Option Explicit
Dim PortAddress, Value, bin, i As Integer 
Private Sub Form_Load()
Value = 0
PortAddress = &H379 'Hier wird die Adresse des Parallelports angegeben 
' Parallelport h378 =Ausgang H379 = eingang
'PortAddress = &H378 'Hier wird die Adresse des Parallelports angegeben
End Sub
Private Sub Timer1_Timer()
Dim a, b, c, e As Long
b = 0
 For a = 0 To 1000000
If Inp(PortAddress) = 127 Then b = b + 1
Next
c = b / 1000000
e = (c - 0.31) / 0.0047 '0.31 Korekturwert
Label1.Caption = Format$(e, "#####0.00")
End Sub

    Public Declare Function Inp Lib "inpout32.dll" _
Alias "Inp32" (ByVal PortAddress As Integer) As Integer
Public Declare Sub Out Lib "inpout32.dll" _
Alias "Out32" (ByVal PortAddress As Integer, ByVal Value As Integer)