TcpReceive

PLCopen motion icon

Function Block - Receives characters over a socket connection.

It is possible the number of characters actually sent is less than the number expected.
- In this case, use this function again to send the pending characters.

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If the socket is no longer valid, close it using the TcpClose function block.

Inputs

Input	Data Type See Data Types.	Range	Unit	Default	Description
Execute	BOOL	0 to 1	N/A	No default	On the rising edge, receive a string over a socket connection.
ID	UDINT	N/A	N/A	No default	The ID of the client socket.
MaxChar	STRING	N/A	User units	No default	The number of characters to receive.

Input

Data Type

See Data Types.

Range

Unit

Default

Description

Execute

BOOL

0 to 1

N/A

No default

On the rising edge, receive a string over a socket connection.

UDINT

N/A

No default

The ID of the client socket.

MaxChar

STRING

N/A

User units

No default

The number of characters to receive.

Outputs

Output	Data Type See Data Types.	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, Recipe, and TCP/IP Function Block ErrorIDs.
Data	STRING	String of received characters.

FBD Language Example

Not available.

FFLD Language Example

Not available.

IL Language Example

Not available.

ST Language Example

(* TcpReceive example *)
CASE StepCounter OF
0:
   Inst_TcpReceive(TRUE, MySocketID, 128);
   StepCounter := StepCounter + 1;
1:
   Inst_TcpReceive(TRUE, MySocketID, 128);
   IF Inst_TcpReceive.Done THEN
      ReceivedData := Inst_TcpReceive.Data;
      Inst_TcpReceive(FALSE, 0, 0);
      StepCounter := StepCounter + 1;
   END_IF;
END_CASE;