Keep tcp connection while disconnect cable

[Nobody/Anonymous]

Luca_TGMX (luca_tgmx@jabber.org)

I have a problem using ethernet connection with a plc:

My software is working great but if I disconnect and reconnect ethernet cable, program crash.

How can I resolve this problem?

The code is something like this:

    fds.rfd=openSocket(102, ip.ascii());
    fds.wfd=fds.rfd;
    di =daveNewInterface(fds,"IF1",0, daveProtoISOTCP, daveSpeed187k);
    res =daveInitAdapter(di);
    dc =daveNewConnection(di, 0, 0, 2);
    res =daveConnectPLC(dc);

    while(1)
    {
    if(daveReadBytes(dc, daveDB, NUM_DB, DE_FINE_DEPOSITO, 2, NULL)==0)
            {
            b=daveGetU8(dc);   
            c=daveGetU8(dc);
            }
    if(b==0 && c==0)
        break;
    usleep(100000);   
    }

THANKS.

[Nobody/Anonymous]

Il problema riguarda la libreria LIBNODAVE...
dovresti fare un debug in c++

[Nobody/Anonymous]

I have the same problem. I tried everything but I couldn't solve it

[afk]

The TCP-connection can't be kept when the cable is disconnected, but with the return-code of daveReadBytes you can detect that there is a failure, and you can try to reconnect until the connection is up again.

Axel

[Nobody/Anonymous]

Luca_TGMX (luca_tgmx@jabber.org)

I've done this but during reconnection I also must call "close(fds.rfd)" to free the socket because it's not enought to call:

daveDisconnectPLC(dc);
daveDisconnectAdapter(di);

Can u tell me why?