CN113847939A - Offline fault diagnosis system and method applied to vehicle instrument - Google Patents
Offline fault diagnosis system and method applied to vehicle instrument Download PDFInfo
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Abstract
The invention discloses an offline fault diagnosis system and method applied to a vehicle instrument, which comprises a fault code recording module, a fault snapshot recording module and a data monitoring module, wherein the fault code recording module is used for recording faults when the faults occur; the fault snapshot recording module is used for recording the driving information record when a fault occurs; the data monitoring module is used for monitoring the change of the data of the instrument in real time and judging whether the input signal of the switch or the input signal of the sensor has a fault or not through the change of the data. By utilizing the system and the method, the fault research and judgment processing time and the function leak repairing time are greatly shortened, the information safety is considered, and the improvement of the after-sale service satisfaction degree and the substantial reduction of the after-sale cost of the whole military vehicle enterprise are realized.
Description
Technical Field
The invention belongs to the technical field of automobile diagnosis, and particularly relates to an offline fault diagnosis system and method applied to a vehicle instrument.
Background
Military vehicle instrumentation has the following characteristics: the sensor signal is many in the function, the function differentiation that repacking function configuration arouses is big, the high required reliability, quick high-efficient maintainability, the high required data security, and the core of instrument diagnostic technique is with monitoring state, detection trouble, judgement trouble, early warning trouble, repair trouble as the main link, realizes final closed loop to ensure that the function of each system of vehicle is in normal condition, guarantee user's car demand. The fault system design of the automobile instrument in the industry takes alarm lamp reminding as a main mode, takes the current fault occurrence, namely sending a fault message as a main mode, takes meter disassembly and replacement as main solving means, and is mainly expressed in the following aspects: the fault code coding and analyzing rule is complex and the phenomenon of error recording happens occasionally; troubleshooting is difficult, and related information records and vehicle states at the time of failure occurrence are lacked; the diagnostic communication mechanism lacks functional partitioning and security level planning.
Disclosure of Invention
The system aims to realize rapid fault detection and rapid fault function problem repair of a combined instrument product through a rigorous offline fault diagnosis system and an application program upgrading process.
The off-line fault diagnosis system applied to the military automobile instrument for realizing one purpose of the invention comprises a fault code recording module, a fault snapshot recording module and a data monitoring module, wherein the fault code recording module is used for recording faults when the faults occur, and the fault codes comprise two coding formats, namely, the same fault is represented and stored by two fault codes; the fault snapshot recording module is used for recording and storing a driving information record at the moment of fault occurrence, the driving information record comprises key stroke data information when the fault occurs, the driving information record comprises two parts, and one part of parameters are received and stored in real time by an instrument through a CAN bus in the vehicle, and include but are not limited to battery input voltage, a vehicle speed value, a rotating speed value, an ignition switch state value, date and time; part of parameters are parameters which are calculated and recorded by the self system, including but not limited to mileage, main oil tank residual oil quantity and auxiliary oil tank residual oil quantity information; when a fault occurs, the driving information record of the first and the last fault is recorded. The data monitoring module is used for monitoring the change of the data of the instrument in real time and judging whether the input of the switch or the signal of the sensor has faults or not through the change of the data.
Further, the fault code recording module further comprises a fault parent-child relationship definition module, and the fault represented by the child fault code is a derivative fault of the fault represented by the parent fault code.
Further, the fault code recording module may suspend recording faults when the vehicle state is unstable, including but not limited to an engine start phase or/and a state within a set time period after the engine start is over.
Further, the system also comprises a key verification module, which is used for verifying whether the key sent by the external diagnostic equipment is correct or not when the external equipment needs to write data into the meter.
The communication mode of the instrument comprises a default security mode, an editing control mode and a programming session mode, when the editing control mode or the programming session mode needs to be entered, the instrument sends seed data to external diagnostic equipment, the diagnostic equipment calculates a corresponding key according to the seed data, the instrument checks whether the key is correct, and the key is correct to allow the instrument to be written.
