Libnodave connection error after 40minutes

[Carllos Alberto Rogenski]

Hi, i developed my application in Visual Basic 6, and use a timer(1second) to receive a value from a PLC.
That works fine.
But after aproximadately 40minutes, he only receive a value 0, if i close and reopen my software, he back to receive a value normaly, but after aproximadately 40 minutes, receive only value 0 again.
I'm using a conection with a CLP Siemens S7 315, and a ethernet TCP/IP connection.
Any idea to resolve my problem?
Thanks!

[Carllos Alberto Rogenski]

My code actually:
Configuration of the module LIBNODAVE:

Private Function initialize(ByRef ph As Long, ByRef di As Long, ByRef dc As Long)
ph = 0
di = 0
dc = 0
Rem uncomment the daveSetDebug... line, save your sheet
Rem run excel from dos box with: excel yoursheet >debugout.txt
Rem send me the file debugout.txt if you have trouble.
Rem Call daveSetDebug(daveDebugAll)
initialize = -1
res = -1
peer$ = Form1.IP_PLC
ph = openSocket(102, peer$)    ' for ISO over TCP
If (ph > 0) Then
        di = daveNewInterface(ph, ph, "IF1", 0, daveProtoISOTCP, daveSpeed187k)
        res = daveInitAdapter(di)
        If res = 0 Then
            MpiPpi = 2
            Rack = 0
            Slot = 2
            dc = daveNewConnection(di, MpiPpi, Rack, Slot)
            res = daveConnectPLC(dc)
        If res = 0 Then
            initialize = 0
        End If
    End If
End If
End Function

Then i added a new function, to easily my configuration in form:

Function SIEMENS_READ(ByVal AREA As String, DB As Integer, ENDERECO As Integer, QTDE As Integer, TIPO As String)
    If QTDE > 222 Then
       MsgBox ("Quantidade de bytes excedida !!")
       SIEMENS_READ = -1
       Exit Function
    Else

    Dim ph As Long, di As Long, dc As Long
    Dim buffer() As Variant
    ReDim buffer(QTDE)
                
    res = initialize(ph, di, dc)
                     
    If res = 0 Then
        pdu = daveNewPDU
        Call davePrepareReadRequest(dc, pdu)
        
     
        ' VERIFICA PARAMETRO AREA
        If AREA = "DB" Then Call daveAddVarToReadRequest(pdu, daveDB, DB, ENDERECO, QTDE)
        If AREA = "M" Then Call daveAddVarToReadRequest(pdu, daveFlags, "0", ENDERECO, QTDE)
        If AREA = "I" Then Call daveAddVarToReadRequest(pdu, daveInputs, "0", ENDERECO, QTDE)
        If AREA = "Q" Then Call daveAddVarToReadRequest(pdu, daveOutputs, "0", ENDERECO, QTDE)
        If AREA = "C" Then Call daveAddVarToReadRequest(pdu, daveCounter, "0", ENDERECO, QTDE)
        If AREA = "T" Then Call daveAddVarToReadRequest(pdu, daveTimer, "0", ENDERECO, QTDE)
        If AREA = "DI" Then Call daveAddVarToReadRequest(pdu, daveDI, DB, ENDERECO, QTDE)
                                   
        resultSet = daveNewResultSet
        res2 = daveExecReadRequest(dc, pdu, resultSet)
        
        ' VERIFICA PARAMETRO TIPO
        If TIPO = "BYTE" Then
            For i = 0 To QTDE - 1
                res3 = daveUseResult(dc, resultSet, i)
                buffer(i) = daveGetS8(dc)
            Next
        End If
                        
        If TIPO = "WORD" Then
            For i = 0 To (QTDE / 2) - 1
                res3 = daveUseResult(dc, resultSet, i)
                buffer(i) = daveGetU16(dc)
            Next
        End If
        
        If TIPO = "INT" Then
            For i = 0 To (QTDE / 2) - 1
                res3 = daveUseResult(dc, resultSet, i)
                buffer(i) = daveGetS16(dc)
            Next
        End If
        
        If TIPO = "DWORD" Then
            For i = 0 To (QTDE / 4) - 1
                res3 = daveUseResult(dc, resultSet, i)
                buffer(i) = daveGetS32(dc)
            Next
        End If
        
        If TIPO = "REAL" Then
            For i = 0 To (QTDE / 4) - 1
                res3 = daveUseResult(dc, resultSet, i)
                buffer(i) = daveGetFloat(dc)
            Next
        End If
              
        daveFree (resultSet)
        daveFree (pdu)
    End If
       
    SIEMENS_READ = buffer()
    
    Call cleanUp(ph, di, dc)
 End If
End Function

And a code used in timer from a form to receive the value from PLC:

Private Sub Timer1_Timer()                                                                               'Timer 1s
    Entradas = SIEMENS_READ("M", "0", "100", "2", "BYTE")                                                  'Faz a leitura da entrada, e envia a um array
    For i = 0 To 1
        For ii = 0 To 7
            Entrada = Entrada & SIEMENS_GETBIT(Entradas(i), ii)                                          'Desmonta o array, convertendo a uma variavel
        Next ii
    Next i
End Sub

I see more detailed informations at today, and this is here:
_A time for stop receive informations of PLC is: exactly 1hour, 21minutes and 44 seconds.
_A number of times the timer run, is exactly 3174 times.

Before this, the program receive a Speed of the machine, which is at a MW100.
After this, the program only receive a 0 speed. And this is resolved when i close my program, and start again(ONLY THE PROGRAM USING THE LIBNODAVE).

Any friend can help me?
I really need help, for apply his library to my work.

[Simon]

You could try running a 2 seconds to see if it runs longer.
Do you keep the connection open?  - I believe there is a Keep Alive feature?
Presumably no other application is accessing the PLC - e.g. an HMI?
No other traffic on the Ethernet (Try running it isolated, PC and Ethernet only)

I wrote something in C on a Linux box but it polls PLC once every minute.
Hope this helps,
Simon

[Carllos Alberto Rogenski]

Sorry man,

I resolved it, after a very time, i see my error in program.
The problem is i open a connection(socket), and without read a instruction of Clean UP, i added with a close connection(port)
The problem is resolved when i change in Clean UP, sloseport to closesocket.
Now, the program is working fine!

NOTE: The PLC is under a network, working with PROFIBUS(traffic with other 6 PLCs) and a ethernet network too, comunicating with software iFix.

The libnodave in ethernet runs fine with other communication of PLC running at the same time ;)