[Application that listens from three PLCs]

Hi,

I am working on .net application that listens on Ethernet from three PLCs witch are connected via switch to PC. I am using .net driver from the Unitronics web site (I used Listener Example solution).

Application should write incoming data in SQL database. I listen on port = 20256, I am getting data from one PLC successfully when one PLC is connected on the switch, but when I connect another one then I can't read from the other and also OnDisconnect event fires.

So:

- How to solve problem when more PLCs try to connect my application, and how to read from all of them at the same time?

- How to solve concurrent access in Database ?

In attachment are two .vlp files from the two PLCs.

Here is a part of the code:

private void ButtonListenOnPort_Click(object sender, EventArgs e)

{

EthernetListener listener = PLCFactory.GetChannel(LocalPort) ?? new EthernetListener(LocalPort, 3, 3000);

listener.OnListenerConnectionAccepted += OnConnect;

listener.OnListenerConnectionClosed += OnDisconnect;

PLCFactory.GetPLC(listener);

}

private void OnConnect(PLC plcfromlistener)

{

_plc = plcfromlistener;

var rw = new ReadWriteRequest[1];

rw[0] = new ReadOperands

{

OperandType = OperandTypes.MI,

NumberOfOperands = 9,

StartAddress = 0

};

try

{

_plc.ReadWrite(ref rw, AsyncReply);

}

catch

{

MessageBox.Show("bla bla");

}

}

private void AsyncReply(IAsyncResult ar)

{

var async = (AsyncResult)ar;

var del = (ReadWriteOperandsDelegate)async.AsyncDelegate;

var rw = new ReadWriteRequest[0];

try

{

del.EndInvoke(ref rw, ar);

}

catch (Exception ex)

{

MessageBox.Show(ex.Message);

return;

}

var values = (object[])(rw[0].ResponseValues);

MethodInvoker mi = delegate

{

var success= new ClassSuccess();

success.Successful = 1;

StoreInClassSuccess(success);

};

UpdateUI(mi);

}

// store in database

public bool StoreInClassSuccess(ClassSuccess entry)

{

try

{

using (var context = new DBEntities())

{

context.ClassSuccess .Add(entry);

context.SaveChanges();

}

}

catch (Exception ex)

{

throw ex;

}

return true;

}

netv570.vlp

netv570n.vlp