The off-line fault diagnosis method applied to the military automobile instrument for realizing the second purpose of the invention comprises the following steps:
s1, detecting the voltage of the input signal in real time by the instrument internal self-checking system, and judging whether a fault exists;
s2, storing the faults discovered by the internal self-checking system of the instrument in a memory in the form of fault codes;
preferably, for faults discovered by the meter internal self-checking system, each fault is stored in the memory in the form of two fault codes, wherein one is a common coding format and is recorded as a first coding format, and the other is an improved coding format and is recorded as a second coding format; compared with the first coding format, the second coding format has lower analysis difficulty, and simultaneously expands the bits for expressing the fault type, thereby increasing the fault types capable of being expressed.
Preferably, when recording the fault code, the fault is selectively recorded according to the predefined parent-child relationship of the fault, when the parent fault occurs, if the child fault occurs at the same time, the child fault is not recorded, and the child fault code is the derivative fault of the parent fault.
Preferably, the fault occurring when the vehicle is in an unstable state including a state within a set period of time after the engine start phase or the end of the engine start is not recorded.
Preferably, the method further comprises the step of controlling security access, when the instrument needs to be written, the key needs to be checked, the instrument checks the key sent by the diagnostic equipment, and only when the key is correct, the external equipment can write to the instrument.
And S3, recording and storing the running information at the fault occurrence time.
And S4, monitoring data change in real time, and judging whether the input of the switch or the sensor signal has a fault or not through the data change.
And S5, the instrument sends the fault code and the running information record to an external diagnosis device.
Further, the meter can send fault codes of two coding modes, and when the external diagnostic equipment supports the first coding format, the meter sends a message containing the fault codes coded in the first coding format to the external diagnostic equipment in a fixed period; when the external diagnostic equipment supports the second coding format, the external diagnostic equipment sends a message for requesting a fault information command to the instrument, and after receiving the request command, the instrument sends the message which is coded in the second coding format and contains the fault code to the external diagnostic equipment.
By utilizing the system and the method, the fault research and judgment processing time and the function leak repair time in the process of function debugging and after-sales service guarantee are greatly shortened, the extremely high information safety is considered, the after-sales service satisfaction degree of military vehicle whole vehicle enterprises is improved, the after-sales cost is greatly reduced, and the win-win situation that the terminal user is satisfied is realized.
Drawings
FIG. 1 is a schematic diagram of a system according to the present invention;
FIG. 2 is a flow chart of a combination meter diagnostic communication mode jump;
FIG. 3 is a schematic diagram of the diagnosis principle of the diagnosis device and the combination meter;
FIG. 4 is a flow chart of a combination meter security access mechanism;
FIG. 5 is a flow diagram of a security access error handling mechanism;
fig. 6 is a security algorithm flow.
Detailed Description
The following detailed description is provided for the purpose of explaining the claimed embodiments of the present invention so that those skilled in the art can understand the claims. The scope of the invention is not limited to the following specific implementation configurations. It is intended that the scope of the invention be determined by those skilled in the art from the following detailed description, which includes claims that are directed to this invention.
Fig. 1 is a schematic diagram of an offline fault diagnosis system applied to a vehicle instrument, which includes a fault code recording module, a fault snapshot recording module, and a data monitoring module.
The fault code recording module is used for recording faults when the faults occur, and the fault codes comprise two encoding formats: the first encoding format and the second encoding format, in this embodiment, the first encoding format is denoted as encoding format a, and may be an SPN (specific sub-component where a fault occurs) + FMI (fault type) format recommended in the SAEJ1939 protocol, that is, a fault code DTC is defined in an SPN + FMI format recommended in the SAEJ1939 protocol used in the conventional commercial vehicle in the prior art, where the SPN is a 19-bit binary number, and the FMI is a 5-bit binary number. For example, assuming that the current SPN is 522540 and the FMI is 17, the encoding is as shown in table 1 below:
TABLE 1
SPN is 522540, which corresponds to 1111111100100101100 binary, high three-digit 111 of the high byte2With FMI component byte 5(11110001), middle byte 11111001200101100 placed in byte 4, low byte2Placed in byte 3, the data stream shown is 0x2cF9F 1.
