发表于:2007-06-14 21:25:00
1楼
这个问题我已经解决了,PLC进行参数设置后要断一下电才行!
现在还有一个问题要请教
采用oncomm事件时,为何不能接收数据啊?
Private Sub MSComm1_OnComm()
Dim data As String, rea As String, a As Integer, b As String
Debug.Print "1:" & data
data = frm1.MSComm1.Input
Debug.Print "2:" & data
a = Val(Asc(Left(data, 1)))
b = GetSumChk(Mid(data, 2, Len(data) - 3))
If a = 2 And b = Mid(data, Len(data) - 1, 2) Then
rea = Mid(data, 6, Len(data) - 8)
frm1.MSComm1.Output = Chr(&H6) + "00FF"
Else
rea = "error"
frm1.MSComm1.Output = Chr(&H15) + "00FF"
End If
Text4.Text = rea
End Sub
程序运行运行成功一次,但是不会退出还在循环,并且第二次到 a = Val(Asc(Left(data, 1)))时,提示错误,“无效的过程调用或参数”;而且以后再试均不成功,错误同上,查看 frm1.MSComm1.Input 里面有数据而,data里面却没有,导致出错 !
请问,这是哪里出问题了啊?请教各位高手帮帮忙啊!谢谢了