Decode CAN Data from BLF Files

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This example shows you how to import and decode CAN data from BLF files in MATLAB® for analysis. The BLF file used in this example was generated from Vector CANoe™ using the "CAN - General System Configuration (CAN)" sample. This example also uses the CAN database file, PowerTrain_BLF.dbc, provided with the Vector sample configuration.

Open the DBC File

Open the database file describing the source CAN network using the canDatabase function.

canDB = canDatabase("PowerTrain_BLF.dbc")

canDB = 
  Database with properties:

             Name: 'PowerTrain_BLF'
             Path: '/tmp/Bdoc24b_2725827_3770958/tp7650169a/vnt-ex06202590/PowerTrain_BLF.dbc'
        UTF8_File: '/tmp/Bdoc24b_2725827_3770958/tp7650169a/vnt-ex06202590/PowerTrain_BLF.dbc'
            Nodes: {2x1 cell}
         NodeInfo: [2x1 struct]
         Messages: {12x1 cell}
      MessageInfo: [12x1 struct]
       Attributes: {11x1 cell}
    AttributeInfo: [11x1 struct]
         UserData: []

Investigate the BLF File

Retrieve and view information about the BLF file. The blfinfo function parses general information about the format and contents of the Vector Binary Logging Format BLF file and returns the information as a structure.

binf = blfinfo("Logging_BLF.blf")

binf = struct with fields:
                  Name: "Logging_BLF.blf"
                  Path: "/tmp/Bdoc24b_2725827_3770958/tp7650169a/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

Read Data from BLF File

The data of interest was logged from the powertrain bus which is stored in channel 2 of the BLF file. Read the CAN data using the blfread function. You can also provide the DBC file to the function call which will enable message name lookup and signal value decoding.

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 
      ⋮

View signals from an "EngineData" message.

blfData.Signals{3}

ans = struct with fields:
    PetrolLevel: 1
       EngPower: 7.5000
       EngForce: 0
    IdleRunning: 0
        EngTemp: 0
       EngSpeed: 750

Repackage and Visualize Signal Values of Interest

Use the canSignalTimetable function to repackage signal data from each unique message on the bus into a signal timetable. This example creates three individual signal timetables for the three messages of interest, "ABSdata", "EngineData" and "GearBoxInfo", from the CAN message timetable.

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  
      ⋮

To visualize the signals of interest, columns from the signal timetables can be plotted over time for further analysis.

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")