As the SAEJ1939 protocol originates from European and American countries, the SAEJ1939 protocol mainly focuses on defining chassis power assemblies such as an engine, a gearbox, an ABS system and the like, and the accurate definition of electrical devices of instruments and vehicle bodies is lacked, so that the SPN is customized by each vehicle enterprise. Meanwhile, in the actual debugging process, the fault code is stored in a data field of a message data packet, and due to a CAN bus protocol mechanism, data with more than eight bytes needs to be unpacked and packaged, so that the coded DTC CAN be often unpacked into a plurality of pieces of message data, the high 3 bits of the SPN are independently in one byte, and when the byte where the coded DTC is located and other bytes of the SPN are unpacked into a plurality of pieces of message data, the difficulty of coding analysis work is increased, and a protocol stack is needed to realize the coding analysis work. In the field environment lacking program analysis, field personnel cannot independently complete decoding work. The problem of complex decoding is solved, and the prior historical parts are taken into consideration; a more flexible and intuitive fault code encoding rule needs to be adopted, and based on the fault code encoding rule, a second encoding format is introduced, which is denoted as encoding format B in this embodiment, and the encoding rule is shown in table 2 below:
the high two bits of the first byte are represented as the current encoding format, which is 10 in this embodiment, and represents that the current encoding format is format B; the low 6 bits and middle bytes of the first byte represent the specific sub-component SPN in which the fault occurs, and a preset mapping relation table exists between the specific sub-component SPN and the SPN definition recommended by the original SAEJ1939 protocol; the last byte represents a specific fault type FMI, and the fault code expression form is more intuitive and clear than the fault code coding format A.
TABLE 2
As can be seen from tables 1 and 2, the encoding format B can completely cover all failure types FMIs defined in the encoding format a, and corresponds to the original FMIs one to one. As shown in Table 3, the FMI of the original encoding format A is 1710The FMI in the corresponding existing coding format B is 0x17, and the representable fault types are expanded from 31 types to 255 types; the design of the sub component SPN where the fault is located in the original coding format A is redundant, 14 bits under the current coding format are enough to cover the type of the original sub component where the fault is located, and the new and old representation modes are in one-to-one correspondence through a preset mapping table. As shown in Table 3 below, the SPN in the original encoding format A is 522540, and the corresponding SPN in the new encoding format B is 4375 (01000100010111)2). The mapping relation is imported into a software database of the controller, one fault corresponds to two fault codes, and the function of storing, recording and reading fault information of the old historical part and the current part is compatible.
TABLE 3
As can also be seen from the data stream display in table 3, the last byte of the encoding format B can visually see the current failure type, but the failure type of the encoding format a and the first 3 bits of the SPN form one byte, so that it is difficult to visually see; and the unpacking and the packing of the CAN bus are added, so that the whole DTC combination process is very complicated.
The two encoding formats are parsed as follows:
the analysis work of the code is mainly finished by diagnostic equipment, the fault information of the code format A is that a data field carried by a set message ID (the data field contains the code A information) is actively pushed by an instrument according to a set period (such as 1s), and a specific message ID head is arranged; the code B is requested to be acquired by the diagnostic equipment and then is replied to the request instruction by the instrument, and also has a specific message ID head.
The instrument supports two diagnostic devices at the same time, if the current diagnostic device only supports the coding format A, the diagnostic device receives the message which is sent by the instrument in a fixed period and adopts the coding format A and analyzes the current fault information, if the current diagnostic device can support a new coding format B, the diagnostic device can actively send a request command message to the instrument, and after the instrument receives the request command of the diagnostic device, the instrument sends a new message which adopts the coding format B.
The following explains the system architecture during fault diagnosis with reference to fig. 3, taking the example that the voltage abnormality and the external device support the coding format B:
the instrument internal fault detection circuit detects voltage abnormity and transmits an analog voltage signal to the single chip microcomputer, the single chip microcomputer transmits data to the MCU processor, the MCU analyzes the existence of the fault according to internal software definition, and two fault codes corresponding to the fault are identified and stored in the memory; when the external diagnostic instrument sends a diagnosis request command through the CAN bus, the CAN transceiver in the instrument transmits diagnosis communication request data to the MCU processor, the MCU processor transmits fault information stored in the memory to the internal CAN transceiver, the internal CAN transceiver transmits the diagnosis data to the diagnostic equipment, and the human-computer interface of the diagnostic equipment displays related information.
