A switchable multi-mode parallel fault injection device

Abstract

This invention discloses a switchable multi-mode parallel fault injection device, belonging to the field of testable technology for fault injection simulation. The device has multiple independent fault injection channels, each with the same configuration structure. Each channel includes a gain module and a fault mode injection module. The gain module consists of an operational amplifier and peripheral circuitry. By adjusting the adjustable resistor in the peripheral circuitry, the gain module can function as an adder or a unity-gain buffer. The short-circuit fault injection module achieves short circuits to ground, power supply, and between channels by connecting a fixed small resistor in series with an adjustable resistor. This invention can inject seven fault modes, meeting the testing requirements of complex scenarios. The hardware design is relatively simple, offering significant advantages in terms of testing flexibility, efficiency, and comprehensiveness.

Description

Technical Field

[0001] This invention relates to a parallel fault injection board capable of simulating multiple faults, belonging to the field of test technology for fault injection simulation technology. Background Technology

[0002] In modern electronic systems, fault injection technology is widely used for reliability testing and verification. It can accurately simulate different types of faults and is crucial for evaluating system performance under extreme conditions. Fault injection is a reliability verification technique that deliberately introduces faults into a system through controlled experiments and observes the system's behavior when these faults are present. Currently, fault injection techniques are generally classified into: hardware-based fault injection, software-based fault injection, and simulation-based fault injection.

[0003] However, most existing equipment can only inject a single fault signal at a time or supports a limited number of fault signal lines, making it difficult to meet the needs of today's complex electrical equipment. Therefore, how to achieve simultaneous fault injection on multiple signal lines has become a critical problem that urgently needs to be solved.

[0004] Existing fault injection techniques have the following main shortcomings:

[0005] (1) The diversity of supported fault types is insufficient. Existing technologies generally support three basic faults (open circuit, short circuit to ground, and short circuit to power supply), and can only perform simple combinations at most. They do not cover fault signal replacement, superposition, and other modes, and cannot meet the testing needs of more complex scenarios.

[0006] (2) Insufficient parallel fault injection capability. Many existing fault injection boards are generally designed for single-fault mode, meaning that only one type of fault can be injected at a time, making it impossible to test the combined impact of multiple faults coexisting on the system.

[0007] (3) The scope of application is limited by hardware design or testing methods. Existing fault injection boards are generally only applicable to specific scenarios, such as digital signal fault injection, and cannot cover more practical applications.

[0008] (4) High implementation and maintenance costs. Existing fault injection boards rely on complex embedded systems or dedicated hardware modules, resulting in high manufacturing and maintenance costs. The high complexity of the design leads to poor product maintainability and increased troubleshooting costs. Summary of the Invention

[0009] To achieve the goal of simultaneously injecting faults into multiple signal lines, this invention provides a parallel fault injection device with switchable multi-mode based on multiple switch control, which can flexibly simulate various fault modes to test the performance of electronic systems under different fault conditions.

[0010] The present invention provides a switchable multi-mode parallel fault injection device, which has n independent fault injection channels, n≥4; each channel adopts the same configuration structure, and the configuration structure of a single channel includes a gain module and a short-circuit fault injection module.

[0011] The gain module consists of an operational amplifier and peripheral circuitry. Specifically: Pin 1 of the operational amplifier is the output, connected to the target device's signal output interface OUT via a tactile switch Sx1; Pin 2 is the operational amplifier's inverting input, connected in series with a resistor Rx3 and grounded; Pin 2 and Pin 1 are connected via an adjustable resistor RHx4. When RHx4 is 0, the gain module functions as a unity-gain buffer; when RHx4 equals the fixed resistor Rx3, the gain module functions as an adder; Pin 3 is the operational amplifier's positive input, connected to the external signal input interface via resistor Rx1, and connected to the target device's signal input interface IN via resistor Rx2 and tactile switch Sx3; Pin 4 is the negative power supply interface, connected to the negative terminal of the power supply; Pin 8 is the positive power supply interface, connected to the positive terminal of the power supply.

