MATLAB J1939 参数组快速入门
此示例说明如何使用存储在 DBC 文件中的信息来创建和管理 J1939 参数组。此示例使用文件 J1939.dbc。当需要向 J1939 网络传输数据时，建议以这种方式创建和使用参数组。
打开 DBC 文件
使用 canDatabase 打开 DBC 文件以访问定义。
db = canDatabase("J1939.dbc")db =
Database with properties:
Name: 'J1939'
Path: 'C:\Users\michellw\OneDrive - MathWorks\Documents\MATLAB\Examples\vnt-ex46196345\J1939.dbc'
Nodes: {2×1 cell}
NodeInfo: [2×1 struct]
Messages: {2×1 cell}
MessageInfo: [2×1 struct]
Attributes: {3×1 cell}
AttributeInfo: [3×1 struct]
UserData: []
创建参数组
使用 j1939ParameterGroup 函数以及数据库中包含的信息创建一个参数组。
pg = j1939ParameterGroup(db, "VehicleDataSingle")pg =
ParameterGroup with properties:
Protocol Data Unit Details:
---------------------------
Name: 'VehicleDataSingle'
PGN: 40192
Priority: 6
PDUFormatType: 'Peer-to-Peer (Type 1)'
SourceAddress: 254
DestinationAddress: 254
Data Details:
-------------
Timestamp: 0
Data: [255 255 255 255 255 255 255 255]
Signals: [1×1 struct]
Other Information:
------------------
UserData: []
设置源地址和目标地址
要完全定义参数组并确定其在网络上传输的路径，请设置源地址和目标地址。
pg.SourceAddress = 30
pg =
ParameterGroup with properties:
Protocol Data Unit Details:
---------------------------
Name: 'VehicleDataSingle'
PGN: 40192
Priority: 6
PDUFormatType: 'Peer-to-Peer (Type 1)'
SourceAddress: 30
DestinationAddress: 254
Data Details:
-------------
Timestamp: 0
Data: [255 255 255 255 255 255 255 255]
Signals: [1×1 struct]
Other Information:
------------------
UserData: []
pg.DestinationAddress = 50
pg =
ParameterGroup with properties:
Protocol Data Unit Details:
---------------------------
Name: 'VehicleDataSingle'
PGN: 40192
Priority: 6
PDUFormatType: 'Peer-to-Peer (Type 1)'
SourceAddress: 30
DestinationAddress: 50
Data Details:
-------------
Timestamp: 0
Data: [255 255 255 255 255 255 255 255]
Signals: [1×1 struct]
Other Information:
------------------
UserData: []
设置优先级
设置 Priority 属性以进一步自定义传输。
pg.Priority = 5;
查看信号信息
使用 Signals 属性查看此参数组的信号值。您可以直接写入和读取这些信号，以将数据打包到参数组中或从中解包数据。
pg.Signals
ans = struct with fields:
VehicleSignal4: -1
VehicleSignal3: -1
VehicleSignal2: -1
VehicleSignal1: -1
更改信号信息
直接写入信号以更改值并读回其当前值。
pg.Signals.VehicleSignal1 = 10
pg =
ParameterGroup with properties:
Protocol Data Unit Details:
---------------------------
Name: 'VehicleDataSingle'
PGN: 40192
Priority: 5
PDUFormatType: 'Peer-to-Peer (Type 1)'
SourceAddress: 30
DestinationAddress: 50
Data Details:
-------------
Timestamp: 0
Data: [10 0 255 255 255 255 255 255]
Signals: [1×1 struct]
Other Information:
------------------
UserData: []
pg.Signals.VehicleSignal2 = 100
pg =
ParameterGroup with properties:
Protocol Data Unit Details:
---------------------------
Name: 'VehicleDataSingle'
PGN: 40192
Priority: 5
PDUFormatType: 'Peer-to-Peer (Type 1)'
SourceAddress: 30
DestinationAddress: 50
Data Details:
-------------
Timestamp: 0
Data: [10 0 100 0 255 255 255 255]
Signals: [1×1 struct]
Other Information:
------------------
UserData: []
pg.Signals.VehicleSignal3 = 1000
pg =
ParameterGroup with properties:
Protocol Data Unit Details:
---------------------------
Name: 'VehicleDataSingle'
PGN: 40192
Priority: 5
PDUFormatType: 'Peer-to-Peer (Type 1)'
SourceAddress: 30
DestinationAddress: 50
Data Details:
-------------
Timestamp: 0
Data: [10 0 100 0 232 3 255 255]
Signals: [1×1 struct]
Other Information:
------------------
UserData: []
pg.Signals.VehicleSignal4 = 10000
pg =
ParameterGroup with properties:
Protocol Data Unit Details:
---------------------------
Name: 'VehicleDataSingle'
PGN: 40192
Priority: 5
PDUFormatType: 'Peer-to-Peer (Type 1)'
SourceAddress: 30
DestinationAddress: 50
Data Details:
-------------
Timestamp: 0
Data: [10 0 100 0 232 3 16 39]
Signals: [1×1 struct]
Other Information:
------------------
UserData: []
pg.Signals
ans = struct with fields:
VehicleSignal4: 10000
VehicleSignal3: 1000
VehicleSignal2: 100
VehicleSignal1: 10
直接写入新数据
您还可以将值直接写入 Data 属性，但通常建议并首选通过 Signals 设置值。
pg.Data(1:2) = [50 0]
pg =
ParameterGroup with properties:
Protocol Data Unit Details:
---------------------------
Name: 'VehicleDataSingle'
PGN: 40192
Priority: 5
PDUFormatType: 'Peer-to-Peer (Type 1)'
SourceAddress: 30
DestinationAddress: 50
Data Details:
-------------
Timestamp: 0
Data: [50 0 100 0 232 3 16 39]
Signals: [1×1 struct]
Other Information:
------------------
UserData: []
pg.Signals
ans = struct with fields:
VehicleSignal4: 10000
VehicleSignal3: 1000
VehicleSignal2: 100
VehicleSignal1: 50