The fault snapshot recording module is used for recording and storing a driving information record at the moment of fault occurrence, wherein the driving information record comprises key stroke data information when the fault occurs;
the running information record at the time of the fault occurrence is stored in an EPROM in the form of fault snapshot data flow, and forms a one-to-one mapping relation with fault codes, and the data snapshots are divided into two groups: the first group is the failure snapshot information at the first occurrence moment, and the second group is the latest failure snapshot information. When the fault information is stored through the diagnosis tool, the fault information can be called and read together; the fault snapshot information is key stroke data information at the fault occurrence moment, and comprises two parts, wherein one part of parameters are received and stored by the instrument in real time through a CAN bus in the vehicle and comprise battery input voltage, a vehicle speed value, a rotating speed value, an ignition switch state value, date and time; and part of parameters are parameters which are calculated and recorded by a system of the device and comprise mileage, residual oil quantity of the main oil tank and residual oil quantity of the auxiliary oil tank.
The data monitoring module is used for monitoring the change of instrument data in real time, and studying and judging whether the input signals of the switch and the sensor are correct and effective or not through the change of data flow, so as to quickly position a fault point;
data states that may be monitored include, but are not limited to: the oil quantity signal value of the main and auxiliary oil tanks, the input state of a main and auxiliary oil tank change-over switch, the front and rear air pressure signal values and the state of a steering lamp.
If the turn signal lamp is manually stirred downwards, the turn signal lamp is in an enabling opening position; observing the actual lighting state of the indicator light of the indicator, and reading the data flow signal value of the indicator light if the indicator light is in the unlighted state; if the turn signal lamp state signal position in the signal value is in an open state at the moment, the input signal of the turn signal lamp switch is judged and analyzed to be effective, and therefore the faults of the instrument are further checked.
The data monitoring module may also be an external diagnostic device, if some of the data cannot be directly implemented by monitoring the data stream signal values. If the rotating speed is monitored, a rotating speed meter driving instruction is sent to the instrument through the CAN tool to drive the rotating speed meter to rotate, whether a pointer at the head of the rotating speed meter correctly responds and rotates is monitored, and further function detection of a stepping motor of the rotating speed meter is achieved.
The fault code recording module also comprises a fault code parent-child relationship definition module, and the fault represented by the child fault code is a derivative fault of the fault represented by the parent fault code.
When many faults occur simultaneously, some faults are not root causes of the current fault but are derived from other faults, such as:
when the instrument detects the fault that the voltage of the storage battery is too high, other controller node loss faults (such as ABS signal loss) can also occur at the moment, but the faults are derivative faults caused by the fact that the system power supply voltage is too high, and the problem that the corresponding ABS signal loss faults generally disappear after the fault that the voltage is too high is solved. Therefore, "the system power supply voltage is too high" and "the ABS signal is lost" are in a parent-child relationship with each other, "the system power supply voltage is too high" is a parent fault of "the ABS signal is lost," the ABS signal is lost "is a child fault of" the system power supply voltage is too high ";
when the instrument detects a BUS OFF fault, because the whole BUS is in a BUS OFF state at the moment, each controller closes the signal transceiver according to an error mechanism of the CAN BUS, and then faults of other signal loss types also occur at the moment, but the faults of the signal loss types are all caused by the BUS OFF fault, and therefore the faults of the other signal loss types are sub-faults of the BUS OFF fault.
When the ABS controller has a frame overtime fault, because the signal of the ABS controller is used for displaying the speedometer, the function of the speedometer is inevitably failed due to the frame overtime of the ABS controller, and therefore the function failure fault of the speedometer is a sub-fault of the frame overtime of the ABS controller.
Therefore, the root cause fault resulting from the current fault is marked as a parent fault, and the faults derived from the parent fault are marked as child faults. The parent-child relationship between faults is preset by the system and can be adjusted according to actual requirements.
Usually, the occurrence of a parent fault necessarily leads to the occurrence of a child fault, and the occurrence of the parent fault and the child fault have a precedence relationship according to the actual situation; if the child fault occurs first and the parent fault does not occur, the system judges that the child fault is a real fault and records a fault code; if the father fault occurs, then the son faults with definite father-son relation all occur, in order to avoid the fault from causing misjudgment interference to maintenance personnel, only the father fault code is recorded, the fault state of the son fault is judged to be the suspension state, and the fault code is not recorded.
The fault code recording module further comprises a pause module for pausing recording faults when the vehicle state is unstable, wherein the unstable state comprises an engine starting stage or a state within a set time length after the engine is started, and the set time length can be a time length not exceeding 5 s.
