s2l2.bas

德州仪器公司的6000系列的程序示例,可以看看实现什么功能,如果需要可以继续上传,配套有电子版说明

Option Explicit
'**********************************************************************
'* S2L2.bas - (Section 2, Lesson 2) RECEIVING AN INTEGER FROM THE
'*                                  TARGET
'*            This is the RTDX Host Client for Section 2, Lesson 2
'*
'* This example receives integer value 5 from the target
'**********************************************************************

'**********************************************************************
' Insert code from Step #3 here - to include RTDX return code contants
'**********************************************************************
Const Success = &H0                     ' Method call is valid
Const Failure = &H80004005              ' Method call failed
Const ENoDataAvailable = &H8003001E     ' No data was available.
                                        ' However, more data may be
                                        ' available in the future.
Const EEndOfLogFile = &H80030002        ' No data was available
                                        ' The end of the log file has
                                        ' been reached.

Sub main()
    '******************************************************************
    ' Insert code from Step #4 here - to declare a variable of type
    '                                 Object. This will be used to
    '                                 access the methods of the
    '                                 interface
    '******************************************************************
    Dim rtdx As Object
    
    Dim data As Long
    Dim status As Long

    On Error GoTo Error_Handler
    '******************************************************************
    ' Insert code from Step #5 here - to create an instance of the RTDX
    '                                 COM Object
    '******************************************************************
    Set rtdx = CreateObject("RTDX")

    '******************************************************************    
    ' Insert code from Step #6 here - to open channel ochan for reading
    '******************************************************************
    status = rtdx.Open("ochan", "R")

    If status <> Success Then
        Debug.Print "Opening of channel ochan failed"
        Goto Error_Handler
    End If

    Do
        ' *************************************************************
        ' Insert code from Step #7 here - to read a 32-bit integer from
        '                                 the target
        '**************************************************************
        status = rtdx.ReadI4(data)
 
        Select Case (status)
            Case Success
                If status = Success Then
                    Debug.Print "Value " & _
                                data & _
                                " was received from the target"
                End If
            Case ENoDataAvailable
                Debug.Print "No data is currently available"
            Case EEndOfLogFile
                Debug.Print "End of log file has been detected"
            Case Failure
                Debug.Print "ReadI4 returned failure"
                Exit Do
            Case Else
                Debug.Print "Unknown return code"
                Exit Do
        End Select
    Loop Until status = EEndOfLogFile

    '******************************************************************
    ' Insert code from Step #8 here - to close the channel
    '******************************************************************
    status = rtdx.Close()

    '****************************************************************** 
    ' Insert code from Step #9 here - to release reference
    '                                 to RTDX COM Object
    '******************************************************************
    Set rtdx = Nothing
    
    Exit Sub

Error_Handler:
Debug.Print "Error in COM method call"
Set rtdx = Nothing

End Sub