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Decode and Write CAN Data in MDF Files
This example shows you how to import and decode CAN data from an MDF file in MATLAB® for analysis, and write the decoded data back to the same file.
The MDF 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.dbc, provided with the Vector sample configuration.
View Details of the MDF File
View metadata of an MDF file using the mdfInfo function.
mdfInfo("Logging_MDF.mf4")ans =
MDFInfo with properties:
File Details
Name: "Logging_MDF.mf4"
Path: "/tmp/Bdoc24b_2725827_3770958/tp7650169a/vnt-ex42187575/Logging_MDF.mf4"
Author: ""
Department: ""
Project: ""
Subject: ""
Comment: ""
Version: "4.10"
InitialTimestamp: 2020-06-25 20:41:13.133000000
Creator Details
ProgramIdentifier: "MDF4Lib"
CreatorVendorName: "Vector Informatik GmbH"
CreatorToolName: "CANoe"
CreatorToolVersion: "13.0.118"
CreatorUserName: "michellw"
CreatorComment: "Created using MdfLog version 1.5.4.0 and Mdf4Lib version 1.7.0.5 X64 (2019-10-22)"
File Contents
Attachment: [5x7 table]
ChannelGroupCount: 62
Event: [0x8 eventtable]
Identify CAN Data Frames
According to the ASAM MDF associated standard for bus logging, the event types defined for a CAN bus system can be "CAN_DataFrame", "CAN_RemoteFrame", "CAN_ErrorFrame" or "CAN_OverloadFrame". This example focuses on extracting the CAN data frames, so the bus logging standard will be discussed using "CAN_DataFrame" event type as example. Additionally, note that a standard CAN data frame has up to 8 bytes for its payload and is used to transfer signal values.
The standard specifies that the channel names of the event structure should be prefixed by the event type name, for instance, "CAN_DataFrame". Typically a dot is used as separator character to specify the member channels, for instance, "CAN_DataFrame.ID" or "CAN_DataFrame.DataLength".
Use the mdfChannelInfo function to locate channel names matching "CAN_DataFrame.*". A table with information on matched channels is returned.
mdfChannelInfo("Logging_MDF.mf4", Channel="CAN_DataFrame.*")
ans=24×13 table
Name GroupNumber GroupNumSamples GroupAcquisitionName GroupComment GroupSourceName GroupSourcePath DisplayName Unit Comment ExtendedNamePrefix SourceName SourcePath
_____________________________ ___________ _______________ ____________________ ____________ _______________ _______________ _______________ ___________ __________________________________________________________ __________________ ___________ __________
"CAN_DataFrame.BitCount" 17 8889 CAN1 <undefined> <undefined> CAN_DataFrame "BitCount" <undefined> Frame length in bits. CAN1 <undefined> CAN1
"CAN_DataFrame.BitCount" 29 7648 CAN2 <undefined> <undefined> CAN_DataFrame "BitCount" <undefined> Frame length in bits. CAN2 <undefined> CAN2
"CAN_DataFrame.BusChannel" 17 8889 CAN1 <undefined> <undefined> CAN_DataFrame "BusChannel" <undefined> Logical bus channel number the frame was sent or received. CAN1 <undefined> CAN1
"CAN_DataFrame.BusChannel" 29 7648 CAN2 <undefined> <undefined> CAN_DataFrame "BusChannel" <undefined> Logical bus channel number the frame was sent or received. CAN2 <undefined> CAN2
"CAN_DataFrame.DLC" 17 8889 CAN1 <undefined> <undefined> CAN_DataFrame "DLC" <undefined> Data length code. CAN1 <undefined> CAN1
"CAN_DataFrame.DLC" 29 7648 CAN2 <undefined> <undefined> CAN_DataFrame "DLC" <undefined> Data length code. CAN2 <undefined> CAN2
"CAN_DataFrame.DataBytes" 17 8889 CAN1 <undefined> <undefined> CAN_DataFrame "DataBytes" <undefined> Payload data bytes containing the signal values. CAN1 <undefined> CAN1
