Tcp_Send Instruction - Siemens SIMATIC S7 System Manual

Libraries
9.4 Open user communication library
9.4.2.4

TCP_SEND instruction

The TCP_SEND instruction transmits the requested number of bytes (DataLen) from the
requested buffer location (DataPtr) over the existing connection (ConnID). You use the
instruction for both TCP protocol and for ISO-on-TCP protocol.
LAD/FBD STL
TCP_SEND Req, ConnID,
DataLen, DataPtr, Done,
Busy, Error, Status
The TCP_SEND instruction initiates sending the specified number of bytes when the
following occur:
● The program calls the instruction with the Req input set to TRUE.
● The connection is not currently busy with another send operation.
The Req input is level-triggered. It is recommended that you put a positive edge trigger on
the Req input so that the instruction does not initiate unintended send operations. The
program ignores the Req input while the TCP_SEND is busy. The Done, Busy, and Error
outputs and the Status output byte show the status of the TCP_SEND for each call.
510
Description
The TCP_SEND transmits the requested number of bytes from the
requested buffer location over an existing connection.
System Manual, V2.3, 07/2017, A5E03822230-AF
S7-200 SMART