COM数据接收有关问题

COM数据接收问题
最近做个电子秤的代码，要接收到重量然后计算价钱。我用vb6.0 添加了段代码，
但是mscomm控件在使用的过程中出了点问题。如果直接运行程序很大几率接收不到返
回的重量，但是如果把断点设在oncomm事件上就肯定可以接收到。请问如何稳定的接收
到数据，代码如下：

初始化并发送命令：

VB code

bytOutput(0) = &H57
        With WeightComm
            .CommPort = Val(sPriceComputingComPort)
            .RThreshold = 1
            .Settings = "9600,N,8,1"
            .InputMode = comInputModeText
            .PortOpen = True
            .output = bytOutput
        End With

触发事件：

VB code

sWeight = ""
    Select Case WeightComm.CommEvent
        Case comEvReceive
            WeightComm.InputLen = 0
            buffer = WeightComm.input
            BytesReceived() = buffer
            For i = 0 To UBound(BytesReceived)
                If i = 2 Or i = 4 Or i = 6 Or i = 8 Or i = 10 Or i = 12 Then
                    sWeight = sWeight & Chr(BytesReceived(i))
                End If
            Next i
        Case comEvSend
    End Select
    
    WeightComm.OutBufferCount = 0
    WeightComm.InBufferCount = 0
    WeightComm.PortOpen = False
    
    sItemWeight = sWeight

------解决方案--------------------
是否应该有等待
------解决方案--------------------
你这个应该是连续发送模式的，你先用串口调试精灵看下能不能正常收到数据，如果能说明问题还是出在代码上。
给你接受部分的串口调试精灵源码供你参考

VB code

'====================================================================================
'                通信触发事件

'====================================================================================

Private Sub MSComm_OnComm()                                                         
    
On Error GoTo Err
    Select Case MSComm.CommEvent                                                   
        Case comEvReceive
            If ChkHexReceive.Value = 1 Then
                Call hexReceive                                                
            Else
                Call textReceive                                                    
        End If
            
        Case comEvSend                                                            
            If ChkHexSend.Value = 1 Then
            Else
                Call textSend                                                      
            End If
            
        Case Else
    End Select
Err:
  
End Sub

'====================================================================================
'               文本接受

'====================================================================================
Private Sub textReceive()

On Error GoTo Err
    InputSignal = MSComm.Input
    ReceiveCount = ReceiveCount + LenB(StrConv(InputSignal, vbFromUnicode))        
    If DisplaySwitch = False Then                                                 
        TxtReceive.Text = TxtReceive.Text & InputSignal                           
        TxtReceive.SelStart = Len(TxtReceive.Text)                                

    End If
    TxtRXCount.Text = "RX:" & ReceiveCount                                         
    
    If ChkAutoClear.Value = 1 Then                                                
        If ReceiveCount >= 65535 Then
            TxtReceive.Text = ""
        End If
    End If
Err:
End Sub 
'====================================================================================
'       十六进制接受

'====================================================================================

Private Sub hexReceive()
 
On Error GoTo Err
    Dim ReceiveArr() As Byte                                                        
    Dim receiveData As String                                                       
    Dim Counter As Integer                                                         
    Dim i As Integer                                                                
    
    If (MSComm.InBufferCount > 0) Then
        Counter = MSComm.InBufferCount                                              
        receiveData = ""                                                           
        
        ReceiveArr = MSComm.Input                                                  

        For i = 0 To (Counter - 1) Step 1                                          

            If (ReceiveArr(i) < 16) Then
                receiveData = receiveData & "0" + Hex(ReceiveArr(i)) & Space(1)     
            Else
                receiveData = receiveData & Hex(ReceiveArr(i)) & Space(1)          
            End If

        Next i
        
        TxtReceive.Text = TxtReceive.Text + receiveData                            
        TxtReceive.SelStart = Len(TxtReceive.Text)                                  
    End If
    
    ReceiveCount = ReceiveCount + Counter                                           
    TxtRXCount.Text = "RX:" & ReceiveCount                                         
    If ChkAutoClear.Value = 1 Then                                                 
        If ReceiveCount >= 65535 Then
            TxtReceive.Text = ""
        End If
    End If
Err:         
End Sub

COM数据接收有关问题

相关推荐