"CAN_DataFrame.DataBytes" 29 7648 CAN2 <undefined> <undefined> CAN_DataFrame "DataBytes" <undefined> Payload data bytes containing the signal values. CAN2 <undefined> CAN2
"CAN_DataFrame.DataLength" 17 8889 CAN1 <undefined> <undefined> CAN_DataFrame "DataLength" <undefined> Length of stored payload in bytes. CAN1 <undefined> CAN1
"CAN_DataFrame.DataLength" 29 7648 CAN2 <undefined> <undefined> CAN_DataFrame "DataLength" <undefined> Length of stored payload in bytes. CAN2 <undefined> CAN2
"CAN_DataFrame.Dir" 17 8889 CAN1 <undefined> <undefined> CAN_DataFrame "Dir" <undefined> Bit signal indicating the direction (Rx, Tx). CAN1 <undefined> CAN1
"CAN_DataFrame.Dir" 29 7648 CAN2 <undefined> <undefined> CAN_DataFrame "Dir" <undefined> Bit signal indicating the direction (Rx, Tx). CAN2 <undefined> CAN2
"CAN_DataFrame.Flags" 17 8889 CAN1 <undefined> <undefined> CAN_DataFrame "Flags" <undefined> Combination of bit flags for the message. CAN1 <undefined> CAN1
"CAN_DataFrame.Flags" 29 7648 CAN2 <undefined> <undefined> CAN_DataFrame "Flags" <undefined> Combination of bit flags for the message. CAN2 <undefined> CAN2
"CAN_DataFrame.FrameDuration" 17 8889 CAN1 <undefined> <undefined> CAN_DataFrame "FrameDuration" ns Duration for transmission of the frame in nanoseconds. CAN1 <undefined> CAN1
"CAN_DataFrame.FrameDuration" 29 7648 CAN2 <undefined> <undefined> CAN_DataFrame "FrameDuration" ns Duration for transmission of the frame in nanoseconds. CAN2 <undefined> CAN2
⋮
The powertrain data of interest was logged from the CAN 2 network. The output above shows that the data from CAN 2 network has been stored in channel group 29 of the MDF file. View details about channel group 29 using the mdfChannelGroupInfo function by specifying the GroupNumber option.
mdfChannelGroupInfo("Logging_MDF.mf4", GroupNumber=29)ans=1×13 table
GroupNumber AcquisitionName Comment NumSamples DataSize Sorted SourceName SourcePath SourceComment SourceType SourceBusType SourceBusChannelNumber SourceSimulated
___________ _______________ ___________ __________ ________ ______ ___________ _____________ _____________ __________ _____________ ______________________ _______________
29 CAN2 <undefined> 7648 206496 true <undefined> CAN_DataFrame <undefined> Bus CAN 2 false
View details about all the channels within channel group 29 using mdfChannelInfo.
mdfChannelInfo("Logging_MDF.mf4", GroupNumber=29)ans=13×13 table
Name GroupNumber GroupNumSamples GroupAcquisitionName GroupComment GroupSourceName GroupSourcePath DisplayName Unit Comment ExtendedNamePrefix SourceName SourcePath
_____________________________ ___________ _______________ ____________________ ____________ _______________ _______________ _______________ ___________ __________________________________________________________ __________________ ___________ ___________
"CAN_DataFrame.BitCount" 29 7648 CAN2 <undefined> <undefined> CAN_DataFrame "BitCount" <undefined> Frame length in bits. CAN2 <undefined> CAN2
"CAN_DataFrame.BusChannel" 29 7648 CAN2 <undefined> <undefined> CAN_DataFrame "BusChannel" <undefined> Logical bus channel number the frame was sent or received. CAN2 <undefined> CAN2
"CAN_DataFrame.DLC" 29 7648 CAN2 <undefined> <undefined> CAN_DataFrame "DLC" <undefined> Data length code. CAN2 <undefined> CAN2
"CAN_DataFrame.DataBytes" 29 7648 CAN2 <undefined> <undefined> CAN_DataFrame "DataBytes" <undefined> Payload data bytes containing the signal values. CAN2 <undefined> CAN2
