claim 1, characterized in that: During the steps of the above method, when the redundant dual cards are powered on and initialized at the same time, the master card and the standby card are determined according to the module address, the backplane heartbeat, and the terminal board channel connection status.

3. The design method for diagnosing and switching dual-card redundancy based on FPGA+ARM as claimed in claim 1, characterized in that: During the steps of the above method, the master-slave state switching of the control module is controlled according to the last bit of the physical address, ARM heartbeat diagnostic information, channel diagnostic information read back by ADC, serial port diagnostic information, backplane heartbeat signal diagnostic information, and terminal board redundant card status information.

4. The design method for diagnosing and switching dual-card redundancy based on FPGA+ARM as claimed in claim 1, characterized in that: During the steps of the above method, the LED redundancy indicator light, backplane heartbeat signal output, and redundant output enable signal output are controlled according to the master, standby, and fault status of the module.

5. The design method for diagnosing and switching dual-card redundancy based on FPGA+ARM as claimed in claim 1, characterized in that: During the execution of each step of the above method, a state machine is used to implement the redundant switching control function of the board.

6. The design method for diagnosing and switching dual-card redundancy based on FPGA+ARM as claimed in claim 1, characterized in that: During the steps of the above method, after the module initialization is completed, the master and standby cards respectively perform real-time diagnosis on the module address, ARM heartbeat, bus communication, backplane heartbeat, and terminal board status.

7. The design method for diagnosing and switching dual-card redundancy based on FPGA+ARM as claimed in claim 1, characterized in that: During the steps of the above method, the fault diagnosis status of each module is exchanged through the heartbeat line and the switching strategy is adjusted.

8. The design method for diagnosing and switching dual-card redundancy based on FPGA+ARM as claimed in claim 1, characterized in that: During the steps of the above method, when the main card diagnoses a module fault and the standby card self-diagnoses no fault, the original main card is switched to the standby card, and the original standby card is upgraded to the main card.

9. The design method for diagnosing and switching dual-card redundancy based on FPGA+ARM as claimed in claim 1, characterized in that: During the steps of the above method, when redundancy switching occurs or the fault diagnosis status of the primary and standby cards changes, the redundancy and fault information will be sent up through the bus.

10. The design method for diagnosing and switching dual-card redundancy based on FPGA+ARM as claimed in claim 1, characterized in that: During the steps of the above method, when the redundant dual cards are powered on and initialized at the same time, the master card and the standby card are determined according to the module address, the backplane heartbeat, and the terminal board channel connection status; the master-slave state switching of the module is controlled according to the last bit of the physical address, the ARM heartbeat diagnostic information, the channel diagnostic information read back by the ADC, the serial port diagnostic information, the backplane heartbeat signal diagnostic information, and the terminal board redundant card status information; according to the master, standby, and fault status of the module, the LED redundant indicator light is controlled to turn on and off, the backplane heartbeat signal output, and the redundant output enable signal output; the state machine is used to implement the redundant switching control function of the board; after the module initialization is completed, the master and standby cards respectively perform real-time diagnosis on the module address, ARM heartbeat, bus communication, backplane heartbeat, and terminal board status; the fault diagnosis status of each module is exchanged through the heartbeat line and the switching strategy is adjusted; when the master card diagnoses a module fault and the self-diagnosis of the standby card is fault-free, the original master card is switched to the standby card, and the original standby card is upgraded to the master card; when redundant switching occurs or the fault diagnosis status of the master and standby cards changes, the redundant and fault information will be sent up through the bus.

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