During the engine starting stage and within a set time length after the engine is started, the voltage of the storage battery is in a large jump voltage reduction moment, the state is judged to be in an unstable state through long-term experience, the instrument can detect faults, the faults detected at the stage are in a pre-judgment suspension state, and after the set time length is exceeded, the instrument MCU analyzes the detection result of the detection circuit, judges whether a fault code is generated, records and stores the fault code.
The system also comprises a key verification module which is used for verifying whether the key sent by the external diagnostic equipment is correct or not when the external equipment needs to write data into the instrument, and the instrument can be written only if the key is correct.
As shown in fig. 2, the communication modes of the meter include a default security mode, an edit control mode, and a programming session mode. The edit control mode and the programming session mode require a verification key.
Each session mode implements different functions: 1. the safety mode is defaulted, the combination meter automatically enters the mode after being electrified, and functions of fault data communication, calling, reading and sending of dynamic and static data, clearing of fault data and the like can be realized in the mode; 2. a basic editing control mode, in which writing and deleting operations of data inside the combination meter can be realized; the function of performing action test by receiving a diagnosis data command and driving an internal load or an actuator of the combination instrument; 3. programming session mode: i.e. application upgrade mode.
The following embodiments describe the method of the present invention applied to off-line fault diagnosis using a vehicle meter, including the steps of:
s1, detecting the state of the input signal in real time by the instrument internal self-checking system, and judging whether a fault exists;
the self-detection system in the instrument detects the input state of the instrument in real time, and the detection content comprises but is not limited to: the system comprises a power supply voltage, the state of a bus signal receiving node (an engine controller, an anti-lock controller, a vehicle body controller, a transmission controller and a transfer case controller), and the input state monitoring of a hard wire sensor (a front hydraulic sensor, a rear hydraulic sensor and an oil quantity sensor).
The power supply voltage usually has an excessively low or high estimation value, and the monitoring judgment is carried out according to the rated voltage UA range. The bus signal fault is mainly whether an input receiving node signal is lost, whether an effective message sent by the node is received or not in a N-time message period is judged, and a message receiving state is monitored through a CAN transceiver, wherein the N-time message period CAN be 5 times of period and is not limited to the value; a failure in the input state of the sensor is typically determined by detecting a state of a level, such as a high level when the design is high, and actually reading a low level determines that a failure exists.
The node timeout fault definition principle is shown in table 4:
| nominal period | Node timeout time | Determination |
| 10-100ms | ≥T*10 | Node timeout |
| 100ms-500ms | ≥T*5 | Node timeout |
| More than 500ms | ≥T*3 | Node timeout |
TABLE 4
S2, storing faults discovered by the internal self-checking system of the instrument in the form of fault codes, wherein the fault codes comprise two types, one type of coding format is the format of SPN + FMI recommended by SAEJ1939 protocol, and the other type of coding format is the coding format B for improving the coding mode;
when the fault codes are recorded, according to the parent-child relationship of the predefined fault codes, namely when a parent fault code occurs, if a child fault code occurs at the same time, the child fault code is not recorded, and the fault represented by the child fault code is a derivative fault of the fault represented by the parent fault code.
Faults that occur when the vehicle is in an unstable state will not be recorded. The unstable state includes a state in a set period after the engine start phase or the engine start end, and the set period may be a period not exceeding 5 seconds, but is not limited thereto. At the moment that the voltage of the storage battery is in a large jump voltage reduction moment, the instrument can detect the fault by judging that the phase is in an unstable state through long-term experience, but the fault detected at the phase is in a pre-judgment suspension state, and after the set time length is exceeded, the instrument MCU analyzes the detection result of the detection circuit, judges whether a fault code is generated, records and stores the fault code.
Preferably, the method further comprises switching the communication mode of the meter, and when the write deletion operation needs to be performed on the meter, the communication command and the security access mechanism need to be diagnosed to switch the mode of the meter to an editing control mode, and the editing control mode can perform read-write operation on the meter.
And S3, recording and storing the running information at the fault occurrence time.
The driving information record comprises the following steps: failure snapshot information on the first and last failures.
The fault snapshot information is key stroke data information at the moment of fault occurrence, and comprises two parts, wherein one part of parameters are stored in a manner that the instrument receives in real time through an in-vehicle CAN bus, and include but are not limited to battery input voltage, a vehicle speed value, a rotating speed value, an ignition switch state value, date and time; some of the parameters are recorded for the calculation of the own system, including but not limited to mileage, remaining fuel of the main fuel tank and remaining fuel of the auxiliary fuel tank.