"CAN_DataFrame.DataLength" 29 7648 CAN2 <undefined> <undefined> CAN_DataFrame "DataLength" <undefined> Length of stored payload in bytes. CAN2 <undefined> CAN2
"CAN_DataFrame.Dir" 29 7648 CAN2 <undefined> <undefined> CAN_DataFrame "Dir" <undefined> Bit signal indicating the direction (Rx, Tx). CAN2 <undefined> CAN2
"CAN_DataFrame.Flags" 29 7648 CAN2 <undefined> <undefined> CAN_DataFrame "Flags" <undefined> Combination of bit flags for the message. CAN2 <undefined> CAN2
"CAN_DataFrame.FrameDuration" 29 7648 CAN2 <undefined> <undefined> CAN_DataFrame "FrameDuration" ns Duration for transmission of the frame in nanoseconds. CAN2 <undefined> CAN2
"CAN_DataFrame.ID" 29 7648 CAN2 <undefined> <undefined> CAN_DataFrame "ID" <undefined> ID of the CAN message. CAN2 <undefined> CAN2
"CAN_DataFrame.IDE" 29 7648 CAN2 <undefined> <undefined> CAN_DataFrame "IDE" <undefined> Identifier Extension bit. CAN2 <undefined> CAN2
"CAN_DataFrame.SingleWire" 29 7648 CAN2 <undefined> <undefined> CAN_DataFrame "SingleWire" <undefined> Bit flag indicating a single wire operation. CAN2 <undefined> CAN2
"CAN_DataFrame.WakeUp" 29 7648 CAN2 <undefined> <undefined> CAN_DataFrame "WakeUp" <undefined> Bit flag indicating a wake-up message (high voltage). CAN2 <undefined> CAN2
"t" 29 7648 CAN2 <undefined> <undefined> CAN_DataFrame "" s <undefined> CAN2 <undefined> <undefined>
Read CAN Data Frames from the MDF File
Read all data in channel group 29 into a timetable using the mdfRead function. The timetable is structured to follow the ASAM MDF standard logging format. Every row represents one raw CAN frame from the bus, while each column represents a channel within the specified channel group. The channels, such as "CAN_DataFrame.Dir", are named to follow the bus logging standard.
data = mdfRead("Logging_MDF.mf4", GroupNumber=29)data = 1x1 cell array
{7648x12 timetable}
canData = data{1}canData=7648×12 timetable
t CAN_DataFrame.BusChannel CAN_DataFrame.Flags CAN_DataFrame.Dir CAN_DataFrame.SingleWire CAN_DataFrame.WakeUp CAN_DataFrame.ID CAN_DataFrame.IDE CAN_DataFrame.FrameDuration CAN_DataFrame.BitCount CAN_DataFrame.DLC CAN_DataFrame.DataLength CAN_DataFrame.DataBytes
__________ ________________________ ___________________ _________________ ________________________ ____________________ ________________ _________________ ___________________________ ______________________ _________________ ________________________ ______________________________
2.2601 sec 2 1 "Tx" 0 0 103 0 128000 67 2 2 {[ 1 0]}
2.2801 sec 2 1 "Tx" 0 0 103 0 128000 67 2 2 {[ 1 0]}
2.3002 sec 2 1 "Tx" 0 0 100 0 232000 119 8 8 {[ 238 2 25 1 0 0 238 2]}
2.3005 sec 2 1 "Tx" 0 0 102 0 240000 123 8 8 {[ 0 128 59 68 0 0 0 0]}
2.3006 sec 2 1 "Tx" 0 0 103 0 128000 67 2 2 {[ 1 0]}
2.3008 sec 2 1 "Tx" 0 0 201 0 196000 101 6 6 {[ 0 0 0 0 172 38]}
2.3009 sec 2 1 "Tx" 0 0 1020 0 110000 58 1 1 {[ 1]}
2.3201 sec 2 1 "Tx" 0 0 103 0 128000 67 2 2 {[ 1 0]}
2.3401 sec 2 1 "Tx" 0 0 103 0 128000 67 2 2 {[ 1 0]}
2.3502 sec 2 1 "Tx" 0 0 100 0 234000 120 8 8 {[ 4 0 25 2 119 1 238 2]}
2.3505 sec 2 1 "Tx" 0 0 102 0 228000 117 8 8 {[53 127 119 64 0 128 187 67]}
2.3507 sec 2 1 "Tx" 0 0 201 0 198000 102 6 6 {[ 0 0 0 0 35 40]}
2.3508 sec 2 1 "Tx" 0 0 1020 0 110000 58 1 1 {[ 1]}
2.3601 sec 2 1 "Tx" 0 0 103 0 128000 67 2 2 {[ 1 0]}
2.3801 sec 2 1 "Tx" 0 0 103 0 128000 67 2 2 {[ 1 0]}
2.4002 sec 2 1 "Tx" 0 0 100 0 234000 120 8 8 {[ 10 0 25 3 119 1 238 2]}
⋮
Decode CAN Messages Using the DBC File
Open the DBC file using the canDatabase function.
