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从 BLF 文件中解码 CAN 数据

此示例说明如何在 MATLAB® 中从 BLF 文件中导入和解码 CAN 数据进行分析。此示例中使用的 BLF 文件是使用 Vector 的 CANoe™ 基于 CAN - General System Configuration (CAN) 采样生成的。此示例还使用 Vector 采样配置提供的 CAN 数据库文件 PowerTrain_BLF.dbc

打开 DBC 文件

使用 canDatabase 函数打开描述源 CAN 网络的数据库文件。

canDB = canDatabase("PowerTrain_BLF.dbc")
canDB = 
  Database with properties:

             Name: 'PowerTrain_BLF'
             Path: '/tmp/Bdoc23b_2361005_1548966/tp60a7197f/vnt-ex06202590/PowerTrain_BLF.dbc'
        UTF8_File: '/tmp/Bdoc23b_2361005_1548966/tp60a7197f/vnt-ex06202590/PowerTrain_BLF.dbc'
            Nodes: {2x1 cell}
         NodeInfo: [2x1 struct]
         Messages: {12x1 cell}
      MessageInfo: [12x1 struct]
       Attributes: {11x1 cell}
    AttributeInfo: [11x1 struct]
         UserData: []

调查 BLF 文件

检索并查看有关 BLF 文件的信息。函数 blfinfo 解析有关 Vector 二进制记录格式 BLF 文件的格式和内容的一般信息,并将信息以结构体形式返回。

binf = blfinfo("Logging_BLF.blf")
binf = struct with fields:
                  Name: "Logging_BLF.blf"
                  Path: "/tmp/Bdoc23b_2361005_1548966/tp60a7197f/vnt-ex06202590/Logging_BLF.blf"
           Application: "CANoe"
    ApplicationVersion: "11.0.55"
               Objects: 43344
             StartTime: 01-Jul-2020 14:47:34.427
               EndTime: 01-Jul-2020 14:48:33.487
           ChannelList: [2x3 table]

binf.ChannelList
ans=2×3 table
    ChannelID    Protocol    Objects
    _________    ________    _______

        1         "CAN"       8801  
        2         "CAN"       7575  

从 BLF 文件中读取数据

从动力总成系统总线记录感兴趣的数据,并存储在 BLF 文件的通道 2 中。使用 blfread 函数读取 CAN 数据。您还可以向函数调用提供 DBC 文件,该函数调用将启用报文名称查找和信号值解码。

blfData = blfread("Logging_BLF.blf", 2, "Database", canDB)
blfData=7575×8 timetable
       Time        ID     Extended           Name                        Data                 Length      Signals       Error    Remote
    __________    ____    ________    __________________    ______________________________    ______    ____________    _____    ______

    2.2601 sec     103     false      {'Ignition_Info' }    {[                       1 0]}      2       {1x1 struct}    false    false 
    2.2801 sec     103     false      {'Ignition_Info' }    {[                       1 0]}      2       {1x1 struct}    false    false 
    2.3002 sec     100     false      {'EngineData'    }    {[      238 2 25 1 0 0 238 2]}      8       {1x1 struct}    false    false 
    2.3005 sec     102     false      {'EngineDataIEEE'}    {[       0 128 59 68 0 0 0 0]}      8       {1x1 struct}    false    false 
    2.3006 sec     103     false      {'Ignition_Info' }    {[                       1 0]}      2       {1x1 struct}    false    false 
    2.3008 sec     201     false      {'ABSdata'       }    {[            0 0 0 0 172 38]}      6       {1x1 struct}    false    false 
    2.3009 sec    1020     false      {'GearBoxInfo'   }    {[                         1]}      1       {1x1 struct}    false    false 
    2.3201 sec     103     false      {'Ignition_Info' }    {[                       1 0]}      2       {1x1 struct}    false    false 
    2.3401 sec     103     false      {'Ignition_Info' }    {[                       1 0]}      2       {1x1 struct}    false    false 
    2.3502 sec     100     false      {'EngineData'    }    {[      4 0 25 2 119 1 238 2]}      8       {1x1 struct}    false    false 
    2.3505 sec     102     false      {'EngineDataIEEE'}    {[53 127 119 64 0 128 187 67]}      8       {1x1 struct}    false    false 
    2.3507 sec     201     false      {'ABSdata'       }    {[             0 0 0 0 35 40]}      6       {1x1 struct}    false    false 
    2.3508 sec    1020     false      {'GearBoxInfo'   }    {[                         1]}      1       {1x1 struct}    false    false 
    2.3601 sec     103     false      {'Ignition_Info' }    {[                       1 0]}      2       {1x1 struct}    false    false 
    2.3801 sec     103     false      {'Ignition_Info' }    {[                       1 0]}      2       {1x1 struct}    false    false 
    2.4002 sec     100     false      {'EngineData'    }    {[     10 0 25 3 119 1 238 2]}      8       {1x1 struct}    false    false 
      ⋮