[0012] The structure of the short-circuit fault injection module includes: connecting the signal input interface IN of the target device to the signal output interface OUT via a tactile switch Sx2; setting three parallel branches on the signal output interface, wherein: the first branch is connected in series with an adjustable resistor RHx1 and a fixed resistor Rx4, and is connected to the inter-channel short-circuit common line via a tactile switch Sx4; the second branch is connected in series with an adjustable resistor RHx2 and a fixed resistor Rx5 via a tactile switch Sx5, and is connected to the positive terminal of the power supply; the third branch is connected in series with an adjustable resistor RHx3 and a fixed resistor Rx6 via a tactile switch Sx6, and is grounded.

[0013] The device of this invention injects seven fault modes through different combinations of on / off switching of tactile switches. The seven fault modes are: no fault, fault signal replacement, fault signal superposition, open circuit, short circuit to ground, short circuit to power supply, and short circuit between channels. The fault modes injected into each channel are independent of each other; multiple channels can inject fault modes in parallel; the no-fault mode can coexist with any fault mode; and the fault modes of fault signal replacement, fault signal superposition, open circuit, short circuit to ground, and short circuit to power supply can all be injected simultaneously in different channels.

[0014] In the device of this invention, the method for achieving fault-free injection of a single channel x is as follows: Close tactile switch Sx2, and open tactile switches Sx1 and Sx3~Sx6. The original signal from the target device is directly transmitted from the input interface IN to the output interface OUT. The method for achieving fault signal substitution injection of a single channel x is as follows: Close tactile switch Sx1, open all tactile switches Sx2~Sx6, adjust the resistance of adjustable resistor RHx4 to 0, and allow the external simulation signal to enter the operational amplifier through resistor Rx1, then be injected into the target device through a unity-gain buffer. The method for achieving superimposed injection of fault signals of a single channel x is as follows: Close tactile switches Sx1 and Sx3, and open tactile switches Sx2 and Sx4~Sx6. Adjust the adjustable resistor RHx4 to be equal to the fixed resistor Rx3. The external simulation signal and the original signal from the target device are gain-adjusted through the operational amplifier, and the superimposed output signal is injected into the target device. The method for achieving open-circuit injection of a single channel x is as follows: Open all tactile switches Sx1~Sx6, creating an open-circuit fault. The method to achieve short-circuit injection to ground for a single channel x is as follows: close tactile switches Sx2 and Sx6, and open tactile switches Sx1 and Sx3~Sx5, so that the signal path of the target device is directly grounded. The method to achieve short-circuit injection to power supply for a single channel x is as follows: close tactile switches Sx2 and Sx5, and open tactile switches Sx1, Sx3, Sx4, and Sx6, so that the signal path of the target device is connected to the power supply, simulating a short circuit to the power supply. The method to achieve short-circuit injection between multiple channels is as follows: k channels have the same power supply and are uniformly grounded; for each of the k channels, close tactile switches Sx2 and Sx4, and open tactile switches Sx1, Sx3, Sx5, and Sx6; n≥k≥2.

[0015] Compared with the prior art, the advantages and positive effects of the present invention are as follows:

[0016] (1) The device of the present invention has precise resistance adjustment capability, achieving flexible current control by connecting a fixed small resistor and an adjustable resistor in series, and ensuring circuit safety; it has an independent multi-channel short-circuit test design, supporting efficient simulation of single-channel or inter-channel short-circuit faults, improving the diversity and complexity of testing; it can realize composite fault injection design, and can simulate multiple fault modes in parallel, such as signal substitution, superposition, short circuit, etc., adapting to complex test scenarios, and can comprehensively evaluate the performance of equipment under various fault conditions. Compared with the prior art, the device of the present invention has significant advantages in terms of testing flexibility, efficiency and comprehensiveness.

