Modbus TCP Client - state connecting

[Damian7546]

Hi,

I have a little problem....
to check connection with my Modbus Client I use this slot:

void MyMbClient::onModbusStateChanged(int state)
{

    if (state == QModbusDevice::UnconnectedState){
        qDebug() <<"Modbus TCP Client Disconnected";
        tim_reconnect.start(10000);
        emit modbusTCPClientConnectedState(true);
    }
    else if (state == QModbusDevice::ConnectedState){
       qDebug() <<"Modbus TCP Client Connected";
       tim_reading_inputRegisters.start(1000);
       emit modbusTCPClientConnectedState(false);
    }
    else if (state == QModbusDevice::ConnectingState){
        qDebug() << "Modbus TCP Client Connecting";
        emit modbusTCPClientConnectedState(true);
    }else
    {
        qDebug() <<"Modbus TCP Client Disconnected";
        tim_reconnect.start(10000);
        emit modbusTCPClientConnectedState(true);
    }
}

When I close app with modbus Server the state changing in above slot on Disconnected. But when I plug off form power the PC with server Modbus application the state not change, why ?

[jsulm]

@Damian7546 said in Modbus TCP Client - state connecting:

But when I plug off form power the PC with server Modbus application the state not change, why ?

Probably because the client has no way to notify the server in this case.

[Damian7546]

@jsulm So how resolve case when the pc will be plug off power , and my client it knew that connection was lost ?

[J.Hilk]

@Damian7546 try exchanging data, if the answer times out -> connection lost

[Damian7546]

@J-Hilk do you mean that i should change value in server for example in Input Register, cyclically 0,1,0..etc and in the Modbus TCP Client check if this vale is changing ?

[J.Hilk]

@Damian7546 no need to change a value, make a cyclic read request

[ryder_z]

Hello, have you solved your problem? I also encountered this problem on Linux, but the Unconnected status can be detected when I disconnect the server in Windows