TCP_Send block

Short summary

Name	`TCP_Send`
→POU type	→function
Category	more system blocks, network blocks , block with internal error diagnostic
→Namespace	`logicals.system.network.tcp`
Graphical interface
Available since	version 3.2.2 (for library `Standard`) – initial variant This block is supported for these target systems or platforms: Raspberry Pi, Revolution Pi platform `WindowsX86` (incl. the built-in PLC under Windows) platform `LinuxX86` version 3.5.0 (for library `Standard`) – restriction "no function blocks with generic data type"

Functionality

The block sends a →TCP packet.

Inputs, outputs, return value

	Identifier	→Data type	Description
Inputs:	`lengthOfDataToSend`	`UDINT`	length of the data to send
	`clientHandle`	`TCP_ClientHandle`	TCP handle
	`flags`	`UDINT`	additional flags for sending
In-outs (VAR_IN_OUT):	`data`	`REAL`, `LREAL`, `USINT`, `UINT`, `UDINT`, `ULINT`, `SINT`, `INT`, `DINT`, `LINT`, `TIME`, `BOOL`, `BYTE`, `WORD`, `DWORD`, `LWORD`, `STRING`, `CHAR`, `DATE_AND_TIME`, `DATE`, `TIME_OF_DAY` , a →user-defined data type or a →function block Restriction: In case of →array data types, only one-dimensional arrays are allowed. Further restriction: In the case of function blocks, no function blocks with a →generic data type are allowed. As a result of this restriction, you cannot use the following blocks as input of the current block: LIMITER_O, LIMITER_U, FORCEMRK, MAX_HOLD, MIN_HOLD, and →vendor-function blocks that have been declared with a generic data type. If you use instances of these function blocks anyway, a linker error will occur when building the application.	content of the sent TCP packet
Return value:	`–` (= `rc`)	`TCP_ErrorCode`	returns the status of the TCP operation: `succeeded`: The operation is successful. `invalidFlags`: The flags are invalid. `invalidHandle`: The handle is invalid. `cannotSendData`: The data cannot be sent. `invalidDataSize`: The length of the data is invalid.

Input EN and output ENO are available when →calling the block. See "Execution control: EN, ENO" for information on input EN and output ENO.

See:

"Blocks for safe logic" whether this block is supported for developing safety-relevant applications.
"Highlighting safe logic in the FBD-editor" for the effects when using the block as a block for safe logic.

Internal error diagnostic for block

The block checks the following error cases:

The flags are invalid.
The handle is invalid.
The data cannot be sent.
The length of the data is invalid.

In such an error case, the output ENO of the block is set to value FALSE (or an equivalent). Moreover, the block returns the appropriate code (see the above table).

Example for usage within ST-editor

See "TCP_ServerOpen block".