canDB = canDatabase("PowerTrain_MDF.dbc")canDB =
Database with properties:
Name: 'PowerTrain_MDF'
Path: '/tmp/Bdoc24b_2725827_3770958/tp7650169a/vnt-ex42187575/PowerTrain_MDF.dbc'
UTF8_File: '/tmp/Bdoc24b_2725827_3770958/tp7650169a/vnt-ex42187575/PowerTrain_MDF.dbc'
Nodes: {2x1 cell}
NodeInfo: [2x1 struct]
Messages: {12x1 cell}
MessageInfo: [12x1 struct]
Attributes: {11x1 cell}
AttributeInfo: [11x1 struct]
UserData: []
The canMessageTimetable function uses the database to decode the message names and signals. The timetable of ASAM standard logging format data is converted into a Vehicle Network Toolbox™ CAN message timetable.
msgTimetable = canMessageTimetable(canData, canDB)
msgTimetable=7648×8 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 the signals stored in the "EngineData" message.
msgTimetable.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(msgTimetable, "ABSdata")signalTimetable1=1147×4 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(msgTimetable, "EngineData")signalTimetable2=1147×6 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(msgTimetable, "GearBoxInfo")signalTimetable3=1147×3 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 {\itEngineData} 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")
Configure Channel Group and Channel Metadata
The ultimate goal of this example is to write the decoded signal data for the three messages of interest, "ABSdata", "EngineData" and "GearBoxInfo", back into the same MDF file into three new channel groups. In this way the raw and decoded data can be stored in one file.
In addition to data in each timetable, metadata is also an important element that could provide descriptive information about the measurement environment. This section demonstrates how to configure the metadata that goes along with the data, as an optional preparation step before writing to file.
Use function mdfAddChannelGroupMetadata to add to each signal timetable the default or inferred metadata for that particular channel group and its channels.
signalTimetable1 = mdfAddChannelGroupMetadata(signalTimetable1); signalTimetable2 = mdfAddChannelGroupMetadata(signalTimetable2); signalTimetable3 = mdfAddChannelGroupMetadata(signalTimetable3);
View the default metadata for each channel group and its channels.
signalTimetable1.Properties.CustomProperties
ans =
CustomProperties with properties:
ChannelGroupAcquisitionName: ""
ChannelGroupComment: ""
ChannelGroupSourceName: ""
ChannelGroupSourcePath: ""
ChannelGroupSourceComment: ""
ChannelGroupSourceType: Unspecified
ChannelGroupSourceBusType: Unspecified
ChannelGroupSourceBusChannelNumber: 0
ChannelDisplayName: ["" "" "" ""]
ChannelComment: ["" "" "" ""]
ChannelUnit: ["" "" "" ""]
ChannelType: [FixedLength FixedLength FixedLength FixedLength]
ChannelDataType: [RealLittleEndian RealLittleEndian RealLittleEndian RealLittleEndian]
ChannelNumBits: [64 64 64 64]
ChannelComponentType: [None None None None]
ChannelCompositionType: [None None None None]
ChannelSourceName: ["" "" "" ""]
ChannelSourcePath: ["" "" "" ""]
ChannelSourceComment: ["" "" "" ""]
ChannelSourceType: [Unspecified Unspecified Unspecified Unspecified]
ChannelSourceBusType: [Unspecified Unspecified Unspecified Unspecified]
ChannelSourceBusChannelNumber: [0 0 0 0]
ChannelReadOption: [Missing Missing Missing Missing]
signalTimetable2.Properties.CustomProperties
ans =
CustomProperties with properties:
ChannelGroupAcquisitionName: ""
ChannelGroupComment: ""
ChannelGroupSourceName: ""
ChannelGroupSourcePath: ""
ChannelGroupSourceComment: ""
ChannelGroupSourceType: Unspecified
ChannelGroupSourceBusType: Unspecified
ChannelGroupSourceBusChannelNumber: 0
ChannelDisplayName: ["" "" "" "" "" ""]
ChannelComment: ["" "" "" "" "" ""]
ChannelUnit: ["" "" "" "" "" ""]
ChannelType: [FixedLength FixedLength FixedLength FixedLength FixedLength FixedLength]