[0017] (2) The device of the present invention supports seven fault modes, including no fault, fault signal replacement, fault signal superposition, open circuit, short circuit to ground, short circuit to power supply, and short circuit between channels, covering more complex and realistic fault types that may occur in real scenarios, and can meet the testing needs in complex scenarios; the device of the present invention can support the parallel injection of multiple faults, and can inject different fault modes into multiple signal channels at the same time; the device of the present invention is more inclined to the real reproduction of actual fault scenarios in analog circuits, and is suitable for debugging and fault tolerance testing of complex electronic devices; the device of the present invention is a fault injection board designed by switch combination, which has low implementation cost, relatively simple hardware design, and limited maintenance cost. Attached Figure Description

[0018] Figure 1 This is a schematic diagram of a multi-mode parallel fault injection device according to an embodiment of the present invention;

[0019] Figure 2 This is a schematic diagram of the gain module connection in the parallel fault injection device according to an embodiment of the present invention;

[0020] Figure 3 This is a schematic diagram of the parallel injection path for fault-free and open-circuit faults according to an embodiment of the present invention;

[0021] Figure 4 This is a schematic diagram of the parallel injection path for signal substitution and signal superposition according to an embodiment of the present invention;

[0022] Figure 5 This is a schematic diagram of the parallel injection path for power supply short circuit and ground short circuit according to an embodiment of the present invention;

[0023] Figure 6 This is a schematic diagram of the inter-channel short-circuit fault injection path according to an embodiment of the present invention. Detailed Implementation

[0024] The present invention will now be described in further detail with reference to the accompanying drawings and embodiments.

[0025] First, let me explain Figures 1-6 The symbols in the diagram represent the following physical meanings: Sx1~Sx6 represent tactile switches, Rx1~Rx6 represent fixed resistors, RHx1~RHx4 represent adjustable resistors, VCCx is the positive terminal of the op-amp power supply, which is connected to the target device power supply, VEEx is the negative terminal of the op-amp power supply, which is grounded in this example, INx represents the target device signal input, OUTx represents the output signal, GNDx represents the ground terminal, and x represents the channel number.

[0026] This invention provides a parallel injection device supporting multiple fault modes, comprising multiple independent fault injection channels, each with the same configuration. A single channel mainly consists of the following components: six tactile switches, one operational amplifier, six fixed resistors, four adjustable resistors, an external signal input interface, a target device raw signal input interface, and a main output interface. Its structural layout is as follows: Figure 1 As shown. Each channel can independently implement multiple fault injection modes, including faultless injection, fault signal replacement, fault signal superposition, open-circuit injection, short circuit to ground, and short circuit to power supply. Figure 1 The illustrated embodiment features four independent fault injection channels, each employing a unified modular configuration. Parallel injection of different fault combinations is supported among the four channels. Furthermore, under level matching conditions, short-circuit fault modes can be implemented across different numbers of channels. By correctly connecting the various units and switching the on / off states of different tactile switches, the parallel fault injection device of this invention can flexibly implement multiple fault injection methods, thereby meeting the needs of complex application scenarios.

[0027] like Figure 2 As shown, the gain modules in each channel of the parallel fault injection device of the present invention consist of operational amplifiers and peripheral circuits. Pin 1 of the operational amplifier is the output, connected to the signal output interface OUT via a tactile switch Sx1; pin 2 is the inverting input, connected in series with a resistor Rx3 and grounded; the inverting input and output of the operational amplifier are connected via an adjustable resistor RHx4. Different values ​​of RHx4 result in different functions for the gain module. When RHx4 is 0, the gain module is a unity-gain buffer; when RHx4 is equal to the fixed resistor Rx3, the gain module is an adder, achieving signal superposition; pin 3 is the non-inverting input, connected to the external signal input interface via a resistor Rx1, and connected to the signal input interface IN of the target device via a resistor Rx2 and a tactile switch Sx3; pin 8 is the positive power interface, connected to the positive terminal of the target power supply; pin 4 is the negative power interface, connected to the negative terminal of the power supply, and grounded when using a single power supply.

