java构建的网站如何跟RS485通信?
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您好，如果有确定的接收字节长度,设置Rthreshold等于接收字节长度有利接收正确率提高.由于你的几个下位机返回数据包字节不等长,你可根据寻址命令发出前预先改变Rthreshold值来保证接收返回符合要求的字节长度.
不然你接收多少字节符合你改发下一寻址命令呢?程序代码处理难度较高.
实际下位机返回数据包可在其代码中补一定其它字节来达到等长,从而使接收代码变得简洁.
等长接收数据后可对接收处理清0来等待下次接收.
补充：
假如下位机的返回数据按地址号能确定接收字节长度，下列代码可实现接收不等长数据，仅供参考：
Private Sub MSComm1_OnComm()
On Error Resume Next
Dim BytReceived() As Byte
Dim strBuff As String
Dim strData As String
Dim i As Integer
Dim x As Integer
Select Case MSComm1.CommEvent
Case 2
MSComm1.InputLen = 0
strBuff = MSComm1.Input
BytReceived() = strBuff
For i = 0 To UBound(BytReceived)
If Len(Hex(BytReceived(i))) = 1 Then
strData = strData & "0" & Hex(BytReceived(i))
Else
strData = strData & Hex(BytReceived(i))
End If
Next
Text3 = Text3 + strData
If Left(strData, 2) = "00" And Len(strData) = 8 Then
Text1(0).Text = Left(strData, 8)
Call DataClear
ElseIf Left(strData, 2) = "01" And Len(strData) = 10 Then
Text1(1).Text = Left(strData, 10)
Call DataClear
End If
End Select
End Sub追问具体用什么接口文档呢？数据接口是什么样的呢？能不能再具体点