ChannelDataType: [RealLittleEndian RealLittleEndian RealLittleEndian RealLittleEndian RealLittleEndian RealLittleEndian]
ChannelNumBits: [64 64 64 64 64 64]
ChannelComponentType: [None None None None None None]
ChannelCompositionType: [None None None None None None]
ChannelSourceName: ["" "" "" "" "" ""]
ChannelSourcePath: ["" "" "" "" "" ""]
ChannelSourceComment: ["" "" "" "" "" ""]
ChannelSourceType: [Unspecified Unspecified Unspecified Unspecified Unspecified Unspecified]
ChannelSourceBusType: [Unspecified Unspecified Unspecified Unspecified Unspecified Unspecified]
ChannelSourceBusChannelNumber: [0 0 0 0 0 0]
ChannelReadOption: [Missing Missing Missing Missing Missing Missing]
signalTimetable3.Properties.CustomProperties
ans =
CustomProperties with properties:
ChannelGroupAcquisitionName: ""
ChannelGroupComment: ""
ChannelGroupSourceName: ""
ChannelGroupSourcePath: ""
ChannelGroupSourceComment: ""
ChannelGroupSourceType: Unspecified
ChannelGroupSourceBusType: Unspecified
ChannelGroupSourceBusChannelNumber: 0
ChannelDisplayName: ["" "" ""]
ChannelComment: ["" "" ""]
ChannelUnit: ["" "" ""]
ChannelType: [FixedLength FixedLength FixedLength]
ChannelDataType: [RealLittleEndian RealLittleEndian RealLittleEndian]
ChannelNumBits: [64 64 64]
ChannelComponentType: [None None None]
ChannelCompositionType: [None None None]
ChannelSourceName: ["" "" ""]
ChannelSourcePath: ["" "" ""]
ChannelSourceComment: ["" "" ""]
ChannelSourceType: [Unspecified Unspecified Unspecified]
ChannelSourceBusType: [Unspecified Unspecified Unspecified]
ChannelSourceBusChannelNumber: [0 0 0]
ChannelReadOption: [Missing Missing Missing]
Create an array to hold the three message names and a cell array to hold the three signal timetables.
msgNames = ["ABSdata", "EngineData", "GearBoxInfo"]; TTs = {signalTimetable1, signalTimetable2, signalTimetable3};
Set property ChannelGroupComment for each timetable in TTs to indicate name of the CAN message from which signal data were decoded.
for ii = 1:numel(TTs) TTs{ii}.Properties.CustomProperties.ChannelGroupComment = sprintf("Signal data from CAN message ""%s"".", msgNames(ii)); end
For each CAN message, get the unit of every signal from canDB using the helper function getSignalUnit available at the end of this script. Set property ChannelUnit for each timetable variable to the obtained unit.
for ii = 1:numel(msgNames) sigNames = TTs{ii}.Properties.VariableNames; for jj = 1:numel(sigNames) sigUnit = getSignalUnit(canDB, msgNames(ii), sigNames(jj)); TTs{ii}.Properties.CustomProperties.ChannelUnit(jj) = sigUnit; end end
View the updated metadata for each channel group and its channels. Note the updated values in property ChannelGroupComment and ChannelUnit.
for ii = 1:numel(TTs) TTs{ii}.Properties.CustomProperties end
ans =
CustomProperties with properties:
ChannelGroupAcquisitionName: ""
ChannelGroupComment: "Signal data from CAN message "ABSdata"."
ChannelGroupSourceName: ""
ChannelGroupSourcePath: ""
ChannelGroupSourceComment: ""
ChannelGroupSourceType: Unspecified
ChannelGroupSourceBusType: Unspecified
ChannelGroupSourceBusChannelNumber: 0
ChannelDisplayName: ["" "" "" ""]
ChannelComment: ["" "" "" ""]
ChannelUnit: ["N" "" "" "mph"]
ChannelType: [FixedLength FixedLength FixedLength FixedLength]
ChannelDataType: [RealLittleEndian RealLittleEndian RealLittleEndian RealLittleEndian]
ChannelNumBits: [64 64 64 64]
ChannelComponentType: [None None None None]
ChannelCompositionType: [None None None None]
ChannelSourceName: ["" "" "" ""]
ChannelSourcePath: ["" "" "" ""]
ChannelSourceComment: ["" "" "" ""]
ChannelSourceType: [Unspecified Unspecified Unspecified Unspecified]
ChannelSourceBusType: [Unspecified Unspecified Unspecified Unspecified]
ChannelSourceBusChannelNumber: [0 0 0 0]
ChannelReadOption: [Missing Missing Missing Missing]
ans =
CustomProperties with properties:
ChannelGroupAcquisitionName: ""
ChannelGroupComment: "Signal data from CAN message "EngineData"."
