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i'm able to plot a real time graph with the data from serial port
but the X axis time scale was the same

e.g 5sec and 30sec is plotting the same width.

any help will be much appreciate

Imports System.Windows.Forms.DataVisualization.Charting
Public Class Form1
    Dim portdata As String
    Dim vArray As Array
    Dim time As String
    Dim engChart As New Series
    Dim pwrChart As New Series

    Private Sub Form1_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
        Chart1.Titles.Add("Wireless energy meter chart")
        engChart.Name = "Energy"
        pwrChart.Name = "Power"
        engChart.ChartType = SeriesChartType.Line
        pwrChart.ChartType = SeriesChartType.Line
        If SerialPort1.IsOpen Then ' check if serial port is open
            SerialPort1.Close()     'close serial port of is open
        End If

        SerialPort1.PortName = "COM1"
        SerialPort1.BaudRate = 9600
        SerialPort1.Parity = IO.Ports.Parity.None
        SerialPort1.DataBits = 8
        SerialPort1.StopBits = IO.Ports.StopBits.One
        SerialPort1.RtsEnable = True

    End Sub

    Private Sub SerialPort1_DataReceived(ByVal sender As System.Object, ByVal e As System.IO.Ports.SerialDataReceivedEventArgs) Handles SerialPort1.DataReceived


        portdata = SerialPort1.ReadExisting

        vArray = Split(portdata, ",")
        Me.Invoke(New EventHandler(AddressOf DoUpdate))
        'My.Computer.FileSystem.WriteAllText("C:\TestFolder1\123.txt", Now, True)
        My.Computer.FileSystem.WriteAllText("C:\TestFolder1\123.txt", portdata, True)

    End Sub
    Public Sub DoUpdate()

        lblEnergyDsp.Text = vArray(0)
        lblPowerDsp.Text = vArray(1)

        engChart.Points.AddXY(time, vArray(0))
        pwrChart.Points.AddXY(time, vArray(1))

    End Sub
    Private Sub Form1_FormClosed(ByVal sender As System.Object, _
                   ByVal e As System.Windows.Forms.FormClosedEventArgs) _
                   Handles MyBase.FormClosed
        ' Close the Serial Port

    End Sub

    Private Sub Timer1_Tick(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Timer1.Tick
        time = TimeOfDay

    End Sub
End Class
Updated 10-Jul-17 3:49am
Thava Rajan 4-Feb-14 0:43am
did show your port data please
S Houghtelin 4-Feb-14 8:23am
+5 for showing your code and for using formatting. You neeed to read up on using the serialport correctly, I see a number of issues and potential for locking the application up.

The only time your chart is updated with new data is when your com event fires. If you want your chart to update once per second call your chart update from your timer event.

You should not be using the thread sleep in your com event, rather set your com port accordingly.
'If you are expecting two bytes set the receive event to fire when you get them.
SerialPort1.ReceivedBytesThreshold = 2
'And if think it take a long time to get those two bytes...
SerialPort1.ReadTimeout = 500
The problem seems lie within your doupdate() subroutine. Replace 'time' for X axis with 'Now'.

Instead of

engChart.Points.AddXY(time, vArray(0))
pwrChart.Points.AddXY(time, vArray(1))


engChart.Points.AddXY(Now, vArray(0))
        pwrChart.Points.AddXY(Now, vArray(1))

Richard Deeming 10-Jul-17 13:16pm
This question was asked and answered THREE YEARS AGO.

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