[0028] In this embodiment of the invention, the operational amplifier used is the MSKSEMI LM358, which can be powered by a single power supply or a dual power supply. The voltage range of the single power supply is 3V to 36V, and the voltage range of the dual power supply is ±18V. This embodiment of the invention adopts the single power supply method, and the power supply is provided by the target device power supply. The voltage range cannot exceed 36V.

[0029] In this embodiment of the invention, the tactile switch used is ROCPU Switches TP-021213, with a rated voltage of 42V.

[0030] The external resistors Rx1, Rx2, and Rx3 of the operational amplifier are fixed resistors, with resistance values ​​typically ranging from 1kΩ to 100kΩ. Resistor RHx4 is an adjustable resistor, with an adjustable range of 1Ω to 100KΩ. In this embodiment of the invention, the resistance values ​​of resistors Rx1, Rx2, and Rx3 are all equal, at 10KΩ.

[0031] The short-circuit fault injection design of the parallel fault injection device of this invention achieves precise control of the resistance value by connecting a fixed small resistor and an adjustable resistor in series and equipping them with resistance measurement terminals. The fixed small resistor can range from 1Ω to 100Ω, and the adjustable resistor can range from 1Ω to 10kΩ. In this embodiment of the invention, the fixed small resistor is set to 10Ω. The fixed small resistor refers to resistors Rx4, Rx5, and Rx6, such as... Figure 1 R14, R15, and R16 are for channel 1. Adjustable resistors refer to resistors RHx1, RHx2, and RHx3, such as... Figure 1 RH11, RH12 and RH13 of the middle channel 1.

[0032] The short-circuit fault injection module constructed in this embodiment of the invention is as follows: Figure 1 As shown, the configuration structure of this module includes: connecting the signal input interface IN of the target device to the signal output interface OUT via a tactile switch Sx2; setting three parallel branches on the signal output interface; the first branch is connected in series with an adjustable resistor RHx1 and a fixed resistor Rx4, and connected to the inter-channel short-circuit common wire via a tactile switch Sx4; the second branch is connected in series with an adjustable resistor RHx2 and a fixed resistor Rx5 via a tactile switch Sx5, and connected to the positive terminal of the power supply; the third branch is connected in series with an adjustable resistor RHx3 and a fixed resistor Rx6 via a tactile switch Sx6, and grounded.

[0033] Based on different switch on / off combinations, the parallel fault injection device of this invention has seven fault mode injection modes: fault-free injection, fault signal substitution, fault signal superposition, open-circuit injection, short circuit to ground, short circuit to power supply, and short circuit between channels. In different channels, each fault mode does not interfere with the others, enabling parallel injection across multiple channels. Fault-free injection can coexist with any fault mode; fault signal substitution, fault signal superposition, open-circuit injection, short circuit to ground, and short circuit to power supply can all be applied simultaneously in different channels, without being limited by the fault modes of other channels.

[0034] Fault-free injection mode is the system's basic operating mode. In this mode, the system directly transmits the input signal to the output, simulating a normal operating state. Figure 1Taking channel one as an example, the specific operation is as follows: switch S12 is closed, and all other switches are open. The original signal from the target device is directly transmitted from the input terminal (IN) to the output terminal (OUT) without any interference or fault injection. This mode is used to verify the normal operating performance of the system, ensuring that the original signal is transmitted to the output terminal without change, thereby guaranteeing the stability of the system when there is no fault. It is also the basis for subsequent fault injection mode switching and adjustment.

[0035] In fault signal replacement mode, the system injects simulated signals to replace normal signals, simulating the failure or malfunction of external signals. Figure 1 Taking channel one as an example, the specific operation is as follows: switch S11 is closed, all other switches are open, and the adjustable resistor RH14 is adjusted to 0. The external simulation signal enters the operational amplifier through resistor R11 and is injected into the target device through a unity-gain buffer. This mode is used to test the system's fault tolerance and stability when receiving erroneous signals or failing to receive valid signals, such as in scenarios where the communication link is broken or the sensor fails. Simultaneously, the input signal ground is consistent with the system ground. When multiple devices are tested together, the external signal source and the device under test share a common ground, avoiding noise or errors caused by ground loops. All ground wires are connected uniformly through appropriate wiring, thereby ensuring grounding consistency between the signal source, operational amplifier, and test equipment.