ChannelGroupSourceName: ""
ChannelGroupSourcePath: ""
ChannelGroupSourceComment: ""
ChannelGroupSourceType: Unspecified
ChannelGroupSourceBusType: Unspecified
ChannelGroupSourceBusChannelNumber: 0
ChannelDisplayName: ["" "" "" "" "" ""]
ChannelComment: ["" "" "" "" "" ""]
ChannelUnit: ["l" "kW" "N" "" "degC" "rpm"]
ChannelType: [FixedLength FixedLength FixedLength FixedLength FixedLength FixedLength]
ChannelDataType: [RealLittleEndian RealLittleEndian RealLittleEndian RealLittleEndian RealLittleEndian RealLittleEndian]
ChannelNumBits: [64 64 64 64 64 64]
ChannelComponentType: [None None None None None None]
ChannelCompositionType: [None None None None None None]
ChannelSourceName: ["" "" "" "" "" ""]
ChannelSourcePath: ["" "" "" "" "" ""]
ChannelSourceComment: ["" "" "" "" "" ""]
ChannelSourceType: [Unspecified Unspecified Unspecified Unspecified Unspecified Unspecified]
ChannelSourceBusType: [Unspecified Unspecified Unspecified Unspecified Unspecified Unspecified]
ChannelSourceBusChannelNumber: [0 0 0 0 0 0]
ChannelReadOption: [Missing Missing Missing Missing Missing Missing]
ans =
CustomProperties with properties:
ChannelGroupAcquisitionName: ""
ChannelGroupComment: "Signal data from CAN message "GearBoxInfo"."
ChannelGroupSourceName: ""
ChannelGroupSourcePath: ""
ChannelGroupSourceComment: ""
ChannelGroupSourceType: Unspecified
ChannelGroupSourceBusType: Unspecified
ChannelGroupSourceBusChannelNumber: 0
ChannelDisplayName: ["" "" ""]
ChannelComment: ["" "" ""]
ChannelUnit: ["" "" ""]
ChannelType: [FixedLength FixedLength FixedLength]
ChannelDataType: [RealLittleEndian RealLittleEndian RealLittleEndian]
ChannelNumBits: [64 64 64]
ChannelComponentType: [None None None]
ChannelCompositionType: [None None None]
ChannelSourceName: ["" "" ""]
ChannelSourcePath: ["" "" ""]
ChannelSourceComment: ["" "" ""]
ChannelSourceType: [Unspecified Unspecified Unspecified]
ChannelSourceBusType: [Unspecified Unspecified Unspecified]
ChannelSourceBusChannelNumber: [0 0 0]
ChannelReadOption: [Missing Missing Missing]
Write Data to MDF File with Customize Channel Group and Channel Metadata
Using the mdfWrite function, write the three timetables in TTs one at a time to Logging_MDF.mf4. Because the MDF file currently has 62 channel groups, TTs{1}, TTs{2} and TTs{3} are written to the end of the file as channel groups 63, 64, and 65.
for ii = 1:numel(TTs) mdfWrite("Logging_MDF.mf4", TTs{ii}) end
Add DBC File to MDF File as Attachment
For convenient access to PowerTrain_MDF.dbc in case you need to perform additional data decoding in the future, you can add the DBC file as an embedded attachment to the MDF file using mdfAddAttachment.
mdfAddAttachment("Logging_MDF.mf4", "PowerTrain_MDF.dbc", Embedded=true)
Close DBC File
Close access to the DBC files by clearing its variable from the workspace.
clear canDBHelper Function
function sigUnit = getSignalUnit(canDB, msgName, sigName) % Look up the unit of a signal in a message from a CAN database. Return the unit as a string. msgIdx = find(strcmp({canDB.MessageInfo.Name}, msgName)); sigIdx = find(strcmp({canDB.MessageInfo(msgIdx).SignalInfo.Name}, sigName)); sigUnit = string(canDB.MessageInfo(msgIdx).SignalInfo(sigIdx).Units); end
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