And S4, monitoring data change in real time, and judging whether the input of the switch or the sensor signal has a fault or not through the data change.
The data which can be monitored comprises but is not limited to the oil quantity signal value of the main and auxiliary oil tanks, the input state of the main and auxiliary oil tank change-over switch and the front and rear air pressure signal values, and whether the input signals of the switch and the sensor are correct and effective or not is researched and judged by monitoring the change of the data, so that the fault point is quickly positioned.
Some faults can not be judged by directly monitoring data flow, for example, the judgment of rotating speed needs to be carried out by writing the instrument through external diagnostic equipment to judge whether faults exist, and a set of information safety protection strategy is designed for ensuring data safety. Mainly has the following aspects: 1) importing a security access mechanism; 2) dividing safety levels; 3) application of a security algorithm; 4) an error handling mechanism is accessed.
The combination meter has two corresponding states: 1. locking state: the application program is normally executed, and the read data stream, the DTC and related data information are diagnosed; 2. an unlocking state: data can be written, and a transmission data packet can be downloaded.
Security access and security level: the security access grades are LEVEL1 and LEVEL 2; LEVEL1 is used for realizing a security access method for writing data into the combination meter and unlocking an application program in the combination meter when a drive function is tested, and as shown in fig. 4, the method adopts a section of polynomial function formula a to calculate a key and unlock the combination meter; LEVEL2 is used to implement a secure access method for downloading program data packets for upgrading an application program of a combination meter, and the method adopts another polynomial function formula B to calculate a key and unlock the combination meter, and is not further described herein.
The following operational steps for the diagnostic device to gain secure access to the meter are described in connection with fig. 4, 5 and 6:
step 2, reading the current state by the instrument, if the current state is an unlocking state, turning to step 4, and if the current state is a locking state, turning to step 3;
step 4, the diagnostic equipment sends an instruction for requesting unlocking of the safety LEVEL LEVEL1 to the instrument;
step 5, the instrument sends seed data A to the diagnostic instrument after receiving the instruction, wherein the seed data A is randomly generated by the instrument and has the length of 4 bytes;
step 6, the diagnostic device calculates the key B through a specific algorithm according to the seed data a, and sends the key B to the meter, and the specific algorithm in the embodiment is described below with reference to fig. 6:
step 6.1, performing exclusive-or operation on each byte of the seed data a and a specific mask to obtain 4 groups of intermediate data, which are marked as Cal [ i ] (i is 1,2,3,4), wherein the mask is defined and distributed by a host factory;
6.2, carrying out bitwise AND operation on Cal [0] and 0x0e, and then shifting the bits to the left by 3 bits to obtain intermediate data KeyA; cal [3] and 0xd0 are subjected to bitwise AND operation and then are shifted to the right by 3 bits to obtain KeyB; performing bitwise OR operation on the KeyA and the KeyB to obtain a 0 th byte Key [0] of the Key;
6.3, carrying out bitwise AND operation on Cal [1] and 0x0e, and then shifting left by 4 bits to obtain intermediate data KeyA; cal [3] and 0xd0 are subjected to bitwise AND operation and then are shifted to the right by 4 bits to obtain KeyB; performing bitwise OR operation on the KeyA and the KeyB to obtain a 1 st byte Key [1] of the Key;
6.4, performing bitwise AND operation on Cal [2] and 0x1d, and then shifting left by 2 bits to obtain intermediate data KeyA; cal [0] and 0xd1 are subjected to bitwise AND operation and then are shifted to the right by 2 bits to obtain KeyB; performing bitwise OR operation on the KeyA and the KeyB to obtain a 2 nd byte Key [2] of the Key;
6.5, carrying out bitwise AND operation on Cal [2] and 0x0e, and then shifting the bits to the left by 3 bits to obtain intermediate data KeyA; cal [1] and 0xd0 are subjected to bitwise AND operation and then are shifted to the right by 3 bits to obtain KeyB; performing bitwise OR operation on the KeyA and the KeyB to obtain a 3 rd byte Key [3] of the Key;
step 6.6, splicing Key [3] -Key [0] obtained in the step into a Key B, and sending the Key B to an instrument through a CAN bus;
step 7, the instrument compares the validity of the key B, if the key B is illegal, the error count is increased by 1, and the key is replied to be illegal; if the error count is legal, resetting the error count, replying to agree with writing, and setting the state of the instrument to be an unlocking state;
the access error handling mechanism is shown in FIG. 5: when the combined instrument receives the invalid key once, the number of the error counter is 1, the invalid key is sequentially accumulated, after the number of the error counter is 3, the combined instrument is accessed by the diagnosis tool again, delay response is carried out on the combined instrument, and the delay time can be 10 s; and after the delay punishment, subtracting 1 from the error counter, successfully unlocking the correct key at any time, and resetting the error counter.