查看来自“EngineData”报文的信号。

blfData.Signals{3}
ans = struct with fields:
    PetrolLevel: 1
       EngPower: 7.5000
       EngForce: 0
    IdleRunning: 0
        EngTemp: 0
       EngSpeed: 750

重新打包并可视化感兴趣的信号值

使用 canSignalTimetable 函数将来自总线上每个唯一报文的信号数据重新打包为一个信号时间表。此示例根据 CAN 报文时间表,为三个感兴趣的报文“ABSdata”、“EngineData”和“GearBoxInfo”创建三个单独的信号时间表。

signalTimetable1 = canSignalTimetable(blfData, "ABSdata")
signalTimetable1=1136×4 timetable
       Time       AccelerationForce    Diagnostics    GearLock    CarSpeed
    __________    _________________    ___________    ________    ________

    2.3008 sec          -100                0            0            0   
    2.3507 sec           275                0            0            0   
    2.4008 sec           275                0            0            0   
    2.4507 sec           275                0            0            0   
    2.5008 sec           275                0            0            0   
    2.5507 sec           275                0            0            0   
    2.6008 sec           275                0            0            0   
    2.6507 sec           275                0            0            0   
    2.7008 sec           350                0            0            0   
    2.7507 sec           425                0            0          0.5   
    2.8008 sec           425                0            0          0.5   
    2.8507 sec           500                0            0          0.5   
    2.9008 sec           575                0            0          0.5   
    2.9507 sec           575                0            0          0.5   
    3.0008 sec           650                0            0          0.5   
    3.0507 sec           725                0            0          0.5   
      ⋮

signalTimetable2 = canSignalTimetable(blfData, "EngineData")
signalTimetable2=1136×6 timetable
       Time       PetrolLevel    EngPower    EngForce    IdleRunning    EngTemp    EngSpeed
    __________    ___________    ________    ________    ___________    _______    ________

    2.3002 sec         1            7.5          0            0            0         750   
    2.3502 sec         2            7.5        375            0            0           4   
    2.4002 sec         3            7.5        375            0            0          10   
    2.4502 sec         4            7.5        375            0            0          17   
    2.5002 sec         5            7.5        375            0            0          23   
    2.5502 sec         6            7.5        375            0            0          30   
    2.6002 sec         7            7.5        375            0            0          36   
    2.6502 sec         8            7.5        375            0            0          43   
    2.7002 sec         9              9        450            0            0          50   
    2.7502 sec        10           10.5        525            0            0          59   
    2.8002 sec        10           10.5        525            0            0          69   
    2.8502 sec        11             12        600            0            0          80   
    2.9002 sec        11           13.5        675            0            0          92   
    2.9502 sec        12           13.5        675            0            0         106   
    3.0002 sec        13             15        750            0            0         121   
    3.0502 sec        13           16.5        825            0            0         136   
      ⋮

signalTimetable3 = canSignalTimetable(blfData, "GearBoxInfo")
signalTimetable3=1136×3 timetable
       Time       EcoMode    ShiftRequest    Gear
    __________    _______    ____________    ____

    2.3009 sec       0            0           1  
    2.3508 sec       0            0           1  
    2.4009 sec       0            0           1  
    2.4508 sec       0            0           1  
    2.5009 sec       0            0           1  
    2.5508 sec       0            0           1  
    2.6009 sec       0            0           1  
    2.6508 sec       0            0           1  
    2.7009 sec       0            0           1  
    2.7508 sec       0            0           1  
    2.8009 sec       0            0           1  
    2.8508 sec       0            0           1  
    2.9009 sec       0            0           1  
    2.9508 sec       0            0           1  
    3.0009 sec       0            0           1  
    3.0508 sec       0            0           1  
      ⋮

为了可视化感兴趣的信号,可以绘制信号时间表中的列随时间变化的图,以便进一步分析。

subplot(3, 1, 1)
plot(signalTimetable1.Time, signalTimetable1.CarSpeed, "r")
title("{\itCarSpeed} Signal from {\itABSdata} Message", "FontWeight", "bold")
xlabel("Timestamp")
ylabel("Car Speed")
subplot(3, 1, 2)
plot(signalTimetable2.Time, signalTimetable2.EngSpeed, "b")
title("{\itEngSpeed} Signal from {\itEngData} Message", "FontWeight", "bold")
xlabel("Timestamp")
ylabel("Engine Speed")
subplot(3, 1, 3)
plot(signalTimetable3.Time, signalTimetable3.Gear, "y")
title("{\itGear} Signal from {\itGearBoxInfo} Message", "FontWeight", "bold")
xlabel("Timestamp")
ylabel("Gear")

Figure contains 3 axes objects. Axes object 1 with title CarSpeed blank Signal blank from blank ABSdata Message, xlabel Timestamp, ylabel Car Speed contains an object of type line. Axes object 2 with title EngSpeed blank Signal blank from blank EngData Message, xlabel Timestamp, ylabel Engine Speed contains an object of type line. Axes object 3 with title Gear blank Signal blank from blank GearBoxInfo Message, xlabel Timestamp, ylabel Gear contains an object of type line.