Read XCP Measurements with Dynamic DAQ Lists

Open the A2L File

An A2L file is required to establish a connection to the XCP server. The A2L file describes all of the functionality and capability that the XCP server provides, as well as the details of how to connect to the server. Use the xcpA2L function to open the A2L file that describes the server model.

a2lInfo = xcpA2L("SampleECU.a2l")

a2lInfo = 
  A2L with properties:

   File Details
                 FileName: 'SampleECU.a2l'
                 FilePath: '/tmp/Bdoc24a_2528353_1101874/tp8faccd1d/vnt-ex17137611/SampleECU.a2l'
               ServerName: 'SampleServer'
                 Warnings: [0x0 string]

   Parameter Details
                   Events: {'Event DAQ 100ms'}
                EventInfo: [1x1 xcp.a2l.Event]
             Measurements: {'Line'  'PWM'  'Sine'}
          MeasurementInfo: [3x1 containers.Map]
          Characteristics: {'Gain'  'yData'}
       CharacteristicInfo: [2x1 containers.Map]
                 AxisInfo: [1x1 containers.Map]
            RecordLayouts: [3x1 containers.Map]
             CompuMethods: [1x1 containers.Map]
                CompuTabs: [0x1 containers.Map]
               CompuVTabs: [0x1 containers.Map]

   XCP Protocol Details
        ProtocolLayerInfo: [1x1 xcp.a2l.ProtocolLayer]
                  DAQInfo: [1x1 xcp.a2l.DAQ]
    TransportLayerCANInfo: [1x1 xcp.a2l.XCPonCAN]
    TransportLayerUDPInfo: [0x0 xcp.a2l.XCPonIP]
    TransportLayerTCPInfo: [1x1 xcp.a2l.XCPonIP]

Start the XCP Sample Server

The XCP Sample server mimics the behavior of a real XCP server in a controlled way. In this case, it serves ONLY for examples with limited functionalities. Use local SampleECU class to create the Sample server object and a Sample server will be created in the MATLAB Workspace. The XCP Sample server only supports CAN, CAN FD, and TCP. This example chooses the CAN FD protocol for demonstration.

sampleServer = SampleECU(a2lInfo,"CAN FD","MathWorks","Virtual 1",1);

Create an XCP Channel

To create an active XCP connection to the server, use the xcpChannel function. The function requires a reference to the server A2L file and the type of transport protocol to use for messaging with the server. The XCP Channel must use the same device and a2l file as the Sample server to make sure they can establish connection with each other.

xcpCh = xcpChannel(a2lInfo,"CAN FD","MathWorks","Virtual 1",1)

xcpCh = 
  Channel with properties:

              ServerName: 'SampleServer'
             A2LFileName: 'SampleECU.a2l'
          TransportLayer: 'CAN FD'
    TransportLayerDevice: [1x1 struct]
              SeedKeyDLL: []
             ConnectMode: 'normal'

Connect to the Server

To make communication with the server active, use the connect function.

connect(xcpCh);

Create the Measurement List for DAQ

A measurement in XCP represents a variable in the memory of the model. Measurements available from the server are defined in the A2L file. One way to read measurement data is using dynamic DAQ lists. Use the createMeasurementList function to create a dynamic DAQ list with a specified event used to trigger the data acquisition and measurements that comprise the list.

createMeasurementList(xcpCh, "DAQ", "Event DAQ 100ms", ["Sine", "PWM", "Line"]);

View configured dynamic DAQ lists using the viewMeasurementLists function.

viewMeasurementLists(xcpCh)

DAQ List #1 using the "Event DAQ 100ms" event @ 0.100000 seconds with timestamp enabled and the following measurements:
   Line
   PWM
   Sine

Acquire Data form XCP Server

Start the configured dynamic DAQ list using the startMeasurement function. It begins the transmission of DAQ data from the server and stores the DAQ data in the XCP channel. After running for a few seconds, stop measurements using the stopMeasurement function.

startMeasurement(xcpCh);
pause(6);
stopMeasurement(xcpCh);

Read All Available Measurement Data

To retrieve all measurement data from the XCP channel in the timetable format, use the readDAQList function. The function requires a reference to the XCP channel. readDAQList returns a timetable with all available samples held by the XCP channel. Measurements returned by readDAQList are fully scaled using the compute methods defined for those measurements in the A2L file.

data = readDAQList(xcpCh);

data contains all measurement lists defined by the createMeasurementList function in a cell array. Each DAQ list represents an index in the returned cell array. In this case only one measurement list was created, so we can visualize the data by calling the corresponding timetable.

data{1}

ans=61×3 timetable
      Time        Line      PWM     Sine 
    ________    ________    ___    ______

    0 sec       0.034069     2     2.4504
    0.05 sec    0.064787     2     2.8372
    0.1 sec     0.094331     2     3.1765
    0.15 sec     0.12401     2     3.4714
    0.2 sec      0.15395     2     3.7108
    0.25 sec     0.18377     2     3.8817
    0.3 sec      0.21374     2     3.9788
    0.35 sec     0.24378     2      3.997
    0.4 sec      0.27373     2     3.9358
    0.45 sec     0.30387     2     3.7965
    0.5 sec      0.33388     2      3.586
    0.55 sec     0.36385     2     3.3126
    0.6 sec      0.39382     2      2.987
    0.65 sec     0.42382     2     2.6218
    0.7 sec      0.45388     2     2.2309
    0.75 sec     0.48395     0     1.8308
      ⋮

Retrieve the Sine Measurement Data

To retrieve the acquired data from the XCP channel for the Sine measurement, find the data in the output timetable from readDAQList function.

plot(data{1}.Sine, "o-")
title("Sine Measurement Data")
xlabel("Data Point")
ylabel("Data Value")

Retrieve the Line Measurement Data

To retrieve the acquired data from the XCP channel for the Line measurement, find the data in the output timetable from readDAQList function.

plot(data{1}.Line, "o-")
title("Line Measurement Data")
xlabel("Data Point")
ylabel("Data Value")

Retrieve the PWM Measurement Data

To retrieve the acquired data from the XCP channel for the PWM measurement, find the data in the output timetable from readDAQList function.

plot(data{1}.PWM, "o-")
title("PWM Measurement Data")
xlabel("Data Point")
ylabel("Data Value")

Disconnect from the Server

To make communication with the server inactive, use the disconnect function. The XCP server can be safely closed after disconnecting.

disconnect(xcpCh);

Clean Up

clear sampleServer a2lInfo