请问各位高手，下面这段程序什么意思，

ElseIf RPLC1 Then
        RPLC1 = False: ParameterForm.OverTimer.Enabled = False
        If RBin(0) = &H2 And LRBin >= 812 Then
            For i = 1 To 809
                sum = sum + CLng(RBin(i))
            Next i
            j = 0
            If sum Mod 256 = AscToLng(RBin(810)) * 16 + AscToLng(RBin(811)) Then
                For i = 0 To 14
                    DataBuffer(i) = DataConvert(AscToLng(RBin(j + 5)), AscToLng(RBin(j + 6)), AscToLng(RBin(j + 7)), AscToLng(RBin(j + 8)))
                    j = j + 4
                Next i
                SendCmd = Chr(5) & "00FFWR0D1000C94B"
                If InfoScroll Then
                    InfoList.Text = InfoList.Text & "TXD: " & SendCmd & vbCrLf
                    InfoList.SelStart = Len(InfoList.Text) - 1
                End If
                MSComm1.Output = SendCmd
                RPLC2 = True
                ParameterForm.OverTimer.Enabled = True
            Else
                MsgBox "参数从PLC读取错误!", vbExclamation, "参数设置"
                ParameterForm.ReadfromPLC.Enabled = True: ParameterForm.WritetoPLC.Enabled = True
            End If
        Else
            MsgBox "参数从PLC读取错误!", vbExclamation, "参数设置"
            ParameterForm.ReadfromPLC.Enabled = True: ParameterForm.WritetoPLC.Enabled = True
        End If