[0036] In fault signal superposition mode, the system simulates the simultaneous presence of normal and fault signals by superimposing the simulated signal with the normal input signal, thus verifying the equipment's performance under signal superposition. Figure 1 Taking channel one as an example, the specific operation involves closing switches S11 and S13, opening the remaining switches, adjusting the adjustable resistor RH14 to be equal to the fixed resistor R13, and then adjusting the gain of the original signal and the simulated signal through an operational amplifier. The final superimposed signal is then injected into the target device. This mode is used to test the system's responsiveness under signal interference, noise, or partial fault conditions, evaluating the system's anti-interference capability against superimposed faults, as well as its stability and response speed under complex conditions such as power fluctuations or noise interference. Furthermore, to ensure signal quality, both the simulated signal source and the target signal source are grounded uniformly to avoid noise or errors caused by ground loops, thereby ensuring the accuracy of the test results.

[0037] The open-circuit fault mode simulates a situation where a signal channel in a system experiences signal loss or disconnection. It is used to test the equipment's fault tolerance and error handling mechanisms during signal interruptions. Specifically, all switches are in the open state, preventing the input signal from reaching the output through any path, thus creating an open-circuit fault. This mode is used to test communication equipment, sensors, and other systems requiring stable signal input. It simulates signal interruptions that may occur during actual operation, evaluating the equipment's fault tolerance and error recovery capabilities.

[0038] Ground short-circuit injection is used to simulate a fault scenario where the signal path is directly connected to ground, testing the system's response capability and protection mechanism under ground short-circuit conditions. Figure 1 Taking channel one as an example, by closing switches S12 and S16, other switches are opened, and the signal path is directly grounded, forming a short circuit. This mode evaluates whether the system can quickly trigger circuit protection functions (such as overcurrent protection) to prevent equipment damage and tests its recovery capability after fault resolution. Ground short-circuit injection is used to test systems that require ground protection, such as sensors, communication modules, or industrial equipment.

[0039] Short-circuit injection into the power supply simulates a short-circuit fault directly connected to the power supply via a simulated signal path. This is used to test the system's power protection capabilities and fault tolerance. Figure 1 Taking channel one as an example, by closing switches S12 and S15, other switches are opened, and the signal path is connected to the power supply, simulating a power short circuit. This mode verifies whether the system can quickly identify short circuit faults, trigger protection measures (such as cutting off the power supply or limiting current), and restore normal operation after the fault is cleared. It can be used for safety testing of critical systems such as communication equipment, industrial controllers, and power modules.

[0040] Inter-channel short-circuit injection simulates short-circuit faults between multiple signal channels, testing the response capability, fault tolerance, and fault isolation capability of a multi-channel system under short-circuit conditions. Taking a two-channel short circuit as an example, when both channels have the same power supply and are uniformly grounded, a short-circuit connection can be achieved between the channels by closing switches Sx4 and Sx2 on each channel. Adding a small resistor in series with an adjustable resistor in the path can accommodate different power supply types and prevent damage to the equipment. This mode can be used in complex scenarios such as multi-channel transmission systems and multi-sensor systems to verify the system's stability under short-circuit conditions, its ability to isolate faults to protect the normal operation of other channels, and its ability to identify and handle faults, thereby ensuring the system's reliability and anti-interference capability.

[0041] Example 1: As Figure 3 The diagram illustrates a combination of fault-free injection and open-circuit fault injection. In Channel 1, with switch S12 closed, the original signal from the target device is directly transmitted from the input terminal (IN1) to the output terminal (OUT1). The original signal is transmitted to the target device without any alteration, thus constituting fault-free injection. In Channel 2, all switches are open, and no signal passes through the circuit, constituting open-circuit fault injection.

