TcpIsConnected

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Function Block A function block groups an algorithm and a set of private data. It has inputs and outputs. - Tests if a client socket is connected.

Inputs

Input	Data Type	Range	Unit	Default	Description
Execute	BOOL	0, 1	N/A	No default	On the rising edge The transition of a digital signal from low to high. AKA: positive edge., test whether a socket is connected.
ID	UDINT	N/A	N/A	No default	The ID of the client socket.

Outputs

Output	Data Type	Description
Done	BOOL	If TRUE, the command completed successfully.
Error	BOOL	If TRUE, an error has occurred.
ErrorID	DINT	Indicates the error if Error output is TRUE. See the table in Search IndexFile and TCP/IP Function Block ErrorIDs.
Connected	BOOL	TRUE if a connection is correctly established.

Remarks

It is possible that the socket becomes invalid if an error occurs in the TCP connection after this function block is called.
Use the TcpIsValid function block after TcpSend.
If the socket is no longer valid, close it using the TcpClose function block.

Figure 1: TcpIsConnected

FBD Language Example

Not available.

FFLD Language Example

Not available.

IL Language Example

Not available.

ST Language Example

(* TcpIsConnected example *)
CASE StepCounter OF
0:
   Inst_TcpIsConnected(TRUE, MySocketID);
   StepCounter := StepCounter + 1;
1:
   Inst_TcpIsConnected(TRUE, MySocketID);
   IF Inst_TcpIsConnected.Done THEN
      MyTcpIsConnected := Inst_TcpIsConnected.Connected;
      Inst_TcpIsConnected(FALSE, 0);
      StepCounter := StepCounter + 1;
   END_IF;
END_CASE;