在 C# 中使用 S7NetPlus 库的 PLC 通信错误

Question

I am developing a windows forms application which will communicate with the Siemens S7-1200 PLC for real accessing real time data from PLC and sending data to PLC. The connection and real time communication is all working fine. But I'm facing issues when

1. Closing the connection to PLC.
2. Ethernet cable is disconnected
3. The PLC is powered off

1. I have used Plc.close() method in the form.closed event. But the connection is not getting closed, instead throwing PLC disconnection error.

2 & 3. I expected same behavior but it is throwing different errors. When ethernet cable was disconnected either at application side or PLC side, the ethernet socket exception is thrown. When the PLC power was turned off the program was still trying to write data to the PLC for some time and then showed the ethernet socket error happened.

Can anyone help me with how to handle these errors?

Answer 1

As you can see on s7netplus repository on Github the PLC class is implementig IDisposeable. In your question there is no code but if you are calling the PLC class with a using statment:

using(Plc plc = new PLC(...) {
  // Do some actions
}

the Close() method is called after the end of the using block (Dispose). So if you are trying to call the Close() method again an exception occurs.

If it is possible, please provide a code example.