GM6-PAFB

3.1 串口初始化程序

If MSComm1.PortOpen <GM6-PAFB> True Then

MSComm1.PortOpen=True

End If

MSComm1.Settings=“9600,E,7,2”

MSComm1.InputLen=0

MSComm1.InBufferCount=0

MSComm1.InputMode=comInputModeText

MSComm1.Handshaking=comNone

 

3.2 计算机与PLC通信的VB程序 

Public Function ReadData(ByVal InputStr As String, ByVal Num1 As Integer, ByVal Num2 As Integer) As String

Dim OutputStr As String

Dim InString As String

Dim ReturnStr As String

Dim EndString As String

Dim FCSString As String

Dim ReturnFCSString As String

Form1.MSComm1.InBufferCount=0

OutputStr=InputStr+FCS（InputStr）+“*”

If Form1.MSComm1.PortOpen=True Then

Form1.MSComm1.Output=OutputStr+Chr$（13）’按照PLC帧格式输出

End If

Do

DoEvents

Loop Until Form1.MSComm1.InBufferCount >=Num2’返回帧的长度

InString=Form1.MSComm1.Input

EndString=Mid$(InString,6,2)’取返回帧的响应码

If EndString GM6-PAFB<> “00”Then

ReadData=“Error”

Exit Function

End If

EndString=Mid$(InString,1,Len(InString)-4) 

ReturnFCSString=Mid$(InString, Len(InString) -3,2)’取返回帧校验码

FCSString=FCS(EndString) 

If FCSString <> ReturnFCSString Then

ReadData=“Error”

Exit Function

End If

If Len（InString）>=Num2 Then

ReturnStr=Mid$(InString, Len(InString)-Num1-3, Num1)’取返回帧的数据，其度为Num1 

ReadData = ReturnStr 

End If

End Function

相关产品：GM6-PAFB , LS模块GM6-PAFB