How to plot a visual basic real time graph

Question

3.53/5 (3 votes)

See more:

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

VB

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.Series.Clear()
        Chart1.Titles.Add("Wireless energy meter chart")
        engChart.Name = "Energy"
        pwrChart.Name = "Power"
        engChart.ChartType = SeriesChartType.Line
        pwrChart.ChartType = SeriesChartType.Line
        Chart1.Series.Add(engChart)
        'Chart1.Series.Add(pwrChart)
        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
        SerialPort1.Open()

    End Sub

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

        System.Threading.Thread.Sleep(500)

        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
        SerialPort1.Close()

    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

Posted 3-Feb-14 18:14pm

Member 10569715

Updated 10-Jul-17 2:49am

Add a Solution

Comments

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.

2 solutions

Add a Solution

Add your solution here

Treat my content as plain text, not as HTML

Preview 0

…

Existing Members

Sign in to your account

...or Join us

Download, Vote, Comment, Publish.

Your Email
Password
Forgot your password?

Your Email
This email is in use. Do you need your password?
Optional Password

I have read and agree to the Terms of Service and Privacy Policy
Please subscribe me to the CodeProject newsletters

When answering a question please:

Read the question carefully.
Understand that English isn't everyone's first language so be lenient of bad spelling and grammar.
If a question is poorly phrased then either ask for clarification, ignore it, or edit the question and fix the problem. Insults are not welcome.
Don't tell someone to read the manual. Chances are they have and don't get it. Provide an answer or move on to the next question.

Let's work to help developers, not make them feel stupid.

This content, along with any associated source code and files, is licensed under The Code Project Open License (CPOL)

Ebena · Answer 1 · 2017-07-10T02:49:00

Solution 2

The problem seems lie within your doupdate() subroutine. Replace 'time' for X axis with 'Now'.

Instead of

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

Try

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

Cheers

Posted 10-Jul-17 2:49am

Ebena

Comments

Richard Deeming 10-Jul-17 13:16pm

This question was asked and answered THREE YEARS AGO.

S Houghtelin · Answer 2 · 2014-02-04T02:14:00

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.

VB

'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