TcpIsConnected

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 Function Block - Tests if a client socket is connected.

Inputs

Input

Data Type

Range

Unit

Default

Description

Execute

BOOL

0 to 1

N/A

No default

On the rising 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

Range

Unit

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 File 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    If the socket is no longer valid, close it using the TcpClose function block.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;

See Also