[0042] Example 2: Combination Figure 4This section explains signal substitution and signal superposition fault injection. Taking channel one as an example, during signal substitution, switch S11 is closed, R11 and R13 are both set to 10kΩ, and RH14 is adjusted to 0Ω. At this time, the operational amplifier forms a unity-gain buffer, i.e., the amplification ratio is 1. The external signal is output with unity gain through the non-inverting amplifier and injected into the target device. The original signal path is broken. At this time, the external signal replaces the original signal and is injected into the target device, which is signal substitution injection. Taking channel two as an example, during signal superposition, switches S21 and S23 are closed, R21, R22 and R23 are all set to 10kΩ, and RH24 is adjusted to 10kΩ. At this time, the operational amplifier forms an adder, i.e., the external signal and the original signal of the target device are superimposed. The superimposed signal is injected into the target device, which is signal superposition injection.

[0043] Example 3: Combination Figure 5 This section explains the injection of faults for short circuits to ground and short circuits to power supply. Taking channel one as an example, for a short circuit to ground, close switches S12 and S16. The fixed resistor R16 is 10Ω, and the adjustable resistor RH13 has an adjustable range of 1Ω to 2kΩ. The adjustable resistor is equipped with resistance measurement terminals at both ends, allowing for precise control of the resistance value. By using this small resistor plus the adjustable resistor, the target device signal is grounded, thus achieving a short circuit to ground. Taking channel two as an example, for a short circuit to power supply, close switches S22 and S25. The fixed resistor R25 is 10Ω, and the adjustable resistor RH22 has an adjustable range of 1Ω to 2kΩ. The adjustable resistor is equipped with resistance measurement terminals at both ends, allowing for precise control of the resistance value. By using this small resistor plus the adjustable resistor, the target device signal is connected to the power supply, thus achieving a short circuit to the power supply.

[0044] Example 4: Combination Figure 6 This section explains the inter-channel short-circuit fault injection. Taking a three-channel short circuit as an example, when an inter-channel short circuit occurs, close switches S12 and S14 for channel one, switches S22 and S24 for channel two, and switches S32 and S34 for channel three. Fixed resistors R14, R24, and R34 are set to 10Ω, while adjustable resistors RH11, RH21, and RH31 have an adjustable range of 1Ω to 2kΩ. The adjustable resistors are equipped with resistance measurement terminals to achieve precise control of the resistance value. Through this protection circuit configuration of small resistors and adjustable resistors, connecting all three channel outputs to the inter-channel short-circuit common connection line achieves inter-channel short-circuit injection.

[0045] Except for the technical features described in the specification, all other technologies are known to those skilled in the art. Descriptions of well-known components and technologies are omitted in this invention to avoid redundancy and unnecessary limitation. The embodiments described above do not represent all embodiments consistent with this application. Various modifications or variations that can be made by those skilled in the art without creative effort based on the technical solutions of this invention are still within the protection scope of this invention.

Claims

1. A parallel fault injection device with switchable multi-mode, characterized in that, The device has n independent fault injection channels, each channel adopts the same configuration structure, and the configuration structure of a single channel includes a gain module and a short-circuit fault injection module; n≥4; let x represent the channel number; The gain module consists of an operational amplifier and peripheral circuitry. Specifically: pin 1 of the operational amplifier is the output, connected to the target device's signal output interface OUT via a tactile switch Sx1; pin 2 is the operational amplifier's inverting input, connected in series with a resistor Rx3 and grounded; pins 2 and 1 are connected via an adjustable resistor RHx4. When RHx4 is 0, the gain module functions as a unity-gain buffer; when RHx4 equals the fixed resistor Rx3, the gain module functions as an adder; pin 3 is the operational amplifier's positive input, connected to an external simulation signal input interface via resistor Rx1, and connected to the target device's signal input interface IN via resistor Rx2 and tactile switch Sx3; pin 4 is the negative power supply interface, connected to the negative terminal of the power supply; and pin 8 is the positive power supply interface, connected to the positive terminal of the power supply. The structure of the short-circuit fault injection module includes: connecting the signal input interface IN of the target device to the signal output interface OUT via a tactile switch Sx2; setting three parallel branches on the signal output interface, wherein: the first branch is connected in series with an adjustable resistor RHx1 and a fixed resistor Rx4, and is connected to the inter-channel short-circuit common line via a tactile switch Sx4; the second branch is connected in series with an adjustable resistor RHx2 and a fixed resistor Rx5 via a tactile switch Sx5, and is connected to the positive terminal of the power supply; the third branch is connected in series with an adjustable resistor RHx3 and a fixed resistor Rx6 via a tactile switch Sx6, and is grounded.

