Option Explicit
    Dim StrInComm1 As String 注释：定义从串口1接收数据变量
    Dim StrInComm2 As String 注释：定义从串口2接收数据变量
    Dim StrOut As String 注释：定义发送数据变量
    
    
    代码段1、
    
    Private Sub Form_Load()
    Text3.Text = 1
    注释：清零
    StrInComm1 = ""
    StrInComm2 = ""
    StrOut = ""
    注释：打开端口
    MSComm1.PortOpen = True
    MSComm2.PortOpen = True
    End Sub
    
    
    代码段2、
    
    Private Sub Form_Unload(Cancel As Integer)
    注释：关闭端口
    MSComm1.PortOpen = False
    MSComm2.PortOpen = False
    End Sub
    
    
    
    代码段3、
    
    Private Sub Timer1_Timer()
    Text3.Text = Text3.Text 1
    注释：每100毫秒从串口接收一次数据
    Dim IntPositionD As Integer 注释：定义“0D”位置变量"
    StrOut = ""
    
    StrInComm1 = StrInComm1 MSComm1.Input 注释：得到串口1数据
    
    StrInComm2 = StrInComm2 MSComm2.Input 注释：得到串口2数据
    
    IntPositionD = InStr(StrInComm1, Chr(13)) 注释：判断从跟串口1中得到的数据是否有回车
    If IntPositionD > 0 Then 注释：如果有
    StrOut = StrOut Left(StrInComm1, IntPositionD) 注释：取出左边的数据
    StrInComm1 = Right(StrInComm1, Len(StrInComm1) - IntPositionD) 注释：取出右边的数据
    End If
    IntPositionD = InStr(StrInComm2, Chr(13)) 注释：注释：判断从跟串口1中得到的数据是否有回车
    If IntPositionD > 0 Then
    StrOut = StrOut Left(StrInComm2, IntPositionD)
    StrInComm2 = Right(StrInComm2, Len(StrInComm2) - IntPositionD)
    End If
    Text2.Text = StrOut 注释：求出发送数据
    Text1.Text = Text1.Text Text2.Text
    End Sub