And 8, after the diagnostic equipment receives the write-in approval command replied by the instrument, the diagnostic equipment can send data to the instrument.
And 9, after the data writing is finished, the diagnosis equipment sends a data writing finishing instruction to the instrument, and the instrument sets the state to be a locking state.
For safety, the meter sends a heartbeat message at a fixed frequency, and after receiving the heartbeat message, the external device needs to reply the heartbeat message, wherein the fixed frequency can be 5s, but is not limited to the value; if the meter does not receive the message returned by the diagnostic equipment in 5 times of the message period (not limited to the value), the message is considered to be overtime, and the current node has a fault; if the continuous messages are overtime, the diagnostic equipment is considered to be disconnected, the meter automatically sets the state to be the locking state, and the continuous messages can be continuously 3 times, but the method is not limited to the value.
And S5, the instrument sends the fault information and the running information record to an external diagnosis device.
Claims (10)
1. The off-line fault diagnosis system applied to the vehicle instrument is characterized by comprising a fault code recording module, a fault snapshot recording module and a data monitoring module, wherein the fault code recording module is used for recording faults when the faults occur; the fault snapshot recording module is used for recording the driving information record when a fault occurs; the data monitoring module is used for monitoring the change of the data of the instrument in real time and judging whether the input signal of the switch or the input signal of the sensor has a fault or not through the change of the data.
2. The system of claim 1, wherein the fault code recording module further comprises a fault parent-child relationship definition module, and the fault represented by the child fault code is a derivative fault of the fault represented by the parent fault code.
3. The system of claim 1, wherein the fault code recording module is configured to suspend recording faults when the vehicle state is unstable, and the unstable state includes an engine start phase or/and a state within a set time period after the engine start is finished.
4. The system of claim 1, further comprising a key verification module for verifying that the key sent by the external diagnostic device is correct when the external device needs to write data to the meter.
5. An off-line fault diagnosis method applied to an automobile instrument is characterized by comprising the following steps:
s1, detecting the state of the input signal in real time by the instrument internal self-checking system, and judging whether a fault exists;
s2, storing the faults discovered by the internal self-checking system of the instrument in a memory in the form of fault codes;
s3, recording and storing the running information record of the fault occurrence time;
s4, monitoring data change in real time, and judging whether a fault exists in a switch input or sensor signal through the data change;
and S5, the instrument sends the fault code and the running information record to an external diagnosis device.
6. The offline fault diagnosis method applied to meters of automobiles as claimed in claim 5, wherein after the internal self-test system of meters finds a fault in step S2, the same fault is stored in the memory in the form of fault codes of two different coding formats, one coding format is the first coding format, and the other coding format is the second coding format.
7. The offline fault diagnosis method applied to the automobile instrument as claimed in claim 6, wherein when the external diagnosis device supports the first coding format, the instrument actively sends the message of the fault code coded in the first coding format to the external diagnosis device at a fixed period; when the external diagnostic equipment supports the second coding format, the external diagnostic equipment sends a message for requesting a fault information command to the instrument, and the instrument receives the request command and then sends a message for coding a fault code in the second coding format to the external diagnostic equipment.
8. The method of claim 5, wherein the step S2 further comprises selectively recording the fault according to a predefined parent-child relationship of the fault, and when the parent fault occurs, if a child fault occurs at the same time, the child fault is not recorded, and the child fault code is a derivative fault of the parent fault.
9. The offline fault diagnosis method for motormeters of claim 5, wherein the step S2 further comprises not recording the fault occurred when the vehicle is in an unstable state, said unstable state comprising a state within a set time period after the engine start phase or the engine start end.
