多通道数据采集

各位高手，最近做了一个多通道的数据采集，遇到了一个麻烦，希望您能帮我一下，我要做的就是用单片机采集数据，然后通过串口送到上位机里，上位机用的是vb，从下位机猜到的是1000个字节的数据，这1000个乬是四个通道的数据，也就是每个通道有250个字节，现在我已经能够顺利采集到了数据了，在vb工程文件中国的textbox显示的是1000个十六进制的数据，现在我想把这十六进制的数据转换成具体的唯一值，我采用的是8位的AD转换器，怎么才能吧这些十六进制转换成正常的十进制的浮点数的位移，传感器输入的是0-5V的电压，所对应的位移是0-1250mm，下面是我的代码，希望高手给我指点一下如何才能将这1000个字节的十六进制的数据转换成十进制的0-1250mm的位移啊？

上位机程序代码

Public Class 多通道数据采集

    Public Delegate Sub myDelegate()

    Private Sub Form1_Load(ByVal sender As Object, ByVal e As System.EventArgs) Handles Me.Load

        For i As Integer = 0 To My.Computer.Ports.SerialPortNames.Count - 1



            cmbSerialPort.Items.Add(My.Computer.Ports.SerialPortNames(i))

        Next

        btnCloseSerialPort.Enabled = False

        SerialPort.Close()

        Timer.Enabled = False

        picState.BackColor = Color.Red

        cmbBoadrate.Items.Add("4800")

        cmbBoadrate.Items.Add("9600")

        cmbBoadrate.Items.Add("57600")

        cmbChanel.Items.Add("通道一")

        cmbChanel.Items.Add("通道二")

        cmbChanel.Items.Add("通道三")

        cmbChanel.Items.Add("通道四")

    End Sub

    Private Sub btnOpenSerialPort_Click(ByVal sender As Object, ByVal e As System.EventArgs) Handles btnOpenSerialPort.Click

        If SerialPort.IsOpen = True Then

            SerialPort.Close()

        End If

        If cmbSerialPort.Text = "" Then

            MessageBox.Show("请选择一个串口", "串口选择警告", MessageBoxButtons.OK, MessageBoxIcon.Error)

        Else

            SerialPort.PortName = cmbSerialPort.Text

            SerialPort.ReadBufferSize = 4096

            SerialPort.BaudRate = cmbBoadrate.Text

            SerialPort.Parity = IO.Ports.Parity.None

            SerialPort.DataBits = 8

            SerialPort.StopBits = IO.Ports.StopBits.One

            SerialPort.DiscardNull = True

            SerialPort.DtrEnable = False

            SerialPort.Encoding = System.Text.Encoding.ASCII

            SerialPort.RtsEnable = False

            SerialPort.Open()

            picState.BackColor = Color.Green

            btnCloseSerialPort.Enabled = True

        End If

    End Sub

    Private Sub btnClear_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnClear.Click

        If MessageBox.Show("清空文本框显示请选择Yes，清零计数器请选择No", "选择一个删除对象", MessageBoxButtons.YesNoCancel, MessageBoxIcon.Information) = Windows.Forms.DialogResult.Yes Then

            txtDataReceive.Text = String.Empty



        Else

            txtNumOfReceive.Text = "0"

            txtNumOfSendChar.Text = "0"



        End If





    End Sub

    Public Sub SendtoSbuf()

        Dim TestArray() As String = Split("fe")

        'Dim str(0)="fe" as string

        Dim hexBytes() As Byte

        ReDim hexBytes(TestArray.Length - 1)

        Dim i As Integer

        For i = 0 To TestArray.Length - 1

            hexBytes(i) = Val("&h" & TestArray(0))

        Next

        SerialPort.Write(hexBytes, 0, 1)

        txtNumOfSendChar.Text = (Val(txtNumOfSendChar.Text) + 1).ToString

    End Sub

    Public Function DecToHex(ByVal DecNumber As Byte) As String '转换成十六进制字符串

        If DecNumber <= 15 Then

            DecToHex = "  0" & Hex(DecNumber)

        Else : DecToHex = " " & Hex(DecNumber)

        End If

    End Function

    Public Sub GetCharFromAndSendToTextBox()

        Dim str_indata As String

        Dim byteToRead As Int16





        byteToRead = SerialPort.BytesToRead '(读取缓冲区的字节长度)

        txtNumOfReceive.Text = (Val(txtNumOfReceive.Text) + byteToRead).ToString



        Dim ch(byteToRead) As Byte



        Dim bytesRead As Int16 = 0

        ' str_indata = SerialPort1.ReadExisting()



        bytesRead = SerialPort.Read(ch, 0, byteToRead)

        



        If bytesRead > 0 Then

            For i As Int16 = 0 To bytesRead - 1

                'System.Threading.Thread.Sleep(50)    ' 这个很重要！

                str_indata = str_indata & DecToHex(ch(i))

            Next

        End If

        With txtDataReceive

            .Font = New Font("Garamond", 12.0!, FontStyle.Bold)

            .AppendText(str_indata)

            .ScrollToCaret()

        End With



    End Sub

    Private Sub btnStartCollectData_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnStartCollectData.Click

    

        If SerialPort.IsOpen = True Then

            SendtoSbuf()

        Else : MessageBox.Show("请打开串口", "警告", MessageBoxButtons.OK, MessageBoxIcon.Asterisk)

        End If





    End Sub



    Private Sub btnCloseSerialPort_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnCloseSerialPort.Click

        SerialPort.Close()

        picState.BackColor = Color.Red

    End Sub



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

        txtDataReceive.Invoke(New myDelegate(AddressOf GetCharFromAndSendToTextBox), New Object() {})



    End Sub



    Private Sub btnCycleCollect_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnCycleCollect.Click

      

        If SerialPort.IsOpen = True Then

            SendtoSbuf()

           

            Timer.Enabled = True

        Else : MessageBox.Show("请打开串口", "警告", MessageBoxButtons.OK, MessageBoxIcon.Asterisk)

        End If



    End Sub



    Private Sub Timer_Tick(ByVal sender As Object, ByVal e As System.EventArgs) Handles Timer.Tick





        SendtoSbuf()

    End Sub



    Private Sub btnStopCollect_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnStopCollect.Click

        Timer.Enabled = False

    End Sub

End Class