2. The apparatus according to claim 1, characterized in that, The device injects seven fault modes through different combinations of on / off switching of tactile switches. The seven fault modes are no fault, fault signal replacement, fault signal superposition, open circuit, short circuit to ground, short circuit to power supply, and short circuit between channels. The fault modes injected into each channel are independent of each other. Multiple channels can inject fault modes in parallel. The no-fault mode can coexist with any fault mode. Fault modes such as fault signal replacement, fault signal superposition, open circuit, short circuit to ground, and short circuit to power supply can all be injected simultaneously in different channels.

3. The apparatus according to claim 1 or 2, characterized in that, In the device described, the method for achieving fault-free injection in a single channel x is as follows: close the tactile switch Sx2, open the tactile switches Sx1 and Sx3~Sx6, and the original signal of the target device is directly transmitted from the input interface IN to the output interface OUT. The method for fault signal replacement injection in a single channel x is as follows: close the tactile switch Sx1, open all tactile switches Sx2~Sx6, adjust the resistance of the adjustable resistor RHx4 to 0, and the external simulation signal enters the operational amplifier through the resistor Rx1 and is injected into the target device through the unity gain buffer. The method for superimposing and injecting fault signals through a single channel x is as follows: close tactile switches Sx1 and Sx3, open tactile switches Sx2 and Sx4~Sx6, adjust the adjustable resistor RHx4 to be equal to the fixed resistor Rx3, adjust the gain of the external simulation signal and the original signal of the target device through an operational amplifier, and inject the superimposed signal into the target device. The method to achieve open-circuit injection in a single channel x is to disconnect all tactile switches Sx1~Sx6, thus creating an open-circuit fault. The method to achieve short-circuit injection to ground in a single channel x is as follows: close tactile switches Sx2 and Sx6, and open tactile switches Sx1 and Sx3~Sx5, so that the signal path of the target device is directly grounded; The method of injecting a short circuit into the power supply using a single channel x is as follows: close tactile switches Sx2 and Sx5, and open tactile switches Sx1, Sx3, Sx4 and Sx6, so that the signal path of the target device is connected to the power supply, simulating a short circuit to the power supply. The method for short-circuit injection between k channels is as follows: the power supply of the k channels is the same and grounded uniformly. For each of the k channels, the tactile switches Sx2 and Sx4 are closed, and the tactile switches Sx1, Sx3, Sx5 and Sx6 are opened; n≥k≥2.

4. The apparatus according to claim 1, characterized in that, The operational amplifier of the device is grounded in the same way as the external simulation signal source and the target device under test.

5. The apparatus according to claim 1, characterized in that, The operational amplifier is powered by a single power supply with a voltage range of 3V to 36V.

6. The apparatus according to claim 1, characterized in that, In the aforementioned gain module, the resistance values ​​of fixed resistors Rx1, Rx2, and Rx3 are all in the range of 1kΩ-100kΩ.

7. The apparatus according to claim 1, characterized in that, In the gain module, the fixed resistors Rx1, Rx2 and Rx3 are all set to have the same resistance value of 10KΩ.

8. The apparatus according to claim 1, characterized in that, In the short-circuit fault injection module, the fixed resistors Rx4, Rx5 and Rx6 have a resistance range of 1Ω to 100Ω, and the adjustable resistors RHx1, RHx2 and RHx3 have a resistance range of 1Ω to 10kΩ.

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