form1.frm

用VB编的rs232例程,只是熟悉一入VB用的,实际应用还要自己改进哟

VERSION 5.00
Object = "{648A5603-2C6E-101B-82B6-000000000014}#1.1#0"; "MSCOMM32.OCX"
Begin VB.Form Form1 
   Caption         =   "Form1"
   ClientHeight    =   4965
   ClientLeft      =   60
   ClientTop       =   345
   ClientWidth     =   7215
   LinkTopic       =   "Form1"
   ScaleHeight     =   4965
   ScaleWidth      =   7215
   StartUpPosition =   3  '窗口缺省
   Begin VB.CommandButton NonPeriodic_Command 
      Caption         =   "Command1"
      Height          =   495
      Left            =   720
      TabIndex        =   0
      Top             =   960
      Width           =   1815
   End
   Begin VB.Timer NonPeriodic 
      Left            =   2880
      Top             =   3720
   End
   Begin VB.Timer Periodic 
      Left            =   2160
      Top             =   3720
   End
   Begin MSCommLib.MSComm MSComm1 
      Left            =   5520
      Top             =   3720
      _ExtentX        =   1005
      _ExtentY        =   1005
      _Version        =   393216
      DTREnable       =   -1  'True
   End
End
Attribute VB_Name = "Form1"
Attribute VB_GlobalNameSpace = False
Attribute VB_Creatable = False
Attribute VB_PredeclaredId = True
Attribute VB_Exposed = False
Private Sub Form_Load()
    MSComm1.CommPort = 1 '选用COM2串行口
    MSComm1.Settings = "115200,N8,1" '波特率9600，无奇偶校验位，8位数据位1位停止位
    MSComm1.InputLen = 0 'Input将读取接收缓冲区的全部内容
    MSComm1.InBufferSize = 1024 '设置接收缓冲区的字节长度
    
    MSComm1.InputMode = comInputModeBinary
    MSComm1.RThreshold = 0
    MSComm1.SThreshold = 0


    MSComm1.PortOpen = True '打开通信口
    MSComm1.InBufferCount = 0 '清除发送缓冲区数据
    MSComm1.OutBufferCount = 0 '清除接收缓冲区数据
    Periodic.Interval = 1000 '设置ls定时间隔，使遥测命令每隔ls发送1次
    NonPeriodic.Interval = 500 '设置0.5s定时间隔，查询命令按钮是否处于激活状态以确定是否发送周期性命令
     
    Periodic.Enabled = True
    NonPeriodic.Enabled = False
    
    
    Command_Pressed = False '命令按钮为未激活状态
    During_Periodic = False '周期性命令数据传输尚未开始
    During_NonPeriodic = False '非周期性命令数据传输尚未开始
End Sub

Private Sub MSComm1_OnComm()
    
    Select Case MSComm1.CommEvent '在此可插入处理各种不同错误或事件的代码

    Case MSComm_EV_RECEIVE
    
        ReceiveString$ = MSComm1.Input
        
        Select Case MSComm1.RThreshold
        
        Case R_PERIODIC_BYTE '周期性命令的应答数据
        
            'Call DisposeData(Periodic_Command) '处理接收数据
            
            During_Periodic = False '设置周期性命令数据传输状态为结束
        
        Case R_NONPERIODIC_BYTE '非周期性命令的应答数据
        
            'Call DisposeData(NonPeriodic_Command) '处理接收数据
            
            During_NonPeriodic = False '设置非周期性命令数据传输状态为结束
        
        End Select
    
    End Select


End Sub

Private Sub NonPeriodic_Command_Click()
 '   Command_Pressed = True '命令按钮激活
    'MSComm1.InputMode = comInputModeBinary
     

'Dim Sendtemp(0) As Byte

'Const SendCmd = &H41

'Sendtemp(0) = SendCmd
'MSComm1.Output = Sendtemp()




'     MSComm1.Output = Chr(151)

    
End Sub

Private Sub NonPeriodic_Timer()
    If During_Periodic = True Or Command_Pressed = False Then Exit Sub '若周期性命令数据传输尚未结束或命令按钮处于激活状态，则退出发送非周期性命令程序。
    
    Command_Pressed = False '命令按钮恢复为未激活状态
    
    'Call SendData(NonPeriodic_Command) '发送非周期性命令
    
    MSComm1.RThreshold = R_NONPERIODIC_BYTE '发送非周期性命令后，设置Rthreshold属性，使主站接收所设定的字节数后引发OnComm事件

End Sub

Private Sub Periodic_Timer()
Dim Sendtemp(0) As Byte

Const SendCmd = &H41

Sendtemp(0) = SendCmd
MSComm1.Output = Sendtemp()

'    If During_NonPeriodic = True Then Exit Sub '若非周期性命令数据传输尚未结束，则退出发送非周期性命令程序。
    
'    During_Periodic = True '设置周期性命令数据传输状态为正在进行中
    
    'Call SendData(Periodic_Command) '发送周期性命令
    
'    MSComm1.RThreshold = R_PERIODIC_BYTE '发送周期性命令后，主站接收R-REMOT- EDATA-BYTE个字节，可引发OnComm 事件

End Sub