10. The offline fault diagnosis method for vehicle instrument as recited in claim 5, further comprising a security access control, wherein when the instrument needs to be written, the instrument needs to be written by checking the key.
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN114815787A (en) * | 2022-06-28 | 2022-07-29 | 航天科技控股集团股份有限公司 | Automatic testing method for fault codes of full liquid crystal instrument |
Citations (11)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1551633A (en) * | 2003-05-20 | 2004-12-01 | 索尼株式会社 | Image decoding device and image decoding method |
| CN1773467A (en) * | 2004-11-12 | 2006-05-17 | 国际商业机器公司 | Storage device having superset format, method and system for use therewith |
| CN103336919A (en) * | 2013-07-17 | 2013-10-02 | 东风电子科技股份有限公司 | System and method for achieving instrument encryption verification control function |
| CN103582883A (en) * | 2011-02-24 | 2014-02-12 | A9.Com公司 | Improved encoding and decoding of variable-length data with group formats |
| CN106557083A (en) * | 2015-09-26 | 2017-04-05 | 广州汽车集团股份有限公司 | The DTC recording method of vehicle electrically controlling unit and vehicle electrically controlling unit |
| CN106855839A (en) * | 2015-12-08 | 2017-06-16 | 中国移动通信集团公司 | A kind of server failure indicating means and device |
| CN108040258A (en) * | 2017-11-21 | 2018-05-15 | 北京臻迪科技股份有限公司 | A kind of coding, coding/decoding method, apparatus and system |
| CN108320351A (en) * | 2018-02-07 | 2018-07-24 | 安徽星网软件技术有限公司 | A kind of vehicle trouble on-line monitoring system and method |
| CN110266437A (en) * | 2019-06-26 | 2019-09-20 | 北京奇艺世纪科技有限公司 | It throws screen message method, throw screen message treatment method, device and terminal |
| CN112333528A (en) * | 2020-10-24 | 2021-02-05 | 北京华亿创新信息技术有限公司 | Stadium information publishing method and device |
| CN113342384A (en) * | 2021-07-07 | 2021-09-03 | 江铃汽车股份有限公司 | Security access strategy for vehicle controller module |
-
2021
- 2021-09-30 CN CN202111160326.7A patent/CN113847939A/en active Pending
Patent Citations (11)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1551633A (en) * | 2003-05-20 | 2004-12-01 | 索尼株式会社 | Image decoding device and image decoding method |
| CN1773467A (en) * | 2004-11-12 | 2006-05-17 | 国际商业机器公司 | Storage device having superset format, method and system for use therewith |
| CN103582883A (en) * | 2011-02-24 | 2014-02-12 | A9.Com公司 | Improved encoding and decoding of variable-length data with group formats |
| CN103336919A (en) * | 2013-07-17 | 2013-10-02 | 东风电子科技股份有限公司 | System and method for achieving instrument encryption verification control function |
| CN106557083A (en) * | 2015-09-26 | 2017-04-05 | 广州汽车集团股份有限公司 | The DTC recording method of vehicle electrically controlling unit and vehicle electrically controlling unit |
| CN106855839A (en) * | 2015-12-08 | 2017-06-16 | 中国移动通信集团公司 | A kind of server failure indicating means and device |
| CN108040258A (en) * | 2017-11-21 | 2018-05-15 | 北京臻迪科技股份有限公司 | A kind of coding, coding/decoding method, apparatus and system |
| CN108320351A (en) * | 2018-02-07 | 2018-07-24 | 安徽星网软件技术有限公司 | A kind of vehicle trouble on-line monitoring system and method |
| CN110266437A (en) * | 2019-06-26 | 2019-09-20 | 北京奇艺世纪科技有限公司 | It throws screen message method, throw screen message treatment method, device and terminal |
| CN112333528A (en) * | 2020-10-24 | 2021-02-05 | 北京华亿创新信息技术有限公司 | Stadium information publishing method and device |
| CN113342384A (en) * | 2021-07-07 | 2021-09-03 | 江铃汽车股份有限公司 | Security access strategy for vehicle controller module |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN114815787A (en) * | 2022-06-28 | 2022-07-29 | 航天科技控股集团股份有限公司 | Automatic testing method for fault codes of full liquid crystal instrument |
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