VB linear stage

Public Class LinearStageForm

    Dim k, counter, delay As Long
    Dim spd, Direction, enable, sensorMax As Short
    Dim startT, chkT As New Double
    Dim pos, min_pos, max_pos As New Integer
    Dim seqSt, seqNext, motionSt, motionNext, command As String
    Dim tmr As PerformanceTimer
    Dim sim, Pause, ptimer As Boolean

    Private Sub LinearStageForm_Load(ByVal sender As Object, ByVal e As System.EventArgs) Handles Me.Load
        sim = True
        ptimer = True
        Pause = True
        StagePosition.Minimum = -1000
        StagePosition.Maximum = 1000
        StagePosition.Value = 0
        spd = 1000
        delay = 85
        counter = 0
        leftLabel.Visible = False
        rightLabel.Visible = False


        If (sim = True) Then
            sim_button.Checked = True
        Else
            Call Initialize_IO()
            sim_button.Checked = False
            position_output.Enabled = False
            position_output.Enabled = False
        End If
        If (ptimer = True) Then
            Call InitializeTimer() ' Initialize the Performance Timer if selected
        End If
    End Sub

    Private Sub sim_button_CheckedChanged(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles sim_button.CheckedChanged
        If sim_button.Checked = True Then
            sim = True
            position_output.Enabled = True
            position_output.Enabled = True
        Else
            sim = False
            Call Initialize_IO()
            position_output.Enabled = False
            position_output.Enabled = False
        End If
    End Sub

    Public Sub InitializeTimer()
        'A routine to initialize the QueryPerformanceTimer
        tmr = New PerformanceTimer
        tmr.StartTimer()
    End Sub

    Public Function GetTimeNow() As Double
        'This function uses either the Timer Property or the Performance Counter depending on the setting of 'the PerformanceTimerFlagSelect
        If (ptimer = True) Then
            tmr.ReadCurrentTimer() ' Read the timer value
            GetTimeNow = tmr.TimeElapsed(PerformanceTimer.PerformanceValue.pvSecond)
        Else
            GetTimeNow = Microsoft.VisualBasic.Timer()
        End If
    End Function

    Private Sub slow_button_CheckedChanged(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles slow_button.CheckedChanged
        If slow_button.Checked = True Then
            spd = 15000
            delay = 250
        End If
    End Sub

    Private Sub medium_button_CheckedChanged(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles medium_button.CheckedChanged
        If medium_button.Checked = True Then
            spd = 7500
            delay = 150
        End If
    End Sub

    Private Sub fast_button_CheckedChanged(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles fast_button.CheckedChanged
        If fast_button.Checked = True Then
            spd = 1000
            delay = 85
        End If
    End Sub
    Private Sub start_button_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles start_button.Click
        start_button.Visible = False
        left_button.Enabled = True
        right_button.Enabled = True
        stop_button.Enabled = True
        stop_button.Text = "PAUSE"

        command = "Idle"
        motionNext = "SendLow"

        Do While (2 > 1) ' This is an infinite loop
            k = k + 1
            If k Mod 3000 = 0 Then      ' The mod function is used so that the following
                ' two statements do not get executed all the time
                System.Windows.Forms.Application.DoEvents() ' Allows background processing
                statebox.Text = seqSt
            End If
            Call sequence() ' This function processes commands
            Call motion()   ' This function simulates (or enabled) stage motion
        Loop
    End Sub
    Public Sub sequence()
        If command = " " Then
            seqSt = seqNext
        Else
            seqSt = command
        End If
        Select Case (seqSt)
            Case "Idle"
                command = " "
                counter = 0
                enable = 0
                If (StagePosition.Value = StagePosition.Minimum) Or sensorMax = 2 Then
                    leftLabel.Visible = True
                    left_button.Enabled = False
                End If
                If (StagePosition.Value = StagePosition.Maximum) Or sensorMax = 1 Then
                    rightLabel.Visible = True
                    right_button.Enabled = False
                End If
                seqNext = "Idle"
            Case "Left"
                command = " "
                leftLabel.Visible = False
                rightLabel.Visible = False
                Direction = 2                   ' Send Cart Left
                enable = 1
                If sim = False Then
                    sensorMax = Read_IO()
                    If sensorMax = 2 Then
                        seqNext = "Idle"
                    Else
                        seqNext = "Left"
                    End If
                Else
                    If StagePosition.Value = StagePosition.Minimum Then
                        seqNext = "Idle"
                    Else
                        seqNext = "Left"
                    End If
                End If
            Case "Right"
                command = " "
                leftLabel.Visible = False
                rightLabel.Visible = False
                Direction = 0                   ' Send Cart Right
                enable = 1
                If sim = False Then
                    sensorMax = Read_IO()
                    If sensorMax = 1 Then
                        seqNext = "Idle"
                    Else
                        seqNext = "Right"
                    End If
                Else
                    If StagePosition.Value = StagePosition.Maximum Then
                        seqNext = "Idle"
                    Else
                        seqNext = "Right"
                    End If
                End If
        End Select
    End Sub

    Public Sub motion()

        motionSt = motionNext
        Select Case motionSt
            Case "SendLow"
                If sim = True Then
                    counter = counter + 1
                    If counter >= spd Then
                        If Direction = 0 Then
                            StagePosition.Value = StagePosition.Value + Enable   ' Move to the right
                        ElseIf Direction = 2 Then
                            StagePosition.Value = StagePosition.Value - Enable ' Move to the left
                        End If
                        position_output.Text = StagePosition.Value
                        counter = 0
                    End If
                Else
                    Send_IO(Direction)      ' Send Low Step Signal
                    motionNext = "SendHigh"
                    startT = GetTimeNow()
                End If
            Case "SendHigh"
                If ((GetTimeNow() - startT) >= (delay * 0.00001)) Then
                    Send_IO(Direction + enable)     ' Move Cart Left(3)/Right(1)
                    motionNext = "SendHigh"
                End If
        End Select
    End Sub

    Private Sub left_button_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles left_button.Click
        command = "Left"
        left_button.Enabled = False
        right_button.Enabled = True
        stop_button.Enabled = True
        stop_button.Text = "PAUSE"
        Pause = True
    End Sub

    Private Sub right_button_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles right_button.Click
        command = "Right"
        left_button.Enabled = True
        right_button.Enabled = False
        stop_button.Enabled = True
        stop_button.Text = "PAUSE"
        Pause = True
    End Sub

    Private Sub stop_button_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles stop_button.Click
        If Pause = True Then
            command = "Idle"
            stop_button.Text = "EXIT"
            left_button.Enabled = True
            right_button.Enabled = True
            Pause = False
        Else
            End
        End If
    End Sub

    Private Sub exit_button_Click(sender As Object, e As EventArgs) Handles exit_button.Click
        Dim Response As Integer
3:
        Response = MessageBox.Show("Do you really want to exit?", "", MessageBoxButtons.YesNo, MessageBoxIcon.Question)
5:
        If Response = vbYes Then
6:
            Me.Close()
7:
        End If

    End Sub
End Class